Search PubMed⌕ Search

Biomedical subjects

V J Caride

Publications and source records attributed to V J Caride.

At least 37 records · Page 2Linked to original sources
PubMed1990

Noninvasive staging of lung cancer. Indications and limitations of gallium-67 citrate imaging.

The results of evaluation of the hila and mediastinum with 67Ga scans are contradictory, as are the recommendations by different investigators on the use of 67Ga scintigraphy in the clinical evaluation of patients with primary lung carcinoma. Nevertheless, the economy and logistic simplicity of evaluating local and distant metastases with a single imaging procedure are attractive, especially because the symptoms may not enable the physician to make a correct identification of the organ systems affected by metastases. Neumann and Hoffer state that "at present conventional Ga-67 scanning techniques cannot be recommended for preoperative staging of mediastinal lymph node metastases in lung cancer patients." According to Waxman, 67Ga scintigraphy, relative to other imaging modalities, is a sensitive indicator of hilar spread of a tumor. However, because of the normally high background activity within the sternum and spine, mediastinal abnormalities may be poorly detected. Since most pulmonary tumors metastasize via regional nodes to the pulmonary hilum and then to the mediastinum, the high sensitivity for the detection of pulmonary hilar abnormalities and the high specificity for detection of mediastinal lesions suggest that gallium scintigraphy is a valuable adjunctive test when used appropriately. The results obtained locally are probably the best guide for individual physicians in the selection of diagnostic tests for their patients. Gallium scans may thus be helpful in the clinical evaluation of patients with lung cancer. Although gallium scans identify mediastinal node involvement, there is considerable controversy over the relationship between the sensitivity and specificity of the method. By detecting distant extrathoracic metastases, the 67Ga scan may identify a small group of patients who can be spared a needless operation. Gallium scanning fails specifically for metastases within the brain; thus, it does not supplant CT scans of the brain and it is less sensitive than bone scans in detecting osseous metastases. Gallium scanning of patients with small-cell lung cancer is not useful in the selection of therapy but does become important from a prognostic standpoint. Patients with extrathoracic involvement by small-cell carcinoma of the lung are known to have limited survival times compared with those of patients with thoracic involvement alone. In identifying patients with extensive disease, the oncologist is thus provided with prognostic information that may be useful in the counseling of the patient and the patient's family.

Citrates↗
PubMed1990

Single perfusion defect and pulmonary embolism: angiographic correlation.

One hundred and thirty-three ventilation-perfusion scans (V-P) with angiographic correlation were retrospectively reviewed to evaluate the frequency of pulmonary emboli (PE) in single perfusion defects (SPD), regardless of ventilation or radiographic findings. By angiography, 15 of 30 SPD cases had PE. Demographic data and clinical presentation were similar for PE and non-PE patients. However, 9 out of 15 patients with PE had recent surgery compared to none of the non-PE patients. SPD were seen in areas of ventilation and chest x-ray abnormalities in 12 of 15 PE and 11 of 19 non-PE cases. Size of the actual lesion was underestimated by scintigraphy in most cases. In 7 of 15 PE cases, the perfusion defect was larger than the corresponding ventilation abnormality. Most SPD were located at the bases. Twelve of 15 SPD in the PE group were at the posterior basilar segment. In the appropriate clinical setting, SPD carries at least a moderate probability for PE. When the clinical suspicion is high, a pulmonary angiography will be needed to confirm the diagnosis.

Angiography↗
PubMed1989

Sucralfate delays gastric emptying of liquids and solids in duodenal ulcer patients.

Gastric emptying studies were performed on nine healthy volunteers and ten duodenal ulcer (DU) patients utilizing a dual radionuclide technique to assess simultaneously emptying rates of liquid (111In labeled water) and solid (99mTc sulfur colloid labeled chicken liver) components of a meal. One gram of sucralfate was compared to placebo in separate days in a randomized double-blind crossover fashion. Subjects ingested the radiolabeled test meal 1 h after receiving medication, and gastric emptying was monitored for 3 h using a gamma camera interfaced with a computer. We found that DU patients had significantly faster gastric emptying of solids (P less than 0.05) compared to normals on the placebo days, while liquid emptying rates were similar. Sucralfate, in the DU patients, significantly (P less than 0.05) slowed gastric emptying of water from 20 to 40 min and emptying of the solid component from 100-160 min after the meal compared to placebo. In normal subjects, gastric emptying of liquids and solids was not significantly affected by sucralfate. We conclude that slowing of gastric emptying, possibly mediated through aluminum ions, occurs in DU patients on sucralfate. This may be one mechanism by which sucralfate enhances healing and decreases recurrence of duodenal ulcer.

