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Biomedical subjects

V J Caride

Publications and source records attributed to V J Caride.

At least 55 records · Page 3Linked to original sources
PubMed1982

Renin-angiotensin and development of collateral circulation after renal ischemia.

Aortic ligation between the origins of the renal arteries in the rat produces a left renal ischemia, renin-dependent hypertension, and a transitory hindlimb paralysis of less than 2 h. Removal of the left ischemic kidney at the time of aortic ligation curtails the rise of blood pressure, plasma renin activity is normal, and paralysis is still present 24 h after surgery. Administration of an angiotensin-converting enzyme inhibitor or saralasin also prevents recuperation from paralysis after aortic ligation. Independent manipulation of the mean arterial pressure or plasma renin activity by pretreatment with reserpine or deoxycorticosterone before surgery shows that the presence or absence of paralysis is dependent on the plasma renin activity and not on the high blood pressure. Blood flow measurements show that paralysis is due to a persistent impairment of blood supply to the hindlimb muscle and not to ischemia of the spinal cord. Infusion of angiotensin II to aortic-ligated, left-renoprival animals tends to restore blood flow to muscle. It is concluded that after renal ischemia the renin-angiotensin system, independent of its hypertensive effect, restores blood flow by stimulating the development of collateral circulation.

Animals↗
PubMed1982

Noninvasive evaluation of bile leakage.

Three patients had internal biliary leakage demonstrated by hepatobiliary scintigraphy. In two, it was secondary to trauma and in one patient, it was related to spontaneous bile leakage of unknown causation. Although ultrasound of the abdomen is a highly accurate modality for the detection and anatomic localization of cystic collections, the ultrasonic features of a biloma are identical to those of other cystic lesions in the abdomen. In many patients, hepatobiliary and gallium scintigraphy ca help in the differentiation between biloma and abscesses. These patients stressed the need for hepatobiliary imaging, multiple projections and delayed views for the detection and localization of abnormal collections of bile. The biliary excretion of gallium should be taken into consideration when interpreting these scans.

Adult↗
PubMed1981

Regeneration of splenic autotransplants in suckling and adult rats.

Homogenates of splenic tissue were autotransplanted within the peritoneal cavity of suckling and adult Sprague-Dawley rats after total splenectomy. All suckling animals had multiple regenerated splenic nodules when killed four months later, but in only 55% was splenic tissue visible by technetium Tc 99m sulfur colloid scan. Splenic tissue was recovered in one of ten adult animals, but the nodule was not visible by scan. The results of this study imply that revascularization of autotransplants might be more successful in a growing than in a mature host. Nuclear scans, although useful, do not always visualize small regenerated splenic autotransplants.

Animals↗
PubMed1981

Liposome accumulation in ischaemic intestine following experimental mesenteric occlusion.

Partial intestinal ischaemia was produced by ligation of selected primary laterals of the mesenteric artery in the rat. Both positively and negatively charged liposomes (multiply labelled with [99mTc]diethylenetriamine pentaacetic acid, [3H]methoxy-inulin, and [4-14C]-cholesterol), administered 24 h following ligation, were accumulated in ischemic (necrotic) intestine.

Animals↗
PubMed1981

Regional myocardial kinetics of lidocaine in experimental infarction: modulation by regional blood flow.

The regional myocardial concentration of lidocaine after intravenous bolus administration was studied in the setting of myocardial infarction in 27 dogs utilizing a 24 hour old infarct model. Myocardial levels of lidocaine measured by gas chromatography were related to regional myocardial blood flow measured by radioactive microspheres in the same sample. A highly significant positive linear relation was noted between relative regional myocardial blood flow and lidocaine tissue concentration in animals killed 1 and 3 minutes after the injection of lidocaine (R2 = 0.81 and 0.85, respectively). This positive linear relation was no longer evident at 5 or more minutes after injection of lidocaine. This lack of linear relation resulted from dramatic reductions in myocardial lidocaine concentration in normally perfused zones with much lesser reductions in lower flow zones. Thus the initial distribution of lidocaine after bolus injection is directly proportional to myocardial blood flow within the first 3 minutes of injection. Thereafter, the washout of lidocaine appears to be the dominant factor in myocardial distribution.

Animals↗
PubMed1981

The role of vertebral veins in the dissemination of prostatic carcinoma.

The concept that the vertebral system of veins acts as a direct conduit in the spread of prostatic carcinoma to the skeletal system is based on the poorly documented observation that this tumor metastasizes preferentially to the pelvis, lumbar spine and sacrum. We analyzed 99mtechnetium bone scans in patients with skeletal metastases from assorted primary tumors and found that the distribution of metastases was virtually identical in patients with prostatic and nonprostatic tumors. Of the patients with prostatic carcinoma 25 per cent had bone scan lesions exclusively outside the region of the sacrum, pelvis and lumbar spine. The distribution of skeletal metastases from prostatic carcinoma does not support the concept that the vertebral veins have a substantial role in the dissemination of this tumor.

Adult↗
PubMed1981

Abdominal and hepatic uptake of 99mTc-pyrophosphate in neonatal necrotizing enterocolitis.

Abdominal 99mTc-pyrophosphate (99mTc-PYP) scans were obtained in 15 neonates: 12 with neonatal necrotizing enterocolitis (NEC), two with osteomyelitis, and one with myocarditis. Ten of the babies with NEC had at least one positive scan; of these 10 studies, seven (Group A) showed both diffuse abdominal uptake and localized hepatic activity, two (Group B) showed abdominal uptake and questionable hepatic uptake, and one (Group C) demonstrated diffuse abdominal uptake only. The other two babies with NEC had normal scans (Group D). Pneumatosis intestinalis was unquestionably present in two patients from Group A and one from Group B. Upon resolution of the clinical findings, all NEC patients had normal scans. A patient with myocarditis had hepatic uptake of 99mTC-PYP while the abdominal scan in the two infants with osteomyelitis was normal. These preliminary observations suggest that further study of a relationship between abdominal scan findings and the course of NEC is warranted.

