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Biomedical subjects

R Gardiner

Publications and source records attributed to R Gardiner.

13 recordsLinked to original sources
PubMed1990

The bistratenes: new cytotoxic marine macrolides which induce some properties indicative of differentiation in HL-60 cells.

The biological effects of cytotoxic macrolide polyethers, the bistratenes, isolated from the ascidian Lissoclinum bistratum, have been examined. Bistratene A was toxic to HL-60 human promyelocytic leukemia cells with an IC50 value of 424 nM. At lower concentrations (10-100 nM), bistratene A induced the incomplete differentiation of these cells along the monocyte/macrophage pathway. These effects were not due to inhibition of DNA synthesis. Bistratene B had similar effects to bistratene A. At micromolar concentrations these compounds enhance the phospholipid-dependent activity of type II protein kinase C from bovine spleen. The bistratenes provide new probes for studying the molecular mechanisms governing cell growth and differentiation.

Acetamides↗
PubMed1987

Reaction of nitric oxide with heme proteins and model compounds of hemoglobin.

Rates for the reaction of nitric oxide with several ferric heme proteins and model compounds have been measured. The NO combination rates are markedly affected by the presence or absence of distal histidine. Elephant myoglobin in which the E7 distal histidine has been replaced by glutamine reacts with NO 500-1000 times faster than do the native hemoglobins or myoglobins. By contrast, there is no difference in the CO combination rate constants of sperm whale and elephant myoglobins. Studies on ferric model compounds for the R and T states of hemoglobin indicate that their NO combination rate constants are similar to those observed for the combination of CO with the corresponding ferro derivatives. The last observation suggests that the presence of an axial water molecule at the ligand binding site of ferric hemoglobin A prevents it from exhibiting significant cooperativity in its reactions with NO.

Animals↗
PubMed1987

Efficacy of postevacuation view after double-contrast barium enema.

A single postevacuation view was obtained in each of 100 consecutive patients undergoing double-contrast barium enema to determine the efficacy of the routine use of this view. This view was unequivocally helpful only when complete appendiceal filling was desired (1% of our series). Otherwise, this view was either noncontributory (95%), of doubtful assistance (3%), or misleading (1%). Therefore, the postevacuation view should not be obtained routinely.

Barium Sulfate↗
PubMed1987

Infective enterocolitides.

Enteric infections, which range from asymptomatic to severe illnesses, are caused by a wide variety of organisms. Radiologic studies, in correlation with clinical findings, may suggest the correct diagnosis, but laboratory examinations are usually required for definitive diagnosis. Radiologic studies can be of help in determining the extent and course of infective enterocolitides.

Bacterial Infections↗
PubMed1984

Gastric restrictive surgery for obesity: early radiologic evaluation.

This study was undertaken to determine the optimal radiologic examination techniques for the period immediately following gastric restrictive surgery to control obesity. Review of 450 examinations performed on 275 patients who underwent varied gastric restrictive procedures indicates that accurate evaluation requires prompt filming of the first swallow of contrast material in a specific initial patient position with only minimal fluoroscopic monitoring. It was found that the optimal patient position can be predicted, before contrast material is administered, by the orientation of the staples on an abdominal radiograph. Right posterior oblique (RPO) is the optimal starting position when vertical staple lines follow gastroplasty with a lesser curvature channel. Left posterior oblique (LPO) is optimal when horizontal staple lines follow gastroplasty. LPO is usually optimal when complex or confusing staple patterns follow gastric bypass operations and revisions of previous procedures to control obesity. However, RPO is the optimal orientation when the revision procedure is a vertical gastroplasty.

Humans↗
PubMed1982

The colitides.

Diverse signs may be seen on barium enema in the various forms of colitis. Barium enema is only reasonably specific in the diagnosis of Crohn's disease and ulcerative colitis once the other possible diseases have been excluded from consideration by biopsy, microscopy, culture, or therapeutic trial. In particular, campylobacter colitis has proved to be such a common entity that many patients originally thought to have had one attack of ulcerative colitis, ischemic colitis, or Crohn's colitis may never have had these diseases. Many of the relatively specific signs can be seen in a variety of conditions. For example, aphthae in the colon may be seen in Crohn's disease, yersinia enterocolitis, Behçet's syndrome, amebiasis, ischemia, tuberculosis, and campylobacter colitis. Continuity of disease is characteristic in ulcerative colitis. Nevertheless, patches of healing may occur, so that a rare patient may be seen during a resolving attack of ulcerative colitis in whom only scattered patches of active disease can be seen on barium enema. In general, few radiologic signs on barium enema are truly specific for one disease, with penumatosis cystoides coli being an exception to this rule. However, the sensitivity of barium enema with currently available materials for double-contrast techniques is such that radiology continues to be useful at present in diagnosing the colitides and in managing patients.

Adult↗
PubMed1981

Colorectal carcinoma missed on double contrast barium enema study: a problem in perception.

A total of 31 cases of primary colorectal carcinoma missed on double contrast barium enema studies over a 5 year period (1976-1980) were collected from six institutions, and the causes of error reviewed. The errors were purely perceptive in 52%, due to a combination of perceptive and technical factors in 32%, and interpretative in 6%. The most common perceptive mistakes were failure to recognize a filling defect in the barium pool and failure to detect the tumor en face in double contrast study. Five cases were only detected at the time of the study as a result of double reading. Ten percent of the lesions could not be seen in retrospect, and therefore can be attributed to failure of the technique itself. At four of the institutions, the double contrast barium enema study missed 11 (6%) of 197 primary colorectal carcinomas. The lesion was invisible in retrospect in only two (1%) of these 197 studies, indicating that the double contrast examination is potentially highly sensitive for detecting colorectal carcinoma. The mainly perceptive nature of the errors indicates the need for more careful viewing of double contrast barium enemas. Familiarity with the different appearances of colorectal carcinoma on double contrast study, together with double-reading by the same or different observers, should reduce the incidence of missed lesions.

Barium Sulfate↗