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Biomedical subjects

C C Williams

Publications and source records attributed to C C Williams.

At least 73 records · Page 4Linked to original sources
PubMed1982

Basal kinetic studies of Tc-99m DMPE as a myocardial imaging agent in the dog.

Newly synthesized Tc-99m dichlorobis(1,2-dimethylphosphino)ethane (DMPE) was investigated as a myocardial imaging agent with respect to its kinetics (dependent on both time and regional coronary blood flow), its percent organ uptake, and its imaging characteristics in the anesthetized dog. Most of these data are compared with those of Tl-201. Blood clearance of the two agents is essentially the same. Compared with Tl-201, Tc-99m DMPE shows faster overall kinetics, higher heart-to-lung ratio, equally good correlation with a wide range of regional blood flows, and higher liver uptake. At the time of peak myocardial uptake, the mean heart uptake of Tl-201 is 4.3%, compared with 2.9% for Tc-99m DMPE, yet only 0.9% uptake of Tc-99m DMPE is found in the lung as compared with 3.3% for Tl-201. These differences result in a heart-to-lung ratio of 2:1 for Tc-99m DMPE and 1:1 for Tl-201, based on the data obtained from the time-activity curve. The quantitative findings are supported by the superior quality of Tc-99m DMPE images of both normal and infarcted dog heart. The high hepatic uptake of Tc-99m DMPE is not a serious problem if images are obtained within 5-60 min after dose. These basic kinetic studies suggest that Tc-99m DMPE is a promising myocardial imaging agent.

Animals↗
PubMed1981

Lithium carbonate in patients with small cell lung cancer receiving combination chemotherapy.

Lithium administration has been shown to attenuate the leukopenia associated with systemic chemotherapy. The results of a randomized trial of lithium in 45 patients with small cell lung cancer who received combination chemotherapy and radiation therapy are reported. Patients randomized to receive lithium were started on 300 mg three times daily for 18 days of every 21 day chemotherapy cycle. Patients who received lithium experienced significantly less mid-cycle leukocyte and neutrophil count depression and spent fewer days with leukopenia and neutropenia than control patients regardless of age or extent of disease. Patients who received lithium spent fewer days hospitalized and fewer days with fever in the presence of severe neutropenia than control patients. The cumulative risk of fever with signs of infection was greater in control patients regardless of age, disease extent or the presence of marrow involvement. Patients who were given lithium received significantly more chemotherapy than control patients. Patient survival was greatest in those with limited disease, in complete responders and in those who received more than 75 percent of their induction chemotherapy although it did not differ between the two study groups. The majority of patients required either reduction or discontinuation of lithium. Those who received lithium continuously demonstrated a higher objective response rate and longer survival than either patients in whom the lithium had to be discontinued or those randomized to the control group. Infection was an important cause of death in the control group and cardiovascular event occurred frequently in the lithium group, but the major cause of death in this patient population remains progressive malignant disease.

Carcinoma, Small Cell↗
PubMed1981

The accuracy of 99Molybdenum assays in 99mTechnetium solutions.

A study was performed to determine the accuracy of 99Mo measurements using three commercial dose calibrators with their 99Mo assay shields. One 99Mo assay shield allowed excessive penetration by the lower energy 99mtc photons, resulting in the calibrator's falsely high interpretation of the activity of 99Mo present in the high-activity 99mTc eluates. All three calibrators performed adequately with a National Bureau of Standards 99Mo standard in equilibrum with 99mTc. By using low-activity aliquots of 99Mo and 99mTc, a low-level linearity test was performed. Two of the calibrators were found to have a threshold of approximately 10 microCi (370 kBq) for a nonzero 99Mo response, although one of these occasionally produced variable nonzero responses below its threshold. Only one of the calibrators was found to reflect accurately the activity of 99Mo present under all conditions tested.

Calibration↗
PubMed1980

The use of lithium carbonate to reduce infection and leukopenia during systemic chemotherapy.

To investigate whether lithium ameliorates the infectious complications that accompany systemic chemotherapy, we studied 45 patients with small-cell bronchogenic carcinoma receiving combination chemotherapy and radiation therapy. Twenty received lithium carbonate, and 25 received no additional therapy. Control subjects experienced more days with neutropenia than the lithium-treated group (2.17 days per 100 patient-days vs. 0.29), more severe febrile episodes (seven patients vs. one patient), more days hospitalized with fever and neutropenia (1.92 per 100 patient-days vs. 0.18), and more infection-related deaths (five vs. none). Infection-free survival was significantly longer in the lithium-treated group than in controls (P less than 0.05). Delay in subsequent chemotherapy was longer (P less than 0.01) and the number of dose reductions greater (P less than 0.01) in the control group. For both leukocytes and neutrophils, the first cycle nadir, mean of all treatment nadirs, and the lowest nadir observed during treatment were significantly higher in the lithium group. Mean mid-cycle monocyte counts were greater in the lithium group (P less than 0.05) and correlated with concurrent serum lithium levels (rs = 0.74, P less than 0.05). We believe that lithium carbonate shows promise as a means of lowering the risk of infection among patients receiving cytotoxic therapy.

Antineoplastic Agents↗
PubMed1980

Survey of 99mTc contamination of laboratory personnel: its degree and routes.

