Early genetic restoration of lubricin expression in transgenic mice mitigates chondrocyte peroxynitrite release and caspase-3 activation.

OBJECTIVE: This study investigated the ability of endogenous lubricin secretion to restore joint health following a brief <21 day, postnatal lubricin-null state, in a C57BL/6J Prg4 gene trap (GT) mouse under the control of cre-recombinase. Previously we showed that re-expression of lubricin at 21 days was partly restorative of joint lubrication. DESIGN: The tibio-femoral joints of adult C57BL/6J mice containing lubricin, lacking lubricin, and postnatally lacking lubricin until restoration of lubricin expression at 7 days or 14 days of age were evaluated ex vivo. At 8-weeks of age, whole joint coefficient of friction (COF), and caspase-3 activation were measured and the tibial-femoral joints histologically analyzed for degenerative changes, following progressive cyclic loading. The peroxynitrite content of femoral head cartilage from these mice prior to cyclic loading was measured. RESULTS: Mice that underwent gene recombination at 7 and 14 days of age did not reestablish low COF as joint cycling time increased and were histopathologically indistinguishable from the joints of lubricin-null littermates. However, cartilage from tibio-femoral joints that underwent recombination at 7 and 14 days of age had significantly fewer caspase-3 positive cells and significantly reduced peroxynitrite content compared to lubricin-null littermates. CONCLUSIONS: The biological effects of lubricin, which include limiting inflammation via peroxynitrite production and caspase-3 activation, may be achieved without completely restituting low COF. However, fully recapitulating low COF may require undamaged cartilage surfaces or absence of biofouling, which may interfere with the activity of lubricin.

Variability of upper firn processes in West Antarctica observed with GPS reflectometry, 2007-2017.

Land ice loss from Antarctica is a significant and accelerating contribution to global sea-level rise; however, Antarctic mass-balance estimates are complicated by insufficient knowledge of surface mass-balance processes such as snow accumulation. These variables are challenging to observe on a continental scale and in situ data are sparse, so we largely rely on estimates from atmospheric models. Here, we employ a novel method, GPS interferometric reflectometry (GPS-IR), to measure upper (<2 m) firn-column thickness changes across a 23-station GPS array in West Antarctica. We compare the results with antenna heights measured in situ to establish the method's daily uncertainty (0.06 m) and with output from two atmospheric reanalysis products to categorize spatial and temporal variability of near-surface processes. GPS-IR is an effective method for monitoring surface mass-balance processes that can be applied to both historic GPS datasets and future experiments to provide critical in situ observations of processes driving surface-height evolution.

Present-day crustal deformation in China constrained by global positioning system measurements.

Global Positioning System (GPS) measurements in China indicate that crustal shortening accommodates most of India's penetration into Eurasia. Deformation within the Tibetan Plateau and its margins, the Himalaya, the Altyn Tagh, and the Qilian Shan, absorbs more than 90% of the relative motion between the Indian and Eurasian plates. Internal shortening of the Tibetan plateau itself accounts for more than one-third of the total convergence. However, the Tibetan plateau south of the Kunlun and Ganzi-Mani faults is moving eastward relative to both India and Eurasia. This movement is accommodated through rotation of material around the eastern Syntaxis. The North China and South China blocks, east of the Tibetan Plateau, move coherently east-southeastward at rates of 2 to 8 millimeters per year and 6 to 11 millimeters per year, respectively, with respect to the stable Eurasia.

Successful treatment of retrograde ejaculation with sperm recovered from bladder washings. A report of two cases.

BACKGROUND: Retrograde ejaculation causes < 2% of male infertility but is the leading cause of aspermia. The incidence of retrograde ejaculation is increasing due to the aggressiveness of modern urologic cancer surgery and an increase in diabetes mellitus. Generally, the only adverse effect is on fertility. Various approaches have been proposed for treatment, ranging from insemination with sperm-rich urine obtained after masturbation to intracytoplasmic sperm injection (ICSI). We used a protocol involving bladder washing. CASES: Case 1 involved a man with retrograde ejaculation secondary to a successful right orchiectomy and retroperitoneal lymph node dissection for stage B1 embryonal cell carcinoma. He was treated with bladder washing and intrauterine insemination. He fathered three children from six insemination cycles. Case 2 involved a man with idiopathic retrograde ejaculation and a wife with ovulatory dysfunction. He received treatment similar to that in case 1 and fathered one child from two insemination cycles. CONCLUSION: Larger studies need to be done specifically comparing treatments. Our method resulted in four normal infants in two couples over eight total insemination cycles and, taken together with other results from the literature, seems a good choice for clinicians who are treating retrograde ejaculation for the first time. We agree with others who have recommended that in vitro fertilization/ICSI not be the first step for treating the usual couples with retrograde ejaculation.

Laparoscopic removal of a perforated intrauterine device from the perirectal fat.

BACKGROUND: The intrauterine device (IUD) was a very common form of birth control in the United States. The most serious potential complication of IUD use is uterine perforation. Uterine perforation is common among women with "lost" IUDs and can cause severe morbidity and mortality and should be carefully managed. The recommended treatment is removal of the perforating IUD. This can usually be managed laparoscopically unless bowel perforation or other severe sepsis is present. METHODS: An intra-abdominal IUD was removed laparoscopically from the perirectal fat of a 49-year-old woman who had been diagnosed over 20 years earlier with an "expelled" IUD. CONCLUSIONS: It is important that the possibility of uterine perforation be considered in anyone who has had a diagnosis of an expelled IUD without actual confirmation that the IUD is no longer present in the body. In any woman who presents with pelvic pain and a history of a "lost" IUD, the surgeon should have a high index of suspicion and obtain radiological studies. It may be advisable to question women about possible IUD use when they present with pelvic pain of unknown origin.

Assessment of GPS carrier-phase stability for time-transfer applications.

We have conducted global positioning system (GPS) carrier-phase time-transfer experiments between the master clock (MC) at the U.S. Naval Observatory (USNO) in Washington, DC and the alternate master clock (AMC) at Schriever Air Force Base near Colorado Springs, Colorado. These clocks are also monitored on an hourly basis with two-way satellite time-transfer (TWSTT) measurements. We compared the performance of the GPS carrier phase and TWSTT systems over a 236-d period. Because of power problems and data outages during the carrier-phase experiment, the longest continuous time span is 96 d. The data from this period show agreement with TWSTT within +/-1 ns, apart from an overall constant time offset (caused by unknown delays in the GPS hardware at both ends). For averaging times of a day, the carrier-phase and TWSTT systems have a frequency uncertainty of 2.5 and 5.5 parts in 10(15), respectively.

Carrier-phase time transfer.

We have conducted several time-transfer experiments using the phase of the GPS carrier rather than the code, as is done in current GPS-based time-transfer systems. Atomic clocks were connected to geodetic GPS receivers; we then used the GPS carrier-phase observations to estimate relative clock behavior at 6-minute intervals. GPS carrier-phase time transfer is more than an order of magnitude more precise than GPS common view time transfer and agrees, within the experimental uncertainty, with two-way satellite time-transfer measurements for a 2400 km baseline. GPS carrier-phase time transfer has a stability of 100 ps, which translates into a frequency uncertainty of about two parts in 10(-15) for an average time of 1 day.