Cryopreservation reduces the ability of hamster 2-cell embryos to regulate intracellular pH.

Vitrification of hamster 2-cell embryos impairs the activity of both the Na(+)/H(+) antiporter and HCO(3)(-)/Cl(-) exchanger; the two transport proteins responsible for the regulation of intracellular pH (pHi). The activities of both the Na(+)/H(+) antiporter and HCO(3)(-)/Cl(-) exchanger were significantly reduced at 4 h following warming compared to freshly collected embryos. Normal levels of activity of both transporters were not restored until 6 h after warming. Thus, cryopreservation of cleavage stage hamster embryos has a detrimental effect on their ability to maintain intracellular ionic homeostasis. Impairment of these pHi regulatory proteins resulted in the pHi of embryos being significantly elevated from the control values of 1.2 to 7.35 for approximately 4 h after warming. In addition, an elevated pHi value significantly impaired oxidative metabolism. Therefore, the loss in developmental competence of embryos following cryopreservation may in part be explained by a reduced ability to regulate intracellular pH that results in perturbations in metabolism and disruption of energy production.

Processing lexically embedded spoken words.

A large number of multisyllabic words contain syllables that are themselves words. Previous research using cross-modal priming and word-spotting tasks suggests that embedded words may be activated when the carrier word is heard. To determine the effects of an embedded word on processing of the larger word, processing times for matched pairs of bisyllabic words were examined to contrast the effects of the presence or absence of embedded words in both 1st- and 2nd-syllable positions. Results from auditory lexical decision and single-word shadowing demonstrate that the presence of an embedded word in the 1st-syllable position speeds processing times for the carrier word. The presence of an embedded word in the 2nd syllable has no demonstrable effect.

Specificity of memory representations for spoken words.

Many theories of spoken word recognition assume that lexical items are stored in memory as abstract representations. However, recent research (e.g., Goldinger, 1996) has suggested that representations of spoken words in memory are veridical exemplars that encode specific information, such as characteristics of the talker's voice. If representations are exemplar based, effects of stimulus variation such as that arising from changes in the identity of the talker may have an effect on identification of and memory for spoken words. This prediction was examined for an implicit and explicit task (lexical decision and recognition, respectively). Comparable amounts of repetition priming in lexical decision were found for repeated words, regardless of whether the repetitions were in the same or in different voices. However, reaction times in the recognition task were faster if the repetition was in the same voice. These results suggest a role for both abstract and specific representations in models of spoken word recognition.

Yolk sac number, size and morphologic features in monochorionic monoamniotic twin pregnancy.

OBJECTIVE: To determine the relation between three characteristics of the yolk sac (number, size and morphologic features) and outcome in monochorionic monoamniotic twin pregnancy. METHODS: The authors reviewed data for the four sets of monochorionic monoamniotic twins detected by first-trimester ultrasonography between January 1990 and June 1994 at their institution. Data analysed included yolk sac number, size and morphologic features, as well as the outcome of the pregnancy. RESULTS: In all four sets of twins, only one yolk sac was identified. In one case the yolk sac was irregular in contour, and in two it was abnormally large. Two of the four mothers delivered healthy twins at 34 weeks gestational age, one had conjoined twins ( and underwent elective termination of the pregnancy), and one had a twin ectopic pregnancy (and underwent salpingectomy). CONCLUSION: A single yolk sac in cases of monochorionic monoamniotic twins may be a normal finding.

Diagnostic imaging management in Manitoba: 1995-2000.

As part of a 5-year imaging management plan being developed for the single insurance carrier in Manitoba, the radiologic utilization for the province was reviewed. For the fiscal year 1993 (April 1, 1992, through March 31, 1993), 1,056,694 imaging studies were performed in a total patient population of 1,133,117 in 81 hospitals and 39 offices in which 648 units of equipment were operated by 773.4 full-time personnel at a cost of $100,302,812 ($75,227,109 in U.S. dollars). The skin dose for the total population for the year was 40,112 Gy, compared with 35,513 Gy in 1979. Since 1979, there has been a 9% increase in the number of radiologic examinations (from 972,426 examinations), a greater need for more personnel to conduct ultrasound, mammography, computed tomography, and magnetic resonance imaging examinations, and striking costs escalation (from $25,082,500 to $100,302,812). Reduction of total funding for imaging services will be possible only if the medical service infrastructure and physician behavior are altered, since imaging is a support service. Hospital services must be integrated and the infrastructure reduced, and physicians must adhere to guidelines and practice protocols for requesting consultations.

