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B Erickson

Publications and source records attributed to B Erickson.

At least 37 records · Page 2Linked to original sources
PubMed1999

The effect of phospholipase A2 inhibitors on proliferation and apoptosis of murine intestinal cells.

BACKGROUND: Group II phospholipase A2 (PLA2) enzymes, the rate controlling enzymes in arachidonic acid metabolism, have been well characterized and subdivided into secretory 14-kDa PLA2 (sPLA2) and cytoplasmic 85-kDa PLA2 (cPLA2). Previous research has demonstrated increased PLA2 in colorectal tumors. The present study was performed to determine the effect of specific PLA2 inhibitors on the proliferation and induction of apoptosis of intestinal epithelial cells. METHODS: A continuously proliferating rat small intestinal cell line (IEC-18) and a mouse colon cancer cell line (WB-2054-M4) were utilized for these experiments. The cells were placed in microwells with serum-free or serum-supplemented media. The effects of serum on proliferation were then evaluated in the presence of the cPLA2 inhibitor, methylarachidonyl fluorophosphate (MAFP), or the sPLA2 inhibitor p-bromophenacyl bromide (BPB). The sPLA2 and cPLA2 protein was estimated by Western blotting. Proliferation of intestinal cells was quantitated by incorporation of [3H]thymidine into DNA and PLA2 activity was evaluated by quantitating arachidonic acid formation and prostaglandin E2 production. RESULTS: Western blotting of IEC-18 and WB-2054 cell protein demonstrated sPLA2 and cPLA2 enzyme in cells incubated in media containing 10% serum. Spontaneous DNA synthesis was present in both cell lines and serum consistently increased proliferation. In IEC-18 cells [3H]thymidine incorporation stimulated by serum was inhibited by MAFP and BPB, while in the malignant cell line, proliferation was inhibited only by BPB. BPB, but not MAFP, produced a dose-dependent increase in apoptotic ratios in both cell lines. Arachidonic acid and PGE2 formation, stimulated by serum, was inhibited by MAFP and BPB. CONCLUSIONS: A differential effect on intestinal cell mitogenesis was seen with different PLA2 inhibitors. The sPLA2 inhibitor, but not the cPLA2 inhibitor, significantly inhibited [3H]thymidine incorporation in the malignant cell line. This occurred with an induction of apoptosis. sPLA2 inhibitors may be specific inhibitors of growth of malignant cells. The inhibition of arachidonic acid and PGE2 production did not correlate with the inhibition of proliferation, suggesting that the two processes may be unrelated.

Acetophenones↗
PubMed1999

The American brachytherapy society survey of brachytherapy practice for carcinoma of the cervix in the United States.

PURPOSE: The purpose of this study was to survey the brachytherapy practice for cervical cancer in the United States. METHODS: The Clinical Research Committee of the American Brachytherapy Society (ABS) performed a retrospective survey of individual physicians of the ABS and American Society of Therapeutic Radiologists and Oncologists regarding the details of the brachytherapy techniques they personally used in the treatment of cervical cancer patients for the year 1995. The replies (some of which may have been an estimate only) were tabulated. The scope of this survey did not allow us to verify the data by chart audits. RESULTS: A total of about 3500 questionnaires were mailed out; 521 responses were received. Of these responders, 206 (40%) did not perform any brachytherapy for carcinoma of the cervix in 1995. Of the other 315 responders reporting a total of 4892 patients treated in 1995, 88% used low dose rate (LDR) while 24% used high dose rate (HDR). There was a wide variation in the doses used. For LDR treatments, the median total external beam radiation therapy (EBRT) dose was 45 and 50 Gy and the LDR dose was 42 and 45 Gy for early and advanced cancers, respectively. For HDR treatments, the median EBRT dose was 48 and 50 Gy and the median HDR dose was 29 and 30 Gy for early and advanced cancers, respectively. The median dose per fraction was 6 Gy for a median of five fractions. Interstitial brachytherapy was used as a component of the treatment in 6% of the patients by 21% of responders. Very few responders treated with pulsed or medium dose rates. CONCLUSION: This retrospective survey showed the current brachytherapy practice pattern in the treatment of cervical cancer in the United States and can serve as a basis for future prospective national brachytherapy data registry. There was wide variation in the practice pattern, emphasizing the urgent need for consensus on these issues.

Brachytherapy↗
PubMed1998

The role of selective cyclooxygenase isoforms in human intestinal smooth muscle cell stimulated prostanoid formation and proliferation.

