Shock-Induced Damage and Dynamic Fracture in Cylindrical Bodies Submerged in Liquid

Understanding the response of solid materials to shock loading is important for mitigating shock-induced damages and failures, as well as advancing the beneficial use of shock waves for material modifications. In this paper, we consider a representative brittle material, BegoStone, in the form of cylindrical bodies and submerged in water. We present a computational study on the causal relationship between the prescribed shock load and the resulting elastic waves and damage in the solid material. A recently developed three-dimensional computational framework, FIVER, is employed, which couples a finite volume compressible fluid solver with a finite element structural dynamics solver through the construction and solution of local, one-dimensional fluid-solid Riemann problems. The material damage and fracture are modeled and simulated using a continuum damage mechanics model and an element erosion method. The computational model is validated in the context of shock wave lithotripsy and the results are compared with experimental data. We first show that after calibrating the growth rate of microscopic damage and the threshold for macroscopic fracture, the computational framework is capable of capturing the location and shape of the shock-induced fracture observed in a laboratory experiment. Next, we introduce a new phenomenological model of shock waveform, and present a numerical parametric study on the effects of a single shock load, in which the shock waveform, magnitude, and the size of the target material are varied. In particular, we vary the waveform gradually from one that features non-monotonic decay with a tensile phase to one that exhibits monotonic decay without a tensile phase. The result suggests that when the length of the shock pulse is comparable to that of the target material, the former waveform may induce much more significant damage than the latter one, even if the two share the same magnitude, duration, and acoustic energy.

Phase coarsening in multicomponent systems

A theory for phase coarsening in multicomponent systems is developed in which both the multicomponent thermodynamic effect and kinetic effect from a nonzero volume fraction are considered. In contrast to previous theory, a diffusion screening zone for a coarsening particle due to nonzero volume fraction is introduced. The evolution equation for phase coarsening in multicomponent systems is derived in a rigorous way in the framework of the maximum rate of dissipation with the constraints of mass and energy conservation. Existing previous relations are recovered and generalized. Some findings such as the relationship between the maximum particle size and volume fraction and particle size distribution in multicomponent systems are discovered.

Continuous time random walk with generic waiting time and external force

We derive an integrodifferential diffusion equation for decoupled continuous time random walk that is valid for a generic waiting time probability density function and external force. Using this equation we also study diffusion behaviors for a couple of specific waiting time probability density functions such as exponential, a combination of power law and generalized Mittag-Leffler function and a sum of exponentials under the influence of a harmonic trap. We show that first two waiting time probability density functions can reproduce the results of the ordinary and fractional diffusion equations for all the time regions from small to large times. But the third one shows a much more complicated pattern. Furthermore, from the integrodifferential diffusion equation we show that the second Einstein relation can hold for any waiting time probability density function.

Integrodifferential diffusion equation for continuous-time random walk

In this paper, we present an integrodifferential diffusion equation for continuous-time random walk that is valid for a generic waiting time probability density function. Using this equation, we also study diffusion behaviors for a couple of specific waiting time probability density functions such as exponential and a combination of power law and generalized Mittag-Leffler function. We show that for the case of the exponential waiting time probability density function, a normal diffusion is generated and the probability density function is Gaussian distribution. In the case of the combination of a power law and generalized Mittag-Leffler waiting probability density function, we obtain the subdiffusive behavior for all the time regions from small to large times and probability density function is non-Gaussian distribution.

Anomalous diffusive behavior of a harmonic oscillator driven by a Mittag-Leffler noise

The diffusive behavior of a harmonic oscillator driven by a Mittag-Leffler noise is studied. Using the Laplace analysis we derive exact expressions for the relaxation functions of the particle in terms of generalized Mittag-Leffler functions and its derivatives from a generalized Langevin equation. Our results show that the oscillator displays an anomalous diffusive behavior. In the strictly asymptotic limit, the dynamics of the harmonic oscillator corresponds to an oscillator driven by a noise with a pure power-law autocorrelation function. However, at short and intermediate times the dynamics has qualitative difference due to the presence of the characteristic time of the noise.

Correlations and fluctuations in phase coarsening

Three-dimensional phase coarsening at various volume fractions is simulated by employing multiparticle diffusion methods. The dynamic process of phase coarsening is visualized through a three-dimensional movie. The present study also characterizes interparticle spacings in polydispersed particle systems and clarifies the controversial mathematical expressions for interparticle spacings used in the literature for 30 years. Consequently, this study reveals spatial, temporal, and nearest-neighbor correlations in polydispersed particle systems. A new three-dimensional movie of a Voronoi network demonstrating these correlations is provided. Our simulation and experiments show that growth rates of individual particles deviate from those of the mean-field theory, which is caused by their differing local environments. Multiplicative noise provides a good basis to describe the stochastic nature of fluctuations during phase coarsening.

Modeling and simulation for phase coarsening: a comparison with experiment

The phase coarsening of precipitates is modeled in the framework of Debye-Hückel theory. The interactions observed among a population of precipitates dispersed throughout a matrix can be described by diffusion screening. The relationship between the maximum particle radius and the volume fraction of the phases is established, and the rate of coarsening is related to the volume fraction and the self-similar particle size distribution. We simulated the dynamics of late-stage phase separation using multiparticle diffusion methods. Experimental measurements on the rates of coarsening of delta(') ( Al3 Li) precipitates in binary Al-Li alloys are compared with our results using modeling and simulation. The theoretically predicted particle size distributions and the maximum radius expected for particles in the microstructure agree well with recent experimental results.