Decidual cyst: endovaginal sonographic sign of ectopic pregnancy.

PURPOSE: To determine the prevalence of decidual cysts in patients with ectopic pregnancy and assess the value of endovaginal sonographic demonstration of decidual cysts in predicting ectopic pregnancy. MATERIALS AND METHODS: A series of 288 proved ectopic pregnancies was reviewed, and a series of 179 patients with pregnancies of less than 8 weeks menstrual age was prospectively examined. RESULTS: Decidual cysts were identified in 30 (14.4%) of 208 ectopic pregnancies. In 12 patients a decidual cyst was the first sonographic sign of ectopic pregnancy, and in six patients it was the only abnormal sonographic finding. Four of five patients with decidual cysts had an ectopic pregnancy. Decidual cysts had a sensitivity of 21%, specificity of 92%, positive predictive value of 80%, and negative predictive value of 42% in the diagnosis of ectopic pregnancy. CONCLUSION: Patients with decidual cysts are at high risk for ectopic pregnancy and should be monitored or treated appropriately, depending on the clinical findings.

Computed tomography for nontraumatic headache: current utilization and cost-effectiveness.

A retrospective study was performed at two teaching hospitals--one in the United States and one in Canada--to determine the results of computed tomography (CT) examinations of the head in patients with nontraumatic headache. Of 1111 examinations performed over a 3-year period, 120 (10.8%) demonstrated an acute intracranial abnormality, such as hemorrhage, infarction or tumour; the frequency of such abnormalities was highest among inpatients and subjects over 40 years of age. Cranial and extracranial abnormalities, such as sinusitis and metastases to the calvarium, were found in 40 (3.6%) of the cases. Chronic abnormalities, such as cerebral atrophy or remote infarction, were the most significant findings in 202 (18.2%) of the cases. The cost of finding each case of acute intracranial abnormality was $5962 (US); for subarachnoid hemorrhage among patients in the emergency department, it was $15,837 (US).

Transvaginal sonography of normal pelvic anatomy.

The major structures of interest in the pelvis for sonography are the uterus and ovaries. TVS, with its superior imaging characteristics, provides better sonographic detail of this anatomy and improves our diagnostic capabilities. It is certainly reasonable to expect this approach to yield even greater improvements in the future as the refinements to the technology continue to evolve.

Endovaginal and translabial ultrasound in pregnancy.

Endovaginal sonography provides earlier and enhanced visualization of the gestational sac and its contents than does transvesical sonography. This paper discusses the role of endovaginal sonography in common first trimester diagnostic problems, including pregnancy dating, first trimester pregnancy loss, ectopic pregnancy, and early diagnosis of fetal anomalies, and reviews the use of endovaginal color flow Doppler in the diagnosis of ectopic pregnancy. A brief discussion of the role of endovaginal and translabial sonography in the second and third trimesters is included.

Yolk sac diameter and shape at endovaginal US: predictors of pregnancy outcome in the first trimester.

Four hundred eighty-six consecutive women who underwent endovaginal sonography when their fetuses were less than 10 weeks menstrual age (MA) were evaluated to establish the normal size and shape of the secondary yolk sac (YS) and to assess the value of YS measurement in predicting pregnancy outcome in the first trimester. A YS diameter more than two standard deviations (SDs) above the mean when compared with the mean gestational sac diameter allowed prediction of an abnormal pregnancy outcome with a sensitivity of 15.6%, a specificity of 97.4%, and a positive predictive value of 60.0%. A YS diameter more than two SDs below the mean allowed prediction of an abnormal outcome with a sensitivity of 15.6%, a specificity of 95.3%, and a positive predictive value of 44.4%. No pregnancy with a normal outcome had a YS diameter of greater than 5.6 mm at less than 10 weeks MA. In six patients, the YS diameter was greater than 5.6 mm. All six had an abnormal outcome. Of seven patients with abnormal YS shape at initial sonography, three had abnormal YS shape at follow-up examinations. All three had an abnormal outcome.

First-trimester umbilical cord cysts.

