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Biomedical subjects

L Riley

Publications and source records attributed to L Riley.

32 records · Page 2Linked to original sources
PubMed1993

Isolated locally recurrent rectal cancer: a review of incidence, presentation, and management.

Locoregional recurrence after treatment for rectal cancer may be largely prevented by wide pelvic surgical margins, adjuvant radiotherapy, and chemotherapy. Approximately half of these recurrences will present with recurrence only at the surgical site; one third to one half will be resectable with conventional surgical procedures, but the rest will require extended resections, including sacrum and hypogastric vessels, to achieve clean margins. Only a small fraction of those treated will be cured. There is no proof that radiotherapy or chemotherapy added to surgical excision afford better results, since no trials have been or are likely to occur, given the rarity of the situation. However, best results seem to follow multimodality therapy using complete surgical resection and radiotherapy (IORT or brachytherapy with or without teletherapy) with chemopotentiation. Yet, there is no multimodality series with a sufficient number of patients and follow-up period to be able to distinguish the actual value of the treatment and which patients are most likely to benefit. It is important to note that there will be some patients with second LRR who can be further aided by aggressive locoregional therapy.

Brachytherapy↗
PubMed1992

The implications of sonographically identified cervical changes in patients not necessarily at risk for preterm birth.

Sonography of the cervix and lower uterine segment has been used in evaluating pregnancies at risk for incompetent cervix and premature labor. Shortened cervix (less than 3 cm) and open internal os with funneling of the membranes into the endocervical canal are sonographic features associated with premature delivery. We identified these sonographic signs in a group of 31 asymptomatic women who were undergoing prenatal sonography for multiple indications, not necessarily related to premature labor or cervical incompetence. Nineteen patients (61%) in this heterogeneous population had pregnancies complicated by preterm labor, clinical evidence of incompetent cervix, or preterm birth. We conclude that the presence of abnormal sonographic features of the cervix seen incidentally during prenatal sonography on asymptomatic patients warrants close clinical attention.

Female↗
PubMed1991

Macrophage exposure to polymethyl methacrylate leads to mediator release and injury.

To understand further the role of macrophages in the loosening of cemented arthroplasty, several in vitro effects of polymethyl methacrylate (PMMA) particle exposure in these cells were studied. The kinetics of arachidonic acid and derived inflammatory mediator release was characterized following macrophage exposure to either PMMA or control polystyrene particles. Temporal release of radiolabeled products by [14C]arachidonate-labeled cells was determined by sequential scintillation counting. Significant dose-dependent release of arachidonic acid mediators by macrophages was observed within half an hour of exposure to either PMMA or styrene particles. Unexposed control cells incubated in media alone did not release detectable amounts of radiolabeled products. The leakage of intracellular lactate dehydrogenase (LDH), a marker of cell injury, was detected spectrophotometrically 4 h following exposure to PMMA but not styrene. PMMA-induced LDH release was dose dependent. In contrast, polystyrene exposure failed to increase LDH release above unexposed control cells. These in vitro studies reveal that macrophages rapidly released arachidonic acid and derived inflammatory mediators in response to both PMMA and styrene particles. However, cells exposed to PMMA are lethally damaged, as reflected by the subsequent leakage of their intracellular LDH. We propose that a similar sequence of events may occur when macrophages encounter PMMA particles at the bone-cement interface. This is characteristic of a foreign body granulomatous response.

Animals↗
PubMed1990

Detection of Shigella in feces using DNA amplification.