Adult↗
PubMed1988

Scintigraphic determination of the effect of metoclopramide and morphine on small intestinal transit time.

To determine if a scintigraphic method could detect pharmacologic changes in small intestinal transit time (SITT), 10 male volunteers were studied at baseline and after intravenously administered metoclopramide (10 mg) and morphine (8 mg). Five of these volunteers were studied with the hydrogen breath test method for comparison. For each of the scintigraphic studies, the volunteers were positioned supine under a large-field-of-view gamma camera after ingesting an isosmotic lactulose solution containing 99mtechnetium-diethylenetriaminepentaacetic acid (DTPA). Data were collected and stored in a computer. Both gastric emptying and SITT were determined. SITT was 81 +/- 11 min (mean +/- S.E.M.; N = 10) during baseline studies, was decreased significantly to 50 +/- 6 min (N = 10; P less than 0.01) after metoclopramide, and was increased significantly to 161 +/- 15 min (N = 8; P less than 0.01) after morphine. Baseline mean values were 86.3 +/- 15 min (N = 15) for the hydrogen breath tests, 47 +/- 8 min (N = 5) for metoclopramide, and 183 +/- 16 min (N = 5) for morphine. For gastric emptying, there was no significant difference in percentage emptying at 1 hr for baseline and metochopramide (82 +/- 5% vs. 88 +/- 4%). Morphine prolonged gastric emptying at 1 hr to 63 +/- 8%. We conclude that the scintigraphic method for measuring SITT permits accurate investigation of the pharmacologic effects on intestinal motility and, in addition, may be a useful research and clinical method for SITT determination.

Adult↗
PubMed1988

Ventilation-perfusion scan in the acutely ill patient with unilateral hyperlucent lung.

A patient with a unilateral hyperlucent lung with acute respiratory complaints is presented. A ventilation-perfusion scan was performed to rule out pulmonary embolism. The perfusion scan ( [99mTC]MAA) showed peripheral perfusion defects in the hyperlucent lung. The ventilation study (133Xe) demonstrated peripheral ventilatory defects on the single breath image in the hyperlucent lung, the filling in of these on the equilibrium view, and diffusely delayed washout in the affected lung. These findings were suggestive of the Swyer-James syndrome and critical in excluding the numerous other causes of unilateral hyperlucent lung, which are discussed. The importance of the ventilation-perfusion study (and particularly the ventilation scan) in the patient with unilateral hyperlucent lung and acute respiratory symptoms is stressed. In addition, a discussion of the Swyer-James syndrome is included.

Aged↗
PubMed1987

The ovarian renin-angiotensin system: renin-like activity and angiotensin II/III immunoreactivity in gonadotropin-stimulated and unstimulated human follicular fluid.

Renin-like activity and angiotensin II/III immunoreactivity in follicular fluids from 34 women stimulated with human menopausal gonadotropin and human chorionic gonadotropin (56.8 +/- 6.5 ng angiotensin I per milliliter per hour and 187 +/- 21 pg/ml [mean +/- SEM], respectively) were much higher (p less than 0.001) than in follicular fluids from 12 unstimulated preovulatory women (1.41 +/- 0.37 ng angiotensin I per milliliter per hour and 58.5 +/- 13.7 pg/ml) and in simultaneously drawn plasma (4.47 +/- 0.73 ng angiotensin I per milliliter per hour and 31.8 +/- 11.6 pg/ml, respectively; p less than 0.001). Plasma renin-like activity and angiotensin II/III immunoreactivity in stimulated cycles did not differ from unstimulated cycles. Follicular fluid angiotensin II/III immunoreactivity correlated significantly with follicular fluid renin-like activity in stimulated (r = 0.72; p less than 0.01) and in unstimulated samples (r = 0.86; p less than 0.01). Significant correlation was found also between follicular fluid renin-like activity and estradiol. A sharp preovulatory rise of renin-like activity and angiotensin II/III immunoreactivity was noted in unstimulated follicular fluid samples collected on cycle days 13 and 14 compared to days 9 through 12 (p less than 0.01). The findings that follicular fluid renin-like activity and angiotensin II/III immunoreactivity are correlated, and that gonadotropins have a stimulatory effect on follicular fluid concentrations support our concept of a physiologic intrinsic ovarian renin-angiotensin system.