Abdomen↗
PubMed1981

Tc-99m HIDA scintigraphy in segmental biliary obstruction.

Segmental biliary obstruction as a result of primary or secondary hepatic malignancy has been reported with increasing frequency. For two representative patients, the clinical and Tc-99m HIDA scintigraphic findings in segmental biliary obstruction are described. The presence of photon-deficient dilated bile ducts in one segment of the biliary tree is highly suggestive of localized biliary obstruction and should be considered in the patient with suspected or proven hepatic malignancy despite the absence of jaundice.

Adenocarcinoma↗
PubMed1981

Tc-99m HIDA cholescintigraphy: the distended photon-deficient gallbladder.

Four patients with distended, photon-deficient gallbladders are presented. Markedly delayed apearance of Tc-99m HIDA in a distended gallbladder may represent chronic cholecystitis, partial obstruction of the common bile duct, or physiologic gallbladder distention. Obtaining delayed images is important in this group of patients to avoid premature diagnosis of cystic-duct obstruction. If the distended gallbladder fails to visualize within 24 hr, hydrops with cystic-duct obstruction is suggested.

Adult↗
PubMed1979

Radiolabeled liposomes as metabolic and scanning tracers in mice. II. In-111 oxine compared with Tc-99m DTPA, entrapped in multilamellar lipid vesicles.

We describe the organ distribution of positively and negatively charged multilamellar lipid vesicles (MLV) labeled with Tc-99m DTPA or In-111 oxine in mice. The organ distribution of MLV (In-111 oxine) is fairly constant throughout 72 hr, indicating that the radiotracer remains associated with cellular structures at the site of MLV uptake. In animals injected with MLV (Tc-99m DTPA), on the other hand, there is continuous leakage of radioactivity from the involved organs. This can be explained by the release of the radiotracer following MLV destruction in the organs. MLV (IN-111 oxine) may be used to study MLV uptake by different organs, whereas MLV (Tc-99m DTPA) may be a good indicator of the destruction rate of lipid vesicles. Various conditions bearing on liposome kinetics merit further study in order to assess the potentialities of these vectors as diagnostic or therapeutic agents.

Animals↗
PubMed1978

Splenic function following experimental dearterialization injury in the suckling rat.

An experimental splenic dearterilization injury was created in 1-wk-old rats to study the effect of vascular trauma on splenic function. Splenic weight significantly decreased 1 wk following injury but returned to control values within a month. Total splenic nuclear activity diminished initially but increased to above control values 1 mo after injury, and finally returned to normal at 2 mo. Survival rate after an intraperitoneal challenge with pneumococcus in groups 1 wk following total splenectomy and partial dearterlization was not significantly different than controls. This study confirmed the clinical impression that vascular injury to the spleen causes only a transient impariment of splenic size and function and provides further incentive to perform splenorrhaphy following splenic trauma.

Animals↗
PubMed1977

Liposome accumulation in regions of experimental myocardial infarction.

The uptake of liposomes bearing positive, negative, or no net charge on their membrane and containing a radioactive tracer, [99mTc]diethylenetriamine pentaacetic acid, was studied in 12 intact dogs 24 hours after the induction of myocardial infarction, and compared to the relative regional myocardial blood flow determined from radioactive microspheres. Positively charged and neutral liposomes concentrate in infarcted regions against a flow gradient, while negative liposomes are passively distributed according to regional blood flow. Because positively charged and neutral lipisomes concentrate in infarct areas and have the ability to incorporate pharmacologic agents in their aqueous or lipid phase, they may serve as vehicles for drug delivery to infarct zones of low flow.

Animals↗
PubMed1977

Recent advances in cancer diagnosis with nuclear medicine techniques.

Recent progress in cancer detection in nuclear medicine has been significant and encouraging. Three main trends are responsible. First, techniques of imaging have improved, often in conjunction with the development of new and better imaging devices. Secondly, new radiopharmaceuticals are being investigated. Finally, interaction with other imaging modalities has started. In general, this yields complementary information further refining the diagnostic process.

Antibodies, Neoplasm↗
PubMed1976

The usefulness of the posterior oblique views in perfusion lung imaging.

A total of 116 perfusion lung images, with and without posterior oblique views, were compared by four trained observers. There was a significant increase in the number of perfusion defects detected when the posterior oblique views were included. Pairs of projections of 89 lung images were read by the four observers. The percentage of correct readings for the posterior oblique views was 78% compared with 63% and 56% for the lateral views and AP views, respectively. Inclusion of the posterior oblique views as a routine part of the examination is recommended.

Humans↗
PubMed1976

Evaluation of liposome-entrapped radioactive tracers as scanning agents. Part 1: Organ distribution of liposome (99mTc-DTPA) in mice.

We describe the use of liposomes as a delivery system for radiopharmaceutical localization. Liposomes [99mTc-DTPA] were injected intravenously in mice and showed preferential uptake in the liver and spleen. There was a steady decline of activity in all organs, suggestive of destruction of liposomes with subsequent release of 99mTc-DTPA into the circulation. Alteration of uptake from liver to spleen, lung, and bone marrow was achieved by prior loading of the circulation with nonradioactive liposomes. The same effect was produced in dogs and demonstrated with scintigraphy. We also showed scintigraphically in dogs how 99mTc-DTPA, when administered entrapped in liposomes, follows the pattern of distribution of liposomes. Liposomes seem to be suitable carriers for radiopharmaceuticals. Further studies should show the possibility of directing liposomes to specific targets.

Animals↗