Biomedical subjects
Publications and source records attributed to Jorge Gutierrez.
We report two cases of an umbilical cord cystic mass detected by sonography in otherwise structurally normal second-trimester fetuses, which were later complicated by a cord hematoma and fetal death.
OBJECTIVE: The purpose of this series is to present our experience with cases of dacryocystocele diagnosed prenatally. The role of prenatal 3-dimensional sonography, as an adjunct to 2-dimensional sonography, in the prenatal assessment of these cases is emphasized. METHODS: A retrospective review of cases was conducted. Information was obtained by reviewing the sonographic reports and medical records. Outcomes were obtained from the referring obstetricians or directly from the parents. RESULTS: Ten fetuses had the diagnosis of a congenital dacryocystocele at a median gestational age of 30.1 weeks (range, 27-33 weeks). In 6 cases, the cystic lesion was unilateral, and in 4 it was bilateral, with a mean largest diameter at the time of diagnosis of 7.5 mm (range, 4-11 mm). There were no other associated findings. Three-dimensional sonography, carried out in 3 cases, clearly depicted the anomaly, the degree of intranasal extension, and swelling below the medial canthal area. Spontaneous resolution was documented prenatally in 5 fetuses, and 1 additional case resolved between the last prenatal scan and the delivery. There were no reported long-term complications associated with this finding, although 1 infant required probing at 2 months of age to resolve the dacryocystocele. CONCLUSIONS: Prenatal diagnosis of dacryocystocele is straightforward. A considerable number of lesions are bilateral, and many resolve in utero spontaneously or neonatally after minimal intervention. For those not resolving by the time of the delivery, ophthalmologic or rhinologic consultation is warranted because of potential complications. Three-dimensional sonography may provide a noninvasive method for evaluating these cystic masses and may contribute to the avoidance of additional diagnostic techniques in the neonatal period.
OBJECTIVE: The purpose of this series is to describe the prenatal sonographic findings and pregnancy outcome in 4 cases of congenital megalourethra. METHODS: Three cases of fusiform-type megalourethra and 1 case of scaphoid-type megalourethtra were diagnosed prenatally by sonography between 20 and 24 weeks' gestation. The key findings for diagnosis included sonographic features of lower urinary tract obstruction in association with dilatation and elongation of the penile urethra in all 4 cases. Severe oligohydramnios was detected at the time of diagnosis in only 1 case. Prenatal chromosome analysis was available in 3 cases and revealed a normal 46,XY karyotype. Information on pregnancy outcome was available in all cases. RESULTS: The parents opted for elective termination of pregnancy in 1 case when decreased amniotic fluid volume and echogenic kidneys were documented at the follow-up scan. Among the 3 ongoing pregnancies, there were 2 premature cesarean deliveries at 28 and 31 weeks and 1 vaginal delivery at term. All neonates had severe lung hypoplasia and died in the early neonatal period. CONCLUSIONS: Congenital megalourethra is associated with poor perinatal outcome. Because this condition can be diagnosed prenatally in the context of lower urinary tract obstruction, detailed examination of the external genitalia in these cases should be mandatory.
Increasing shortage of cadaveric grafts demands the utilization of living donor and split liver grafts. The purpose of this study was to 1) define the "small-for-size" graft in a pig liver transplant model 2) evaluate pathological changes associated with small-for-size liver transplantation. Pigs were divided into four groups based on the volume of transplanted liver: (a) control group (n=4), 100% liver volume (LV) (b) group I (n=8), 60% LV (c) group II (n=8), 30% LV (d) group III (n=15), 20% LV. Tacrolimus and methyl prednisone were administered as immunosuppression. Animals were followed for 5 days with daily serum biochemistry, liver biopsies on day 3 and 5 for light microscopy, and tissue levels of thymidine kinase (TK) and ornithine decarboxylase (ODC). Liver grafts were weighed pretransplant and at sacrifice. All the recipients of 100%, 60%, and 30% grafts survived. Transplantation of 20% grafts (group III) resulted in a 47% mortality rate. Group III animals showed significantly prolonged prothrombin times (p<0.05), elevated bilirubin levels (p<0.05), and ascites. The rate of regeneration, as indicated by TK activity and graft weight was inversely proportional to the size of the transplanted graft. The severity of the microvascular injury was inversely proportional to graft size and appeared to be the survival-limiting injury. Frank rupture of the sinusoidal lining, parenchymal hemorrhage, and portal vein injury were prominent in group III animals 1 hour following reperfusion. This study established a reproducible large animal model of partial liver grafting; it defined the small-for-size syndrome in this model and described the associated microvascular injury.