Angiotensin II↗
PubMed1987

Diagnosis of discitis by SPECT technetium-99m MDP scintigram. A case report.

A 29-year-old male presented with a two month history of intermittent low back pain following a febrile illness. Two planar bone scans performed with Tc-99m MDP were normal despite roentgenographic and SPECT scintigraphic evidence of discitis. This case demonstrates the increased sensitivity of SPECT in the diagnosis of discitis.

Adult↗
PubMed1986

Effects of local heat on blood flow in infected and normal hands.

Changes in response to heat in the dermal, subcutaneous, and muscle blood flow in the hands of 10 patients with hand infections were studied using 133Xe and recording of clearance data. A further 15 normal hands were studied in a similar manner. The application of topical heat to normal hands resulted in a decrease in the dermal blood flow (p less than 0.001), an increase in the subcutaneous blood flow (p less than 0.05), and perhaps an increase in the intramuscular flow (p less than 0.1). This suggests that surface heat promotes a shunting of the blood from the skin to deeper tissue layers. In infected hands, the blood flow was found to be significantly increased threefold in the intradermal circulation (p less than 0.01) and eightfold in the subcutaneous circulation (p less than 0.03) when compared to controls. In contrast to normal hands, in the infected hands, the blood flow decreased in all three compartments by 50 percent following application of heat. The blood flow of the normal hand in patients with infection did not respond to heat in the normal pattern. We conclude that the application of local heat to normal tissues results in shunting of blood flow from superficial tissues such as dermis to deeper ones such as subcutaneous fat and muscle. In infected tissues, the blood flow was found to be much higher than normal; however, the traditional belief in the improvement in blood flow by the application of heat was not confirmed.(ABSTRACT TRUNCATED AT 250 WORDS)

Bacterial Infections↗
PubMed1985

Renin-like activity in ovarian follicular fluid.

Angiogenesis is a feature of ovarian follicle and corpus luteum development. Ovarian homogenates and follicular fluid (FF) contain factors that stimulate new vessel formation. Because the renin-angiotensin system has been shown to facilitate angiogenesis, renin activity was measured in FF and plasma from 20 normal, ovulatory women who were undergoing in vitro fertilization and were therefore stimulated with human menopausal gonadotropin/human chorionic gonadotropin. Serum estradiol (E2) and FF E2 and progesterone (P) were also determined and correlated with FF and plasma renin activity. FF renin activity was significantly higher than plasma renin activity (55.8 +/- 7.9 versus 3.8 +/- 0.7 ng of angiotensin I/ml/hour, P less than 0.001). Positive correlations were found between FF E2 and renin activity (r = 0.53, P less than 0.05). There was also a correlation between plasma renin activity and serum E2 (r = 0.69, P less than 0.05). No correlation was present between FF P and renin activity. The high renin-like activity present in FF after stimulation with gonadotropins could be involved in the mechanism of angiogenesis and may play an important role in events related to reproductive processes.

Estradiol↗
PubMed1985

Effect of sucralfate and an aluminum hydroxide gel on gastric emptying of solids and liquids.