A rapid diagnostic method employing a polymerase chain reaction procedure (PCR) was used to identify Shigella and enteroinvasive Escherichia coli. This procedure amplified a region of the invasive-associated locus (ial) from a crude DNA extract of feces. A synthetic 21-base oligonucleotide corresponding to the ial gene sequence was shown to specifically hybridize only with enteroinvasive E. coli (EIEC) strains and Shigella species. Upon PCR amplification, a 320-base pair fragment was generated in DNA extracted from feces reconstituted with EIEC or Shigella flexneri but not in DNA from 70 normal stools lacking these organisms and could be readily detected by the ial probe. For identifying Shigella and EIEC, the PCR assay was 10(5)- and 10(2)-fold more sensitive than standard biochemical tests and the macrocolony hybridization assay, respectively. These findings demonstrate a novel methodology for rapid, sensitive, and culture-independent diagnosis of diarrhea caused by these pathogens and underscores the utility of PCR in the diagnostic laboratory.

Base Sequence↗
PubMed1990

Financial impact of a rapid CK-MB-specific immunoassay on the diagnosis of myocardial infarction.

The purpose of this study was twofold. First, we evaluated the financial impact of a rapid, monoclonal antibody-based CK-MB mass assay (Stratus, Dade Division, Baxter Laboratories, Miami, Fla) for the direct measurement of CK-MB in serum samples from 65 patients admitted to the coronary care unit with the possible diagnosis of acute myocardial infarction. Second, we evaluated retrospectively the Stratus assay and an activity assay (electrophoresis) for CK-MB in the following patient categories: acute myocardial infarction treated with and without thrombolytic therapy, angina, congestive heart failure, skeletal muscle trauma, and the acutely ill without acute myocardial infarction. The advantageous features of the Stratus mass assay were as follows. First, the laboratory was able to perform the assay more frequently because of the short assay time per specimen (less than 10 minutes) without additional personnel. This had a substantial impact on the clinician's ability to diagnose acute myocardial infarction and to move patients out of an intensive care unit at substantial financial savings to the patient, the hospital, or the third-party payer. Second, the Stratus assay was able to detect low levels of CK-MB (1 to 2 micrograms/L) in the presence of low total creatine kinase activity (less than 100 U/L). Third, the Stratus assay showed no interference due to very-high-total creatine kinase activities (greater than 100,000 U/L), CK-BB, macro-creatine kinase, and mitochondrial creatine kinase.

Blood Protein Electrophoresis↗
PubMed1987

Treatment of metastatic renal cell carcinoma with coumarin (1,2-benzopyrone) and cimetidine: a pilot study.

Forty-five patients with metastatic renal cell carcinoma were treated with coumarin (1,2-benzopyrone) and cimetidine. Patients received coumarin, 100 mg orally daily; cimetidine administration, 300 mg orally four times daily, was initiated on day 15 of therapy, and treatment with both drugs was continued until progression of disease. Three patients are too early to evaluate (on study less than or equal to 2 months with no change in tumor status). Objective responses (greater than or equal to 50% reduction in measurable disease) occurred in 14 of 42 evaluable patients (33.3%) (the 95% confidence interval based on this rate is +/- 14.3%), with three complete responses and 11 partial responses (PR). Complete responses lasted 9.5, 4+, and 9.5+ months. The median duration of response for the PR group was 5 months (range, 4 to 21+ months). Twelve patients experienced stabilization of disease ranging from 4 to 16.5+ months. No response was seen in 16 patients. There was no symptomatic, hematologic, or chemical (organ dysfunction) toxicity among the 45 patients treated. Coumarin and cimetidine appear to be safe and active agents in the treatment of metastatic renal carcinoma. Further studies are required to determine the optimal dose and scheduling of these agents.

Adult↗
PubMed1986

Primary neoplasms of the cervical spine. Diagnosis and treatment of twenty-three patients.