PURPOSE: To perform in vitro and in vivo tests using a clinical lithotripter in order to determine whether a bifocal reflector is more efficient and produces the same or less tissue damage than a conventional ellipsoidal reflector for electrohydraulic lithotripters. MATERIALS AND METHODS: A standard ellipsoidal and a novel bifocal reflector were tested on a Tripter Compact lithotripter (Direx Medical Systems, Petach Tikva, Israel). The bifocal reflector was constructed by joining two sectors of two rotationally symmetrical ellipsoidal reflectors having different distances between their foci. The F1 foci of the sectors coincided, creating a separation between the F2 foci. The fragmentation efficiency of the reflectors was compared using kidney-stone models. Shockwave-induced trauma was evaluated in vivo by treating both kidneys of six healthy dogs. One kidney was exposed to shockwaves generated with the conventional reflector, and the other kidney was treated using the bifocal reflector. Pressure measurements were obtained for both reflectors using needle hydrophones. RESULTS: The new design appeared to be more efficient than the conventional reflector in breaking up kidney-stone models. Tissue damage did not increase when using the bifocal reflector. CONCLUSION: The use of bifocal, instead of standard ellipsoidal, reflectors should be considered as an alternative to improve extracorporeal shockwave lithotripsy.
OBJECTIVE: In patients with malignant glioma previously treated with surgery, radiation, and chemotherapy, clinical and radiographic signs of recurrent disease often require differentiation between radiation necrosis and recurrent tumor. Published work suggests that although magnetic resonance spectroscopy (MRS) can reliably differentiate pure tumor, pure necrosis, and spectroscopically normal tissues, it may not be particularly helpful because most patients have mixed histological findings comprised of necrosis and tumor. To improve our clinical ability to discriminate among these histological entities, we have analyzed MRS in conjunction with apparent diffusion coefficient (ADC) sequences derived from magnetic resonance imaging. METHODS: In 18 patients, spectroscopic and diffusion-weighted images were obtained before surgery for suspected recurrent neoplastic disease. Spectral data for pure tumor, pure necrosis, and mixed tumor and necrosis were derived from 65 spectroscopic observations in patients with previously treated gliomas (n = 16) and metastatic tumors (n = 2). Spectral data for choline (Cho), N-acetylaspartate (NAA), creatine (Cr), and lipid-lactate were analyzed separately and in conjunction with ADCs in all patients (15 observations of pure tumor, 33 observations of pure necrosis, and 13 observations of mixed tumor and necrosis). Histological specimens were obtained stereotactically at the time of surgery (<48 h after image acquisition) for recurrent disease and digitally co-registered with MRS data. RESULTS: ADC values for pure tumor, pure necrosis, and mixed tumor and necrosis were 1.30, 1.60, and 1.42, respectively. Cho/NAA less than 0.20, NAA/normal Cr greater than 1.56, and NAA/Cho greater than 1.32 increase the odds that a tissue biopsy will be pure necrosis versus mixed tumor and necrosis. Although various values of all MRS ratios analyzed may provide positive correlations for histopathological differentiation of tissue between that of pure tumor and that of pure necrosis, the addition of ADC values to only NAA/Cho and NAA/normal Cr increases the odds of correct differentiation between pure tumor and pure necrosis. The addition of ADC values does not provide additional information beyond that of MRS in distinguishing specimens of mixed tumor and necrosis from either pure tumor or pure necrosis. CONCLUSION: It has been demonstrated that MRS ratio analysis may allow for the clinical discrimination between specimens of pure tumor and pure necrosis, and the addition of ADC data into this analysis may enhance this specific differentiation. However, although a trend toward correlation between ADC values and the various histopathological features was noted, the direct addition of ADC data does not seem to allow further discrimination, beyond that provided by MRS, among specimens of mixed tumor and necrosis and either pure tumor or pure necrosis.