Our purpose was to investigate whether an aluminum-containing compound (sucralfate) and an aluminum-containing antacid (Amphojel; Wyeth Laboratories), both of which are commonly used in peptic ulcer disease, affect gastric emptying. Gastric emptying was studied in ten healthy subjects with the double isotope technique to assess simultaneous emptying rates of the solid and liquid components of a meal. 99mTechnetium sulfur colloid-labeled chicken liver served as the solid component and 111indium diethylenetriamine penta-acetic acid-labeled water was the liquid component. In a randomized, double-blind fashion, 1 gm sucralfate and 30 ml aluminum hydroxide gel were compared with placebo on separate days. Subjects ate the isotope-labeled test meal after dosing, and gastric emptying was monitored for 3 hours by a gamma-camera interfaced with a computer. There was no significant change in gastric emptying of either solids or liquids after sucralfate. The aluminum hydroxide gel slowed the gastric emptying rate for solids more than did the placebo, but this difference was significant only at the intervals of 165 and 180 minutes after the meal. We conclude that aluminum in the form of therapeutic doses of sucralfate does not delay gastric emptying of solids or liquids in normal subjects, while the larger amount of aluminum in therapeutic doses of the antacid gel has some slowing effect on gastric emptying of the solid components of a meal.

Adult↗
PubMed1985

Liposomes as carriers of imaging agents.

This review discusses the utilization of liposomes as imaging agents or as vehicles for contrast materials. The initial approach was the use of radiolabeled liposomes for scintigraphy. To this end liposomes were either labeled in the lipid membrane or aqueous radiotracers were incorporated inside the lipid vesicles. The lipid labeling provides a more stable association of the radioactive tracer and the lipid vesicles, while the use of water-soluble radiotracers provides a wider selection of compounds. Early attempts at selective tumor imaging using radiolabeled liposomes were unsuccessful. The use of monoclonal antibodies attached to liposomes offers new hopes. Several strategies have been proposed in this respect and several others can be envisioned. The use of liposomes permits the use of several administration routes for imaging agents. Of particular interest is the subcutaneous administration for lymph node visualization. Liposomes offer clear advantages over most radiocontrast agents for prolonged hepatosplenic contrast enhancement. This is particularly relevant in the diagnostic evaluation of the abdomen with computed tomography. Important research efforts are being conducted in this area. Two different approaches have been advanced: the incorporation of contrast agents into liposomes and the preparation of radiopaque liposomes from radiodense lipids. Nuclear magnetic resonance imaging can also benefit from contrast agents. Several centers are investigating this exciting field using liposomes loaded with paramagnetic elements.

Humans↗
PubMed1984

The mechanism of liposome accumulation in infarction.

This paper explores the mechanism(s) whereby liposomes accumulate in chronically ischaemic myocardium and intestine. Plasma prepared from venous blood obtained at sites of myocardial and intestinal infarction does not promote the lysis of positively and negatively charged liposomes in vitro. Albumin-bound lysophosphatidylcholine (greater than or equal to 2 mM) lyses positively and negatively charged liposomes in vitro at similar rates. [99mTc]Diethylenetriamine pentaacetic acid (DTPA) entrapped in positively charged liposomes was accumulated in ischaemic rat caecum/colon 6 and 24 h after mesenteric ligation. Presumably allied to the accumulation of liposomal components, necrotic caecum/colon showed marked Ca2+ accumulation and phospholipid depletion. It is postulated that Ca2+ and Ca2+-activated membrane phospholipases may be implicated in the mechanism of liposome accumulation in chronic ischaemia.

Animals↗
PubMed1984

Relaxation enhancement using liposomes carrying paramagnetic species.

Studies were performed to investigate the effects upon the relaxation times of mouse organs of intravenously administered Mn-DTPA entrapped in multilamellar liposomes, Mn-DTPA, 0.9% NaCl entrapped in liposomes, 0.9% NaCl. Manganese concentrations in injectates and tissues were assessed with 54Mn and atomic absorption. T1 and T2 of freshly excised tissues were measured in an NMR spectrometer at 20 MHz and 37% C with IR and CPMG sequences. Entrapment of Mn-DTPA in liposomes increased 54Mn accumulation in liver by 207% and in spleen 1208% and reduced 54Mn in heart by 20% and in kidney by 24% relative to free Mn-DTPA. Statistically significant increases in relaxation rates were produced. However, the increase in relaxation rate per unit concentration of Mn in tissue is reduced by 31% in liver and 62% in spleen when Mn is delivered inside liposomes. These observations have implications for the design of NMR contrast agents.

