Test and evaluation of exercise-enhanced preoxygenation in U-2 operations

BACKGROUND: Preoxygenation to prevent decompression sickness (DCS) during U-2 reconnaissance flights requires considerable time and occasionally does not provide adequate protection. Increasing preoxygenation within a practical period of time provides marginally increased protection and is not always operationally feasible. Including exercise during preoxygenation to increase muscle tissue perfusion, cardiac output, and ventilation can improve the quality of the denitrogenation. METHODS: A pilot, who reported two cases of DCS during his first 25 U-2 high flights involving cabin altitudes of 29,000-30,000 ft, volunteered to test exercise-enhanced preoxygenation. He performed 10 min of strenuous upper and lower body exercise at the beginning of preoxygenation prior to subsequent high flights without increasing total preoxygenation time. RESULTS: The exercise was performed at 75% of maximal oxygen uptake based on the estimated maximal oxygen uptake determined during an Air Force aerobic fitness test and heart rate. The pilot's next 36 high flights, using exercise-enhanced preoxygenation, were completed with no reports of DCS. CONCLUSIONS: This statistically significant operational test reinforced the laboratory studies. Implementation of this procedure for reducing DCS in susceptible U-2 pilots and collecting additional data from the U-2 pilot population is recommended.     

Sarcomatoid renal cell carcinoma: Rapid dissemination detected on FDG PET‐CT

We present the FDG PET‐CT findings in a patient with persistent pain 7 weeks after a nephrectomy and lymph node dissection for a sarcomatoid renal cell carcinoma. Although conventional imaging was unable to detect evidence of metastatic spread outside the para‐aortic nodes, a PET‐CT scan showed unexpected extensive dissemination. Currently, there are no reports in the literature of the PET‐CT findings in sarcomatoid renal cell carcinomas.     

Initiating activity of the anti-estrogen tamoxifen, but not toremifene in rat liver

A striking difference between two structurally related anti-estrogen medicines is that tamoxifen is strongly hepatocarcinogenic in the rat, whereas toremifene lacks such activity. To study the basis for this difference, the initiating potential of tamoxifen and toremifene were studied by measurement of rapid induction of hepatocellular altered foci (HAF) that express placental-type glutathione S-transferase in the livers of female Sprague-Dawley (S-D) rats and female Fischer 344 (F344) rats. Both agents were administered by gavage at equimolar doses up to a dose that produced marked weight gain suppression. In rats given the high dose of 40 mg/kg per day tamoxifen continuously for 36 weeks, 75% of S-D rats developed liver neoplasms, in contrast to only 10% of F344 rats. In the S-D strain, tamoxifen produced a tendency to increased HAF at 2 weeks at the dose of 40 mg/kg per day and by 12 weeks, a dose-related increase was evident. In contrast, toremifene induced no HAF even at the equimolar high dose of 42.4 mg/kg per day for 12 weeks. The induction of HAF by tamoxifen was less in the F344 rats. Neither agent elicited increases in hepatocellular proliferation in S-D or F344 rats. When phenobarbital was administered for 24 weeks as a promoting agent after the anti-estrogens, S-D rats given tamoxifen at 20 mg/kg per day for 12 weeks, developed liver neoplasms, but not F344 rats or rats of either strain given even a higher dose (42.4 mg/kg) of toremifene. Thus, tamoxifen has initiating activity in these rat strains whereas toremifene does not.      

Use of pelvic ultrasound to monitor ovarian and uterine maturity in childhood onset anorexia nervosa.

This study reports the use of pelvic ultrasound scanning in childhood onset anorexia nervosa. The aim was to determine the weight and weight for height ratio (wt/ht) that would correspond with ovarian and uterine maturity and therefore offer the optimal opportunity for the start or resumption of menstruation. On initial assessment, all children had mean weight, wt/ht, ovarian and uterine volumes significantly below expected. At follow up, half the children had started or resumed menstruation. When compared with those who had persisting amenorrhoea, the recovered children had a significantly higher mean weight (48.4 kg v 43.8 kg), mean wt/ht (96.5% v 87.5%), mean ovarian volume (6.2 ml v 4.9 ml), and mean uterine volume (14.6 ml v 10.8 ml). The study indicates that conventional target weight and wt/ht in anorexia nervosa may be too low to ensure ovarian and uterine maturity, and that pelvic ultrasound, which is well tolerated by this group of children, is a useful addition to their management.     

Myelin thickenings in val 102/fs null mutation of MPZ gene

Painful sensory neuropathies consist of a wide range of neuropathies that can involve large as well as small nerve fibres. Even if most cases remain of unknown cause, some of them may be associated with an underlying disorder such as diabetes, HIV, infections, amyloidosis, and Sjogren's syndrome. Since in some cases an autoimmune mechanism has been postulated, we investigated a panel of circulating autoantibodies including anti‐gliadin (AGA), anti‐endomysium (EmA), anti‐transglutaminase (tTGA) and anti‐nuclear (ANA) antibodies in the sera of patients with unexplained painful sensory neuropathies in order to identify other potentially treatable disorders. We tested the sera of 10 patients (4M; 6F) previously investigated for other causes of neuropathies, including anti‐nerve, onconeural, anti‐extractable nuclear, anti‐neutrophil cytoplasmic, anti‐thyroglobulin (TgA) and anti‐peroxidase (TPOA) antibodies. We found the presence of AGA positivity in 4 patients (40%), ANA in 7 (70%) and AGA + ANA in 4 (40%), two of whom were negative for celiac disease by gastrointestinal biopsy. None of the patients had EmA positivity. Three (30%) had TgA and TPOA and none had anti‐nerve or onconeural antibodies. Whether the presence of circulating autoantibodies in patients with unexplained painful neuropathy reflects an autoimmune involvement which may be amenable to immune therapy and not only to symptomatic treatment remains to be established.