Noise of microstructural environments in late-stage phase coarsening

Multiparticle diffusion equations were modeled to simulate the dynamics of late-stage phase coarsening in the region of lower volume fractions. Local environmental information and particle interactions within each coarsening "locale" are included in our simulations. These studies reveal that locale fluctuations occur in the growth rates of particles due to their differing environments. Multiplicative noise provides a sound basis to describe locale fluctuation in late-stage coarsening. A Fokker-Planck equation for the particle size distribution and its asymptotic solution are obtained.

Simulating formation of voids in charged colloids by brownian dynamics

Using Brownian dynamics simulations and Sogami's effective pair potential with a long-range attractive term for the colloidal particles, we report that the mechanism of making voids in charged colloids is the long-range attractive interaction between particles. The present results are in good agreement with the experimental observations of stable voids in equilibrium with ordered structures, which may not be explained by repulsive potentials without a long-range attractive interaction such as the Derjaguin-Landau-Vervey-Overbeck potential. Our results are also in a good agreement with Monte Carlo simulation results. The voids have been reported with ordered structure in charged colloids by Brownian dynamics simulations.

Stroke complicating pregnancy and the puerperium

BACKGROUND

The role of nonobstetric factors, such as stroke, in maternal mortality has become of increasing importance because maternal deaths resulting directly from obstetric causes are decreasing. Strokes contribute to high mortality and morbidity, and are severe complications during pregnancy and puerperium. The objective of this study was to investigate the maternal outcome of patients with complications of stroke during pregnancy and puerperium. The causes, incidence and essential management of stroke are also reviewed.

METHODS

During the 10-year period from January, 1986, to January, 1996, women who suffered from stroke during pregnancy, or up to six weeks postpartum, and were discharged from our hospital were identified. Stroke was defined as the abrupt onset of a focal neurologic syndrome that consisted of hemorrhagic and ischemic central nervous system events. All were assessed using computerized tomography or magnetic resonance imaging. Neurologists reviewed each case from the medical records.

RESULTS

Thirteen women who had had a stroke during pregnancy or puerperium were identified. Nine of these women had intracerebral hemorrhage and four had ischemic strokes. During this 10-year period, approximately 85,321 women gave birth at the Mackay Memorial Hospital, and the incidence of stroke was approximately 1 in 6,500 pregnancies. Among the nine cases of hemorrhagic strokes, three women had preeclampsia and one had gestational diabetes mellitus. Mortality from strokes was 38%, and 63% of survivors had residual neurologic deficits; 46% of the strokes occurred during the puerperium.

CONCLUSIONS

Stroke during pregnancy and puerperium causes high mortality and morbidity. Early diagnosis and adequate treatment cannot be overemphasized, as prompt and proper management is beneficial for outcome. The same meticulous care provided during the antepartum and intrapartum periods should be continued into the puerperium.

Accuracy of frozen section diagnosis in gynecology

OBJECTIVE

A retrospective study was undertaken to evaluate the accuracy of frozen section diagnosis in gynecological surgery.

METHODS

We compared the results of 792 consecutive gynecological frozen section diagnoses with their final diagnoses from January 1991 to June 1996. Slides for which the frozen section diagnosis was uncertain or incompatible with the final diagnosis were reviewed by an attending pathologist to determine the possible causes.

RESULTS

A total of 299 ovarian, 390 lymph node, 56 uterine lesions, and 77 other tissue samples were obtained. The frozen section diagnosis was compatible with the final diagnosis in 97.5% of cases. The sensitivity for nonbenign lesions was 90.9%, and the specificity was 99.5%. There were no false positives or overestimated cases; 1.3% of cases were falsely negative, 0.4% underestimated the degree of malignancy, and 0.9% were uncertain. Possible causes for incompatible or uncertain frozen section diagnoses were analyzed. The accuracy of frozen section diagnoses for ovarian, lymph node, uterine, and other tissues was also evaluated. Frozen section was found to identify correctly 13 of 17 ovarian malignancies metastaic from other organs, 14 of 15 germ cell malignancies, and 3 of 4 dysgerminomas. The low sensitivity in ovarian borderline malignancy was due to the even lower sensitivity in its mucinous subgroup. The relationship between section numbers and accuracy of frozen section diagnosis in mucinous ovarian tumors was assessed.

CONCLUSIONS

Frozen section diagnosis in gynecology is sufficiently accurate for clinical use, with a low false negative rate and an even lower false positive rate. Most incompatible frozen section diagnoses occurred in ovarian lesions, especially in mucinous ovarian tumors. Performing multiple sections (at least one section for every 10 cm in diameter) is recommended in the frozen section diagnosis of mucinous ovarian tumors.

Impact of reverse end-diastolic flow velocity in umbilical artery on pregnancy outcome after the 28th gestational week

BACKGROUND

The aim of this study was to discuss pregnancy outcome in chromosomally and structurally normal fetuses having reverse end-diastolic flow velocity (REDFV) on Doppler umbilical artery velocimetry (DUAV) in the third trimester.

METHODS

DUAV was performed in the high risk pregnancy antepartum fetal surveillance. We excluded gestational age less than 28 weeks, multiple pregnancies, and chromosomal or congenital anomalies. Thirty cases were categorized as having REDFV The pregnancy outcome was investigated in these cases.

