Biodegradation of international jet A-1 aviation fuel by microorganisms isolated from aircraft tank and joint hydrant storage systems.

Microorganisms contaminating international Jet A-1 aircraft fuel and fuel preserved in Joint Hydrant Storage Tank (JHST) were isolated, characterized and identified. The isolates were Bacillus subtillis, Bacillus megaterium, Flavobacterium oderatum, Sarcina flava, Micrococcus varians, Pseudomonas aeruginosa, Bacillus licheniformis, Bacillus cereus and Bacillus brevis. Others included Candida tropicalis, Candida albicans, Saccharomyces estuari, Saccharomyces cerevisiae, Schizosaccharomyces pombe, Aspergillus flavus, Aspergillus niger, Aspergillus fumigatus, Cladosporium resinae, Penicillium citrinum and Penicillium frequentans. The viable plate count of microorganisms in the Aircraft Tank ranged from 1.3 (+/-0.01) x 104 cfu/mL to 2.2 (+/-1.6) x 104 cfu/mL for bacteria and 102 cfu/mL to 1.68 (+/-0.32) x 103 cfu/mL for fungi. Total bacterial counts of 1.79 (+/-0.2) x 104 cfu/mL to 2.58 (+/-0.04) x 104 cfu/mL and total fungal count of 2.1 (+/-0.1) x 103 cfu/mL to 2.28 (+/-0.5) x 103 cfu/mL were obtained for JHST. Selected isolates were re-inoculated into filter sterilized aircraft fuels and biodegradation studies carried out. After 14 days incubation, Cladosporium resinae exhibited the highest degradation rate with a percentage weight loss of 66 followed by Candida albicans (60.6) while Penicillium citrinum was the least degrader with a weight loss of 41.6%. The ability of the isolates to utilize the fuel as their sole source of carbon and energy was examined and found to vary in growth profile between the isolates. The results imply that aviation fuel could be biodegraded by hydrocarbonoclastic microorganisms. To avert a possible deterioration of fuel quality during storage, fuel pipe clogging and failure, engine component damage, wing tank corrosion and aircraft disaster, efficient routine monitoring of aircraft fuel systems is advocated.

Stress fractures of the upper extremity.

Stress fractures are common injuries in the athletic population. Although much of the published literature has focused on lower extremity stress injuries, these injuries also occur in the upper extremities. Stress injuries of bone result from repetitive loads smaller than would be required to cause an acute fracture. As bone is repetitively stressed, it behaves like any solid substance. If deformity occurs within its elastic range, it returns to its original configuration. If stressed into its plastic range, permanent deformity occurs, and microfractures propagate, causing structural failure and complete fracture of the involved bone. High clinical suspicion is required for diagnosis because of historical and physical features can be vague. Plain radiographs are often inconclusive, but bone scans and MR imaging usually help elucidate the diagnosis. Most upper extremity stress injuries will heal with nonoperative management. In rare situations these injuries can progress to nonunion, which requires surgical correction.

Endometrial thickness: individual and mean growth profiles for different hormone replacement regimens.

Currently, there is a paucity of data describing endometrial growth, with most studies concentrating on endometrial thickness immediately prior to implantation or embryo transfer. This study looked at the individual and combined growth profiles of 67 volunteers receiving three different hormone replacement regimens. Each treatment regimen was in excess of that considered necessary for optimal growth, and all promoted an endometrial thickness that would be considered satisfactory for embryo transfer. Three patterns of growth were identified, but overall there was a decrease in the rate of endometrial growth with duration of treatment. As expected, analysis of variance did not show a significant difference between the mean growth profiles for the three hormone replacement regimens. The correlation (r = 0.45, P < 0.0001) between rank order on day 3 and day 10 of treatment indicates that interim analysis during early treatment cannot accurately predict later thickness, but a doubling of endometrial thickness can be expected in most cases. A relationship between endometrial thickness and either the treatment dose or serum concentrations of oestradiol was not found. These findings suggest that manipulation of endometrial growth is not possible by adjustment of either the treatment dose or serum concentration. The findings indicate that treatment beyond 12 days does not promote either a clinically significant increase in endometrial thickness of an excessive thickness, suggesting that maintenance of an oocyte recipient in a pseudo-follicular phase is unlikely to be disadvantageous to implantation.

The role of relaxin in the pregnancy associated reduction in plasma osmolality.