Cystic masses of the umbilical cord have been detected in the 2nd and 3rd trimesters of pregnancy in association with fetal abdominal wall defects and chromosomal anomalies. With high-resolution endovaginal ultrasound (US), umbilical cord cysts can be visualized during the 1st trimester. Their origin and significance must be considered for proper obstetric management. The authors report eight cases in which cystic masses of the umbilical cord were detected during US examinations performed at 8-9 weeks menstrual age. In the five cases followed to term, both the infant and the umbilical cord were found to be normal at physical examination. Sonographically, all cysts appeared to be eccentric in relation to the umbilical cord, and, although all were closer to the fetus, the cysts were clearly extraembryonic. Cyst size was 2.0-7.5 mm (mean, 5.2 mm). Seven cysts resolved by 12 weeks menstrual age. The incidence of cysts in patients who underwent US at the authors' institution between 8 and 12 weeks menstrual age was 0.4%; the true frequency is unknown without routine 1st-trimester scanning of all patients.

Noninvasive diagnosis of resistant ovary syndrome by ultrasonography.

OBJECTIVE: To compare transvaginal ultrasonographic features of the ovaries and endometrium of patients with premature ovarian failure to normally cycling women on oral contraceptives (OCs), menopausal women with an equivalent duration of amenorrhea to the premature ovarian failure group, and patients with Turner's syndrome. DESIGN: Transvaginal ultrasonography in groups of women with premature ovarian failure, OC, and menopause. SETTING: All subjects were studied in an academic tertiary care center. PATIENTS/PARTICIPANTS: Seventeen women with premature ovarian failure, 20 volunteers on OC, 20 with menopause, and 4 patients with Turner's syndrome were studied. INTERVENTION: None, except for OCs in the OC group only. MAIN OUTCOME MEASURES: Frequency of ovarian, ovarian follicle, and endometrial visualization and their respective measurement in the three groups. RESULTS: At least one ovary was visualized in 84% of the premature ovarian failure patients as compared with 95% of the OC and menopause groups and 25% of the Turner patients. Mean ovarian volume was smaller in the premature ovarian failure group as compared with the OC group but equal to that of the menopause group. In the premature ovarian failure group, 41% had follicles in their ovaries as compared with 95% in the OC group, 5% in the menopause group, and none in the Turner group. The number of follicles per ovary was significantly lower in the premature ovarian failure as compared with the OC group, whereas only one subject had a single follicle in the menopause group. Premature ovarian failure subjects with follicles had larger ovaries than those without follicles. Endometrial thickness was not different among the groups. CONCLUSION: Ultrasonography may serve to identify a substantial subset (approximately 40%) of premature ovarian failure patients with ovarian follicles and potential for fertility consistent with the diagnosis of resistant ovary syndrome.

Normal pelvic anatomy using transvaginal scanning.

The fine spatial and contrast resolution accorded by TVS provides us with the opportunity to see the uterus, ovary, and larger pelvic vessels with detail and accuracy. Other structures may also be visualized but not with the same finesse, regularity, or attention. Transvaginal color Doppler imaging and pulsed waveform analysis capabilities now provide us with the opportunity of distinguishing vascular and nonvascular structures, and gives us the ability to determine the normal and abnormal flow characteristics of pelvic viscera. Improvements in TVS technology will undoubtedly expand our future capabilities and applications.

Endovaginal sonographic diagnosis of ectopic twin gestation.

Endovaginal sonography has permitted earlier diagnosis of ectopic pregnancy. Twin ectopic pregnancy is rare. Until now, antenatal diagnosis of twin ectopic pregnancy using endovaginal sonography had not been reported. Three cases of twin ectopic pregnancy diagnosed via the intracavitary probe are presented.

The potential use of expert systems to enable physicians to order more cost-effective diagnostic imaging examinations.

Educating physicians to order diagnostic imaging examinations more cost-effectively is a difficult and time consuming task, which may be assisted significantly by the use of an expert system. This report is based on a study undertaken at the Health Sciences Centre in Winnipeg, Manitoba, to determine the feasibility of implementing an expert system to aid physicians in selecting appropriate imaging studies. The report reviews the potential benefits, requirements, and limitations of expert systems under development, and highlights the major issues to be considered in choosing such a system for implementation. An extensive literature search was done and is included to aid the reader interested in pursuing this opportunity for improving the cost-effective utilization of expensive diagnostic imaging resources.