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Biomedical subjects

K J Taylor

Publications and source records attributed to K J Taylor.

At least 19 recordsLinked to original sources
PubMed1992

A randomized study of propranolol on postprandial portal hyperemia in cirrhotic patients.

Propranolol, a nonselective beta-adrenergic blocker, has been shown to reduce portal pressure and the risk fo variceal bleeding. The portal pressure-reducing effect of propranolol is mediated by splanchnic arterial constriction, which decreases portal flow. A double-blind randomized control study (crossover on 2 consecutive days) was designed to compare the effects of propranolol vs. placebo on portal flow in cirrhotic patients during fasting and after a standardized meal. Portal flow was measured with an ATL Ultramark 8 echo-Doppler system (Advanced Technological Laboratories, Bothel, WA) in 23 cirrhotic patients. Fasting portal flow and heart rate were obtained at baseline and 2 hours after the administration of propranolol or placebo. A standard test meal was then given, and measurements were repeated 30 minutes later. Thirteen patients (group 1) received placebo on day 1 and propranolol on day 2, whereas 10 patients (group 2) received propranolol on day 1 and placebo on day 2. In group 1 patients, heart rate declined by 20% (P less than 0.0001) and portal flow decreased by 12% (P less than 0.05) after propranolol administration. Similar reductions were found in heart rate (-21%, P less than 0.0001) and portal flow (-17%, P less than 0.001) for group 2 patients. For all 23 patients, 2 hours after propranolol administration, heart rate declined by 21% (P less than 0.0001) and portal blood flow was reduced by 14% (P less than 0.0001). The 10 patients who received propranolol on day 1 (group 2) showed a carryover effect of propranolol on day 2. On day 2, baseline portal flow and heart rate values were significantly lower than baseline values on day 1. This long-lasting effect of a single dose of propranolol may be caused by the longer half-life of propranolol in cirrhotic patients. The postprandial portal blood flow percentage increase after the meal was similar for both placebo and propranolol. Propranolol did not blunt postprandial hyperemia. However, whereas the absolute value of blood flow after the meal increased significantly in comparison with baseline in placebo-treated patients (P less than 0.001), this did not occur with propranolol. Furthermore, in propranolol-treated patients the absolute value of blood flow after the meal was lower than in placebo-treated patients. This may constitute a protective effect of propranolol in portal hypertension.

Female↗
PubMed1992

Echo-Doppler evaluation of acute flow changes in portal hypertensive patients: flow velocity as a reliable parameter.

In order to evaluate the behavior of the portal vein cross-sectional area during changes in portal flow, two groups of subjects were analyzed in two blinded cross-over studies using echo-Doppler flowmetry. The first group (I) consisted of 21 patients with cirrhosis and 16 controls. They received a standardized meal which is known to increase portal flow. The second group (II) consisted of 31 patients with cirrhosis who received a dose of propranolol which is known to decrease portal flow. In Group I, 30 min after the meal, the portal vein blood velocity increased by 35 +/- 6% (p less than 0.01) in cirrhotic patients and by 55 +/- 5% (p less than 0.01), in normal subjects. The portal vein cross-sectional area increased significantly in normal subjects (22 +/- 2%, p less than 0.01) but not in cirrhotic patients (4 +/- 2%, n.s.). In Group II, 2 h after propranolol, there was a significant decrease in portal blood velocity (-14 +/- 2%), whereas the portal vein cross-sectional area did not show any significant changes. These data demonstrate that, in portal hypersensitive patients, the portal area measured by echo-Doppler flowmetry can be assumed to be constant and hence its calculation to estimate changes in portal blood flow can be omitted. Therefore, the use of blood velocity alone is suggested to monitor acute changes in flow in portal hypertension using Doppler flowmetry. The elimination of the portal vein cross-sectional area measurement simplifies the quantitative calculation of portal hemodynamics and increases the reliability of the technique by avoiding a source of error.

Aged↗
PubMed1992

Risk factors for early intraventricular hemorrhage in low birth weight infants.

