Escherichia coli viability in an isochoric system at subfreezing temperatures.

In comparison with isobaric (constant pressure) freezing, isochoric (constant volume) freezing reduces potential mechanical damage from ice crystals and exposes stored biological matter to a lower extracellular concentration, at the price of increased hydrostatic pressure. This study evaluates the effects of isochoric freezing to low temperatures and high pressures on Escherichia coli (E. coli) survival. The viability of E. coli was examined after freezing to final temperatures between -5 °C and -20 °C for periods from 0.5 h to 12 h, with recovery periods from 0 h to 24 h. Freezing for up to two hours to -10 °C and -15 °C had little effect on the percentage of viable E. coli, relative to the controls. However, after two hours of exposure at -20 °C, when left to recover for 24 h, a 75% reduction in survival is observed. Furthermore, after 12 h of isochoric freezing at -15 °C and -20 °C, E. coli population is reduced by 2.5 logs while freezing to these temperatures in conventional isobaric atmospheric conditions reduces population by only one log. This suggests that the combination of low temperature and high pressure experienced during isochoric freezing close to the triple point may be more detrimental to biological matter survival than the combination of elevated concentration, low temperature, and ice crystallization experienced during conventional freezing, and that this effect may be related to the time of exposure to these conditions.

Pilot Test of a Culturally Appropriate Diabetes Prevention Intervention for At-Risk Latina Women.

Purpose The purpose of the study was to test the preliminary effectiveness, feasibility, and acceptability of a peer-led, culturally appropriate, Diabetes Prevention Program (DPP)-based lifestyle intervention for Latina women at high-risk for type 2 diabetes (T2DM). Methods Participants (N = 61) were overweight/obese (body mass index [BMI] ≥25) Latina women with no diabetes, at elevated risk either due to midlife age (45-65 years; n = 37) or history of gestational diabetes mellitus (n = 24). The study used a 1-group pretest-posttest design and offered 12 weeks of peer-led education sessions in a community setting. The intervention targeted physical activity and dietary behaviors to facilitate weight reduction and included culturally appropriate content, age-specific health information, and stress/emotion management strategies. Clinical and self-report assessments were conducted at baseline, month 3, and month 6. Results Mean participant age was 47.8 years (SD = 10.8). Most (91.2%) were born in Mexico, and 43.3% had a ninth-grade education or less. At month 6, participants achieved a mean reduction of 4.1% body weight (7 lb [3.2 kg]). Statistically significant improvements were observed for dietary behaviors, stress, and depression symptoms. Attrition was low, 5% (3 women). Focus groups indicated that intervention content increased knowledge, was applicable, highly valued, culturally relevant, and would be recommended to others. Conclusions This culturally tailored DPP adaptation was feasible and acceptable for 2 groups of Latina women at high-risk for T2DM and showed preliminary effectiveness in reducing weight and modifying self-reported dietary behaviors, stress, and depression symptoms. Further research is needed to identify ways to enhance weight loss and diabetes prevention in this at-risk, underserved population.

Novel cryoneurolysis device for the treatment of sensory and motor peripheral nerves.

INTRODUCTION: Cryoneurolysis is the direct application of low temperatures to reversibly ablate peripheral nerves to provide pain relief. Recent development of a handheld cryoneurolysis device with small gauge probes and an integrated skin warmer broadens the clinical applications to include treatment of superficial nerves, further enabling treatments for pre-operative pain, post-surgical pain, chronic pain, and muscle movement disorders. AREAS COVERED: Cryoneurolysis is the direct application of cold temperatures to a peripheral nerve, resulting in reversible ablation due to Wallerian degeneration and nerve regeneration. Use over the last 50 years attests to a very low incidence of complications and adverse effects. Cryoprobes have traditionally been applied through a surgical incision; but, recent technical advances allow percutaneous administration. A new hand-held device is now approved for use within the United States. Cryoneurolysis has been used to treat postoperative and chronic pain states as well as spasticity. Expert commentary: Changes in the US healthcare system such as a push for the reduction of opioid use and the incorporation of Diagnostic Related Group codes, as well as recent technological advances including a handheld unit that allows for treatment of superficial nerves while protecting the skin from damage, may contribute to the resurgence of cryoneurolysis for the treatment of peripheral nerves.

The effect of undissolved air on isochoric freezing.

This study evaluates the effect of undissolved air on isochoric freezing of aqueous solutions. Isochoric freezing is concerned with freezing in a constant volume thermodynamic system. A possible advantage of the process is that it substantially reduces the percentage of ice in the system at every subzero temperature, relative to atmospheric freezing. At the pressures generated by isochoric freezing, or high pressure isobaric freezing, air cannot be considered an incompressible substance and the presence of undissolved air substantially increases the amount of ice that forms at any subfreezing temperature. This effect is measurable at air volumes as low as 1%. Therefore eliminating the undissolved air, or any separate gaseous phase, from the system is essential for retaining the properties of isochoric freezing.

Development and validation of a new method for locating patella sensory nerves for the treatment of inferior and superior knee pain.

BACKGROUND: Radiofrequency ablation and percutaneous cryoneurolysis to relieve knee pain requires treating large areas to ensure coverage due to high variability in the sensory innervation of the knee and limitations of current methods for defining treatment targets. This study sought to define and validate a new treatment approach targeting the major sensory nerves of the superior patella and expand upon previous work to define a more efficient treatment approach targeting the sensory nerves of the inferior patella. METHODS: Transcutaneous electrical nerve stimulation and ultrasound were used to evaluate the location and relationship of the cutaneous nerves to the superior and inferior aspects of the knee in 25 healthy volunteers. Using information derived from these evaluations, investigators defined new linear target treatment areas, or treatment lines, using anatomical landmarks, which were validated against locations of sensory nerves through cadaveric dissection of 15 fresh specimens. RESULTS: The proposed treatment lines captured the vast majority of nerve branching variations during cadaveric validation. CONCLUSION: This study defined treatment lines, identifiable using only anatomical landmarks, which effectively target the nerves responsible for superior and inferior knee pain and reduce the total treatment area and procedure time when administering treatments such as radiofrequency ablation and cryoneurolysis.

