Motion compensation for adaptive horizontal line array processing

Large aperture horizontal line arrays have small resolution cells and can be used to separate a target signal from an interference signal by array beamforming. High-resolution adaptive array processing can be used to place a null at the interference signal so that the array gain can be much higher than that of conventional beamforming. But these nice features are significantly degraded by the source motion, which reduces the time period under which the environment can be considered stationary from the array processing point of view. For adaptive array processing, a large number of data samples are generally required to minimize the variance of the cross-spectral density, or the covariance matrix, between the array elements. For a moving source and interference, the penalty of integrating over a large number of samples is the spread of signal and interference energy to more than one or two eigenvalues. The signal and interference are no longer clearly identified by the eigenvectors and, consequently, the ability to suppress the interference suffers. We show in this paper that the effect of source motion can be compensated for the (signal) beam covariance matrix, thus allowing integration over a large number of data samples without loss in the signal beam power. We employ an equivalent of a rotating coordinate frame to track the signal bearing change and use the waveguide invariant theory to compensate the signal range change by frequency shifting.

Space radiation absorbed dose distribution in a human phantom

The radiation risk to astronauts has always been based on measurements using passive thermoluminescent dosimeters (TLDs). The skin dose is converted to dose equivalent using an average radiation quality factor based on model calculations. The radiological risk estimates, however, are based on organ and tissue doses. This paper describes results from the first space flight (STS-91, 51.65 degrees inclination and approximately 380 km altitude) of a fully instrumented Alderson Rando phantom torso (with head) to relate the skin dose to organ doses. Spatial distributions of absorbed dose in 34 1-inch-thick sections measured using TLDs are described. There is about a 30% change in dose as one moves from the front to the back of the phantom body. Small active dosimeters were developed specifically to provide time-resolved measurements of absorbed dose rates and quality factors at five organ locations (brain, thyroid, heart/lung, stomach and colon) inside the phantom. Using these dosimeters, it was possible to separate the trapped-proton and the galactic cosmic radiation components of the doses. A tissue-equivalent proportional counter (TEPC) and a charged-particle directional spectrometer (CPDS) were flown next to the phantom torso to provide data on the incident internal radiation environment. Accurate models of the shielding distributions at the site of the TEPC, the CPDS and a scalable Computerized Anatomical Male (CAM) model of the phantom torso were developed. These measurements provided a comprehensive data set to map the dose distribution inside a human phantom, and to assess the accuracy and validity of radiation transport models throughout the human body. The results show that for the conditions in the International Space Station (ISS) orbit during periods near the solar minimum, the ratio of the blood-forming organ dose rate to the skin absorbed dose rate is about 80%, and the ratio of the dose equivalents is almost one. The results show that the GCR model dose-rate predictions are 20% lower than the observations. Assuming that the trapped-belt models lead to a correct orbit-averaged energy spectrum, the measurements of dose rates inside the phantom cannot be fully understood. Passive measurements using 6Li- and 7Li-based detectors on the astronauts and inside the brain and thyroid of the phantom show the presence of a significant contribution due to thermal neutrons, an area requiring additional study.

On-line microdialysis-high-performance liquid chromatographic determination of aniline and 2-chloroaniline in polymer industrial wastewater

Determination of aniline and 2-chloroaniline in polymer industrial wastewater was examined using high-performance liquid chromatography with on-line microdialysis. After dilution, aniline and 2-chloroaniline in the sample were diffused through a cellular dialysis membrane into the perfusion stream under controlled conditions. Conditions for obtaining optimum dialysis efficiency such as flow-rate and polarity modifier in the perfusion stream, pH and added salt in the sample solution, as well as chromatographic conditions were investigated. The results indicate that the dialysis achieved at a sample matrix pH value of 9.5 with 0.1 M NaCl addition, and the perfusate at 10-microl/min flow-rate offered optimum dialysis efficiency. The aniline and 2-chloroaniline were well separated in an acceptable time on a reversed-phase C18 column eluted with 40% aqueous methanol solution at pH 7.0 and 1.0 ml/min flow-rate. The proposed method provided a very simple procedure to determine aniline and 2-chloroaniline in wastewater. Application was illustrated by the analysis of aniline and 2-chloroaniline in wastewater released from a polymer factory.