Recent data suggest that the ovarian peptide relaxin is responsible for the pregnancy-associated fall in plasma osmolality in the rat. In order to test whether relaxin has the same role during human pregnancy, plasma osmolality, electrolytes, urea and creatinine were measured in samples obtained at 10, 20 and 30 weeks gestation from singleton pregnancies conceived following ovum donation (OD, n = 12), spontaneously (N, n = 12) and following in-vitro fertilization and embryo transfer (IVF, n = 14). These groups were chosen, as relaxin concentrations throughout pregnancy are undetectable (OD), elevated (IVF) or normal (N). Thus, if relaxin alone is responsible for the fall in plasma osmolality associated with pregnancy in the human, then plasma osmolality would be expected not to fall during pregnancy in the OD group and to show a consistent decline from OD to N to IVF throughout pregnancy. Plasma osmolality fell significantly during pregnancy in both the OD and N groups, but not the IVF group. In addition, plasma osmolality was only significantly greater in OD when compared with IVF group at 10 weeks gestation; thereafter there were no significant differences between the groups with regard to plasma osmolality. Similarly, at 10 weeks the plasma concentrations of sodium and potassium were significantly higher in the OD than in either the N or IVF groups. Thus, although relaxin may be important in the initial control of plasma osmolality, other factors, probably derived from or regulated by the feto-placental unit, supersede it as pregnancy advances.

Arthroscopy of the elbow.

As our understanding of the anatomy and function of the elbow joint continues to grow and technology continues to advance, our ability to correct disorders of the elbow with arthroscopic techniques will expand. Today, we are at the brink of major advances in the arthroscopic evaluation and treatment of elbow ailments. Many open surgical procedures currently being performed will undoubtedly be adapted for an arthroscopic approach, as we are already seeing in the treatment of radiocapitellar arthrosis, tennis elbow, arthrofibrosis, and ulnohumeral arthroplasty. Elbow procedures, such as ligamentous tightening, fracture treatment with bioabsorbable devices, and biologic joint replacement will be commonly performed in the future with the aid of the arthroscope. Although elbow arthroscopy is technically demanding, it is a highly effective surgical technique in treating many intra-articular disorders with minimal morbidity. Most of the complications associated with elbow arthroscopy can be avoided by adhering to strict and proper surgical technique. Successful elbow arthroscopy requires a thorough understanding of local gross and arthroscopic anatomy. To maintain proper orientation at all times, the skin should be properly marked before starting the procedure. The joint should be kept distended during initiation of portals to move the neurovascular structures away from the arthroscopic instruments. Nonvented cannulas with blunt trocars should be used to allow for safe passage of instruments and to avoid multiple capsular punctures. Finally, the elbow should remain flexed to 90 deg during most of the procedure, thus keeping the neurovascular structures in the antecubital fossa relaxed. If these techniques are followed, the surgical morbidity should remain low, and surgeon and patient will find elbow arthroscopy tremendously effective.

Birth weight: nature or nurture?

OBJECTIVE: To investigate the relative role of environmental and genetic factors in the determination of birth weight following ovum donation. METHODS: Data from 62 cases of ovum donation were used to examine the relative influence of donor and recipient on birth weight. RESULTS: The only discernible factors that significantly influenced birth weight were gestational age and recipient's weight. Donor weight, her own birth weight, and the birth weight of the donor's own children were not significantly correlated with the birth weight of the child following ovum donation. CONCLUSIONS: It is concluded that the environment provided by the human mother is more important than her genetic contribution to birth weight.

Serum concentrations of luteinizing hormone and progesterone in ovum recipients: their relationship with pregnancy and miscarriage.

Our objective was to test the hypothesis that the association between elevated luteinizing hormone (LH) concentrations and miscarriage is mediated via an effect of LH on the maternal environment, rather than on the oocyte. The impact of maternal age, ovarian function, previous IVF attempts, therapeutic (buserelin) and hormonal (LH, oestradiol, progesterone) effects occurring on the day of zygote intra-Fallopian transfer (ZIFT) or embryo transfer, and of oocyte or embryo numbers, whether they were fresh or frozen, and their mode of transfer on the occurrence of pregnancy and miscarriage following ovum donation (n = 57) were investigated. The cycles were divided by outcome into non-pregnant (n = 26), miscarriage (n = 19) and normal term pregnancy (n = 12). The circulating concentrations of LH were greater in miscarriage cycles (P = 0.046) and cycles ending in pregnancy (P = 0.04) than in non-pregnant cycles, while the concentrations of progesterone were greater in non-pregnant (P = 0.029) and miscarriage (P = 0.015) cycles than in cycles ending in pregnancy. Frozen embryos were used more frequently in non-pregnant compared to cycles ending in pregnancy (P = 0.016). Multiple regression analysis was used to investigate which factors are associated with miscarriage and identified progesterone concentrations at the time of transfer as being the only significant variable (r = 0.48, F = 8.5, P = 0.007).(ABSTRACT TRUNCATED AT 250 WORDS)

Superovulation, IGFBP-1 and birth weight.