Intestinal smooth muscle plays a major role in the repair of injured intestine and contributes to the prostanoid pool during intestinal inflammatory states. Cyclooxygenase (COX), which catalyzes the conversion of arachidonic acid to prostanoids exists in two isoforms, COX-1 and COX-2. The purpose of this study was to determine the relative contributions of COX-1 and COX-2 in the production of prostanoids by human intestinal smooth muscle (HISM) cells when stimulated by interleukin-1beta (IL-1beta) and lipopolysaccharide (LPS). Furthermore the effects of specific COX-1 and COX-2 inhibitors on the proliferation of smooth muscle cells was also evaluated. Confluent monolayer cultures of HISM cells were incubated with IL-1beta or LPS for 0-24h while control cells received medium alone. PGE2 and PGI2 as 6-keto-PGF1alpha and LTB4 were measured by a specific radioimmunoassay. COX enzymes were evaluated by Western immunoblotting. Unstimulated and stimulated cells were exposed to the specific COX-1 inhibitor valerylsalicylic acid (VSA) and the COX-2 inhibitors NS-398 and SC-58125. The effects of serum on proliferation were then evaluated in the presence of each of the specific COX inhibitors by incorporation of 3H-thymidine into DNA. IL-1beta and LPS increased both PGE2 and 6-keto-PGF1alpha in a dose dependent fashion with enhanced production detected two hours following exposure. Neither stimulus stimulated LTB4 release. Immunoblot analysis using isoform-specific antibodies showed that both COX-1 and COX-2 were present constitutively. Furthermore, COX-1 was upregulated by each inflammatory stimulus. In a separate set of experiments cells were pretreated with either the selective COX-1 inhibitor VSA or the selective COX-2 inhibitors NS-398 or SC-58125 prior to treatment with IL-1beta or LPS. The COX-1 and COX-2 inhibitors decreased both basal and IL-1beta and LPS stimulated prostanoid release. Spontaneous DNA synthesis was present and serum consistently increased proliferation. 3H-thymidine incorporation, stimulated by serum, was inhibited by both COX-1 and COX-2 inhibitors. This study suggests that the prostanoid response stimulated by proinflammatory agents of gut-derived smooth muscle cells appears to be mediated by both COX-1 and COX-2 enzymes. Proliferation of smooth muscles cells also appears to be influenced by both COX-1 and COX-2.

Blotting, Western↗
PubMed1997

Clinical indications for brachytherapy.

Brachytherapy, or placing radioactive sources either temporarily or permanently into or near a malignant tumor, is a long-established cancer treatment method. During the past 25 years, brachytherapy has become safer and more versatile than earlier radium therapy, and its indications have increased dramatically during this period. One estimate is that at least 5-10% of all patients needing radiation therapy require brachytherapy. The site-specific clinical indications and methods for brachytherapy implementation are described.

Biliary Tract Neoplasms↗
PubMed1997

Interstitial implantation of gynecologic malignancies.

Interstitial implantation is invaluable in the management of patients with extensive or large volume gynecologic malignancies, significant anatomical distortion, or recurrent disease. Such techniques are necessary components of the brachytherapy services available to patients with gynecologic malignancies giving superior results in terms of local tumor control and survival compared to those achieved with external beam alone or inadequate intracavitary applications. Local tumor control with an acceptable risk of complications can be achieved for these challenging disease presentations if these techniques are implemented skillfully through the joint efforts of the radiation oncologist and gynecologic surgeon.

Anesthesia, Epidural↗
PubMed1996

CT-guided interstitial implantation of gynecologic malignancies.

PURPOSE: To establish the efficacy of computed tomography (CT)-based planning and analysis of transperineal implants. METHODS AND MATERIALS: For patients with bulky disease or geometrically unfavorable anatomy, transperineal interstitial implantation of gynecologic tumors offers an alternative to standard intracavitary techniques. Control of dose rate and total dose distributions to produce a homogenous, low dose rate implant presents a challenge to the radiation oncologist in these complex implants, as does the relationship of these distributions to the patients's anatomy. We have used CT imaging following needle implantation, prior to source loading, in 25 patients (28 implants), as an aid in both the planning of the implant and the analysis of the dosimetry. RESULTS: The spatial relationship between the needles and the normal anatomy can be clearly defined, despite the presence of some artifacts. Tumor volume is less clearly visualized but the adequacy of needle placement can be assessed and adjusted if necessary. Modifications of the planned source placement, based upon the location of specific needles and critical structures, can be made prior to loading the patient. Dose rate and total dose distributions are displayed with the appropriate anatomy on axial images and on reconstructed sagittal and coronal planes. Multiple points of dose specification for the rectum and the bladder are easily defined. Dose rate adjustment can be made by selectively changing the activity associated with a particular needle or needles. Multiple implants as well as external beam irradiation can also be integrated. CONCLUSIONS: CT-based dosimetry has permitted intelligent planning decisions to be made prior to and during these implants. It has further allowed more accurate anatomically based dosimetric analysis, with visualization and control of dose rate and total dose distributions displayed together with the patient's anatomy. This more elaborate analysis should ultimately lead to a better understanding of the reasons for local control and complications and their relationships to dose rate, total dose, and volume.