Isochoric preservation: a novel characterization method.

Isochoric (constant volume) preservation is an alternative to traditional cryopreservation methods because it requires less cryoprotectant and is simple to operate. In order to validate that this method automatically minimizes the pressure for a given temperature, pressure and temperature data were collected from a specially designed pressure vessel. This vessel was then used to examine the effect of an isochoric environment on freezing point nucleation in an aqueous antifreeze protein solution, and to generate pressure-temperature phase diagrams for various cryoprotectant solutions. Our results show that the isochoric pressure vessel follows the pressure-temperature phase diagram of water, thereby minimizing the pressure for the given temperature. We also show that the nucleation temperature of the antifreeze protein in an isochoric vessel is lower than that of the isobaric method. Furthermore, the nucleation temperature decreased with increasing concentration in the isochoric vessel while the isobaric nucleation temperature showed no change. These results indicate that the isochoric environment imposes additional constraints on ice formation and warrants further study as these results may change when a different type of cryoprotectant is used. Finally, all of the cryoprotectant phase diagrams exhibited a similar pressure-temperature slope indicating that, regardless of the cryoprotectant used or the mechanism by which it suppresses freezing, isochoric freezing affects the molecules in the same manner. Together, all of these results indicate that the isochoric method of preservation is a valuable tool for characterizing the thermodynamic properties of cryoprotectants and has great potential as a cryopreservation method in the field of cryobiology.

Non-invasive cryolipolysis for subcutaneous fat reduction does not affect serum lipid levels or liver function tests.

BACKGROUND AND OBJECTIVE: Cryolipolysis provides a method of non-invasive fat reduction that significantly reduces subcutaneous fat without injury to adjacent tissues. Preliminary animal and human data have suggested that cryolipolysis has no effect on serum lipid profiles or liver tests. This study was intended to more fully document any effect of this procedure on lipid and liver-related blood tests. STUDY DESIGN/MATERIALS AND METHODS: Forty subjects with fat bulges on their flanks ("love handles") were treated bilaterally with a non-invasive device (Zeltiq Aesthetics, Pleasanton, CA) that precisely cools tissue to achieve a reduction in the fat layer. Serum lipid levels and liver tests were measured prior to treatment, and at 1 day and 1, 4, 8, and 12 weeks post-treatment. RESULTS: No meaningful changes in mean values were observed for any blood lipid level or liver test at any point over the 12-week follow-up period. CONCLUSION: Cryolipolysis, when used for reduction of subcutaneous flank fat, is not associated with changes in serum lipids or liver test results.

Cryolipolysis for noninvasive fat cell destruction: initial results from a pig model.

BACKGROUND: Liposuction is one of the most frequently performed cosmetic procedures in the United States, but its cost and downtime has led to the development of noninvasive approaches for adipose tissue reduction. OBJECTIVE: To determine whether noninvasive controlled and selective destruction of fat cells (Cryolipolysis) can selectively damage subcutaneous fat without causing damage to the overlying skin or rise in lipid levels. METHODS: Three Yucatan pigs underwent Cryolipolysis at 22 sites: 20 at cooling intensity factor (CIF) index 24.5 (-43.8 mW/cm(2)), one at CIF 24.9 (-44.7 mW/cm(2)), and one at CIF 25.4 (-45.6 mW/cm(2)). Treated areas were evaluated using photography, ultrasound, and gross and microscopic pathology. Lipids were at various times points. One additional pig underwent Cryolipolysis at various days before euthanasia. RESULTS: The treatments resulted in a significant reduction in the superficial fat layer without damage to the overlying skin. An inflammatory response triggered by cold-induced apoptosis of adipocytes preceded the reduction in the fat layer. Evaluation of lipids over a 3-month period following treatment demonstrated that cholesterol and triglyceride values remained normal. CONCLUSIONS: Cryolipolysis is worthy of further study because it has been shown to significantly decrease subcutaneous fat and change body contour without causing damage to the overlying skin and surrounding structures or deleterious changes in blood lipids.

Clinical efficacy of noninvasive cryolipolysis and its effects on peripheral nerves.

BACKGROUND: Cryolipolysis provides a method for noninvasive fat reduction that significantly reduces subcutaneous fat in a pig model without apparent damage to skin and surrounding structures. This study aimed to determine whether fat reduction in humans caused by cold exposure is associated with alteration in local sensory function or nerve fibers. METHODS: In this study, 10 subjects were treated with a prototype cooling device. Fat reduction was assessed in 9 of the 10 subjects via ultrasound before treatment and at the follow-up visit. Sensory function was assessed by neurologic evaluation (n = 9), and biopsies (n = 1) were collected for nerve staining. RESULTS: Treatment resulted in a normalized fat layer reduction of 20.4% at 2 months and 25.5% at 6 months after treatment. Transient reduction in sensation occurred in six of nine subjects assessed by neurologic evaluation. However, all sensation returned by a mean of 3.6 weeks after treatment. Biopsies showed no long-term change in nerve fiber structure. There were no lasting sensory alterations or observations of skin damage in any of the subjects evaluated. CONCLUSION: Noninvasive cryolipolysis results in substantial fat reduction within 2 months of treatment without damage to skin. The procedure is associated with modest reversible short-term changes in the function of peripheral sensory nerves.