RESULTS

There were three stillbirths and 12 neonatal deaths, resulting in a perinatal mortality rate of 50%. Twenty-eight patients (93.3%) had complications with preeclampsia (20 of severe degree and eight moderate). Cesarean section was performed on 24 patients (80%) due to acute fetal distress. The mean gestational age at delivery was 31.8+/-3.2 weeks. The mean diagnosis-to-delivery interval was 10+/-8.2 hours. The average birth weight was 970+/-270 gm, 28 (93.3%) were found to be below the 10th percentile of ideal birth weight. An umbilical artery pH less than 7.2 at delivery was found in 12 of 18 examined cases (66.7%). Twelve out of 15 placentae (80%) showed significant infarcts on pathological examination. All newborns (100%) needed admission to the neonatal intensive care unit.

CONCLUSIONS

REDFV on DUAV represents an ominous and severe fetal condition with an adverse pregnancy outcome, especially in conditions associated with preeclampsia and/or intrauterine growth retardation. Intensive and frequent surveillance and aggressive management at the appropriate time would improve perinatal outcome.

Primary retroperitoneal liposarcoma mimicking ovarian cancer: a case report

Primary retroperitoneal liposarcoma is a rare malignancy comprising about only 0.1% of all cancers. It produces nonspecific symptoms and is often extensive when diagnosed. In this report, we present a case of a 68-year-old female patient who had a 29-kg retroperitoneal liposarcoma. Her early symptoms--including vague digestive disturbances, increasing abdominal girth and an abdominal mass, and clinical examinations such as sonography and computed tomography scan led to a preoperative diagnosis of ovarian cancer, until surgical and pathologic confirmation. Gross, radical resection of the tumor was successfully performed, and provided the most effective primary therapeutic approach. Histopathology revealed a mixed-type liposarcoma, with metastasis to the appendix. A poor prognosis was expected. Postoperative periodic follow-up was started to monitor for early detection of recurrence.

Periurethral fat injection in the treatment of recurrent genuine stress incontinence

PURPOSE

We evaluated the efficacy, safety and mechanism of periurethral fat injection in the treatment of recurrent genuine stress incontinence.

MATERIALS AND METHODS

Periurethral fat injections were performed in 26 patients for the treatment of recurrent genuine stress incontinence. A complete urogynecological study, including a 1-hour pad test, urodynamic studies and chain urethrocystography were done in each case and were repeated at least 3 months after operation. Each patient was followed for at least 12 months.

RESULTS

Of 26 patients 13 (50%) were dry after operation and 4 (15.4%) showed improvement and were satisfied with the results of the operation, giving a total success rate of 65.4%. There were 6 cases of immediate postoperative minor complications (23%). Average volume of injected fat was 14.8 +/- 4.8 cc, which did not affect the success rate. Preoperative and postoperative chain urethrocystographic values for bladder neck descent in reference to the pubosacral tip line showed no statistical difference between successfully and unsuccessfully treated groups. Urodynamic studies in all cases showed no differences relating to operation. However, minimal urethral resistance increased from 0.122 +/- 0.061 to 0.205 +/- 0.134 (p = 0.023) in the treatment success group. This change was not demonstrated in the treatment failure group.

CONCLUSIONS

Periurethral fat injection for the treatment of recurrent genuine stress incontinence is a simple technique that works by the increment of urethral resistance. It has an acceptable success rate without financial outlay for the injected material.

Prospective comparison of laparoscopic and traditional colposuspensions in the treatment of genuine stress incontinence

OBJECTIVE

To compare prospectively the results of laparoscopic and traditional colposuspensions in the treatment of genuine stress incontinence and to evaluate the efficacy, technique, and functional and anatomical changes after these two procedures.

MATERIALS AND METHODS

Ninety-two patients with urodynamically proven genuine stress incontinence participated in this study, with 46 patients randomly allocated to laparoscopic colposuspension, and the other 46 patients to the traditional procedures. All patients had repeat studies at least 3 months after operation.

RESULTS

The bladder neck position was significantly elevated after operation either at rest or during straining in both groups (all p < 0.001), but it was higher in the traditional group than the laparoscopy group during straining (p < 0.05). Comparison of urodynamics before and after operation in both groups showed significantly increased minimal urethral resistance and improved pressure transmission ratios at the proximal urethra (Q2). The blood loss was less in the laparoscopy group. The duration of bladder drainage after laparoscopic colposuspension was shorter, and was not affected by subsequent laparotomy. The operative time was almost the same. The success rate of the laparoscopy group was lower than that of the traditional group (80.4% vs. 95.6%, p = 0.044). The complication rates were 10.8% and 17.4% respectively.

CONCLUSION

Laparoscopic colposuspension is an effective method for the treatment of GSI, as documented by anatomical and functional assessments. However, the success rate is still lower than for the traditional procedure.

First report of distal obstructive uropathy and prune-belly syndrome in an infant with amniotic band syndrome

We describe the first report of distal obstructive uropathy and prune-belly syndrome in an infant with amniotic band syndrome. Prenatal ultrasonographic examination in the third trimester revealed intermittent oligohydramnios, bilateral hydronephrosis, and megacystis. Postnatally, the infant was found to have a scalp defect, a skin pedicle, pseudosyndactyly and constriction rings on the hands, marked distention of the abdomen, a fibrous band attached to the proximal urethra causing urethral stricture, a swollen penile shaft, bilateral talipes equinovarus, and syndactyly of the feet. Multiple fibrous amniotic bands could be identified in the placenta. Our case shows that fetal distal obstructive uropathy can be associated with the congenital constriction band syndrome.

