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Biomedical subjects

K C Farmer

Publications and source records attributed to K C Farmer.

At least 19 recordsLinked to original sources
PubMed2000

5-aminosalicyclic acid and olsalazine inhibit tumor growth in a rodent model of colorectal cancer.

The ability of 5-aminosalicylic acid and olsalazine to inhibit colonic aberrant crypts and tumors was investigated in 1,2-dimethylhydrazine-treated rats. The effect of these drugs on the rates of tumor apoptosis and proliferation was studied as potential mechanisms for their action. 5-Aminosalicylic acid reduced the number of aberrant crypt foci by over one third, while olsalazine had no effect on this parameter. However, both agents effectively reduced tumor number and load, increased the rate of tumor apoptosis, and reduced the rate of tumor cell proliferation. In conclusion, 5-aminosalicylic acid and olsalazine are both ultimately effective chemopreventive agents in this model; however, only 5-aminosalicylic acid inhibited the formation of aberrant crypt foci. The inhibitory effect of these agents in tumors is related to the inhibition of proliferation and the induction of apoptosis.

Aminosalicylic Acids↗
PubMed1999

Methods for measuring and monitoring medication regimen adherence in clinical trials and clinical practice.

Researchers and clinicians have used numerous methods in their attempts to adequately assess patient compliance (adherence) with medication regimens and to identify noncompliant patients. Large variations have been reported in the extent of noncompliance in individual patients and large populations. In addition, nonadherence has often been poorly defined. Direct measures of adherence include drug assays of blood or urine, use of drug markers with the target medication, and direct observation of the patient receiving the medication. Indirect measures of adherence imply that the medication has been used by the patient; these measures include various forms of self-reporting by the patient, medication measurement (pill count), use of electronic monitoring devices, and review of prescription records and claims. Compliance measures should be assessed on the basis of their validity (sensitivity and specificity or statistical correlation) and the reference standard used. Many early studies used pill counts as a reference standard, but electronic monitoring devices such as the Medication Event Monitoring System have replaced pill counts as the reference standard. The choice of a method for measuring adherence to a medication regimen should be based on the usefulness and reliability of the method in light of the researcher's or clinician's goals. Specific methods may be more applicable to certain situations, depending on the type of adherence being assessed, the precision required, and the intended application of the results.

Clinical Trials as Topic↗
PubMed1998

Effectiveness of prostaglandin E2 intracervical gel (Prepidil), with immediate oxytocin, versus vaginal insert (Cervidil) for induction of labor.

OBJECTIVE: Our purpose was to compare the effectiveness of labor induction with use of prostaglandin E2 either as an intracervical gel (Prepidil), with immediate oxytocin, or as a sustained-release vaginal insert (Cervidil) with subsequent oxytocin as needed. STUDY DESIGN: Hospitalized patients at >/=37 weeks' gestation requiring labor induction and having an unfavorable cervix (Bishop score </=6) were randomly assigned to receive either Prepidil or Cervidil. Oxytocin was begun immediately after Prepidil placement or 30 minutes after removal of the Cervidil insert if needed. RESULTS: Of the 150 patients, there were no differences in demographics and eventual pregnancy outcomes between the Prepidil group (n = 77) and the Cervidil group (n = 73). Those pregnancies receiving the Prepidil-immediate oxytocin regimen were delivered sooner than those receiving the Cervidil among nulliparous (11.3 +/- 7.3 hours vs 25.2 +/- 12.5 hours, P <.001) and multiparous (8.4 +/- 7.8 hours vs 18.4 +/- 7.2 hours, P <.001) women. The mean cost savings, which favored the Prepidil-immediate oxytocin regimen, was $458 (range $204 to $630) per patient. CONCLUSION: Compared with Cervidil, the Prepidil-immediate oxytocin regimen resulted in a shorter induction-to-vaginal delivery interval and in more hospital cost savings without increasing adverse outcomes.

Administration, Intravaginal↗
PubMed1997

The case for sunscreens. A review of their use in preventing actinic damage and neoplasia.

BACKGROUND: Recent controversy surrounding sunscreens has stimulated a reexamination of their use. The purposes of this article are to weigh the evidence regarding the value of sunscreens in preventing actinic damage and neoplasia and to evaluate the merit of objections that have been raised against their use for this purpose. Scientific aspects of damage from UV light, neoplasia, and sunscreens are reviewed. The value of sunscreen use in preventing actinic damage is discussed and a number of sunscreen controversies are revisited. OBSERVATIONS: The evidence favors the safety and efficacy of sunscreens for the prevention of actinic damage, melanoma, and nonmelanoma skin cancer. CONCLUSION: Sunscreens continue to be a practical and useful tool for the prevention of actinic damage and neoplasia.