Radiogenic transformation of human mammary epithelial cells in vitro

Cancer induction by space radiations is a major concern for manned space exploration. Accurate assessment of radiation risk at low doses requires basic understanding of mechanism(s) of radiation carcinogenesis. For determining the oncogenic effects of ionizing radiation in human epithelial cells, we transformed a mammary epithelial cell line (185B5), which was immortalized by benzo(a)pyrene, with energetic heavy ions and obtained several transformed clones. These transformed cells showed growth properties on Matrigel similar to human mammary tumor cells. To better understand the mechanisms of radiogenic transformation of human cells, we systematically examined the alterations in chromosomes and cancer genes. Among 16 autosomes examined for translocations, by using fluorescence in situ hybridization (FISH) technique, chromosomes 3, 12, 13, 15, 16, and 18 appeared to be normal in transformed cells. Chromosomes 1, 4, 6, 8, and 17 in transformed cells, however, showed patterns different from those in nontransformed cells. Southern blot analyses indicated no detectable alterations in myc, ras, Rb, or p53 genes. Further studies of chromosome 17 by using in situ hybridization with unique sequence p53 gene probe and a centromere probe showed no loss of p53 gene in transformed cells. Experimental results from cell fusion studies indicated that the transforming gene(s) is recessive. The role of genomic instability and tumor suppressor gene(s) in radiogenic transformation of human breast cells remains to be identified.

Phonological studies of the new gas-induced agitated reactor using computational fluid dynamics

An ozone-induced agitated reactor has been found to be very effective in degrading industrial wastewater. However, the cost of the ozone generation as well as its short residence time in reactors has restricted its application in a commercial scale. An innovated gas-induced draft tube installed inside a conventional agitated reactor was proved to effectively retain the ozone in a reactor. The setup was demonstrated to significantly promote the ozone utilization rate up to 96% from the conventional rate of 60% above the onset speed. This work investigates the mixing mechanism of an innovated gas-induced reactor for the future scale-up design by using the technique of computational fluid dynamics. A three-dimensional flow model was proposed to compute the liquid-gas free surface as well as the flow patterns inside the reactor. The turbulent effects generated by two 45 degrees pitch-blade turbines were considered and the two phases mixing phenomena were also manipulated by the Eulerian-Eulerian techniques. The consistency of the free surface profiles and the fluid flow patterns proved a good agreement between computational results and the experimental observation.

Microdialysis of salicylic acid from viscous emulsion samples prior to high-performance liquid chromatographic determination

A micro-dialysis method was developed to isolate aqueous salicylic acid from viscous emulsion samples prior to HPLC determination. The optimal conditions for obtaining dialysis efficiency of salicylic acid as well as chromatographic conditions were investigated. Experimental results indicated that the dialysis achieved at pH 2.0 (0.025 M phosphate solution), 0.5 M NaCl addition, and 50-microl/min flow-rate of perfusion stream offered an optimal result. The proposed method provided a simple procedure for isolating salicylic acid from viscous emulsion samples. Application was illustrated by the analysis of salicylic acid in cosmetic products.

Accuracy of sonography in predicting the outcome of fetal congenital diaphragmatic hernia

BACKGROUND

The outcome of congenital diaphragmatic hernia (CDH) remains poor despite recent advances in neonatal care. This study was designed to evaluate the role of sonography in predicting the outcome of CDH.

METHODS

Pregnancies with CDH were studied. Fetal survival, morbidity, combined anomalies and mortality were recorded. Seven parameters were recorded, including the presence of hydramnios, side of herniation, cardiac deviation, stomach presence, gestational age at the time of finding the CDH and time of postpartum herniorrhaphy. The predictive values of these parameters for fetal outcome were analyzed.

RESULTS

A total of 31 pregnancies were studied. There were 11 cases (35.5%) of termination, seven cases (22.6%) of perinatal death, four cases (12.9%) of late death and nine cases of survival (29%). The survivor group included four cases (44.4%) of complete recovery and five cases (55.6%) with persistent morbidity. There were 15 cases of simple CDH including eight cases of cardiac anomalies (ventricular-septal defect, atrial-septal defect, patent ductus arteriosus and ventricular dilatation). There were eight cases with severe anomalies (3 with trisomy 18, 2 with Cantrell's pentalogy, 1 with trisomy 13, 1 with cystic hygroma and one with Tetralogy Fallot). Among the seven parameters studied, gestational age at the time of finding the CDH and hydramnios were related to fetal survival.