Cervical cancer in young women in Taiwan: prognosis is independent of papillomavirus or tumor cell type

The objective of this study was to address the hypotheses that younger patients with cervical cancer have a uniquely worse clinical outcome and/or are more likely to have adverse tumor cell types or specific human papillomaviruses (HPV). Cases of stage Ib-IIa cervical cancer among women 35 years of age or younger (82) and over 35 (54) were analyzed and compared with respect to the following: (1) histologic type (squamous vs nonsquamous), (2) human papillomavirus (HPV) type via polymerase chain reaction, and (3) clinical parameters, including tumor size, nodal metastases, and recurrence/persistence. Patients 35 years of age or younger had a survival similar (71.2% vs 72.4%) to that of older women from the same institution. In the younger group, outcome was not correlated with the presence or absence of HPV or HPV type. Nonsquamous carcinomas, including adenocarcinoma and small cell carcinoma, were strongly associated with HPV18, were more prevalent in the younger group, and had a slightly higher risk of recurrence/persistence; however, these differences were not significant and 71% of the recurrences were squamous cell carcinomas. Thus, in young Taiwanese women with stage Ib-IIa cervical cancer, the majority of deaths cannot be attributed to a specific HPV type or unique tumor morphology.

Risk factors for preterm birth in an upper middle class Chinese population

OBJECTIVE

To examine the risk factors associated with preterm birth in an upper middle class Chinese population.

STUDY DESIGN

From March 1994 to February 1995, a total of 301 cases (gestational age between 20 and 37 weeks) and 656 controls (gestational age at or greater than 37 weeks) were recruited at Mackay Memorial Hospital, Taipei, Taiwan. Using a case-control study design, logistic regression was used to examine the relative significance of various risk factors associated with preterm birth.

RESULTS

Age and educational level were identified as significant risk factors for preterm birth. Multiple pregnancies, fetal congenital anomalies, placenta previa or abruptio placentae, and preeclampsia were found to be strongly associated with preterm birth (crude odds ratios between 6.37 and 25.89); vaginal bleeding during or after the first trimester, prior history of preterm delivery, and two or more previous first trimester abortions were associated with preterm birth to a lesser extent (crude odds ratios between 1.67 and 2.9). The magnitude of the increased risk associated with these variables in preterm birth did not show change to any great extent after age and educational level were adjusted for. Further stratification of these cases into groups with and without premature rupture of the membranes (PROM), showed that a multiple pregnancy was still the leading risk factor of preterm birth in both groups. Carrying an abnormal fetus was the next important risk factor for preterm birth in cases with PROM, but was less important in the group without PROM. However, placenta previa or abruptio placentae and preeclampsia were the next most important factors in the group without PROM.

CONCLUSIONS

Unfavorable current obstetric conditions and a history of more than two prior abortions and preterm delivery were positively associated with preterm birth.

Prenatal diagnosis of partial monosomy 13q associated with occipital encephalocoele in a fetus

The pre- and postnatal findings of a fetus with a de novo del(13)(pter-->q21:) and an occipital encephalocoele are described. Maternal serum alpha-fetoprotein (AFP) screening at 19 weeks' gestation demonstrated a high level of 2.5 multiples of the median (MOM) and ultrasonography at 27 weeks' gestation showed severe intrauterine growth retardation, cardiomegaly, an occipital encephalocoele, and a calvarial defect. Genetic amniocentesis revealed a karyotype of 46,XX,del(13)(pter-->q21:). The proband postnatally displayed additional abnormalities such as microphthalmia, hypertelorism, large low-set ears, and micrognathia. We discuss the association of central nervous system (CNS) malformations with 13q deletions and emphasize that pregnancies with neural tube defects warrant cytogenetic analysis, especially when additional fetal abnormalities and neonatal dysmorphism are observed.

Treatment of cervical pregnancy with methotrexate

OBJECTIVES

To review our experience with early ultrasonographic diagnosis and fertility-preserving complete medical treatment of cervical pregnancy.

METHODS

From January 1989 to December 1994, 11 cases of cervical pregnancy diagnosed by ultrasonography and treated with methotrexate were evaluated. Patients were treated as follows: systemic administration of methotrexate with leucovorin rescue, a single dose of 50 mg of methotrexate intramuscular injection, or transvaginal ultrasonographically-guided intra-amniotic instillation of 50 mg of methotrexate.

RESULTS

The mean age of these patients was 33.3 +/- 6.2 years and gestational age at diagnosis ranged from 32 to 73 days. The maximal serum beta-hCG measured was 135,000 mIU/ml, and the time required for return to normal levels ranged from 20 to 157 days. The ectopic gestation was successfully ablated in all cases, and none required hysterectomy.

CONCLUSION

If a cervical pregnancy is present and diagnosed early, methotrexate treatment, administered either systemically or locally, is effective as the definitive therapy.

Factors influencing the prolonged second stage and the effects on perinatal and maternal outcomes

OBJECTIVE

To examine the factors influencing the prolonged second stage and the maternal-perinatal outcomes after a prolonged second stage of labor.

METHODS

Between January 1993 and June 1993, 165 women who delivered with a prolonged second stage of labor were enrolled in this study. The control group was 1750 term pregnancies that delivered under 2 hours in the second stage. Maternal and neonatal outcomes included one and 5 minute Apgar scores, umbilical blood gas determination, thick meconium stain, fetal trauma, and length of hospital stay.

