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Biomedical subjects

A C Gonzalez

Publications and source records attributed to A C Gonzalez.

At least 19 recordsLinked to original sources
PubMed1987

Spontaneous hypertriglyceridemic obesity and hyperglycemia in an inbred line of rats.

A genetically mild obesity syndrome of pubertal onset in a highly inbred line of rats differentiated as beta (beta) has been described. It was discovered in both sexes fed a stock diet for rodents. Hyperphagia was not noticeable. Total fat content reached 31 percent of total body weight in mature males. Obesity was associated with normal plasma cholesterol values and hypertriglyceridemia. Fasting blood sugar levels at maturity were within the normal range for rats, but significantly higher than in lean alpha (alpha) controls. This syndrome developed into a mild glucose intolerance and glucosuria in older obese rats.

Adipose Tissue↗
PubMed1985

Acute right ventricular failure is caused by inadequate right ventricular hypothermia.

The hypothesis of this study was that inadequate right ventricular hypothermia contributes to the right ventricular dysfunction occasionally observed after cardiac operations. Dogs were placed on cardiopulmonary bypass, and 60 minute periods of hypothermic myocardial ischemia were imposed. Left ventricular temperature was always maintained at 15 degrees C and right ventricular temperatures were maintained at 15 degrees C (Group I, n = 8), 25 degrees C (Group II, n = 8), and 35 degrees C (Group III, n = 8). These temperatures were produced by infusion of hypothermic crystalloid cardioplegic solution and appropriate topical cooling and heating of the left and right ventricles, respectively. Multiple indices of ventricular function were obtained 15, 30, 45, and 60 minutes after bypass and compared to prebypass control values. In all Group I animals (left ventricular temperature = 15 degrees C, right ventricular temperature = 15 degrees C), postischemic indices of right ventricular function were not different from control values (p = NS). In Group II (left ventricular temperature = 15 degrees C, right ventricular temperature = 25 degrees C), two animals died 30 and 45 minutes after bypass, respectively, of right ventricular failure. In the other six animals in Group II, all indices of right ventricular function were significantly reduced (p less than 0.05) except for right ventricular systolic pressure. In Group III (left ventricular temperature = 15 degrees C, right ventricular temperature = 35 degrees C), two animals could not be weaned from cardiopulmonary bypass because of right ventricular akinesia. Six animals were weaned from bypass, but two died 15 minutes, one died 30 minutes, and one 45 minutes after bypass. Two animals lived 60 minutes, but all indices of right ventricular function were decreased. Failure to maintain right ventricular temperatures below 25 degrees C during 1 hour of cardiac ischemia in the dog can result in fatal right ventricular failure.

Animals↗
PubMed1984

Amputation stumps studied by bone scanning. Work in progress.

Nine diabetic and 7 nondiabetic (post-trauma) patients 24 to 63 years of age (mean, 49) were scanned following amputation below the knee, which was bilateral in 4. A three-phase scanning technique (flow, blood pool, and delayed equilibrium images) was employed, using Tc-99m-etidronate. Duration of the arterial and capillary phases was estimated during flow. Activity at the tip of the stump was plotted as a function of (a) time since amputation and (b) flow measurements. Activity was found to diminish over a period of nearly 50 months, usually becoming minimal or undetectable after 18 months. The stump demonstrated relative stasis compared to the intact limb, particularly in diabetics and patients with long-standing amputation.

Adult↗
PubMed1981

Ultrasonographic determination of lumbar spine angulation.

Abdominal ultrasonograms of recumbent, supine adult subjects were used to measure the angle formed between the horizontal plane and a plane along the anterior border of upper lumbar vertebral bodies. The angle, referred to as phi, for male and female subjects averaged 8.8 degrees. When this angle was compared in subjects with the hips flexed and extended, there was no significant difference. There was a significant difference between subjects in a recumbent position and a standing position. The amount of angulation was compared to the age of the individual and found to have a low correlation coefficient. The angle phi appears to be a good indicator of the amount of lordosis, it related well to previous methods of measuring lordosis, and it is a benign procedure in a genetically sensitive region.