Animals↗
PubMed1997

Off-label prescribing during pregnancy.

Obstetricians frequently prescribe drugs for indications other than those on the product label. Reasons for such off-label use during pregnancy include prevention of repetitive abortion, inhibition of premature labor, reduction of fetal or neonatal infection, reduction in development of preeclampsia and its complications, and ripening of the cervix or induction of labor. A physician has a legal right to prescribe for off-label indications despite regulatory, manufacturer, and cost constraints. Such prescribing habits would not be considered experimental if based on sound scientific evidence. Adequate and well-controlled studies are difficult, however, to perform during pregnancy. Evidence of widespread use and support from another qualified clinician are methods of justifying off-label prescribing. Each patient is entitled to know why she and her fetus would benefit from the treatment and whether any unnecessary risk is anticipated. Legible documentation of these discussions in the medical records is important.

Drug Approval↗
PubMed1997

Patterns of uterine activity. Using oxytocin after intracervical PGE2.

OBJECTIVE: To compare patterns of uterine activity from low-dose oxytocin begun immediately or six hours after intracervical placement of prostaglandin E2 (PGE2) gel for the induction of labor. STUDY DESIGN: A total of 50 nonlaboring women at term with an unfavorable cervix (Bishop score < or = 4) were given a 0.5-mg dose of PGE2 gel. Each was then randomized either to be observed or to receive a low dose of oxytocin (2 mU/min, increased by 2 mU/min at 30-minute intervals, as necessary). After the six-hour observation, the patient was reexamined, and a low dose of oxytocin was either begun or continued. An adequate sample size (21 per group) was calculated for evaluating uterine activity changes. Comparisons were made using chi 2 testing, Student's t test and analysis of variance, as appropriate. RESULTS: There were no differences between the two groups in maternal race, gestational age, predose Bishop score, predose uterine activity or indication for induction. Uterine contractions became more frequent (P < .01) and were judged to be more intense (P < .02) and earlier when oxytocin was used immediately after PGE2 placement. No uterine hyperstimulation or abnormal fetal heart rate pattern was observed that required discontinuation of the oxytocin. The percentages of cases delivering vaginally within 24, 36 and 48 hours were greater when oxytocin was begun immediately in nullipara (P < .01). CONCLUSION: Low-dose oxytocin may be started immediately after instilling intracervical PGE2, with shortened time until the onset of adequate contractions.

Administration, Intravaginal↗
PubMed1996

Sun exposure, sunscreens, and skin cancer prevention: a year-round concern.

OBJECTIVE: To review the role of sunlight in skin aging and skin cancer formation, and to provide guidelines on the use of sunscreens to minimize the adverse effects of sun damage. DATA SOURCES: A MEDLINE search of applicable articles on ultraviolet (UV) radiation, melanoma, sunscreens, and skin cancer, evaluating both human and animal studies. Published and unpublished original research as well as clinical experience were also used. DATA SYNTHESIS: The interaction of UV radiation and skin type plays a central role in melanoma formation. Mortality from melanoma is highest in geographic locations near the equator, where UV intensity is greatest. The incidence of melanomas in light-complected individuals (skin types I-III) is several times higher than those with darker skin types (types IV-VI), even in similar geographic regions. The UVB portion of the spectrum appears to be primarily responsible for skin cancer formation and photoaging, while short wave UVA rays play a significant contributing role. Regular sunscreen use has been shown to reduce the formation of precancerous actinic keratoses (AK) lesions by 36%. A dose-response relationship has also been found between the amount of sunscreen used and AK formation. CONCLUSIONS: Sunscreens have now been shown to reduce the carcinogenic effects of sunlight in humans. Patients should be advised of the long-term consequences of sun exposure and the benefits of regular sunscreen use.

Clinical Trials as Topic↗
PubMed1995

Caffeine phenotyping of cytochrome P4501A2, N-acetyltransferase, and xanthine oxidase in patients with familial adenomatous polyposis.

Patients with familial adenomatous polyposis (FAP) and age and sex matched controls were tested for cytochrome P4501A2 (CYP1A2), N-acetyltransferase, and xanthine oxidase activities using caffeine urinary metabolites as a discriminator. FAP patients showed significant underactivity of N-acetyltransferase (which inactivates some carcinogens) and significant overactivity of CYP1A2 (which activates some carcinogens). Xanthine oxidase activity, which can generate free radicals and cause cellular damage, was significantly increased in the FAP patients. All but one of the FAP patients had undergone colectomy. A separate group of six patients was therefore assessed before and at an average time of eight weeks after colectomy. No effect on enzyme activity was seen. The differences in enzyme activities detected in this study could produce an excess of active carcinogenic metabolites in the bile of FAP patients and contribute to the high risk for intestinal cancer in FAP.

