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Biomedical subjects

J F Gibbs

Publications and source records attributed to J F Gibbs.

31 records · Page 2Linked to original sources
PubMed1994

Cellular heterogeneity in DNA damage and growth inhibition induced by ICI D1694, thymidylate synthase inhibitor, using single cell assays.

Heterogeneity in the response of the HCT-8 (human ileocecal adenocarcinoma) tumor cell line to a new thymidylate synthase inhibitor, ICI D1694, was investigated in terms of induction of DNA single-strand breaks and cytotoxicity, applying the single cell alkaline gel (SCG) electrophoresis assay and the individual colony formation assay (iCFA), respectively. ICI D1694 induced maximal total DNA single-strand breaks 24 hr after a 2-hr drug exposure with incomplete repair by 72 hr. The level of DNA damage was concentration dependent and paralleled cellular growth inhibition in vitro. The proportion of cells with DNA damage and the extent of DNA single-strand breaks increased with drug concentration. At 1 microM ICI D1694 (IC95), a significant level of DNA damage was detected in 58% of the cells; however, 25% of the cells had little or no damage. Using the iCFA system, it was observed that with 1 microM ICI D1694, only 2.6% of the seeded cells maintained a colony growth rate similar to that of the control colonies, and 22% of the cells were growing significantly more slowly. In conclusion, the SCG assay and the iCFA identified subpopulations of cells that were unaffected by ICI D1694. Although these cells represented only a small proportion of the total cell population, this phenomenon of heterogeneity in response to ICI D1694 might limit its therapeutic efficacy.

Cell Division↗
PubMed1992

The use of marginal donors for liver transplantation. A retrospective study of 365 liver donors.

A total of 365 donor hepatectomies performed between May 1985 and March 1990 were reviewed and analyzed retrospectively to identify risk factors associated with poor graft function and to study the outcome of grafts retrieved from "marginal" donors. The donor mean age was 27.1 years (8-69 years). Mean ICU donor stay was 2.7 days (range 0 to 18 days), and the mean ischemic time was 8.6 hr (range 3 to 22 hr). The pancreas was retrieved in 39 donors. Donor's weight above 100 kg was the only variable found to be associated with both significantly increased 3-month graft loss (P less than 0.01) and early hepatocellular damage--AST or ALT greater than 2000 U/ml, 1st day posttransplant (P less than 0.02). Prolonged stay in the ICU (greater than 3 days), although associated with a significantly increased rate of hepatocellular damage (P less than 0.05), did not affect early graft survival. A systolic blood pressure less than 90 mmHg despite the use of high-dose dopamine (greater than 15 micrograms/mg/min), but not each of these variables itself, was also associated with a significantly increase rate of hepatocellular damage (P less than 0.001). All other variables, including age greater than 50, ischemic time greater than 12 hr, combined liver-pancreas procurement, and liver function test abnormalities, did not affect the outcome. We conclude that extending our limits to accept donors of the higher age group and those who have moderately abnormal liver function tests or a prolonged ischemic time will not jeopardize our results. It is suggested to perform liver biopsy in overweight donors during the retrieval to prevent using grafts with severe fatty infiltration. It is hypothesized that hormonal changes, starvation, and increased risk to develop infection might jeopardize the outcome of grafts from donors with a prolonged ICU stay. Although 70% of the early hepatocellular injuries are reversible, the remaining 30% result in graft failure.

Adolescent↗
PubMed1990

Liver transplantation, 1990: a Dallas perspective.

A retrospective analysis was undertaken on patients undergoing liver transplantation between April 1985 and May 1980 at Baylor University Medical Center, Dallas, Texas. A total of 358 patients were evaluated, 416 of whom received liver transplants, including 15 simultaneous liver/kidney transplants. The overall patient survival in this group was 82% at 1 year and 75% at 3 years, using Kaplan-Meier life tables.

Adult↗
PubMed1986

Percutaneous gastrostomy and gastroenterostomy: 1. Techniques derived from laboratory evaluation.

Various techniques, guidance systems, instruments, and the postmortem effects of percutaneous gastrostomy (PG) and percutaneous gastroenterostomy (PGE) were evaluated in 30 laboratory animals and five human cadavers. Methods to distend the stomach included air, fluid, intragastric balloon, and percutaneous needle inflation; a variety of trocar systems and catheters inserted by Seldinger technique (including those adapted from other uses and several designed specifically) were assessed. Fluoroscopy was the preferred guidance system, though sonography proved valuable (liver position, depth calculation to the stomach, localization of vessels to avoid), and the entire PG procedure was performed under sonographic guidance in four animals. Although the procedure was safe in most cases, several major complications did occur: laceration of a low-lying liver with exsanguination, malpositioned catheters in the lesser sac and adjacent to the spleen, and violation of the backwall of the stomach with laceration of celiac and splenic vessels. The animals and cadavers underwent autopsy. Autopsy revealed that firm gastrocutaneous tracts were formed by 7 days. There were few instances of wound infection, intraperitoneal fluid leakage, or evidence of trauma to the stomach when the catheters were well seated. Injury to the inferior epigastric artery is a potential hazard, and in cadaver dissections was located between the middle third and outer margin of the rectus abdominis muscle. Laboratory experience has been, and continues to be, an important means to improve and use new techniques for PG and PGE.

Animals↗
PubMedDate not supplied

Effective follow-up strategies in soft tissue sarcoma.