INTRODUCTION: It seems that vasoconstriction induced by 12 Kv shock waves reduces kidney lesions caused by subsequent application of 24 Kv shock waves. The lowest shock wave voltage to induce this protective effect is not known yet and may be lower than the common energy setting of commercial lithotripters. Because of this we propose the application of shock waves as a tissue protecting method. MATERIALS AND METHODS: Preliminary pressure measurements were performed on an experimental unmodified HM3 lithotripter (at 12 and 24 Kv), using a 20 ns rise time needle hydrophone connected to a 100 MHz digital oscilloscope. Ten pressure records were obtained at different aging of the spark plug. A new spark plug was used for each voltage. Pressure measurement were also performed on a Tripter compact lithotripter at 6 positions along the focal axis, starting at F2 and moving away from the reflector, using maximum voltage and capacitance (22 Kv, HI-2). The position on the focal axis of the Tripter Compact with the same pressure as measured at 12 Kv on the HM3 at F2 was chosen as the prophylactic treatment spot (PTS). In vivo pressure measurement were done on the Tripter Compact placing the needle hydrophone inside the lower pole of the right kidney of an anesthetized healthy 25 kg female pig. Measurements were done at the same positions mentioned above, without moving the hydrophone, inside the pig. For both in vitro and in vivo measurements, the radiopaque hydrophone was aligned with the focal axis, using the fluoroscopy system of the lithotripter. RESULTS: The mean positive pressure peak at the second focus of the HM3 lithotripter was 64 and 153 mV at 12 Kv, respectively. Coefficients of variations were 0.28 and 0.13. No significant pressure differences were detected below 700 and 2220 discharges with the HM3 and the Tripter compact, respectively. The difference peak amplitudes are all significant (p<0.01 in a one tailed test) with the exception of F2 and F2+1 Ohm. CONCLUSIONS: Prophylactic administrations of out-of-focus shock waves may reduce tissue damage during SWL. Experiments in vivo are underway in order to prove this hypothesis.
Ectodermal dysplasia is the term used to describe a group of rare congenital anomalies characterized by abnormal development of 1 or several ectoderm-derived tissues. At least 154 different types, divided into 11 clinical subgroups, have been recognized. Among them, the hypohidrotic type is the most common form, with an incidence of 1 per 10,000 to 1 per 100,000 live births. This condition, originally known as anhidrotic ectodermal dysplasia because of the notable reduction of sweat gland function, is clinically characterized by hypohidrosis, hypotrichosis, and hypodontia. Most cases are inherited as an X-linked recessive trait, with the gene responsible being mapped to Xq12-q13.1. The autosomal recessive and dominant patterns of inheritance have also been documented. Prenatal diagnosis of this condition has been reported previously in high-risk pregnancies on the basis of histologic analysis of fetal skin obtained by second-trimester fetoscopy-guided skin biopsy. DNA-based linkage analysis has also made the diagnosis possible with the use of chorionic villi in the first trimester. In this report, we describe noninvasive prenatal diagnosis of hypohidrotic ectodermal dysplasia in a pregnancy at risk for this condition. The diagnosis was achieved by identification of the distinct facial features at 30 weeks' gestation on three-dimensional (3D) ultrasonography.
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Raltitrexed (Tomudex), a classical folate antagonist, is a selective inhibitor of thymidylate synthase (TS). It has significant single-agent activity in metastatic colorectal cancer. Severe life-threatening toxicity related to the administration of 5-fluorouracil and leucovorin is described in two patients, both of whom were not deficient in dihydropyrimidine dehydrogenase. Raltitrexed was administered to both patients with clinically acceptable side effects and allowed a TS inhibitor to be administered as part of an adjuvant program.