Adult↗
PubMed1979

The natural history of pancreatic pseudocysts: a unified concept of management.

Between 1971 and 1976, ninety-three patients with a clinical diagnosis of pseudocyst confirmed by ultrasonography were identified from a group of 923 patients admitted for pancreatic disease. Uncertainties in diagnosis and/or rapid progression of underlying pancreatitis led to urgent laparotomy and drainage in eleven of the ninety-three patients. Another twenty-eight patients underwent elective drainage of the pseudocyst. The remaining fifty-four constituted the study group and were followed with serial clinical and sonographic examinations until either spontaneous resolution occurred, complications developed, or the patients did not return. Complications arising during the period of observation in the untreated patients (rupture, abscess, jaundice, and hemorrhage) occurred more than twice as commonly as spontaneous resolution (41 per cent versus 20 per cent), and led directly to death in seven cases (14 per cent). No deaths occurred in the group of patients undergoing elective surgical drainage (p less than 0.05). The interval between presumed formation of the pseudocyst and the development of a complication averaged 13.5 +/- 6 weeks. Prolonged observation of pancreatic pseudocysts in the expectation of spontaneous resolution exposed the patient to an unwarranted risk, which, after seven weeks, greatly exceeded the mortality of elective surgery.

Abscess↗
PubMed1979

Megalocytic interstitial nephritis: ultrasonic and radiographic changes.

The radiologic and ultrasonic findings are presented in a case of megalocytic interstitial nephritis, a very rare condition, in many ways similar to renal malacoplakia. The role of ultrasound in the interpretation of the radiographic changes is discussed. Excretory urography will demonstrate a nonspecific renal mass effect and angiography may rule out evidence of tumor. Ultrasonic correlation can be highly suggestive of an interstitial parenchymal lesion.

Diagnosis, Differential↗
PubMed1978

Limitations in prediction of gestational age and birth weight by ultrasonographic methods.

The index of predictability of estimated gestational age (EGA) and birth weight (BW) from biparietal diameter (BPD) was tested in 1333 normal pregnancies; 96% of the patients were black. The correlation BPD and actual weeks to delivery was 0.834, r2 =69.5%. Confidence limits were established and a nomogram for EGA was derived. Our nomogram and two similar ones were compared. The overall correlation between them was good, but that for specific BPD and EGA was not. In addition, our BPD values were smaller for corresponding gestational ages in other nomograms. The overall accuracy of estimated delivery date was +/- 1.6 weeks. We were not able to predict birth weight at all from a single, random BPD measurement. We have demonstrated the serious limitations that exist in the prediction of gestational age from previously established nomograms. We infer that this error is even greater when homogenous populations are so studied. We suggest that any published BPD-EGA or BPD-BW nomogram be given close, intensive statistical scrutiny, within the population studied, before it is used. When such scrutiny is not possible, serial sonographic determinations, or longitudinal use of growth charts, would be more acceptable.

Adolescent↗
PubMed1978

Ultrasonic examination of the gallbladder: a review.

Ultrasonography is a helpful, non-invasive, and relatively inexpensive adjuvant to oral cholecystography for evaluating the gallbladder and its diseases. This method can be highly accurate in detecting gallstones and is specially useful when there is non-visualisation in radiographic contrast studies. Various ultrasound patterns of gallstones are described. All these patterns should demonstrate a sonic shadow in association with an intraluminal defect. Sonography is particularly useful in demonstrating cholelithiasis and organ dilatation in suspected acute cholecystitis. In addition to gallbladder disease, this technique simultaneously offers pertinent anatomical information about the porta hepatis. This information would otherwise require additional diagnostic investigation. Because, in many instances, sonography is non-specific, or blind to certain gallbladder non-calculous filling defects, and because of present lack of uniform standard quality control methods for performing this procedure, it should be considered only as a complementary, imaging procedure to oral cholecystography.

Acute Disease↗
PubMed1978

Ultrasonographic evaluation of vascular access complications.