The records of twenty-three patients with a primary benign or malignant osseous neoplasm of the cervical spine were reviewed in an attempt to clarify the most appropriate diagnostic and treatment methods for such tumors. Thirteen patients had a benign tumor and ten patients had a malignant tumor. Nineteen patients had been followed for two to eighteen years (average, six years), and four had died from the malignant disease between one and five months after its discovery. In addition to surgery, medical treatment in the ten patients with a malignant tumor included radiation therapy in seven and chemotherapy in two. Surgical treatment consisted of an anterior and posterior partial resection combined with an arthrodesis in four patients; an anterior partial resection in three, two with an arthrodesis; a posterior partial resection and an arthrodesis in two; and a biopsy but no further treatment in one patient. The duration of survival ranged from one to five months for four patients and from two to three years for four, and was eight and sixteen years in two patients. Two of the thirteen patients with a benign tumor received radiation therapy. Surgical treatment included both an anterior and a posterior resection with arthrodesis in four, an anterior resection in three (with arthrodesis in two), a posterior resection in four (with arthrodesis in three), and a biopsy without surgical resection in two. At follow-up, twelve patients were pain-free and had a solid arthrodesis, although one had required a repeat excision posteriorly. One patient with Gorham's disease (diffuse hemangiomatosis) died. During the period of thirty years (1953 to 1983) when these patients were seen, both the diagnostic methods available and the surgical approaches used have changed. Our present opinion is that all primary osseous lesions of the cervical spine should be carefully defined by arteriography, tomography, bone-scanning, computed tomographic scanning, and myelography in order to properly plan the surgical approach. Total excision of suspect malignant lesions is not attempted, but a major intralesional excision should be carried out to decompress neural and vascular structures and to obtain a biopsy specimen, followed by an arthrodesis to stabilize the spine. For both malignant and benign tumors, an anterior resection should be performed if the tumor is located anteriorly, and a posterior approach should be used if the tumor is predominantly in the posterior vertebral elements. Both of these procedures should be combined with an arthrodesis.(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent↗
PubMed1983

Hypocalcemia and inhibition of parathyroid hormone secretion after administration of WR-2721 (a radioprotective and chemoprotective agent).

We investigated the causes of the hypocalcemia associated with WR-2721, an investigational drug that protects normal tissues against the toxic effects of radiation and chemotherapy. Sixteen patients with advanced cancers had serial measurements of serum calcium and other studies of blood chemistry before and after taking the compound. In all 16 patients (18 courses) the mean serum calcium level fell from 2.33 to 1.90 mmol per liter (9.33 to 7.62 mg per deciliter, P less than 0.001) after WR-2721, and in all 8 patients from whom data were obtained, serum calcium levels remained depressed at 24 hours. In 12 patients, ionized calcium levels dropped from 0.98 to 0.80 mmol per liter (P less than 0.01). Serum magnesium values fell from 0.96 to 0.74 mmol per liter (1.91 to 1.48 mg per deciliter, P less than 0.001). There were no changes in arterial pH or serum phosphate concentrations. In nine patients urinary calcium excretion rose from 3.96 to 10.68 mumol per minute (P less than 0.01) after WR-2721. Despite hypocalcemia, parathyroid hormone levels fell in all subjects. WR-2721 also inhibited the release of parathyroid hormone from bovine parathyroid cells incubated in vitro in low (0.5 mM) concentrations of calcium. We conclude that WR-2721 inhibits the secretion of parathyroid hormone and enhances calciuria, thereby leading to hypocalcemia.

Amifostine↗
PubMed1976

Use of disposable products in surgical practice.

Disposable products today are an important part of the multibillion dollar health devices industry. A few heavy-usage and low-usage examples of disposable products used by surgeons are chosen to demonstrate that in a 1,000-bed hospital, economy is rarely, if ever, a reason for converting from reusables to disposables. The actual reasons are more closely related to individual preference, availability, convenience, dependability, safely, and, in some cases, manufacturer's promotion. In a 24-hospital study of surgical apparel, it was found that only caps, masks, shoe covers, and other small items approached partly in cost between disposable and reusable items, where as the per-use cost of reusable larger items such as gowns and drapes was still much lower than that of their disposable counterparts. However, each hospital must make its own decisions based on all factors, not on economy alone.

Cellulose↗