OBJECTIVE: The differentiation of tumor recurrence from radiation necrosis in patients with malignant gliomas who have been treated previously remains a challenge. Magnetic resonance imaging, single-photon emission computed tomography, and positron emission tomography cannot provide definitive histopathological insight. Multivoxel proton magnetic resonance spectroscopic imaging ((1)H MRSI) may be reliable in guiding the clinical management of untreated patients; however, its value in managing previously treated patients remains unclear. METHODS: Twenty-seven patients who had been treated previously with surgery, radiotherapy, and chemotherapy and reoperated for clinical and/or radiographic signs that caused suspicion for recurrent disease were studied. Tissues were categorized into four groups: spectroscopically normal, pure tumor, mixed tumor and radiation necrosis, and pure radiation necrosis. Spectral data for choline (Cho), lipid-lactate (Lip-Lac), N-acetylaspartate, and creatine (Cr) were analyzed as Cho/normal Cr (nCr), Lip-Lac/Cho, Lip-Lac/nCr, N-acetylaspartate/Cho, N-acetylaspartate/nCr, and Cho/normal Cho (nCho). Stereotactic biopsies were obtained within 48 hours of (1)H MRSI and were directly correlated digitally with (1)H MRSI data. Logistic regression analysis was performed on the basis of data obtained from 99 (1)H MRSI observations to determine whether the (1)H MRSI ratios varied according to tissue category. RESULTS: (1)H MRSI ratios were found to distinguish pure tumor from pure necrosis. The odds of a biopsy's being pure tumor and having either a Cho/nCr value greater than 1.79 or a Lip-Lac/Cho value less than 0.75 are seven times the odds of that biopsy's being pure necrosis (odds ratio, 7.00; P = 0.0136). The odds of a biopsy's being pure necrosis and having either a Cho/nCr value less than 0.89 or a Cho/nCho value less than 0.66 are six times the odds of that biopsy's being pure tumor (odds ratio, 5.71; P = 0.0329). The odds of a biopsy's being pure necrosis and having either a Lip-Lac/Cho value greater than 1.36 or a Lip-Lac/nCr value greater than 2.84 are more than five times the odds of the biopsy's being pure tumor (odds ratio, 5.25; P = 0.0322). In addition, although only marginally significant, Lip-Lac/Cho and Lip-Lac/nCr ratios distinguish pure tumor from pure necrosis. No values suggested that mixed specimens could be distinguished in a statistically significant way from either pure tumor or pure necrosis. CONCLUSION: The data that we gathered suggest that metabolite ratios derived on the basis of (1)H MRSI spectral patterns do allow reliable differential diagnostic statements to be made when the tissues are composed of either pure tumor or pure necrosis, but the spectral patterns are less definitive when tissues composed of varying degrees of mixed tumor and necrosis are examined.
BACKGROUND: Recent studies have suggested that periodontal disease is a risk factor for preterm low birth weight (PLBW). A randomized controlled trial was undertaken to help further evaluate the proposed association between periodontal disease and PLBW. METHODS: Four hundred pregnant women with periodontal disease, aged 18 to 35, were enrolled while receiving prenatal care in Santiago, Chile. Women were randomly assigned to either an experimental group (n = 200), which received periodontal treatment before 28 weeks of gestation or to a control group (n = 200) which received periodontal treatment after delivery. Previous and current pregnancies and known risk factors were obtained from patient medical records and interviews. The primary outcome assessed was the delivery at less than 37 weeks of gestation or an infant weighing less than 2,500 g. RESULTS: Of the 400 women enrolled, 49 were excluded from the analyses for different reasons. The incidence of PLBW in the treatment group was 1.84% (3/163) and in the control group was 10.11% (19/188), (odds ratio [OR] 5.49, 95% confidence interval [CI] 1.65 to 18.22, P= 0.001). Multivariate logistic regression analysis showed that periodontal disease was the strongest factor related to PLBW (OR 4.70, 95% CI 1.29 to 17.13). Other factors significantly associated with such deliveries were: previous PLBW (OR 3.98, 95% CI 1.11 to 14.21), less than 6 prenatal visits (OR 3.70, 95% Cl 1.46 to 9.38), and maternal low weight gain (OR 3.42, 95% CI 1.16 to 10.03). CONCLUSIONS: Periodontal disease appears to be an independent risk factor for PLBW. Periodontal therapy significantly reduces the rates of PLBW in this population of women with periodontal disease.
PURPOSE: To evaluate whether, in principle, the mean CT attenuation values of kidney stones could predict fragmentation by shockwaves. MATERIALS AND METHODS: Four types of artificial kidney stones having different CT attenuation values were tested. Artificial stones were weighed and exposed to 700 shockwaves at 21 kV at the focus of an electrohydraulic lithotripter. Fragments were strained through meshes with 2x2-mm and 3.1x3.1-mm openings. The material left on the meshes after shockwave exposure was dried and weighed on a precision scale. Half of all artificial stones were saturated by immersing them in water several days before fragmentation. Fragmentation coefficients (i.e., percent weight loss) were associated with CT attenuation values using a statistical model. RESULTS: Higher CT numbers resulted in lower fragmentation coefficients. Artificial stone weight was inversely proportional to the percent weight loss. Larger fragments were obtained at lower fragmentation coefficients. Statistical analysis revealed that fragmentation can be predicted knowing the weight and the CT number of a stone before shockwave application. CONCLUSION: Prediction of the number of shockwaves necessary for successful SWL could be possible. Our statistical model proved to fit in vitro fragmentation of artificial stones; however, clinical application requires further research.