Because earlier studies suggested that preterm infants with germinal matrix hemorrhage or intraventricular hemorrhage or both (GMH/IVH) present within the first 12 postnatal hours are at greatest risk for the development of high-grade hemorrhage and neurodevelopmental disability, we examined the risk factors for this insult among 229 neonates of 600 to 1250 gm birth weight in a multicenter study. All had echoencephalography (ECHO) within the first 11 hours and serially for the next 20 days; risk factor data were collected prospectively. Forty-three infants had GMH/IVH within the first 5 to 11 hours (mean age at ECHO 7.7 hours): 18 GMH and 21 grade II, 1 grade III, and 3 grade IV IVH. One hundred eighty-six infants did not have GMH/IVH at a mean age of 7.9 hours. Both groups of infants were similar in birth weight, gestational age, maternal risk factors, cord pH values, and surfactant therapy before ECHO. The group with early IVH had more vertex presentations than the group without early IVH (79% vs 55%, p = 0.043), less maternal tocolytic use (42% vs 60%, p = 0.029), and more vaginal deliveries (67% vs 44%, p = 0.005). In the first 21 days, severe IVH developed in 12 infants with early IVH and in 6 infants without early IVH (p < 0.001). There were more neonatal deaths (16% vs 6%, p = 0.035) and more deaths at any time during the primary hospitalization (23% vs 9%, p = 0.010) among the early IVH group than among the group without early IVH. Multivariate analysis indicated that the mode of delivery, fetal presentation, and birth weight were important and independent prognostic indicators of IVH.

Birth Weight↗
PubMed1992

Ectopic pregnancy: evaluation with endovaginal color flow imaging.

Endovaginal sonography and endovaginal color flow imaging were compared in 155 patients with clinical suspicion of ectopic pregnancy. Sixty-five patients (42%) had surgically confirmed ectopic pregnancies. Thirty-six of the pregnancies were diagnosed with endovaginal sonography alone, the criteria being an extrauterine sac or ectopic fetus (sensitivity, 54%). Sixty-two ectopic pregnancies were diagnosed with endovaginal color flow imaging (sensitivity, 95%) when an ectopic fetus or sac was seen or placental flow was identified in an adnexal mass separate from the ovary and uterus. The diagnosis of ectopic pregnancy was excluded with endovaginal sonography (specificity, 98%) and endovaginal color flow imaging (specificity, 98%) by finding an intrauterine gestation, nonvisualization of an adnexal mass, and absence of placental flow. Three false-positive and three false-negative diagnoses were made with endovaginal color flow imaging (positive predictive value, 97%). The addition of color Doppler flow imaging to endovaginal sonography allows increased sensitivity in the detection of ectopic pregnancy.

Adult↗
PubMed1992

Doppler color imaging. Peripheral arteries.

The impact of DCI on the evaluation of peripheral vascular disease is considerable. In essence, it is noninvasive angiography without the limitations of that modality. However, the pressure gradient can only be inferred, and pull-through pressure gradients are still the most accurate estimation of adequacy of flow. Nonetheless, segmental blood pressures and the peak velocities measured by duplex Doppler provide a noninvasive alternative for estimating pressure gradients. DCI imaging has greatly improved the perception of focal abnormalities and allows rapid appreciation of global hemodynamics. As further technical refinements improve resolution and sensitivity, color Doppler may eventually supplant angiography as the primary imaging modality in peripheral arterial diagnosis, reserving arteriography for interventional procedures.

Aneurysm↗
PubMed1992

Doppler color imaging. Obstetric and gynecologic applications.

The addition of pulsed and color Doppler has greatly added to the diagnostic potential for obstetric and gynecologic ultrasound. In addition to improved morphologic detail inherent in the use of EVUS, new information is available on perfusion and the physiologic changes associated with the menstrual cycle and early pregnancy. The absence of luteal flow strongly predicts unsuccessful pregnancy outcome in patients undergoing therapy for infertility. This introduces the possibility of more economic use of expensive treatments. Later in pregnancy, DCI aids in the efficient and accurate performance of Doppler spectral sampling and contributes to the evaluation of structural and functional abnormalities of the fetus, umbilical cord, and placenta. Applications in the evaluation of patients with suspected ectopic pregnancy, incomplete abortion, and pseudosac are welcome additions for clinical problems that currently result in many malpractice suits. Finally, the recognition of neovascular flow, especially in the ovary, raises hope for improved and earlier diagnosis of ovarian cancer.