CONCLUSIONS

Sonography assists in predicting the postnatal outcome of CDH. Diagnosis of CDH at less than 25 weeks' gestation and the existence of hydramnios are associated with higher mortality. Postnatal therapy and prenatal surgical intervention are necessary to salvage fetuses in the presence of these two situations. The survival rate of infants with CDH was 45%. Of these, 55.6% had persistent morbidity. Prenatal counseling should reflect this.

Gender prevalence in twin-twin transfusion syndrome

BACKGROUND

This study aimed to determine the gender prevalence of fetuses complicated with twin-twin transfusion syndrome (TTTS).

METHODS

All cases of TTTS corresponded with the following major criteria: a single placenta, monochorion, the same gender, and a combination of polyhydramnios-oligohydramnios. At least one of three minor criteria were required for the establishment of TTTS, including a stuck twin, a birth weight discordance exceeding 20%, and hemoglobin difference > 5 g/dl.

RESULTS

Fifty-six twin pregnancies met the above criteria, of which 33 (58.9%) twin pairs were female. The female tendency existed, but there was a non-significant difference. Mean gestational age at diagnosis was 20.2 +/- 3.2 weeks. The birth weight discordance exceeding 20% was present in 50 of 56 (89.3%), and mean growth discordance was 32% +/- 8%. A stuck twin was noted in 37 of 56 cases (66.1%). The mortality of fetuses or neonates was 34.8% (39/112), including 8 (7.1%) fetal deaths and 31 (27.6%) neonatal deaths. There were no differences in maternal age, parity, or gestational age of delivery between male and female pregnancies.

CONCLUSION

Although the female preponderance did not reach statistical significance, the female tendency might still exist after a larger series analysis. The female tendency may be the result of the gender difference in monochorionic twins. The gender difference could provide research implications and a diagnostic warning for clinicians in monochorionic twin pregnancies before the presence of TTTS.

[Clinical research on arteriovenous internal fistula made by various blood vessels]

OBJECTIVE

To compare the permeability and incidence rate of complication of arteriovenous internal fistula made by autogenous, homologous, and artificial Teflon blood vessels.

METHODS

Two hundred and forty one cases with arteriovenous internal fistula made by autogenous, homologous, and artificial Teflon blood vessels were followed up to compare the permeability and incidence rate of complication at 6 months, 1 year, 3 years, and 5 years.

RESULTS

The incidence rate of complication of autogenous blood vessels was lowest, it had no statistical differences compared with arteriovenous internal fistula made by homologous blood vessels. The permeability of arteriovenous internal fistula made by homologous blood vessels was highest, and it had no statistical differences compared with autogenous blood vessels. The permeability of arteriovenous internal fistula made by artificial Teflon blood vessels was lowest, but the incidence rate of complication was highest, and it had significantly statistical differences compared with arteriovenous internal fistula made by autogenous blood vessels (P < 0.01).

CONCLUSION

Arteriovenous internal fistulas made by autogenous and homologous blood vessels have high permeability and low incidence rate of complication, they are superior to the arteriovenous internal fistula made by artificial Teflon blood vessels.

Oncogenic transformation of mammalian cells by ultrasoft X-rays and alpha particles

For a better understanding of oncogenic cell transformation by ionizing radiation, we conducted experiments with ultrasoft X rays and low energy alpha particles. Confluent C3H10T1/2 cells were irradiated by Al-K (1.5 keV) X rays or alpha particles from plutonium through a thin mylar sheet, on which the cells attached and grew. Our results indicated that Al-K X rays were more effective in causing cell inactivation and oncogenic transformation than 60Co gamma rays but less effective than 1.0 and 3.7 MeV alpha particles. There was no significant difference between 1.0 and 3.7 MeV alpha particles in transforming cells although the latter were slightly more effective than the former in producing lethal effect. These results indicated that track structure is important in causing biological effects by ionizing radiation.

