Largest recent impact craters on Mars: Orbital imaging and surface seismic co-investigation.

Two >130-meter-diameter impact craters formed on Mars during the later half of 2021. These are the two largest fresh impact craters discovered by the Mars Reconnaissance Orbiter since operations started 16 years ago. The impacts created two of the largest seismic events (magnitudes greater than 4) recorded by InSight during its 3-year mission. The combination of orbital imagery and seismic ground motion enables the investigation of subsurface and atmospheric energy partitioning of the impact process on a planet with a thin atmosphere and the first direct test of martian deep-interior seismic models with known event distances. The impact at 35°N excavated blocks of water ice, which is the lowest latitude at which ice has been directly observed on Mars.

Introducing residents to a career in management: the Physician Management Pathway.

To prepare their students and residents for the practice of medicine in a rapidly changing environment, medical educators must teach the business of medicine as well as the science and art of medicine. Recognizing the value of and demand for physician leaders, the authors sought to introduce residents to diverse aspects of medical administration within the context of an academically rigorous internal medicine residency program. The Physician Management Pathway (PMP) was developed in 1997 to expose interested residents to the management concepts employed by physician managers; to help physician trainees begin to develop the leadership and technical skills they will use as physician managers; to provide career mentoring; to provide experiences that enrich the resident's training in clinical medicine; to enhance resident-directed educational activities; and to produce physicians who can successfully work in any health care environment. The PMP curriculum consists of a monthly seminar series, a preceptorship experience in the second year of residency, and a supervised project in the third year. The program was not designed to provide competency in management, but rather is intended to provide an opportunity for new physicians to explore options in this exciting and changing profession.

Enhanced gamete interaction in the sperm penetration assay after coincubation with pentoxifylline and human follicular fluid.

OBJECTIVE: To evaluate the effect of pentoxifylline and heat-inactivated human follicular fluid (FF) on performance in the sperm penetration assay (SPA) as a paradigm for the effect of these agents on human sperm-egg interaction in vivo and in vitro fertilization. DESIGN: Semen specimens from men undergoing SPA testing for evaluation of suspected male factor infertility were coincubated with neat medium or media supplemented with pentoxifylline or human FF in a nonblinded manner. PARTICIPANTS: Twenty male factor infertility patients. INTERVENTIONS: Semen specimens were preincubated with: [1] pentoxifylline 0.25 mg/mL; [2] 10% human FF; [3] pentoxifylline+human FF; and [4] neat Biggers, Whitten, and Whittingham medium. MAIN OUTCOME MEASURES: Differences in the rate of penetration of zona-free hamster oocytes. RESULTS: Preincubation with either human FF or pentoxifylline produced a significant improvement in hamster egg penetration rates. Coincubation with a combination of human FF and pentoxifylline resulted in a significant enhancement of penetration as compared with single agent treatment. CONCLUSIONS: Coincubation of sperm with human FF and pentoxifylline may provide a means of enhancing sperm activity for insemination and assisted reproduction.

Periovulatory calcium channel blockade enhances reproductive performance in an animal model for endometriosis-associated subfertility.

Current evidence suggests that peritoneal inflammatory cell hyperactivation may be the essential pathologic abnormality in patients with endometriosis-associated subfertility. In these experiments we utilized an animal model to evaluate the use of an immunomodulatory agent as an alternative treatment for endometriosis-associated subfertility. The right uterine horn of 12 golden hamsters was resected and 2 x 2 mm squares were explanted onto the left uterine mesentery. Controls included hamsters undergoing uterine horn resection without endometrial explantation (n = 6) and nonsurgically treated animals (n = 6). Ovulation induction was initiated 6 weeks postoperatively with 40 IU of pregnant mare's serum gonadotropin on day 1 and 40 IU of human chorionic gonadotropin on day 3. Groups of six explant-bearing hamsters and six nonsurgical control hamsters were treated with verapamil (250 micrograms/kg every 8 hours subcutaneously), a calcium channel-blocking agent known to inhibit macrophage activation, from day 1 to 48 hours after administration of human chorionic gonadotropin. Animals were then killed and the number of embryos and oocytes in left tube counted as a reflection of reproductive performance. Fertilization was completely inhibited in animals bearing uterine explants. Treatment with verapamil dramatically reversed this effect. These data suggest that periovulatory treatment with an immunomodulatory agent such as verapamil may be an effective alternative to conventional treatment for endometriosis-associated subfertility.

Poloxamer 407 as an intraperitoneal barrier material for the prevention of postsurgical adhesion formation and reformation in rodent models for reproductive surgery.