Animals↗
PubMed1984

Scintigraphic determination of small intestinal transit time: comparison with the hydrogen breath technique.

The hydrogen breath test was used as a standard against which a scintigraphic method for determination of small intestinal transit time was evaluated and compared. A total of 19 male volunteers ranging in age from 23 to 28 yr participated in the study. The subjects ingested an isosmotic lactulose solution containing 99mtechnetium-diethylenetriaminepentaacetic acid (Sn) and then remained supine under a large field of view gamma-camera that interfaced with a computer system. Data were visually analyzed and then quantified to determine gastric emptying and small intestinal transit time. The small intestinal transit time ranged from 31 to 139 min with the scintigraphic method and 30 to 190 min with the hydrogen breath test (r = 0.77). The mean small intestinal transit time for 20 individual determinations with the scintigraphic method, 73.0 +/- 6.5 min (mean +/- SEM), was similar to the results from the hydrogen breath test technique, 75.1 +/- 8.3 min. Thirteen volunteers underwent two studies with the scintigraphic method separated by intervals ranging from 2 days to 8 wk. Individual variations in small intestinal transit time were significantly correlated with individual variations in gastric emptying (p less than 0.05). We conclude that the scintigraphic method allows accurate determination of gastrocecal time and is a noninvasive technique which may be a useful clinical test for small intestinal transit time as well as for providing information on the pathophysiology and pharmacology of intestinal motility.

Adult↗
PubMed1984

Discordant inter-kit results in the radioimmunoassay for choriogonadotropin in serum.

Discordant results for concentrations of choriogonadotropin (HCG) in sera from five of 162 women are reported, as determined with four commercial radioassay kits: Becton-Dickinson, Clinetics, Corning, and Hybritech. Results ranged from 11.2 to 36.7 int. units/L, when assayed with the Becton-Dickinson kit, but HCG was not detectable when assayed with the other kits. None of the patients was pregnant, and none had evidence of persistent trophoblastic or nontrophoblastic disease. Concentrations of lutropin, follitropin, thyrotropin, triglycerides, cholesterol, protein, and albumin were normal. Assay of diluted sera did not parallel the standard curve, and nonspecific binding in the patients' samples was negligible. Some kits for HCG may be influenced by inherent methodological factors or interfering serum constituents, which can lead to spurious results.

Adult↗
PubMed1982

Regional myocardial lidocaine concentration following continuous intravenous infusion early and later after myocardial infarction.

The regional concentration of lidocaine using a double constant infusion technique (250 micrograms/kg/min x 15 minutes followed by 35 micrograms/kg/mg/min x 120 minutes) was studied immediately (2 hours) in seven dogs and 24 hours (six dogs) after myocardial infarction. Tissue levels were determined by gas chromatography and related to regional myocardial blood flow as determined by the radioactive microsphere technique in multiple samples. At 2 hours after infarction a significantly higher lidocaine concentration (4.1 +/- 0.42 micrograms/g) was found in zones with greatly reduced blood flow (regional myocardial blood flow less than 0.2 ml/min per g) when compared with that (2.6 +/- 0.19 micrograms/g) in zones with normal blood flow (regional myocardial blood flow greater than 0.8 ml/min per g) (p less than 0.01). In contrast, in the 24 hour model the opposite situation was observed. Although the concentration of lidocaine in the infarct zone was substantial, a significant decline in lidocaine tissue concentration was found in the zones of lowest blood flow (regional myocardial blood flow less than 0.2 ml/min per g) when compared with that in normal zones (1.76 +/- 0.21 versus 3.38 +/- 0.21 micrograms/g, p less than 0.001). In addition, no significant differences in lidocaine concentrations were found between endocardium and epicardium in any of the groups other than those related to regional myocardial blood flow. Thus, with the double constant infusion technique, lidocaine reached normal and ischemic myocardium in concentrations equivalent to therapeutic plasma concentrations, even in lower infarct blood flow zones, with no significant differences between endocardium and epicardium. Of perhaps greater significance, the age of the ischemic insult is an important determinant of lidocaine tissue distribution in infarcted myocardium.

Animals↗