The value of surveillance for detection of recurrences in patients with soft tissue sarcoma (STS) after definitive surgical resection of the primary tumor is based on the premise that early recognition and treatment of local or distant recurrence can prolong survival. Surveillance strategies should meet the criteria of easy implementation, accuracy, and cost-effectiveness. Although guidelines have been proposed for follow-up of patients with STS, there are few data in the medical literature on the effectiveness of these recommendations. We reviewed the effectiveness of a surveillance program for primary extremity STS in an effort to provide an evidence-based rationale for follow-up of STS. We concluded that clinical assessment of patient symptoms, chest X-ray imaging, and physical examination are effective strategies for follow-up of extremity STS. Chest X-ray imaging also appears to be cost-effective, at least for high-grade extremity STS. Imaging of the primary extremity site by computed tomography (CT) scan or magnetic resonance imaging (MRI) on an annual basis and routine laboratory blood tests were ineffective strategies for recurrence detection. However, certain patient characteristics such as body habitus, previous radiation therapy, and location of the primary tumor site may require the use of CT scans and MRI for adequate clinical assessment. The role of specific surveillance strategies for recurrence detection for sarcomas of the trunk, head and neck, retroperitoneum, and viscera has yet to be defined.

Continuity of Patient Care↗
PubMedDate not supplied

Primary extremity sarcoma: what is the appropriate follow-up?

BACKGROUND: Our objective was to evaluate the effectiveness of follow-up tests for detecting first local and distant recurrences in patients with primary extremity soft tissue sarcoma. METHODS: We retrospectively analyzed all adult cases of primary extremity soft tissue sarcoma (n = 174) treated between 1982 and 1992. Patients were observed every 3 months for 2 years, every 4 months the third year, every 6 months the next 2 years, and annually, thereafter. Each visit consisted of taking the patient's history, a physical examination, a complete blood count, a blood chemistry panel, and a chest x-ray. For high-grade tumors, the primary site was imaged annually when clinically appropriate. RESULTS: Of 141 patients who were assessable, 29 patients developed local recurrence and 57 developed distant recurrence. All but one of the local recurrences was detected on the basis of an abnormal physical examination. Of the 29 patients who developed local recurrence, 25 were resected. Distant metastases were detected because of symptoms in 21 cases. Of the 36 asymptomatic lung recurrences, 30 were detected by follow-up chest x-ray. Of the 36 asymptomatic lung recurrences, 24 patients underwent metastasectomy. The positive and negative predictive values of surveillance chest x-ray were 92% and 97%, respectively. Laboratory testing never led to the detection of recurrence. CONCLUSIONS: Close surveillance by clinical assessment and chest x-ray is appropriate for follow-up observation of patients with primary extremity soft tissue sarcoma.

Extremities↗
PubMedDate not supplied

Accuracy of pathologic techniques for the diagnosis of metastatic melanoma in sentinel lymph nodes.

BACKGROUND: Sentinel lymph node (SLN) biopsy can accurately predict the presence of metastatic melanoma (MM) and has been used to identify patients with occult metastases. We present an analysis of the sensitivity and specificity of standard pathological techniques including intraoperative frozen section, permanent section, and immunohistochemistry in diagnosing MM within the SLN. METHODS: Sixty-nine consecutive patients with primary malignant melanoma thickness of >1.0 mm or thinner lesions invading the reticular dermis (Clark level IV) who underwent SLN biopsy were reviewed. Lymph nodes were examined intraoperatively by frozen section (FS), permanent section (H&E), and by immunohistochemistry (IH) for S-100 protein and HMB45. RESULTS: MM was found in 14 of 69 cases (20%). Permanent section H&E was performed in all cases, FS in 64 cases, and IH in 65 cases. FS analysis diagnosed MM in 4 of 14 cases (29%), was suspicious in 2 of 14 (14%), and falsely negative (FN) in 8 of 14 (57%) ultimately found to be positive with further workup. Within the FN group, MM was identified on review of the original FS slides in 3 of 8 cases (38%). Furthermore, within the FN group, the remaining 5 cases were identified as positive for MM by either permanent and/or deeper H&E sections and IH. IH alone with permanent H&E sections would have diagnosed MM in only 8 of 10 cases (80%) that were FS negative or suspicious. In no cases was MM identified by IH alone with the permanent and deeper H&E sections being negative. It is noteworthy that no false-positive cases were identified. CONCLUSIONS: Intraoperative FS has low sensitivity in identifying MM within the SLN. IH alone does not increase the diagnostic yield. A combination of permanent H&E sections with deeper levels and S-100 and HMB45 IH dramatically increases the overall diagnostic sensitivity of SLN biopsy. Definitive diagnosis should await permanent H&E sections and IH staining.

Adult↗
PubMedDate not supplied

A phase I study of fever-range whole body hyperthermia (FR-WBH) in patients with advanced solid tumours: correlation with mouse models.

Various studies in animal tumour models have revealed the potential of fever-range whole body hyperthermia (FR-WBH) to be used in cancer therapy. To determine the safety of FR-WBH treatment in the clinic, patients with advanced solid tumours were heated in the outpatient setting to 39-39.5 degrees C for 3 or 6h, or 39.5-40 degrees C for 6h using the Heckel-HT 2000 apparatus. These WBH treatments were well tolerated, with no significant adverse events related to cardiac, hepatic, renal or pulmonary systems. In the majority of patients, flow cytometric analysis of peripheral blood leukocyte populations indicated that there were transient decreases in the number of circulating T lymphocytes and a concomitant decrease in the number of L-selectin positive lymphocytes in the peripheral blood. These findings closely mimic the affects seen previously in pre-clinical murine studies in which this same fever-like treatment was shown to inhibit tumour growth. These studies have established the safety of this treatment and will allow for future clinical trials where application of FR-WBH treatment can be combined with other anti-cancer therapies, including immunotherapy and chemotherapy.

Adult↗