Chemical fingerprinting of naphthenic acids and oil sands process waters-A review of analytical methods for environmental samples

This article provides a review of the routine methods currently utilized for total naphthenic acid analyses. There is a growing need to develop chemical methods that can selectively distinguish compounds found within industrially derived oil sands process affected waters (OSPW) from those derived from the natural weathering of oil sands deposits. Attention is thus given to the characterization of other OSPW components such as oil sands polar organic compounds, PAHs, and heavy metals along with characterization of chemical additives such as polyacrylamide polymers and trace levels of boron species. Environmental samples discussed cover the following matrices: OSPW containments, on-lease interceptor well systems, on- and off-lease groundwater, and river and lake surface waters. There are diverse ranges of methods available for analyses of total naphthenic acids. However, there is a need for inter-laboratory studies to compare their accuracy and precision for routine analyses. Recent advances in high- and medium-resolution mass spectrometry, concomitant with comprehensive mass spectrometry techniques following multi-dimensional chromatography or ion-mobility separations, have allowed for the speciation of monocarboxylic naphthenic acids along with a wide range of other species including humics. The distributions of oil sands polar organic compounds, particularly the sulphur containing species (i.e., OxS and OxS2) may allow for distinguishing sources of OSPW. The ratios of oxygen- (i.e., Ox) and nitrogen-containing species (i.e., NOx, and N2Ox) are useful for differentiating organic components derived from OSPW from natural components found within receiving waters. Synchronous fluorescence spectroscopy also provides a powerful screening technique capable of quickly detecting the presence of aromatic organic acids contained within oil sands naphthenic acid mixtures. Synchronous fluorescence spectroscopy provides diagnostic profiles for OSPW and potentially impacted groundwater that can be compared against reference groundwater and surface water samples. Novel applications of X-ray absorption near edge spectroscopy (XANES) are emerging for speciation of sulphur-containing species (both organic and inorganic components) as well as industrially derived boron-containing species. There is strong potential for an environmental forensics application of XANES for chemical fingerprinting of weathered sulphur-containing species and industrial additives in OSPW.

[Increasing frequency of bariatric surgery interventions since replacement of gastroplasty by laparoscopic gastric banding in the treatment of morbid obesity]

Between 1984 and 1996 we performed a Mason gastroplasty for the treatment of morbid obesity: 14 patients (average age 40 (26-48) years, body mass index (BMI) 48 (37-71) kg/m2, excessive body weight 67 (41-116) kg). Since the end of 1996 we now apply adjustable laparoscopic gastric banding (lab band): 73 patients (average age 39 (22-64) years, BMI 45 (32-69) kg/m2, excessive body weight 66 (41-116) kg). We compared the early and late results of both methods. Early results: no relevant morbidity or mortality for neither method. Late/intermediate results: reoperation rate for both methods 15%. After an average of 3.7 years the excessive body weight loss (EWL) for gastroplasty was 54 (22-96)%. The EWL after lab band for 24 patients after 12 months was 47 (11-127)% and for 8 patients after 18 months 51 (28-139)%. Since the introduction of the lap band the number of bariatric operations has greatly increased. Nevertheless, the perioperative complication rate has remained low, and the long-term outcome is similar for both methods.

Hypomagnesemia in infants of diabetic mothers: perinatal studies

Fifty-six diabetic mothers and their infants were studied prospectively from birth. Twenty-one of 56 IDM had serum Mg less than or equal to 1.5 mg/dl, on at least one occasion during the first 3 days. Serum Mg in these hypomagnesemic infants did not demonstrate the normal increase with postnatal age that was present in normomagnesemic infants. Decreased neonatal serum Mg was related to increased severity of maternal diabetes, young mothers, mothers for lower gravidity, and prematurity. Decreased serum Mg, alone or with decreased ionized or total Ca, did not correlate with neuromuscular irritability in the infants. Decreased serum Mg in IDM was associated with decreased maternal serum Mg, decreased neonatal ionized and total Ca, increased serum P, and decreased parathyroid function. Serum Mg was not related to dietary P intake, or urinary Ca or P excretion. Thus, transitory neonatal hypomagnesemia occurs in IDM; it is speculated that factors causing HM might include maternal HM or neonatal hyperphosphatemia, and that the HM is related to the hypocalcemia and functional hypoparathyroidism of IDM.

Parathyroid function in infants of diabetic mothers

Serum parathyroid hormone and total and ionized Ca, Mg, and P levels were determined serially from birth to 96 hr of age in 28 infants of diabetic mothers (IDM, 15 Class A, 13 Class B, C, D) and their respective mothers at the time of delivery. In spite of marked decreases in concentrations of serum total and ionized Ca from birth to 24 to 48 hr, there was an insignificant increase in serum PTH values over this period in infants of insulin-dependent mothers. Infants of Class A diabetic mothers had an equivocal PTH response. Nineteen term control infants were similarly examined and had a significant increase in serum PTH postnatally. Relatively higher values of serum ionized Ca at birth in IDM were followed by greater decreases in ionized Ca from birth to 24-48 hr of age, and by decreased neonatal parathyroid function. The data support functional hypoparathyroidism as a basis for the hypocalcemia and hyperphosphatemia of IDM. It is speculated that increased concentrations of serum ionized Ca in utero and suppression of activity in the fetal parathyroid glands may be a cause for the functional hypoparathyroidism.