In this study, the effect of superovulation on the circulating levels of insulin-like growth factor binding protein-1 (IGFBP-1) has been investigated. IGFBP-1 levels were measured in singleton pregnancies achieved either naturally (n = 203) or following superovulation, in-vitro fertilisation and embryo transfer (IVF-ET) with either pituitary desensitisation with buserelin and superovulation with human menopausal gonadotrophin (b/hMG) followed by IVF-ET (n = 15) or with clomiphene citrate and hMG (CC/hMG) followed by IVF-ET (n = 15, 1st trimester only). The circulating levels of IGFBP-1 were similar in all three groups during the first trimester, and in both normal and b/hMG pregnancies in the second, but were significantly higher during the third trimester in b/hMG pregnancies than in normal pregnancies (P = 0.0002). The birth weights were significantly lower in the b/hMG group (P = 0.04), but not in the CC/hMG group compared with natural conceptions. Gestational age at delivery was similar in control and b/hMG pregnancies, but significantly reduced in CC/hMG pregnancies (P = 0.04). These data suggest that pregnancies achieved following superovulation with b/hMG are associated with elevated levels of IGFBP-1 during the third trimester of pregnancy and reduced birth weight.

Insulin-related growth factor binding protein-1 levels in ovum donation pregnancies.

The finding that endometrial maturation may be delayed following hormone replacement therapy has suggested that a generalised endometrial dysfunction may exist in ovum recipients. In order to investigate this suggestion further, circulating levels of IGFBP-1 were measured in samples taken throughout pregnancies conceived either spontaneously or following ovum donation. When analysed at two-weekly intervals, the serum levels of IGFBP-1 in ovum donation pregnancies failed to show the expected peak towards the end of the first trimester and were significantly reduced at week ten (U = 364.5, p = 0.0002) and twelve (U = 138.0, p = 0.0047). For the remainder of pregnancy, circulating IGFBP-1 levels were similar in both groups. The birth weight of children born to the ovum donation group was not significantly different from a normal control group, suggesting that circulating levels of IGFBP-1 in early pregnancy do not reflect local function and that IGFBP-1 does not have an essential function (in relation to birth weight) in early pregnancy.

Endometrial thickness: a predictor of implantation in ovum recipients?

In a retrospective study, the relationship between endometrial thickness and pregnancy rate has been studied in 59 ovum recipient women. Transvaginal ultrasound assessment of endometrial thickness was performed immediately prior to ovum transfer: 19 pregnant recipients had a mean endometrial thickness of 10.24 mm +/- 2.63 SD, 40 nonpregnant recipients had an endometrial thickness of 8.62 mm +/- 3.49 SD (t = 1.805, P = 0.0382). Only two pregnancies occurred in 15 recipients with an endometrial thickness < 7.5 mm, and none when the endometrial thickness was < 5 mm. Our results indicate that endometrial thickness is related to the functional receptivity of the endometrium.

Age, pregnancy and miscarriage: uterine versus ovarian factors.

This study was performed to evaluate the relative contribution of oocyte and uterine factors to the age-related reduction in fecundity. The pregnancy and miscarriage rates in women receiving donated oocytes were compared to those in women using their own oocytes in in-vitro fertilization (IVF) and gamete intra-Fallopian transfer (GIFT) procedures. Oocyte donation with embryo transfer was performed on 241 women in 371 cycles; 116 of these women became pregnant (48% per patient and 31.5% per cycle) of whom 40 (35%) miscarried, giving a live birth rate of 20.5%. Assisted conception, in the form of IVF/GIFT procedures, was performed on 1331 women using their own oocytes in 2194 cycles; 627 of these women became pregnant (47% per patient and 28.7% per cycle), of whom 228 (36%) miscarried, giving a live birth rate of 18.2%. Neither the age of the donor nor the age of the recipient was related to pregnancy rate. The age of the donor, however, was directly related to the miscarriage rate. On the other hand, the age of patients undergoing IVF/GIFT was inversely related to the pregnancy rate and directly related to the miscarriage rate. In women of 40 years or over, the overall pregnancy and live birth rates were significantly higher and the miscarriage rate was significantly lower in the group receiving donated oocytes compared to the group using their own oocytes. In summary, we suggest that the age-related decline in fecundity is associated with the age of the oocytes rather than the age of the uterus.