RESULTS

Factors such as nulliparity (p < 0.005), maternal weight gained during pregnancy (p < 0.01), active phase length (p < 0.05), persistent occiput posterior position (p < 0.05), station at complete cervical dilation (p < 0.05) and a need of instrumental vaginal delivery (p < 0.05) were significantly associated with a prolonged second stage of labor. Maternal and neonatal outcomes were not different significantly between the study and control group.

CONCLUSION

The maternal and perinatal well-beings from the normal second stage group did not appear to be more favorable than the prolonged second stage. Under monitored condition, if the fetal heart rate is considered normal, then the natural labor course could be continued.

Pelvic abscess caused by Salmonella: a case report

We report a case of a 28-year-old woman, with no history of sexual activity, who developed a cul-de-sac abscess and bilateral salpingitis caused by Salmonella group C1. This paper documents our limited experience with such an unusual event and suggests that gastrointestinal pathogens should be considered as potential etiologic organisms in patients presenting with pelvic infection and gastroenteritis.

Prenatal detection of the separation of the great toe, toe syndactyly, and large bilateral choroid plexus cysts in a fetus with trisomy 18

Prenatal sonographic presentation of toe deformities is associated with fetal aneuploidies. This report presents a second-trimester fetus with large bilateral choroid plexus cysts, clenched hands, separation of the great toe, toe syndactyly, abnormal double maternal serum biochemical screening results, and trisomy 18. We suggest a careful ultrasound screening of the fetal limbs and other organs once a choroid plexus cyst has been identified. If abnormal sonographic findings are present, or if the results of the maternal serum biochemical screening are abnormal, karyotyping should be recommended.

Sonographic and clinical findings of granulosa cell tumor

BACKGROUND

Granulosa cell tumor (GCT) accounts for roughly 1.5% of all ovarian neoplasms and 5-10% of ovarian cancers. GCT, which may have profound end-organ effects, has attracted a significant amount of attention despite its rarity. This tumor is rare, and difficult to diagnose before operation. Until now, no specific sonographic findings have been reported.

METHODS

Twelve cases of pathologically proven GCTs were diagnosed from June 1985 to March 1993. Nine of those cases had preoperative sonographic pictures taken.

RESULTS

Eight out of the nine cases tested exhibited a complex multicystic sonographic pattern. For a case evaluated by a transvaginal color and pulsed Doppler assessment, the blood vessels located in the central part with diffuse dispersed vascular arrangement were found to have a resistance index of 0.38 and a pulsatility index of 0.50. The most common complaints of our patients were postmenopausal bleeding and lower abdominal pain.

CONCLUSIONS

We conclude that complex multicystic sonographic features observed by high-resolution ultrasonography, in conjuction with a high preoperative estradiol level and clinical symptoms, may help to establish a preoperative diagnosis of GCT.

Implications of prolonged fetal heart rate deceleration during the second stage of labor

In order to evaluate the neonatal outcomes of infants who had prolonged fetal heart rate (FHR) deceleration during the second stage of labor, the neonatal outcomes of 24 infants born after vaginal delivery at 37 to 42 weeks of gestation with prolonged FHR deceleration during the second stage of labor were compared with the outcomes of 28 infants of a similar gestational age who had normal FHR patterns. No differences in the Apgar scores, mean umbilical PaCO2, PaO2, HCO3- or base deficit values were observed between the two groups, but the mean pH values differed significantly. The occurrences of a 1-minute Apgar score < 7, umbilical arterial pH < 7.20, presence of meconium and admission to the neonatal intensive care unit were higher in the study group, but were not significantly different. None of the 24 infants with prolonged FHR deceleration experienced birth trauma, meconium aspiration, neonatal seizure or neonatal death, but three were found to have congenital heart disease. We conclude that prolonged FHR deceleration during the second stage of labor without FHR abnormalities during the first stage of labor is not always associated with an adverse neonatal outcome and does not mandate the need for surgical or immediate vaginal delivery. Their appearance on FHR tracings requires the implementation of additional methods to assess fetal well-being and also to diagnose fetal distress.

Central and peripheral hemodynamics in severe preeclampsia

BACKGROUND

Doppler velocimetry, a new tool for measuring blood flow, vascular resistance, and central hemodynamics can be applied to monitor those patients at risk and provide therapeutic concepts for preeclampsia. This study was designed to use a Doppler velocimetry study to correlate the relationship between central hemodynamics, uteroplacental circulation, and the perinatal outcome in severe preeclampsia.

METHODS

Thirty-one patients with severe preeclampsia, not superimposed with any medical disorder and not on antihypertensive treatment prior to admission, were enrolled in this study. On admission, laboratory determination of the maternal blood chemistry and hematogram, together with a Doppler ultrasound study of the maternal hemodynamics, and umbilical and uterine arteries, were performed. Antihypertensive agents including hydralazine, atenolol, and labetolol were given according to the state of the maternal central hemodynamics. Data were collected on the general status of the patients, the results of the Doppler ultrasound study, and the perinatal outcome.

RESULTS

Patients were divided into three groups based on the systemic vascular resistance. The left ventricular function and cardiac index declined with increase in vascular resistance. The high-resistance group had a significantly high incidence of infants small for gestational age. Poor fetal growth in the high-resistance group could be attributed to the summation of underperfusion due to decreased uteroplacental blood flow and was frequently associated with maternal hemoconcentration.