Comtemporary adhesion-prevention regimens for infertility surgery emphasize the use of barrier materials to effect physical separation of injured surfaces before reperitonealization. Poloxamer 407 is a biocompatible polymer that displays reverse thermal gelation characteristics; that is, the material exists as a liquid at room temperature and as a solid at body temperature. These properties make it an ideal material for use in laparoscopic surgery. The antiadhesion properties of poloxamer 407 were evaluated in two models. In the first experiment, Golden hamsters were subjected to a standardized adhesion-producing lesion in the left uterine horn. Poloxamer solutions in concentrations ranging from 15-35% were applied to the injured horn. Location, thickness, and extent of adhesion formation were assessed 14 days later. Significant reduction in post-traumatic adhesion formation was observed following treatment with the 30-35% solutions. The second experiment was designed as a paradigm of the typical situation encountered in infertility surgery: prevention of adhesion reformation after lysis of established adhesions. New Zealand White rabbits were subjected to three laparotomies at 14-day intervals for placement of the adhesion-producing lesion, evaluation (prescore) and surgical lysis of induced adhesions, and subsequent evaluation of adhesion reformation (post-score). The effect of applying poloxamer 407 after adhesiotomy was compared with controls (no treatment). Adhesion reformation (post-score) was markedly reduced by poloxamer-407 treatment. Further trials of this material in the clinical setting are indicated.

Treatment of infertility due to retrograde ejaculation: a simple, cost-effective method.

Our data indicate that an appropriate therapy for the infertility associated with retrograde ejaculation is isolation of sperm from voided urine after orgasm, plus IUI. This technique is simple and can be performed in the physician's office, in contrast to more complex techniques such as GIFT or in vitro fertilization.

Changes in the LH response to GnRH in the ovine fetus and neonate.

The in vivo responsiveness of the ovine fetal and neonatal pituitary was investigated using acute and chronic preparations. Several studies were performed on six fetuses and six lambs from 112 days' gestation through 5 weeks after birth. Ten micrograms of gonadotropin-releasing hormone (GnRH) was injected intravenously into each fetus and lamb, and serial blood samples were collected from the fetus, ewe and lamb. The luteinizing hormone (LH) content of each sample was determined by species-specific radioimmunoassay. Both the fetus and the neonate showed a response to GnRH. A significant elevation of LH was found in all animals by 15 minutes. There was no response in the ewe when GnRH was injected into its fetus. Great variability in response was noted among various age groups and between animals, with the maximum individual LH response reaching 33.7 ng/ml. The maximum LH response of the neonate during the first week of life was significantly depressed (p < 0.05) as compared to that of the fetus and the older neonate.

Menopause, medroxyprogesterone and breathing during sleep.

Twenty-one postmenopausal women were monitored for sleep-disordered breathing and nocturnal oxygen desaturation to evaluate the contribution of progestational hormones to the occurrence of these sleep events. For approximately one month 11 subjects received 30 mg of medroxyprogesterone (MPG) daily, and 10 received placebo tablets in a randomized, double-blind controlled study. Respiration, saturation and electroencephalography were monitored during one night of sleep before and one night after therapy. Contrasted with the low incidence of disordered breathing and desaturation in premenopausal women, 71 percent of the postmenopausal women had such events. In the placebo-treated group, all measured variables of sleep and breathing were identical on the two nights, which suggested that the findings of a single night of sleep monitoring may be representative of other nights of sleep. Although several subjects appeared to show improvement with MPG, only the maximum duration of apnea was significantly reduced the second night (p less than 0.03).

PIP: 21 postmenopausal women were monitored for sleep-disordered breathing and nocturnal oxygen desaturation to evaluate the contribution of progestational hormones to the occurrence of these sleep events. For approximately one month, 11 subjects received 30 mg of medroxyprogesterone (MPG) daily, and 10 received placebo tablets in a randomized, double-blind controlled study. Respiration, saturation and electroencephalography were monitored during one night of sleep before and one night after therapy. Contrasted with the low incidence of disordered breathing and desaturation in premenopausal women, 71% of the postmenopausal women had such events. In the placebo-treated group, all measured variables of sleep and breathing were identical on the 2 nights, suggesting that the findings of a single night of sleep monitoring may be representative of other nights of sleep. Although several subjects appeared to show improvement with MPG, only the maximum duration of apnea was significantly reduced the 2nd night (p0.03). The study supports the observation that disordered breathing and desaturation are similarly frequent in postmenopausal women and in men.

46,XX hernia uterus inguinale and vaginal agenesis.

The first reported case of hernia uterus inguinale in a chromosomally normal 46,XX female is presented. The diagnosis should be suspected in patients presenting with primary amenorrhea, a normal hair pattern, and an inguinal mass.

Oligohydramnios and transient neonatal anuria: a possible association with the maternal use of prostaglandin synthetase inhibitors.

The chronic use of prostaglandin synthetase inhibitors is reported in a pregnant patient with severe juvenile rheumatoid arthritis. Aspirin and indomethacin, along with corticosteroids, were required to prevent significant progression of the disease. Pregnancy was complicated by oligohydramnios and intrauterine growth retardation. The infant suffered transient anuria. The effects of prostaglandin synthetase inhibitors on renal vascular function is reviewed, and a possible association between the chronic ingestion of these drugs and compromised renal function in the newborn is pointed out.