Color↗
PubMed1992

Arterial vascular ultrasonography.

A new generation of high frequency, high resolution ultrasound scanners has provided unprecedented information about the state of the arterial wall in a variety of superficial vessels and can document the disturbed flow within them. The information now available is of great clinical value to many clinicians, including vascular surgeons and subspecialty internists who care for individuals at risk for accelerated atherosclerosis and other vascular diseases.

Arterial Occlusive Diseases↗
PubMed1991

Ultrasound imaging of pancreatico-duodenal transplants.

A preliminary investigation of the role of ultrasound, including color and duplex Doppler, was performed in recipients of cadaveric pancreatico-duodenal transplants. Twenty such examinations were done on three patients. Three different complications were noted: rejection, pancreatitis, and peripancreatic abscess. The mean normal resistive index (RI) was 0.71 +/- 0.12. The normal allograft anteroposterior (AP) dimension ranged from 1.5 to 2.0 cm. Intraparenchymal and main feeding vessels were demonstrated easily. RI calculations alone were not helpful in diagnosing graft rejection. However, this diagnosis can be made using a new biochemical marker, serum anodal trypsinogen. We conclude that when used in conjunction with a reliable biochemical marker for rejection (serum anodal trypsinogen), ultrasound, including color and duplex Doppler, provides an important adjunct for the rapid, inexpensive, and complete evaluation of patients with pancreatico-duodenal transplants.

Cadaver↗
PubMed1990

Renal masses: characterization with Doppler US.

The vascularity of indeterminate renal masses in 70 patients was investigated prospectively with duplex ultrasound. The peak-systolic Doppler shift frequency obtained from the renal mass was utilized to attempt distinction between benign and malignant lesions. With use of the criterion of a peak-systolic Doppler shift frequency of 2.5 kHz or greater as evidence of neovascularity, 26 of 37 malignant lesions demonstrated tumor signals (70% sensitivity). Thirty-one of 33 benign lesions lacked tumor signals (94% specificity). Both of the false-positive lesions were infections with inflammatory masses, with peak frequencies of 3.0 and 3.7 kHz. Tumor vascularity in most malignant renal mass lesions gives rise to abnormal, high-frequency, Doppler-shifted signals that can aid the differential diagnosis of renal masses.

Carcinoma, Renal Cell↗
PubMed1979

Diagnostic imaging procedures in acute pancreatitis. Comparison of ultrasound, intravenous cholangiography, and oral cholecystography.

To evaluate the role of intravenous cholangiography (IVC), ultrasound andoral cholecystography in the diagnosis of gallstone pancreatitis, 20 patients with acute pancreatitis were studied during the first three days of an attack. The IVC successfully demonstrated the common bile duct and gallbladder in 17 (85%) 20 patients. The ultrasound studies showed the gallbladder in all 18 patients in whom the gallbladder was present. The common duct was not seen by ultrasound in any patient and the pancreas was abnormal in all patients. In the three patients with gallbladder stones these were identified on both IVC and ultrasound. Common duct stones in three patients were seen only by IVC (two of these patients had concurrent gallbladder stones and one after cholecystectomy). Oral cholecystography was of limited usefulness, although the 50% visualization rate was higher than the literature suggests.

Acute Disease↗
PubMed1979

Gray scale ultrasound in identification of lymphoma complicating lymphomatoid granulomatosis.

Lymphomatoid granulomatosis is a necrotizing vasculitis involving multiple organs which may be associated with lymphomatous transformation. A case of lymphomatoid granulomatosis is presented in which gray scale ultrasound identified lymphomatous transformation involving the right kidney and retroperitoneum, thus preventing unnecessary surgery. Ultrasound is a valuable modality for identifying and characterizing abdominal masses in patients at risk for neoplastic disease.

Adult↗
PubMed1979

Ultrasound evaluation of bladder calculi.

A case is presented in which the identification of intravesical calculi by ultrasound was an aid in management. Bladder stones appear as high intensity echoes within the bladder, have an associated acoustic shadow and shift to the dependent portion of the bladder with alterations in position. Ultrasound provides a rapid, safe imaging technique to diagnose or verify the presence of bladder calculi.

Child, Preschool↗