CONCLUSIONS

Although global vasospasm has been considered to be the basic pathophysiology of preeclampsia, the central hemodynamics varies between, and even in the same, patients. Regional vasospasm in the uteroplacental circulation occurs earlier than in the systemic circulation as a whole. A high cardiac-output in low systemic-vascular-resistance might compensate in those pregnancies with high uterine artery resistance to maintain adequate uteroplacental perfusion.

Effects of severe preeclampsia with different doppler velocimetries on extra- and intrauterine environments

We evaluated the perinatal outcome of fetuses and maternal condition of 47 patients with severe preeclampsia. Antepartum fetal surveillance (within 2 days of delivery or fetal death) included the nonstress test, Doppler velocimetry of the umbilical and uterine arteries, amniotic fluid assessment, maternal blood chemistry and hemogram. Pregnancies with abnormal Doppler velocimetry in the umbilical and uterine arteries had poor perinatal outcomes as judged by the incidence of abnormal antepartum fetal surveillance, acute fetal distress mandating immediate delivery, small for gestational age infants, perinatal morbidity and mortality and prematurity. These fetuses were at a high risk of acute and chronic hypoxia. Maternal blood chemistries and hemograms revealed a high incidence of hepatocellular dysfunction, renal insufficiency, hemoconcentration and thrombocytopenia. In cases of severe preeclampsia, those with abnormal Doppler velocimetry of both umbilical and uterine arteries, had poor extra- and intrauterine environments. Therefore, aggressive rather than expectant management was more suitable. For those with normal umbilical artery resistance and either normal or abnormal uterine artery resistance, careful management with close monitoring of both maternal and fetal status was possible in patients who were far from term.

Cryptococcal meningitis in pregnancy

The case of an 18-year-old pregnant woman with cryptococcal meningitis treated with amphotericin B and flucytosine since the third trimester of pregnancy is reported. She delivered a normal baby. The maternal outcome was favorable. There is no evidence of congenital infection in the newborn.

What kind of maternal factor might predict poor perinatal outcome in severe preeclampsia?: a study based on doppler velocimetry

BACKGROUND

Umbilical artery Doppler velocimetry has been used as an important perinatal tool to identify fetal compromise. However, the fact that it is both expensive and time-consuming makes it not always available. This study was a search for any maternal serum laboratory test which might be much simpler and easier than Doppler velocimetry, and still determining the perinatal outcome in severe preeclampsia.

METHODS

Forty-seven patients with severe preeclampsia were enrolled in this study. Doppler velocimetry of umbilical artery, maternal serum biochemistry and hematological tests were all performed within two days prior to delivery or fetal death.

RESULTS

By choosing a maternal hematocrit (Hct) of greater than 44% as the cutoff value, a significantly higher incidence of adverse perinatal events was noted in patients with abnormal value than those with normal value. Abnormal Hct level as a predictor of adverse perinatal outcome had a sensitivity of 50.0%, a specificity of 84.2%, a positive predictive value of 53.3% and a negative predictive value of 63.8%.

CONCLUSIONS

This study found that elevated maternal Hct (> 44%) levels might indicate a condition of hemoconcentration with reduced placental perfusion in severely preeclamptic patients. Hct level can serve as a clinically useful predictor of adverse perinatal outcome.

Prenatal diagnosis of omphalocele associated with umbilical cord cyst

BACKGROUND

To study the cytogenetics, ultrasound findings, biochemical screening, perinatal outcome, and associated abnormalities in cases of omphaloceles associated with umbilical cord cysts.

METHODS

From 1988 to 1994, three cases of omphaloceles with umbilical cord cysts were identified at Mackay Memorial Hospital. We compared the clinical data of our three cases with six other cases in the published literature.

RESULTS

Two cases of omphaloceles with umbilical cord cysts were affected with trisomy 18. One had bilateral choroid plexus cyst, intrauterine growth retardation, low levels of maternal serum alpha-fetoprotein and free beta-human chorionic gonadotropin, and the other had cleft lip and palate, single umbilical artery and intrauterine growth retardation. An elevated level of maternal serum alpha-fetoprotein was found in the case with normal karyotype. Elevated levels of amniotic fluid alpha-fetoprotein were found in two cases. Rupture of the umbilical cord cyst and disruption of the umbilical cord occurred in one case at delivery. Based on the gross and microscopic examinations, the cord cysts we observed are likely to be pseudocysts.

CONCLUSION

The umbilical cord cysts most commonly associated with omphaloceles are pseudocysts and allantoic cysts. Among our three cases and the six other cases published in the literature, four out of these nine cases were trisomy 18. Prenatal diagnosis of omphaloceles or umbilical cord cysts by ultrasound warrants cytogenetic analysis and detailed sonogram to rule out the possible combination of both abnormalities and trisomy 18. If an omphalocele is associated with a large umbilical cord cyst and a normal karyotype, cesarean section is recommended to prevent the dilemma of intrauterine vascular compromise of umbilical blood flow during labor.

Acute pancreatitis in pregnancy

BACKGROUND

Discuss the course of acute pancreatitis in pregnant patients and demonstrate that most attacks of pancreatitis in pregnancy are mild.

METHODS

This article is a retrospective case series study. Eight patients with acute pancreatitis during pregnancy were seen in referral-based obstetric practice at our department in the last 5 years. Five of them had either gallstones or hyperlipidemia. Two patients had both gallstones and hyperlipidemia. One patient was lost to follow-up at 33 weeks gestation. The others were followed at least one month post-partum. Conservative treatment was instituted for pancreatitis and a fat-restricted diet was instituted for hyperlipidemia.

