Investigation into the subambient behavior of aqueous mannitol solutions using temperature-controlled Raman microscopy.

The aim was twofold; to demonstrate the ability of temperature-controlled Raman microscopy (TRM) to locate mannitol within a frozen system and determine its form; to investigate the annealing behavior of mannitol solutions at -30 degrees C. The different polymorphic forms of anhydrous mannitol as well as the hemihydrate and amorphous form were prepared and characterized using crystal or powder X-ray diffractometry (XRD) as appropriate and Raman microscopy. Mannitol solutions (3% w/v) were cooled before annealing at -30 degrees C. TRM was used to map the frozen systems during annealing and was able to differentiate between the different forms of mannitol and revealed the location of both beta and delta polymorphic forms within the structure of the frozen material for the first time. TRM also confirmed that the crystalline mannitol is preferentially deposited at the edge of the frozen drop, forming a rim that thickens upon annealing. While there is no preference for one form initially, the study has revealed that the mannitol preferentially transforms to the beta form with time. TRM has enabled observation of spatially resolved behavior of mannitol during the annealing process for the first time. The technique has clear potential for studying other crystallization processes, with particular advantage for frozen systems.     

Neonatal blood pressure and salt taste responsiveness

To test the association between neonatal blood pressure (BP) and salt taste response, 283 healthy hospitalized neonates were administered small drops (0.06 mL) of water and 0.1 molar (mol/L) and 0.3 mol/L NaCl solutions by means of cannulas through a nipple with a pressure transducer to record sucking responses. Neonatal and 1-month BPs were recorded by ultrasound. Mean number of sucks per burst was scored as "aversive" if the 0.3 mol/L salt minus water difference score was < or =-10 mean sucks per burst, "preferential" if this difference was >0, and "neutral" otherwise. Babies with "preferential" responses had higher diastolic BPs than those with neutral (1.9 mm Hg) or aversive responses (3.1 mm Hg) (P trend=0.05). After adjustment for age, gender, birth weight, and activity for babies with at least one grandparent receiving antihypertensive medication, mean adjusted systolic pressure was 6.7 mm Hg higher (P=0.003) (P trend=0.003) and mean adjusted diastolic pressure was 5.0 mm Hg higher (P=0.010) (P trend=0.011) in neonates with preferential versus aversive salt taste responses. There was no relation of BP to sucking responses to sweet (sucrose) stimuli. Neonates can distinguish between dilute salt solutions and water. This response is related to BP and might be a potential risk factor for high BP later in life.     

Evaluation of compression in intramedullary hindfoot arthrodesis

Compression was evaluated in an intramedullary hindfoot arthrodesis cadaver model using an external fixator and a "second generation" intramedullary compression nail. Four cadaver specimens were used. Four trials were done with each specimen. Trial 1: manual compression with the 1st generation nail. Trial 2: external fixator for compression with the 1st generation nail. Trial 3: external fixator for compression with the 2nd generation nail. Trial 4: nail-mounted compression device with the 2nd generation nail. In Trial 1 it was not possible to obtain or maintain compression. In Trial 2 large values of compression were obtained with the external fixator, however compression was not maintained after the first generation nails were locked and the fixator was removed. In Trial 3 large values of compression were obtained with the external fixator, but minimal compression was maintained after the second-generation nails were locked and the fixator was removed. In Trial 4 large values of compression were obtained with the compression device and greater than 60% of the compression was maintained after the nail was locked and the compression device was released. The study revealed that both the external fixator and the compression device could produce compression. The external fixator is useful as an aid in the O.R. However, in this study significant compression was maintained only with utilization of the compression device.     

Irreversible spinal cord injury as a complication of subarachnoid ethanol neurolysis

ARTICLE ABSTRACT: Subarachnoid neurolysis using ethanol to destroy selectively the posterior roots of the spinal cord is a method for providing pain relief in patients with advanced cancer. Weakness of the extremities is a complication of the procedure that has been attributed to spread of the neurolytic agent to the anterior roots. The authors provide evidence of spinal cord injury as a cause of lower extremity weakness in a patient after subarachnoid ethanol neurolysis.     