Acetyltransferases↗
PubMed1994

CT appearances of desmoid tumours in familial adenomatous polyposis: further observations.

Intra-abdominal desmoid tumours represent a major cause of morbidity and mortality in patients with familial adenomatous polyposis (FAP), and such patients are also liable to develop musculoskeletal desmoids. We have reviewed the CT appearances of 44 desmoid lesions (28 intra-abdominal and 16 musculoskeletal) in 20 patients with FAP. We found a considerable heterogeneity in the CT appearance of musculoskeletal and intraabdominal desmoids, with respect to their density, definition and change in size or density on follow-up, not only between different patients but also in patients with multiple lesions, who rarely showed identical appearances of all lesions. In some cases, mesenteric tumours may initially present as ill-defined soft tissue infiltration of mesenteric fat, becoming larger and more mass-like with time. On medical treatment, shrinkage was seen infrequently in musculoskeletal desmoids, and not at all with mesenteric lesions. CT evidence of bowel involvement by intra-abdominal lesions was frequent, most commonly appearing as 'tethering' or encasement of bowel loops. The presence of a large mesenteric mass (> 10 cm diam.), multiple mesenteric masses, extensive small bowel involvement and/or bilateral hydronephrosis were associated with ultimate death.

Adenomatous Polyposis Coli↗
PubMed1993

Randomized controlled trial of the effect of sulindac on duodenal and rectal polyposis and cell proliferation in patients with familial adenomatous polyposis.

Twenty-four patients with familial adenomatous polyposis who had previously undergone prophylactic colectomy and had advanced duodenal polyposis were entered into a randomized trial to assess the effect of the non-steroidal anti-inflammatory drug sulindac on duodenal and rectal polyps. Polyp size and number were assessed by videotaped duodenoscopy (and rectoscopy in 14 patients) at entry and after 6 months of treatment; the tapes were compared by two assessors who were unaware of the randomization and the shuffled chronological order of the recordings. Mucosal cell proliferation was measured by in vitro incorporation of 5-bromo-2'-deoxyuridine. Sulindac therapy was associated with a reduction in epithelial cell proliferation in the duodenum (median labelling index (LI) 15.8 versus 14.4 per cent, P = 0.003) and a trend towards duodenal polyp regression (P = 0.12). In the rectum, cell proliferation showed a marked reduction (median LI 8.5 versus 7.4 per cent, P = 0.018), and significant (P = 0.01) polyp regression was seen. Rectal polyposis was less severe than that in the duodenum and responded more dramatically. Sulindac is a possible treatment for patients in whom rectal polyps have failed to show significant regression after ileorectal anastomosis and who are unsuitable for pouch surgery; it may be useful in early duodenal polyposis or as an adjunct after duodenal clearance.

Adenomatous Polyposis Coli↗
PubMed1993

Colectomy with ileorectal anastomosis lowers rectal mucosal cell proliferation in familial adenomatous polyposis.

Rectal polyp regression has been observed in familial adenomatous polyposis (FAP) after colectomy and ileorectal anastomosis (IRA). In view of the association between risk of neoplasia and epithelial cell turnover rates, a study was conducted to determine the effect of colectomy and IRA on rectal mucosal proliferation in FAP. Endoscopic biopsies of flat rectal mucosa were taken from 12 FAP patients with an established IRA and 10 FAP patients prior to colectomy. Mucosal proliferation was assessed by flash-labeling S-phase cells with bromodeoxyuridine. Labeled cells were visualized on paraffin sections with an immunohistochemical stain using a monoclonal antibody to bromodeoxyuridine. Twenty crypt columns were analyzed. The mean labeling index (percent labeled cells/crypt) of the FAP patients with established IRAs (7.0 +/- 1.4 percent) was significantly less than that of the precolectomy patients (12.8 +/- 3.0 percent) (Mann-Whitney U test, P = 0.0004). Comparison of labeled distribution curves shows a contraction of the crypt proliferative zone in the IRA group. Colectomy with IRA in FAP is associated with a significant reduction in rectal mucosal cell proliferation. These findings support the claim of reduced risk of rectal cancer following this procedure in FAP and are of relevance to the study of environmental vs. genetic control of cell proliferation.

Adenomatous Polyposis Coli↗