Endometrial estrogen and progesterone receptors in a uterus didelphys.

A 23-year-old woman with a uterus didelphys and a totally occluded left tube had a hysterectomy one year after having a child. Endometrial estrogen and progesterone receptors, both cytoplasmic and nuclear, were determined in five longitudinal sections of each horn. The amount and distribution of these receptors were normal, but the receptor content of the right horn was higher than that of the left.

PIP: A 23-year-old white woman was admitted with a complaint of increasing dysmenorrhea since the birth of her child 1 year before. She was diagnosed as having a uterus didelphys and a totally occluded left tube, and hysterectomy was performed. 5 longitudinal sections of each uterine horn was examined for both progesterone and estrogen endometrial nuclear and cytoplasmic hormone receptors. Cytoplasmic receptor values were in the expected normal range, and in general descended from the fundus to the cervix as in normal uteri. Nuclear receptor values were also in the expected range for secretory nuclei and their distrubtion was as seen in normal uteri. Both receptors (estrogen + progesterone; cytoplasmic + nuclear) however, were higher in the right horn vs. the left horn; this difference is ascribed to the woman's earlier pregnancy.

Carbohydrate metabolism and the semen profile: glucose, insulin, and sperm studies.

Twenty-seven men attending an infertility clinic received detailed studies of their ejaculate and carbohydrate metabolism. The latter was done using a 3-hour oral glucose tolerance test with a 100-gm glucose load and measuring both blood glucose and plasma insulin levels. There was no significant difference in either the blood glucose or the plasma insulin values between the men with normal sperm counts and those with abnormal sperm counts. These data suggest that mild subclinical states of carbohydrate abnormalities do not routinely alter male fertility.

The choice of sterilizing procedure according to its potential reversibility with microsurgery.

Twenty-seven women were evaluated for reversal of previous tubal sterilization in the 2-year span beginning January 1, 1976. Of the thirteen who came to surgery, only seven were able to undergo reanastomosis. Five of these seven had had Pomeroy type ligations and two had ahd "one-burn" electrocoagulation. Six patients who had had "two- or three burn" electrocoagulation did not have sufficient length of fallopian tube remaining. Tubal patency was achieved in 87.5% of those who underwent reanastomosis. The pregnancy rate was 37.5%, with no ectopic pregnancies. Electrocoagulation is not recommended in healthy young women.

PIP: The type of tubal ligation originally performed affects subsequent ability to achieve successful reversal of sterilization procedure. Unfortunately, too little attention has been given to the potential reversibility of a sterilization procedure. This study (spanning 2 years) evaluates 3 groups of women (N=27) for reversal of previous tubal ligation by the Dept. of Obstetrics and Gynecology of the University of Florida. The women were assigned to 3 groups based on the outcome of evaluation (of fertility potential) and surgical procedure performed. Group 1 was comprised of women who came for evaluation but did not have any surgical procedure, while Group 2 consisted of women who had laparoscopic findings precluding any type of reanastomosis; Group 3 consisted of women who had had reanastomosis of at least one tube. The technique described by Winston, with minor modifications, was the microsurgical technique used for reanastomosis. Of the 13 who requested surgery, only 7 underwent reanastomosis; 5 of these had had Pomeroy-type ligations, and 2 had had "1-burn" electrocoagulation. 6 patients who had had "2-or-3 burn" electrocoagulation did not have adequate tubal length. 87.5% of those who were reanastomosed achieved tubal patency. Pregnancy rate was 37.5%, and there were no ectopic pregnancies. Electrocoagulation should be advised for patients with medical indication for permanent sterilization or those who are over 35 years of age. All other cases should utilize techniques with potential for reversibility, while ensuring sterility. Minilap with resection of a small portion of the isthmic segment via the Pomeroy method or its modification appears to be the best procedure to use.

Distribution of cytoplasmic estrogen and progesterone receptors in human endometrium.

Unoccupied estrogen receptors and progesterone receptors were measured in the cytoplasm of five sections along the length of endometrium obtained from noncancerous, premenopausal hysterectomy specimens. The concentrations of the two receptors were measured with tritiated estradiol or R5020 (a synthetic progestin), the latter two having been purified by high-pressure liquid chromatography, and were found to be highest in the fundus and lowest in the cervix. Progesterone receptor levels, ranging from 50 to 3,500 fmoles of R5020 bound per milligram of protein, were generally much higher in each section of the endometrium than estrogen receptor levels, which ranged from 0 to 500 fmoles of estradiol bound per milligram of protein. Near ovulation it seemed that the distribution profiles of both receptors became very steep, with more than a tenfold difference in the receptor levels being found between the fundus and the cervix. Receptor levels measured in endometrial samples obtained by curettage or aspiration should be interpreted with caution.