New paradigms and improved results for the surgical treatment of acute type A dissection

OBJECTIVE: To examine the effect of an integrated surgical approach to the treatment of acute type A dissections. SUMMARY BACKGROUND DATA: Acute type A dissection requires surgery to prevent death from proximal aortic rupture or malperfusion. Most series of the past decade have reported a death rate in the range of 15% to 30%. METHODS: From January 1994 to March 2001, 104 consecutive patients underwent repair of acute type A dissection. All had an integrated operative management as follows: intraoperative transesophageal echocardiography; hypothermic circulatory arrest (HCA) with retrograde cerebral perfusion (RCP) to replace the aortic arch; HCA established after 5 minutes of electroencephalographic (EEG) silence in neuromonitored patients (66%) or after 45 minutes of cooling in patients who were not neuromonitored (34%); reinforcement of the residual arch tissue with a Teflon felt "neo-media"; cannulation of the arch graft to reestablish cardiopulmonary bypass at the completion of HCA (antegrade graft perfusion); and remodeling of the sinus of Valsalva segments with Teflon felt "neo-media" and aortic valve resuspension (78%) or replacement with a biologic or mechanical valved conduit (22%). RESULTS: Mean age was 59 +/- 15 (range 22-86) years, with 71% men and 13% redo sternotomy after a previous cardiac procedure. Mean cardiopulmonary bypass time was 196 +/- 50 minutes. Mean HCA with RCP time was 42 +/- 12 minutes (range 19-84). Mean cardiac ischemic time was 140 +/- 45 minutes. Eleven percent of patients presented with a preoperative neurologic deficit, and 5% developed a new cerebrovascular accident after dissection repair. The in-hospital death rate was 9%. Excluding the patients who presented neurologically unresponsive or with ongoing cardiopulmonary resuscitation (n = 5), the death rate was 4%. In six patients adverse cerebral outcomes were potentially avoided when immediate surgical fenestration was prompted by a sudden change in the EEG during cooling. Forty-five percent of neuromonitored patients required greater than 30 minutes to achieve EEG silence. CONCLUSION: The authors have shown that the surgical integration of sinus segment repair or aortic root replacement, the use of EEG monitoring, partial or total arch replacement using RCP, routine antegrade graft perfusion, and the uniform use of transesophageal echocardiography substantially decrease the death and complication rates of acute type A dissection repair.     

External Cephalic Version at Term

Summary: The case notes of women with singleton term (37 weeks' gestation and beyond) breech presentation and delivery were retrospectively reviewed. Thirty-two of the 72 women in the study group had attempted external cephalic version at term, with a success rate of 53% (17 women). The Caesarean section rate was significantly lower in the group which had attempted ECV compared to the group which did not.     

Mechanical suitability of glycerol-preserved human dura mater for construction of prosthetic cardiac valves

We have examined the tensile viscoelastic properties of fresh and glycerol-preserved human dura mater, and correlated the results with structural information from the scanning electron microscope. The interwoven laminar structure of dura produces rather high flexural stiffness, while the crossed-fibrillar laminae produce planar mechanical isotropy. Glycerol storage shifts the stress-strain curve to lower strain, reduces stress relaxation and creep, and lowers the ultimate tensile strength and strain at fracture. These changes may be due to glyceraldehyde crosslinking, or to increased interfibrillar friction. The latter hypothesis suggests that glycerol storage may reduce the fatigue lifetime of the tissue.     

Joint distraction for the treatment of ankle osteoarthritis

Joint distraction has demonstrated substantial promise in the treatment of tibiotalar arthritis. Its minimally invasive nature, combined with the fact that it does not seem to "burn any bridges," lends considerable clinical appeal. Even if joint distraction provides only temporary relief and clinical results slowly deteriorate over time, more definitive and committed procedures potentially can be forestalled for a considerable period of time. Nevertheless, the current literature and clinical experience with this technique is limited. Further research and analysis is ongoing and will be necessary to understand, validate, and refine this novel approach to ankle arthritis.     

Feasibility and benefits of a parent-focused preschool child obesity intervention

OBJECTIVES: This field study tested the feasibility and benefits of a program to promote 6 targeted parental behaviors to prevent obesity in children served by the Special Supplemental Nutrition Program for Women, Infants, and Children (WIC). METHODS: Two WIC sites participated in a nonrandomized, controlled 1-year prospective study to assess parents' self-reported behavior changes. RESULTS: Statistical analyses of preintervention and postintervention assessments of parental behavior demonstrated significant changes in 2 behaviors: frequency of offering the child water and frequency of engaging in active play with the child. In both cases, the intervention proved effective in increasing the desired behavior. CONCLUSIONS: The findings demonstrate the feasibility of changing parental behaviors through multidimensional education in a WIC clinic setting.