RESULTS

There was no maternal mortality and only one fetal death. Acute pancreatitis occurred in both primipara and multipara patients. Preterm labor or preeclampsia may occur in pregnancy complicated by acute pancreatitis. Most patients experience relief from the pancreatitis soon after delivery. Two patients underwent cesarean section, one was due to fetal distress and the other was elective.

CONCLUSIONS

Early diagnosis and treatment is of utmost importance. Gallstones and/or hyperlipidemia seems to have a specific link with acute pancreatitis in pregnancy. Although acute pancreatitis is a rare complication of pregnancy, we present evidence that both maternal and fetal mortality can be minimized if appropriately treated.

Transvaginal ultrasound-guided aspiration in the treatment and follow-up of tubo-ovarian abscess: a report of two cases

Two cases of tubo-ovarian abscess are presented in this study; treatment and follow-up were undertaken by transvaginal ultrasound. Transvaginal ultrasound-guided aspiration with anti-microbial therapy may be a useful alternative for treatment of unruptured tubo-ovarian abscess.

Relationship between acute fetal distress and maternal-placental-fetal circulations in severe preeclampsia

BACKGROUND

Hypoxic complications are thought to be the result of vascular lesions in the maternal-placental or fetal-placental circulation, with a resultant decrease in blood flow. This study was designed 1) to explore what kind of pathophysiological changes occur in the maternal-placental-fetal circulations associated with acute fetal distress, and 2) to determine whether umbilical velocimetry can be used as a predictor of acute hypoxia in severe preeclampsia.

METHODS

Eighty-nine cases of severe preeclampsia, who had Doppler ultrasonography, maternal blood chemistry and hematogram examinations all performed within two days of delivery or fetal death, were studied.

RESULTS

According to the absence or presence of acute fetal distress as determined by the fetal heart rate pattern, patients were divided into two groups: distress group and non-distress group. There was no significant difference between the two groups in maternal general status. However, patients in the distress group had a significantly shorter gestation age on admission and at delivery (p < 0.00001). In the distress group, the perinatal outcome was poor. Newborns in the distress group had, significantly, a lower birthweight, and a higher incidence of SGA, 1-min Apgar scores of less than 7, and fetal acidosis (pH < 7.2) (p < 0.001). Doppler ultrasonography also showed a significantly higher incidence of abnormal umbilical artery Doppler waveforms in the distress group (p < 0.05). However, there was no difference between the two groups in the uterine artery Doppler velocimetry. Maternal blood chemistry and hematogram examinations revealed significantly higher blood levels of hemoglobin, hematocrit, blood urea nitrogen, and creatinine but lower levels of total protein and albumin in the distress group. An abnormal umbilical artery SD ratio (> 95th centile) as a predictor of acute fetal compromise, judged by the incidence of abnormal fetal heart tracing mandating emergency delivery, 1-minute Apgar scores of less than 7, 5-minute Apgar scores of less than 7, and a pH value for the umbilical arterial blood of less than 7.2, had a sensitivity of 40.5-75%, specificity of 71.8-80%, positive predictive value of 12.5-75%, and negative predictive value of 64.5-98.4%.

CONCLUSION

In severe preeclampsia, early onset of disease superimposed with maternal hemoconcentration might initiate an acute insult and predispose the fetus to acute hypoxia.

Laparoscopic para-aortic lymph node sampling in the staging of invasive cervical carcinoma: including a comparative study of 21 laparotomy cases

OBJECTIVES

To assess the efficacy and risks of laparoscopic para-aortic lymph node sampling compared with standard laparotomy in staging cervical carcinoma.

METHODS

From August 1993 through July 1994, 38 patients with biopsy-proven invasive cervical carcinoma (24 early and 14 advanced invasive cancers) were entered into the study. This was a prospective study of laparoscopic para-aortic lymphadenectomy in invasive cervical carcinoma, with patients serving as their own controls. Video laparoscopic lymph node sampling was performed. In patients with early invasive cancer, the nodes were sent for frozen section and, if negative, laparotomy was performed to look for any residual nodes. Radical hysterectomy was performed immediately if residual nodes were negative. Patients with either nodal metastasis on frozen section or with advanced cancer underwent para-aortic lymphadenectomy only. The operative technique was also evaluated.

RESULTS

Laparoscopy required an average of 77 min (S.D. 40), with an average blood loss of 116 ml (S.D. 321). The average number of nodes was 15 (S.D. 7). At subsequent laparotomy the average number of residual nodes found was 0.4 (S.D. 0.9) and none showed metastasis. One vena cava laceration and one ureteral injury required immediate repair, and two patients were too obese to undergo laparoscopy.

CONCLUSIONS

Laparoscopic para-aortic lymph node sampling is a less invasive, reliable method for staging invasive cervical carcinoma and can substitute for traditional open procedures. The incidence of risks with this method appears to be low.

Preeclampsia in multiple pregnancy

BACKGROUND

Preeclampsia is one of the most common pregnancy-induced complications, and results in a large number of maternal deaths. How pregnancy incites or aggravates hypertension remains unresolved; despite decades of intensive research directed to hypertensive disorders, they remain among the most important unresolved problems in obstetrics. The incidence of preeclampsia is increased in multiple pregnancies, and several preeclampsia-related fetal risks may be particularly hazardous to the babies of multiple gestations.