In 24 patients, sonograms were obtained of 25 vascular accesses, 16 of which were bovine grafts, 7 arteriovenous fistulae, 1 a polytetrafluoroethylene graft, and 1 an external Silastic shunt. On the sonograms, the lumen, course, and insertions of the vascular grafts and fistulae were outlined, anterior and posterior aneurysms demonstrated, hematomas differentiated from aneurysms, and intrinsic distinguished from extrinsic lesions. The authors conclude ultrasonography is a valuable adjunct to clinical evaluation in assessing certain complications of vascular access.

Adult↗
PubMed1977

Retropenal abcess secondary to a ruptured retrocecal appendix diagnosed by ultrasound B scan and 67 Ga radionulide scan.

Standard roentgenographic criteria for anterior-posterior (AP) displacement of the kidney may not reveal small, uniformly distributed, perirenal masses. Ultrasound, on the other hand, is an axial display and thus is quite sensitive to such changes. A case of ruptured retrocecal appendix is presented in which the intravenous pyelogram was negative. In the sonogram, however, a slight separation was seen between the renal parenchyma and the posterior abdominal muscle wall. This led to further investigation and the diagnosis of an unsuspected retrorenal abscess.

Abdomen↗
PubMed1977

Preoperative diagnosis of pancreatic carcinoma by percutaneous aspiration biopsy.

Carcinoma of the pancreas and chronic pancreatitis may be extremely difficult to differentiate by standard diagnostic methods preoperatively as well as at the operating table. Operative pancreatic biopsy may have a high morbidity, rare mortality, and can be misleading. Percutaneous aspiration biopsy may be of great potential benefit. It provides additional histological material not usually available, and an accurate diagnosis of malignancy can be made. In select patients a needless laparotomy may be avoided. It appears to be a safe procedure that should be considered in the evaluation of the patient with suspected pancreatic malignancy in which a mass lesion is demonstrated by ultrasonography, computerized tomography, angiography, or retrograde pancreatography.

Adult↗
PubMed1977

Ultrasonographic abdominal aortography.

B-mode ultrasonography is an easily performed and accurate method of studying the abdominal aorta. The procedure is totally noninvasive and does not require patient hospitalization to detect aortic aneurysmal dilatation. Aneurysm size, extent, and associated aneurysmal clot formation can be determined more accurately than with contrast aortography. Para-aortic abdominal masses or organs that transmit pulsations can be detected where an aneurysm was originally suspected. Studies for serial size determination or postoperative follow-up are quickly and inexpensively performed, making this procedure the choice diagnostic modality for abdominal aortic aneurysms.

Aorta, Abdominal↗
PubMed1977

Value of perfusion lung scans in selection of patients for vena cava interruption.

Sixty-seven patients with pulmonary embolic disease (diagnosed clinically and with perfusion lung scans) were studied. In 48 of them, the scans were interpreted as positive for pulmonary emboli and in 19, as questionable. All 67 patients underwent pulmonary arteriography. The pulmonary arteriogram showed no evidence of pulmonary embolus in 11 of the 48 patients with positive findings on lung scan and no evidence in 12 of the 19 patients with questionable lung scan. Because of the high false-positive rate of the perfusion lung scan, we strongly recommend angiographic confirmation of pulmonary embolism when interruption of inferior vena cava is contemplated for the prevention of recurrence of pulmonary embolism.

Adolescent↗
PubMed1977

Imaging of experimental myocardial contusion: observations and pathologic correlations.

Myocardial contusions of variable severity were experimentally produced by an air-driven piston or serrated clamp in 29 dogs. Two 99mTc-labeled bone-seeking agents (99mTc pyrophosphate and 99mTc tetracycline) were used with cardiac scintigraphy to determine the sensitivity of these agents in detecting different degrees of myocardial damage. Results showed that 99mTc tetracycline was not a suitable scanning agent. 99mTc pyrophosphate produced positive scans in cases of complete (or nearly complete) transmural myocardial necrosis. Positive cardiac scans in clinical myocardial contusion may indicate the severity of the lesions and have prognostic significance.

Animals↗