Precipitate delivery and postpartum hemorrhage after term induction with 200 micrograms misoprostol

Misoprostol has been widely applied in early pregnancy termination and term pregnancy induction. However, the upper dosage limit of misoprostol through vaginal route has not been firmly established. Most popular dosages of vaginal misoprostol recommended are 25, 50 or 100 micrograms. There are no reports on the dangers of high-dosage misoprostol 200 micrograms as used in term labor induction. We present a primiparaous woman who was administered 200 micrograms misoprostol vaginally for term labor induction. The following precipitate delivery resulted in multiple lacerations of the isthmus, cervix and vagina, postpartum hemorrhage and disseminated intravascular coagulopathy. Inevitably, a hysterectomy was performed. A postsurgical check of the uterus confirmed lacerations of the isthmus and internal cervix. This rare complication suggests the possible dangers of vaginal misoprostol doses as high as 200 micrograms for term induction of labor at term.

Twin vs. singleton pregnancy. Clinical characteristics and latency periods in preterm premature rupture of membranes

OBJECTIVE

To compare the clinical characteristics and latency periods (latencies) of preterm premature rupture of the membranes (PPROM) in twin vs. singleton pregnancy.

STUDY DESIGN

Between January 1986 and December 1996, data on all women with singleton and twin gestations complicated by PPROM were reviewed. Perinatal morbidity, mortality and latencies between singleton and twin pregnancies were compared. A further division according to PPROM at < 30 and > or = 30 weeks' gestation was made in both groups. Their latencies were compared.

RESULTS

A total of 131 singleton and 48 twin pregnancies with PPROM between 20 and 36 weeks' gestation were included in this series. Regardless of the gestational age at PPROM, the mean latencies of singleton and twin pregnancies were statistically similar (4.4 +/- 3.3 vs. 3.4 +/- 2.9 days, nonsignificant). When PPROM occurred at > or = 30 weeks, the latency of twin pregnancies was shorter than that of singleton pregnancies (2.5 +/- 1.9 vs. 3.7 +/- 2.6 days, P < .05). In both groups, the latencies of PPROM at < 30 weeks were longer than that at > or = 30 weeks (singleton, 5.6 +/- 4.0 vs. 3.7 +/- 2.6 days, P < .005; twin, 4.8 +/- 3.5 vs. 2.5 +/- 1.9 days, P < .05). We also observed a higher percentage of deliveries within the initial 48 hours in twin pregnancies: 50% of women delivered within 48 hours after PPROM and 91.7% within 7 days. In contrast, 26.7% and 85.5% of singleton pregnancies with PPROM were delivered within 48 hours and 7 days, respectively. Perinatal and neonatal outcomes in both groups were similar.

CONCLUSION

This investigation provides the basis for patient counseling and management in twin pregnancies with PPROM. In general, singleton and twin pregnancies with PPROM had similar latencies. Latency in PPROM at < 30 was longer than that of PPROM at > or = 30 weeks' gestation in both singleton and twin pregnancies. When PPROM occurred at < 30 weeks' gestation, both groups appeared to have similar latencies. In pregnancies with PPROM at > or = 30 weeks' gestation, latency in twins was shorter than in singleton pregnancies. In twin pregnancies with PPROM after 30 weeks' gestation, prompt steroid administration for fetal lung maturity should be considered.

The prenatal diagnosis of Pierre-Robin sequence

The purpose of this study was to evaluate the spectrum of prenatal sonographic and chromosomal findings, associated anomalies and perinatal and neonatal outcomes in cases with Pierre-Robin sequence. All cases (20) with Pierre Robin sequence, who were born at China Medical College Hospital between 1990 and 1997, were included and analysed in this series. 12 pregnancies (60 per cent) were complicated by polyhydramnios and 9 (45 per cent) were combined with cleft palate. Four cases (20 per cent) with cardiac anomalies were also observed. Two fetuses (10 per cent) had abnormal karyotyping (one trisomy 21, one trisomy 18). All fetuses were delivered at or near term. Male deviation was observed in cases with isolated Pierre-Robin sequence or combined mild anomalies (male female ratio: 13:3). Two neonatal mortalities and three with mental retardation were observed. This investigation provides a basis for counselling patients with fetal micrognathia or neonatal Pierre-Robin sequence. The main prenatal sonographic findings of Pierre-Robin sequence are micrognathia, polyhydramnios and cleft palate. In cases of polyhydramnios, sonographic examination of the facial profile and palate are recommended. After the finding of polyhydramnios, micrognathia, and even cleft palate, clinicians should be aware of the possibility of neonatal Pierre-Robin sequence. Cardiac evaluation and karyotyping is also recommended.

