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Biomedical subjects

J Whitley

Publications and source records attributed to J Whitley.

12 recordsLinked to original sources
PubMed1994

A peptide related to gastrin releasing peptide is synthesised and secreted by the ovine endometrium in early pregnancy.

We have previously shown that the peptide immunoreactivity related closely to the mitogen GRP is expressed by the pregnant ovine endometrium during the final third of pregnancy. In this study we have established that GRP is also expressed early in ovine pregnancy and have quantified the temporal changes in synthesis, storage and secretion of GRP in the peri- and post-attachment period. Secreted GRP peptide levels rise 10 fold just prior to implantation, while endometrial peptide and mRNA concentrations increase 4 and 13 fold respectively between day 17 and 20, immediately following attachment and corresponding to the onset of placentome development. The main molecular form of endometrial GRP has similar binding characteristics on RP-HPLC to GRP 18-27, but is larger. We conclude that a GRP-like peptide is expressed by the pregnant ovine endometrium from early in pregnancy until term, and that it is likely to play an important role in fetal or uterine maturation.

Animals↗
PubMed1989

Bedside blood gas and electrolyte monitoring in critically ill patients.

A major advantage of near-patient testing is time savings that facilitate important diagnostic and therapeutic decisions. Recent technologic advances have made available a number of systems that allow for near-patient testing. The reliability of these instruments must be validated in the clinical setting in the hands of their intended users. We evaluated the Gemstat blood gas, electrolyte, and Hct portable analyzer in the critical care setting when used by numerous individuals with no previous laboratory training. Blood gas, Na, K, and Hct results were highly correlated with those from the clinical laboratories (PaO2, r = .96; PaCO2, r = .92, pH, r = .96; Na, r = .93; K, r = .95; Hct, r = .91). The Gemstat represents a new generation of portable, rapid, safe, and accurate instruments that are well suited for ICU settings. The instrument can facilitate clinical management of patients, and may improve patient care.

Blood Gas Analysis↗
PubMed1989

Tumor volume and treatment outcome in small cell lung carcinoma.

The volume of some tumors correlates with local disease control, response, and survival. Small cell lung carcinoma presents with variable and often large intrathoracic masses. We assessed volume by two methods (summation of cross-sectional areas and Simpson's rule for estimating volume) and correlated volume with treatment outcome. Twenty-nine patients with small cell lung carcinoma (12 limited disease and 17 extensive disease) were analyzed for volume outcome correlations. There were five early deaths. Twenty-four had response correlations (11 limited disease and 13 extensive disease). Eighteen of the twenty-four achieved complete response. There was no apparent correlation between complete and/or partial response and pretreatment tumor volume. There was no apparent correlation between survival and volume. The methods of volume assessment correlate well with each other (r = 0.88) and either can be used with accuracy. So far there is also no correlation between chest tumor volume and intrathoracic recurrence. Our projections suggest that there is a low probability of correlating chest tumor volume and either response or survival. This is in keeping with the disseminated nature of the tumor which is its limiting factor in survival.

Carcinoma, Small Cell↗
PubMed1982

Volume determinations in computed tomography.

Modern computed tomographic (CT) scanners allow reasonably high-resolution cross-sectional visualization of most viscera and masses. To determine the accuracy of CT volume estimation, CT volumes of inanimate objects, cadaver kidneys and spleens, and in vivo balloons were performed. Regions of interest were outlined by a hand-operated cursor, and the computer program calculated the cross-sectional area in square millimeters and in pixels. A second computer program used Simpson's rule to calculate the volume from these multiple cross-sectional area. Calculated CT volumes were within +/-10% of directly measured volumes. Tumor masses being treated by chemotherapy were followed up clinically and by CT. Volume changes determined by CT are believed to be equal to and frequently more sensitive than clinical examination. From our experimental CT and clinical experiences, accuracy can be affected by (1) respiratory movement; (2) rapid changes in in vivo blood volume; (3) low CT number-gradient at the objects' periphery; (4) observer error in cursor tracing of the desired structure; and (5) mathematical errors inherent in Simpson's rule. We conclude that CT can estimate volumes of CT definable masses and can be useful in following tumor response to therapy.

Female↗
PubMed1982

Computed tomographic evaluation of carcinoma of the cervix.

To assess the accuracy of computed tomography (CT) in staging advanced carcinoma of the cervix, 18 staging evaluations were performed in 16 patients with locally advanced (FIGO Stage IB-IVA) cervical carcinoma. CT staging results were compared with the results of clinical staging and postoperative staging. CT was accurate in 12/18 (66%) cases, clinical staging was accurate in 10/18 (55%) cases, and clinical staging with cystoscopy was accurate in 14/18 (78%) cases. CT staging failed to detect microscopic pelvic sidewall involvement and bladder involvement when there was no contrast material in the bladder. In the detection of para-aortic lymph node involvement by tumor, there were 12 true-negative, 4 true-positive, 1 false-positive, and 1 false-negative study (sensitivity = 80%, specificity = 92%). It is concluded that CT is equal in accuracy to other clinical staging techniques and offers the advantage of visualizing the tumor, which allows for more accurate determination of radiation portals.