Internal contamination of personnel preparing 99mTc labeled radiopharmaceuticals was confirmed by detection of radioactivity in urine. Observation of work habits, whole-body scanner studies, nose swabs, and wipe tests in the hot laboratory demonstrated that: (a) contamination of the laboratory coat occurred during radiopharmaceutical preparation; (b) the degree of personnel contamination appeared to be higher among the short in stature; and (c) no gross evidence was found to indicate that internal contamination took place through an air-borne route. While the calculated internal radiation dose is minimal, even this could be avoided if particular precautionary practices are observed.

Absorption↗
PubMed1978

Histologic changes in Paget's disease treated with calcitonin.

In recent years the use of calcitonin in the medical treatment of Paget's disease of bone has been gaining in popularity. Seventeen patients on long term calcitonin therapy showed objective morphologic evidence of improvement in the quality of bone matrix deposition, in the trabecular organization, and in the parameters used to evaluate the rates of bone turnover. The usefulness of bone biopsy and fine detail radiography of the biopsy core in evaluating the progress of disease and the effects of therapy is discussed. It is concluded that the longer the period of therapy and follow-up, the higher the proportion of patients showing histologic evidence of improvement.

Aged↗
PubMed1978

Social work and nursing in hospital settings: a study of interprofessional experiences.

Social workers and nurses in hospitals often work together on interdisciplinary health care teams. Collaboration between these two professions can be enhanced through a better understanding of each other's roles, skills, and practice expectations. One way to acquire knowledge in these areas is through opportunities to interact with individuals from the other discipline. This article reports the findings of a study that investigated the kinds of interprofessional experiences occurring between hospital social workers and nurses during their educational preparation and clinical practice.

Education, Nursing↗
PubMed1978

Collimator evaluation for Tl-201 myocardial imaging.

Three collimators--high-resolutions, converging, and pinhole--were evaluated for Tl-201 myocardial imaging. Line spread function, sensitivity measurements, and phantom and animal studies were used. Features common to all the collimators were: a) better resolution at a closer distance with higher count density, and b) higher infarct detection rate in the tangenital projection than in the en face view relative to the lesion. Furthermore, an infarct in the epicardial location was better visualized than one in the endocardial location. In terms of resolution and sensitivity, the high-resolution collimator was found to be satisfactory in most clinical imagings, but for visualization of an infarct, its size by weight must be over 10--12 g. The pinhole collimator could resolve an infarct as small as 7 g, and use of the pinhole yielded a diagnostic accuracy of over 90%, compared with 75-80% for the high-resolution collimator. Although the low sensitivity of the pinhole collimator precludes its routine clinical use, the selected view would increase diagnostic accuracy. The converging collimator performed poorly in terms of lesion detectability, and its routine clinical use is not encouraged. The conclusion drawn here is valid in the system we have studied, but the variety of converging collimators must be evaluated further for their specific purposes.

Animals↗
PubMed1977

The intensive care unit: social work intervention with the families of critically ill patients.

Hospital intensive care units can be a significant practice area for social workers. Nowhere are families in more obvious crises than when faced with the life-threatening illness of a significant other who may be unresponsive and dependent on a frightening array of highly technical equipment. Using the crisis model for their intervention, social workers can significantly lessen the trauma experienced by these families. Additionally, they can develop other supportive hospital resources such as family groups and volunteer services to help meet their needs.

Adaptation, Psychological↗
PubMed1977

Stability of aqueous perchlorate formulations.

The stability of three aqueous perchlorate formulations used in nuclear medicine was studied as a function of the formulation and storage temperature. The formulations were intravenous potassium perchlorate solution, oral sodium perchlorate-sorbitol solution and oral potassium perchlorate in cherry syrup solution. The assays were conducted gravimetrically by precipitation with tetra-n-pentylammonium bromide. All formulations were found to be stable at least nine months. It is recommended that any formulation containing potassium perchlorate be kept at room temperature since precipitation of the active ingredient may occur if refrigerated. Sodium perchlorate formulations, however, may be refrigerated if desired because of their greater solubility.

Drug Stability↗
PubMed1977

A comparison of technetium etidronate and pyrophosphate for acute myocardial infarct imaging.

Etidronate and pyrophosphate, labeled with Tc-95m and Tc-99m, were studied in experimentally infarcted mongrel dogs. A distribution study was conducted 2 hr after simultaneous administration of both agents in two groups of dogs. In one group, the injection was made 15 min after release of a 2-hr coronary arterial ligation. Another group was injected 48 hr after release of the ligation. The uptakes for each radiopharmaceutical and the ratio of uptakes for each sample were computed. The data show pyrophosphate to be a superior agent for the imaging of acute myocardial infarcts because of the higher uptake by infarcted myocardium and the greater contrast between infarcted myocardium and neighboring organs.

Acute Disease↗
PubMed1976

Comparison of commercial pyrogen testing laboratories.

The pyrogen test results of four laboratories were compared to determine if any inconsistencies existed. Samples submitted for pyrogen testing were of two types: (1) radiopharmaceuticals which had been allowed to decay to negligible activity or mock radiopharmaceuticals prepared with saline instead of pertechnetate, and (2) positive controls of bacterial endotoxin. The drugs used in the eight-rabbit tests included 99mTc-macroaggregated albumin, 99mTc-human serum albumin, 99mTc-sulfur colloid, saline and iodinated fibrinogen. Laboratory A showed a 52% failure rate for the testing of 36 preparations. Samples identical to those not passed by laboratory A were passed by laboratories B, C and D. It is recommended that all users of pyrogen testing laboratories periodically submit samples of known apyrogenicity for testing.

Animals↗