Proton radiobiology and uncertainties

This paper briefly reviews proton radiobiology. Clinical applications of protons produced by accelerators have led to a significant biological literature that contributes to our goal of estimating the proton shielding requirements for human interplanetary missions. Protons are primarily a low-LET radiation with biological effects much like gamma radiation. There are however data indicating enhanced biological effectiveness for small doses of very low energy (<10 MeV) stopping protons, and some limited data for extremely high energy protons (>0.5 GeV).

Estimate of the frequency of true incomplete exchanges in human lymphocytes exposed to 1 GeV/u Fe ions in vitro

PURPOSE

To study the frequency of true incomplete exchanges induced by high-LET radiation.

MATERIALS AND METHODS

Human lymphocytes were exposed to 1 GeV/u Fe ions (LET = 140 keV/microm). Chromosome aberrations were analysed by a fluorescence in situ hybridization using a combination of whole-chromosome-specific probes and human telomere probes. Chromosomes 1, 3 and 4 were investigated.

RESULTS

The percentage of incomplete exchanges was between 23 and 29% if telomere signals were not considered. The percentage decreased to approximately 10% after ruling out false incomplete exchanges containing telomere signals. The final estimation of true incomplete exchanges was <10%.

CONCLUSION

Within a degree of uncertainty, the percentage of true incomplete exchanges in 1 GeV/u Fe ion-irradiated human lymphocytes was similar to that induced by gamma rays.

Primary hyperparathyroidism in pregnancy--report of 3 cases

Three cases of primary hyperparathyroidism in pregnancy are described. Patient 1 developed left thigh pain and lower abdominal pain at 34 weeks' gestation. Patient 2 had right flank pain and lower abdominal pain at 32 weeks' gestation. Both patients accepted medical therapy initially, which resulted in poor control of hypercalcemia. Patient 1 delayed her parathyroidectomy until the postpartum period; she had maternal hypercalcemia and neonatal hypocalcemia. Patient 2 accepted parathyroidectomy at 32 weeks' gestation with an uneventful outcome for both mother and baby. Patient 3 was asymptomatic; her hyperparathyroidism was diagnosed postpartum after neonatal hypocalcemia and agreed to parathyroidectomy. All 3 patients had a parathyroid adenoma.

Succinylcholine-induced cardiac arrest in unsuspected becker muscular dystrophy--a case report

A five year-old boy undergoing elective tonsillectomy sustained cardiac arrest following the administration of a single dose of succinylcholine during induction of anesthesia. With a 10-minute cardiopulmonary resuscitation (CPR) during which intravenous calcium gluconate, epinephrine, and sodium bicarbonate were given and DC counter shock applied, we were successful to restore cardiac activity without neurological sequelae. The cause of cardiac arrest we speculated was hyperkalemia, possibly secondary to succinylcholine-induced rhabdomyolysis. It is suggested that succinylcholine should not be used in patients with known or suspected muscular dystrophy.

Unexpected pheochromocytoma--a case report of anesthesia in a uremic patient

Pheochromocytoma is an uncommon neoplasm causing blood pressure changes. It may go undiagnosed in uremic patients in whom hypertension is common. The preferential diagnostic work-up, including urine and serum catecholamine measurements, is unsuitable for uremic patients due to anuria and inherent increases in serum catecholamine levels. Here, we present a case of uremia, scheduled for right adrenalectomy and simple nephrectomy, who had been sustaining hypertension. Malignant hypertension was only discovered during surgical manipulation of the adrenal tumor. Pheochromocytoma was highly suspected. The patient was treated with nitroglycerin, fentanyl, and increased concentration of isoflurane to deepen the anesthesia. However, the results were only fair and after ligation of the tumor veins, hypotension ensued. Pathological examination verified the diagnosis of pheochromocytoma. In reviewal of the whole course of treatment, it was considered that the placement of a pulmonary artery catheter to detect volume shifts and changes in hemodynamic status was indicated. Related papers were reviewed and application of diagnostic tools and their limitations, safety and efficacy of anesthetics and vasodilators, and possible complications relevant to management of pheochromocytoma were also discussed. In conclusion, it is important to remain alert, administer agents cautiously, and set up complete monitoring if needed, and carry out postoperative intensive care to lessen complications in the anesthetic management of this rare and dangerous incidentaloma encountered during anesthesia.