Carcinoma↗
PubMed1982

Liver injury and complications in the postoperative trauma patient: CT evaluation.

Twenty-eight patients with surgically documented and classified hepatic injury were studied by computed tomography (CT) in the postoperative period. CT demonstrated no abnormalities in 12 of these patients, most of whom had sustained simple lacerations of the liver. Of the 16 patients with abnormal scans, perihepatic fluid collections were present in six, five of whom had simple lacerations at surgery. The other 10 patients had CT evidence of parenchymal abnormalities, and all of these had sustained major hepatic injuries. CT is useful in depicting the postoperative anatomy, and in many cases demonstrates the nature and extent of damage; the likelihood of finding an abnormality varies with the severity of the injury, even though repair has been attempted. The frequent problem of postoperative sepsis is also amenable to CT evaluation, but the changes demonstrated are often nonspecific and the possibility of residual hepatic injury has to be considered. Finally, CT can document healing of parenchymal injury.

Abscess↗
PubMed1979

Digital radiology in trauma using small-dose exposure.

The microdose radiology system produces a large-field examination within thirty seconds on a video monitor. This video image can be manipulated in the same manner as a computed tomography (CT) scan. The system was installed at the Maryland Institute for Emergency Services (MIEMS) to examine severely injured patients. No major abnormalities were overlooked during the examination of these patients. The microdose system is useful in providing extensive radiologic information immediately applicable to the care of massively traumatized patients.

Evaluation Studies as Topic↗
PubMedDate not supplied

Effectiveness of small-group self-instruction in radiographic anatomy.

A small-group self-instructional program with 11 slide-tape units was designed to teach medical students radiographic anatomy concurrently with their course in gross anatomy. The effectiveness of the program was examined by administering an objective multiple choice examination at three medical schools. One school offered the slide-tape program alone; one, the slide-tape program plus lecture-demonstrations; and one acted as a control. The results indicate that students will, on their own, learn some radiographic anatomy. With exposure to an objectives-based, small-group slide-tape program, the students can learn significantly more. Such a slide-tape program plus lecture-demonstrations can further enhance learning. Student attitudinal results were uniformly positive toward this slide-tape program.

Anatomy↗
PubMedDate not supplied

Use of the computed tomographic whole body scanner to stage and follow patients with advanced ovarian carcinoma.

Advanced ovarian carcinoma continues to be a difficult tumor to evaluate noninvasively. Recent developments in chemotherapy have enhanced response rates in this disease, thus improving the likelihood of tumor regression. Computed Tomography (CT) allows the noninvasive estimation of tumor extent in patients with ovarian carcinoma. Seventeen patients with epithelial ovarian carcinoma had 22 whole body CT scans performed either just prior to or following laparotomy. For determination of tumor involvement, when the CT was positive, a high pathologic correlation was found at liver, ascitic, peritoneal, mesenteric, and omental sites (sensitivity). When the cT was negative, high pathologic correlation was found at ascitic and mesenteric sites (specificity). Lower and negative correlation at other disease sites is attributed to difficulty of CT detection of small (1 cm) tumor nodules on visceral surfaces. Eighteen patients with advanced ovarian carcinoma were followed prospectively during treatment with repetitive CT scans. CT results were compared with physical examination, other radiologic studies, and clinical status. In 83% (15/18) of patients and 88% (59/67) of CT scans performed, CT was found to contribute useful management information. Clinical decisions were made on the basis of CT alone in 43% (29/67) of scans performed. These data suggest that CT scanning is very useful in the staging and follow-up of patients with ovarian carcinoma and can replace other radiologic procedures, but it is not completely accurate and needs to be correlated with physical examination and in cases without tumors visible with CT, with laparotomy.

Female↗
PubMedDate not supplied

Experimental simulation evaluation of ECG-gated heart scans with a small number of views.

Computed tomography (CT) scanning techniques designed to visualize the beating heart utilize the electrocardiogram (ECG) waveform to gate or select the phase of the cardiac cycle being imaged. Most such methods require that each slice to be imaged be scanned many times to obtain the usual number of projections in a single phase interval of the cardiac cycle. We are studying a new method in which only a single scan of 20 s should be required per imaged slice. The central problem in the proposed technique is to test the diagnostic utility of images reconstructed from a very limited number (about 25) of projections. An essential part of the proposed algorithm is the elimination of all material outside a circle chosen to contain only the heart and the structures immediately surrounding it. Experiments are reported here on scans of calf's heart in an 11-cm container of water, with most views deleted so as to simulate the results from this type of gated scan. The results show that if no high-contrast objects are within the chosen circle, then image quality is satisfactory and could be clinically useful.

Animals↗