Effect of breathing supplemental oxygen on motion sickness in healthy adults

OBJECTIVE: To compare the effects of breathing supplemental oxygen vs air on alleviating motion sickness in healthy adults. SUBJECTS AND METHODS: Between April and July 2002, 20 healthy subjects were exposed to a provocative motion on 2 occasions (1-week interval) according to a randomized, counterbalanced, crossover design. During motion, subjects rated their nausea (1, no symptoms, to 4, moderate nausea) every 30 seconds. Once mild nausea occurred, subjects began breathing supplemental oxygen or air through a face mask. Motion ceased when moderate nausea occurred, but subjects continued breathing study gases for 5 minutes while recovering. Recovery was assessed for 20 minutes after motion. RESULTS: There were no significant differences in the rate of increase in symptom severity or the rate of recovery between the 2 conditions. CONCLUSION: Breathing supplemental oxygen had no advantage over breathing air in reducing motion sickness in healthy adults.     

Trihalomethane exposures from municipal water supplies and selected congenital malformations

BACKGROUND: Concerns about potential health effects of trihalomethanes (THMs) have prompted investigations on whether infants whose mothers were periconceptionally exposed to drinking water containing THMs are at greater risk of congenital malformations. METHODS: We used two large case-control maternal interview studies that were conducted among California deliveries from 1987 through 1991. One study comprised 538 infants/fetuses with neural tube defects (NTDs) and 539 nonmalformed control infants. The second study included an additional 265 infants with NTDs, 207 infants with conotruncal heart defects, 409 infants with orofacial clefts, and 481 control infants. Expert personnel from municipal water companies estimated THM levels for a particular residence and specific periconceptional time period using quarterly monitoring measurements. Estimates were also made for four individual THM levels and for the total THM level. RESULTS: NTD risk in the first study was inversely associated with total THM exposure. Although the second study did not show the same inverse relationship for NTDs, there were no positive associations of NTDs or the other malformations with total THM as estimated from continuous models. Elevated risks were observed for the lowest category of exposure (1-24 ppb), but risks were either not substantially elevated or were imprecise for higher exposure levels. Thus no evidence was observed for an exposure-response relation. CONCLUSIONS: Our results do not provide a clear pattern of association between THM exposure and risks of specific congenital malformations. Imprecise exposure measures coupled with a lack of information about other possible sources of THM exposure may have caused associations to be underestimated.     

Blood pressure and cardiovascular involvement in children with neurofibromatosis type1

We evaluated blood pressure in a sample of patients with neurofibromatosis type 1 (NF1), using ambulatory blood pressure monitoring (ABPM), to determine whether ABPM, when compared with casual BP recordings, allowed the detection of a higher risk for hypertension. We also evaluated the correlation between BP and vascular abnormalities. We studied 69 NF1 patients (36 males and 33 females) with a mean age of 11±4 years, divided into group A, with 24-h mean systolic blood pressure (SBP) or diastolic blood pressure (DBP) <95th percentile, and group B, with mean SBP or DBP >95th percentile. Standard electrocardiography and M-mode, two-dimensional echocardiography were performed and all patients were in sinus rhythm. ABPM identified 11 hypertensive patients (16%); 5 had a mean SBP >95th percentile, 3 mean SBP–DBP >95th percentile, and 3 a mean DBP >95th percentile. Laboratory and other investigations to exclude secondary hypertension were normal. Cardiac abnormalities were found in 13 of the 69 patients (18.8%) with NF1. There were no significant clinical and cardiac differences between the normotensive and hypertensive group. Our data emphasize the importance of periodic ABPM in NF1 patients to diagnose hypertension early and avoid target organ damage and increased mortality.     

Survival in infants with Down syndrome, Metropolitan Atlanta, 1979-1998

OBJECTIVE: Factors influencing survival among persons with Down syndrome (DS) are not well understood. We sought to evaluate survival of infants with DS and potential prognostic factors. STUDY DESIGN: Infants with DS who were born alive during 1979 to 1998 were identified using the Metropolitan Atlanta Congenital Defects Program (MACDP), a population-based surveillance system. To document vital status, we used data from hospital records, the National Death Index (NDI), and Georgia vital records. We estimated survival probability using the Kaplan-Meier product limit method and hazard ratios using a Cox proportional hazards model. RESULTS: Survival probability to 1 year was 92.9% (95% CI: 90.9-94.9) and to 10 years was 88.6% (95% CI: 85.0-92.2). Univariate analysis demonstrated that black maternal race, low birth weight, preterm birth, lower paternal education, presence of heart defects, and presence of other major congenital anomalies were important prognostic factors. After multivariate analysis, maternal race, presence of heart defects, low birth weight, and an interaction between maternal race and presence of heart defects were significantly associated with mortality risk. CONCLUSIONS: A racial disparity is apparent in survival for children with Down syndrome. Further study is needed to elucidate possible reasons for the racial disparity.     

Compartmental analyses of plasma 13C- and 2H-labeled n-6 fatty acids arising from oral administrations of 13C-U-18:2n-6 and 2H5-20:3n-6 in newborn infants

Efficacy of (13)C-U-18:2n-6 and (2)H(5)-20:3n-6 toward synthesis of labeled-20:4n-6 was studied in newborn infants utilizing compartmental models of plasma labeled n-6 fatty acids (FA). Ten infants received oral doses of (13)C-U-18:2n-6 and (2)H(5)-20:3n-6 ethyl esters (100 and 2 mg/kg, respectively). Rate constant coefficients and half-lives (t((1/2))) of n-6 FA were determined from the time-course concentrations of labeled-FA. Plasma n-6 FA values approximated steady state concentrations. Synthetic and utilization rates were calculated. Eight percent (range, 2-21%) of plasma (13)C-U-18:2n-6 was used for synthesis of (13)C-18:3n-6, -20:2n-6, and -20:3n-6. Seventy percent of (13)C-20:3n-6 (mean, CV: 0.26) was available for synthesis of (13)C-20:4n-6. The percentage of (2)H(5)-20:3n-6 converted to (2)H(5)-20:4n-6 was lower (mean: 26%, p < 0.02) than the (13)C-labeled analogue. Turnover of 18:2n-6 in subjects and of 20:4n-6 in plasma was 4.2 g/kg/d (CV: 0.58) and 4.3 mg/kg/d (CV: 0.81), respectively. Intake of 18:2n-6 and 20:4n-6 were estimated to be 3.0 g/kg/d (+/-1.7) and 2.8 mg/kg/d (+/- 2.2), respectively. Infants required additional 18:2n-6 and 20:4n-6 (mean: 1.2 g and 1.5 mg/kg/d) above predicted intake amounts to maintain plasma concentrations of 18:2n-6 and 20:4n-6, in order to spare FA from fat stores.     

Oncocytic Cell Tumors of the Thyroid: Factors Predicting Malignancy and Influencing Prognosis, Treatment Decisions, and Outcomes

Background  

The distinction between malignant and benign thyroid oncocytic cell tumors (OCTs) before and during surgery still represents a diagnostic challenge. We focused on the search for specific factors that predict malignancy and influence the prognosis of OCTs, and for their most appropriate management.