Prenatal diagnosis of Apert syndrome

Apert syndrome (AS) is clinically characterized by typical facial features and symmetrical syndactyly of the digits. AS is inherited as an autosomal dominant trait. Recently, a fibroblast growth factor receptors 2 (FGFR2) mutation, either C934G or C937G, was identified in exon IIIa. Our report documents an affected mother and son in whom one of the two mutations in AS had occurred sporadically in the mother. The diagnosed of AS was based on associated abnormal physical features and on molecular genetic analysis. A C-to-G transversion at position 937 of the cDNA resulting in a proline-to-arginine substitution at codon 259 was found in the mother. In her second pregnancy, prenatal diagnosis by both restriction analysis and direct sequencing was undertaken and this showed that the female fetus had not inherited the mutation.

Rejoining and misrejoining of radiation-induced chromatin breaks. IV. Charged particles

We have recently reported the kinetics of chromosome rejoining and exchange formation in human lymphocytes exposed to gamma rays using the techniques of fluorescence in situ hybridization (FISH) and premature chromosome condensation (PCC). In this paper, we have extended previous measurements to cells exposed to charged particles. Our goal was to determine differences in chromatin break rejoining and misrejoining after exposure to low- and high-linear energy transfer (LET) radiation. Cells were irradiated with hydrogen, neon, carbon or iron ions in the LET range 0.3-140 keV/microm and were incubated at 37 degrees C for various times after exposure. Little difference was observed in the yield of early prematurely condensed chromosome breaks for the different ions. The kinetics of break rejoining was exponential for all ions and had similar time constants, but the residual level of unrejoined breaks after prolonged incubation was higher for high-LET radiation. The kinetics of exchange formation was also similar for the different ions, but the yield of chromosome interchanges measured soon after exposure was higher for high-LET particles, suggesting that a higher fraction of DNA breaks are misrejoined quickly. On the other hand, the rate of formation of complete exchanges was slightly lower for densely ionizing radiation. The ratios between the yields of different types of aberrations observed at 10 h postirradiation in prematurely condensed chromosome preparations were dependent on LET. We found significant differences between the yields of aberrations measured in interphase (after repair) and metaphase for densely ionizing radiation. This difference might be caused by prolonged mitotic delay and/or interphase death. Overall, the results point out significant differences between low- and high-LET radiation for the formation of chromosome aberrations.

Intramural pregnancy with negative maternal serum beta-hCG. A case report

BACKGROUND

Intramural pregnancy is the rarest form of ectopic pregnancy. The diagnosis depends upon the sonographic finding of intramural gestational sac-like growth and persistent high beta-human chorionic gonadotropin (beta-hCG) levels after dilatation and curettage. No authors mentioned negative beta-hCG result in such situation. Rarely has the literature contained preoperative sonograms and photographs of postoperative gestational tissue.

CASE

A 31-year-old woman presented with vaginal spotting for five months. Six months earlier she underwent dilatation and curettage for blighted ovum at 8 weeks' gestation. Since then, incidental vaginal spotting was noted. Sonography demonstrated an intramural cyst with fetal pole-like growth. Serum beta-hCG, diagnostic dilatation and curettage, and hysteroscopic examination were negative. Laparotomy for excision of the cyst confirmed an intramural pregnancy.

CONCLUSION

Because of the long period after fetal wastage, negative serum beta-hCG was noted in this case. Negative serum beta-hCG was unreliable in the exclusion of intramural pregnancy. With the sonographic appearance of intramural gestational sac-like growth, in spite of a negative serum beta-hCG the clinician should be alert to the possibility of intramural pregnancy.