METHODS

The records of 561 women with multiple pregnancies delivered consecutively at Mackay Memorial Hospital were reviewed retrospectively. Thirteen mild cases and 39 severe cases of preeclampsia in multiple pregnancies were compared with 52 control cases of multiple pregnancies without preeclampsia, but matched for maternal age and parity. The categories for comparison included parity, gestational age, time of onset of preeclampsia, route of delivery, mean birth weight, growth discordancy, maternal complications, neonatal morbidity and mortality.

RESULTS

The incidence of preeclampsia in our consecutive series of 561 multiple pregnancies was 9.3% compared with 1.8% in singleton pregnancies (p < 0.0001). In primiparas with multiple pregnancies, the incidence of preeclampsia was 12.2% compared with 6.2% (p < 0.05) in multiparas. Breech presentation was the most common indication for Cesarean section in all groups. The preeclamptic group had a significantly higher rate of Cesarean section compared with the control group (p < 0.006), with prolonged labor and fetal distress were the two main reasons for this difference. Severe preeclamptic patients had babies with significantly lower mean birth weights (p < 0.05), higher incidence of intrauterine growth retardation (p < 0.025) and neonatal respiratory distress syndrome (p < 0.0008) compared with those of the control group. All seven cases with maternal complications were in the severe preeclamptic group.

CONCLUSIONS

An unfavorable perinatal outcome was found to be associated with severe, but not with mild, preeclampsia in multiple pregnancies.

Perinatal characteristics of low birthweight infants in postdate pregnancies

BACKGROUND

Early literature discussed postdate pregnancy in relation to difficult delivery of mothers with an excessively large fetus; more recent reports imply that the risk of perinatal death exists especially for the small, growth-retarded fetus. However there is little in the literature concerning low birthweight infants in postdate pregnancies.

METHODS

A 6-year retrospective review of 135 low birthweight infants with 40 or more weeks' gestation was conducted. Among the subjects, 19 cases had a gestational age greater than 42 weeks (Group 1), 26 cases, between 41 and 42 weeks (Group 2), and 90 cases, between 40 and 41 weeks (Group 3). Assess was made of the outcomes of low birthweight infants in postdate pregnancies, comparing Group 1 with Group 2 and Group 3.

RESULTS

Group 1 infants had significantly higher rates of chromosomal (21.1%) and congenital (31.6%) abnormalities and perinatal mortality (21.1%) than either Group 2 or Group 3 infants. Also, in Group 1 there were two cases of polyhydramnios and they both had abnormal karyotypes.

CONCLUSIONS

The outcome of low birthweight infants in postdate pregnancies appears to be worse than predicted. This finding could offer for managing the cases which have a high frequency of abnormal karyotype (21.1%), especially when combined with polyhydramnios.

Transvaginal color flow imaging in the follow-up of invasive gestational trophoblastic disease: a case report

A case of invasive gestational trophoblastic disease after partial hydatidiform mole was presented in this study in which the diagnosis was made along with the treatment being monitored by means of transvaginal color Doppler ultrasound. In this case, the appearance or disappearance of vascular changes induced by invasive mole corresponded with serum beta human chorionic gonadotropin (beta-hCG) titer. Vascular changes displayed on color Doppler scanning may thus complement the application of hCG in postmolar pregnancy surveillance.

Doppler velocimetry study of maternal hemodynamics and fetal vascular pattern in a case of chronic hypertension with superimposed severe preeclampsia and impending fetal death

A case is presented of chronic hypertension with superimposed severe preeclampsia; absence of end-diastolic velocity in the umbilical artery had been noted at gestational age of 20 weeks. Because the fetus was previable, the mother was treated with pharmacotherapy according to the maternal hemodynamics; uteroplacental circulation and fetal vascular blood flow were monitored by Doppler velocimetry. Deterioration of the fetal condition occurred during crossover of maternal hemodynamics from a low-resistance to a high-resistance state. Serial Doppler velocimetry studies done within 40 minutes of fetal death are described. There were two types of absent end-diastolic velocity in the umbilical artery, and the pathophysiology and clinical management may be quite a different in these two situations.

Decreased amniotic fluid index in term pregnancy. Clinical significance

In a study of 331 term pregnancies a four-quadrant technique was used to obtain amniotic fluid index measurements, and the results were compared with the current widely used single-pocket measurement. In contrast to the "2-cm rule," the amniotic fluid index measurements consistently demonstrated higher sensitivity in predicting poor fetal outcome with no decrease in specificity. It was noted that pregnancies with an index of < or = 8 cm showed higher incidences of meconium staining, cesarean delivery for fetal distress, abnormal fetal heart rate monitoring and Apgar scores of < or = 7 or less at one minute.

Prenatal diagnosis of meconium peritonitis--a case report with literature review

A case of meconium peritonitis that was diagnosed ultrasonographically in the second trimester is presented. Fetal ascites, intraabdominal calcification and polyhydramnios were detected on antenatal ultrasonography. Specks of calcification were also demonstrated on abdominal radiography postnatally. The obstetric and neonatal implications of meconium peritonitis are discussed with literature review.

Congenital complete atrioventricular block--two cases report

We encountered two cases of congenital complete atrioventricular block out of 23,400 deliveries during the past 3 years. Two-dimensional and M-mode fetal echocardiography revealed complete atrioventricular block without structural abnormality. Anti-Ro (SS-A) antibodies were present in both the mother and infant of these two cases. The ventricular rates of these two infants were 31 and 80 beats/min respectively. Pacemaker implantation was performed for the first infant.