Malignancy following renal transplantation

BACKGROUND

A markedly increased incidence of malignancy in transplant recipients is well recognized. However, the incidence and pattern of post-transplantation malignancies shows some discrepancy among different reports. The renal transplant recipients monitored at Taichung Veterans' General Hospital comprise the largest group in Taiwan. An analysis of the characteristics of post-transplant malignancies emphasizes the differences from malignancies that occur in the Taiwanese general population and those reported in Western countries.

METHODS

The incidence and characteristics of de novo malignancy in 390 renal transplant recipients who underwent renal transplantation between May 1983 and June 1996 were analyzed. A total of 232 men and 158 women (mean age at transplantation: 38.5 +/- 10.7 years) were included. The relative risk for developing malignancies was calculated based on the sex- and age-matched cancer incidence of reference for the Taiwanese population; data from the Cancer Registry Annual Report in Taiwan (1989) was obtained for comparison.

RESULTS

A total of 25 cancers were diagnosed in 24 renal transplant recipients, for an incidence of 6.2%. The relative risk of renal malignancy was 13.8-fold higher among transplant recipients than in the general population. The impact of gender and age on the development of post-transplantation malignancy was not significant. The most common types of cancer were transitional cell carcinoma (TCC) of the urinary tract (8/25), and hepatoma (8/25), followed by two cases of Kaposi's sarcoma. Aside from immunosuppressive agents, the high incidence of hepatoma and TCC may be attributed to the high incidence of hepatitis infection and the possible carcinogenic effect of abnormal milieu induced by uremia per se. Survival was largely dependent on the extent of disease at presentation, and post-transplantation cancer did not show more aggressive behavior if detected early.

CONCLUSIONS

The high cumulative incidence of malignancies makes it imperative to define an effective safe immunosuppressive regimen to achieve a lower risk of malignancies. In the future, the prime approach to treatment of post-transplantation malignancies should begin with early detection and ensuing aggressive treatment to improve the outcome.

Rupture of rudimentary horn pregnancy: a case report

A rare case of rupture of a noncommunicating rudimentary horn pregnancy is presented. The pregnancy continued to 16-weeks' gestation, when the rudimentary horn ruptured. The patient had signs and symptoms of massive hemoperitoneum. An emergency exploratory laparotomy revealed a ruptured rudimentary horn and an intact amnionic sac. Prompt excision of the rudimentary horn was performed. The relative literature and factors associated with a rudimentary horn pregnancy are reviewed and discussed.

Estimate of true incomplete exchanges using fluorescence in situ hybridization with telomere probes

PURPOSE

To study the frequency of true incomplete exchanges in radiation-induced chromosome aberrations.

MATERIALS AND METHODS

Human lymphocytes were exposed to 2 Gy and 5 Gy of gamma-rays. Chromosome aberrations were studied using the fluorescence in situ hybridization (FISH) technique with whole chromosome-specific probes, together with human telomere probes. Chromosomes 2 and 4 were chosen in the present study.

RESULTS

The percentage of incomplete exchanges was 27% when telomere signals were not considered. After excluding false incomplete exchanges identified by the telomere signals, the percentage of incomplete exchanges decreased to 11%. Since telomere signals appear on about 82% of the telomeres, the percentage of true incomplete exchanges should be even lower and was estimated to be 3%. This percentage was similar for chromosomes 2 and 4 and for doses of both 2 Gy and 5 Gy.

CONCLUSIONS

The percentage of true incomplete exchanges is significantly lower in gamma-irradiated human lymphocytes than the frequencies reported in the literature.

Sonographic diagnosis of triplet tubal pregnancy after in vitro fertilization and embryo transfer

Ectopic pregnancy (EP) after in vitro fertilization and embryo transfer (IVF/ET) is not rare, but triplet tubal pregnancy after IVF/ET is very rare. We describe a patient with hydrosalpinx in whom a triplet tubal pregnancy occurred on the same side as the hydrosalpinx. Close hormonal and sonographic monitoring of pregnancies achieved through IVF is recommended to ensure the early diagnosis of EP and to avert complications. A triplet tubal EP was considered highly probable after 3 gestational sacs were observed outside the uterus during sonography performed at 6 weeks' gestation. Therapeutic laparoscopy was then performed because methotrexate treatment failed. Appropriate management strategies are discussed.