Brachytherapy↗
PubMed1996

The last word?

Explore the source record for details and available documents.

Animals↗
PubMed1995

Comparison of high dose-rate and low dose-rate dose distributions for vaginal cylinders.

PURPOSE: The identification of appropriate high dose-rate parameters required to produce a "uniform" dose distribution on the surface of a vaginal cylinder. The high dose-rate dose distribution is then compared to the traditional low dose-rate dose distributions obtained with Burnett cylinders. METHODS AND MATERIALS: Dose distributions were calculated for 2, 3, and 3.5 cm diameter Burnett cylinders with and without crossing sources. Three models for the high dose-rate cylinders were developed and compared. High dose-rate dose distributions were calculated for 2, 3, and 3.5 cm diameter cylinders with and without anisotropic corrections for various dose specification points. RESULTS: Low dose-rate distributions are not uniform over the surface of the applicator. The exact distribution depends upon cylinder diameter and upon the exact source loading. High dose rate dose distributions can be configured to provide for a "uniform" dose on the surface, if an apex dose specification point is used together with dose specification points on the surface of the applicator opposite each dwell position. CONCLUSIONS: The conversion of low dose rate techniques to high dose rate techniques for vaginal cylinders involves an appreciation of the details of dose distributions of both approaches. The comparison between traditional low dose-rate distributions and high dose-rate distributions shows that, unlike the low dose-rate distributions, a relatively uniform high dose-rate distribution can be obtained independent of cylinder diameter. The clinical significance of the differences in the low dose-rate and high dose-rate dose distributions remains to be determined by long-term follow up of patients treated with high dose-rate techniques.

Carcinoma↗
PubMed1994

Seroconversion in patients attending sexually transmitted disease clinics.

OBJECTIVES: To characterize recent HIV seroconverters in a sexually transmitted disease (STD) clinic population, and examine changing transmission patterns. METHODS: We conducted a case-control study nested within a retrospectively defined cohort of individuals attending Baltimore STD clinics between January 1988 and July 1990. Seroconverters, who tested HIV-positive after having a negative test, were compared to both HIV-negative controls, who were also tested twice, and a second, prevalent HIV-positive control group. Controls were matched 2:1 by sex, clinic, and month of HIV test. RESULTS: Forty-nine out of 6175 (0.79%) patients tested at least twice had documented HIV-1 seroconversion. On multivariate analysis, seroconversion was significantly associated with self-reported injecting drug use [odds ratio (OR), 7.3; 95% confidence interval (CI), 2.3-23)], with being a man who has had sex with other men (OR, 3.5%; 95% CI, 1.2-10), or with having sex with a known HIV-infected person (OR, 11; 95% CI, 1.3-96). Thirty-five per cent of seroconverters did not report a risk for HIV infection, and a higher proportion of recent seroconverters also reported no risk. Compared to the prevalent positive control group, more seroconverters reported no risk and a lower proportion reported recognized risks. A diagnosis of gonorrhea was also significantly associated with seroconversion (OR, 2.5; 95% CI, 1.1-5.7). CONCLUSIONS: These data suggest increasing heterosexual transmission of HIV in this inner-city STD clinic population. Incident STD, in particular gonorrhea, may increase a patient's risk for HIV infection, suggesting that patients with STD should be targeted aggressively for HIV prevention activities.

Adult↗
PubMed1994

Interdisciplinary team approach in the rehabilitation of hip and knee arthroplasties.

Use of an interdisciplinary case management team approach in the treatment of patients with hip or knee arthroplasty has resulted in a decrease in length of stay and achievement of functional outcomes at the authors' center. Case management was used to standardize patient care and to measure each patient's progress toward independence against established criteria of treatment outcomes. Outcomes established for physical therapy were ambulation distance, performance of a home exercise program, stair climbing, amount of active knee flexion (for knee arthroplasties), and incorporation of hip precautions. Outcomes for occupational therapy were bed mobility, chair transfers, toilet transfers, and activities of daily living with emphasis on lower extremity dressing. The case management team consists of an occupational therapist, an occupational therapy assistant, a physical therapist, and two nurses. The specific role of the occupational therapy personnel in this team approach is to maximize, by discharge, a patient's functional level of independence in activities of daily living. Data from a 6-month period indicated that occupational therapy goals were achieved for 79% of the 33 knee arthroplasty patients and 73% of the 37 hip arthroplasty patients.

Activities of Daily Living↗
PubMed1993

Characteristics of epidemic hepatitis A in Baltimore City: implications for control measures.

In 1988, a hepatitis A epidemic began in Baltimore, Maryland. A total of 607 cases were reported to the Baltimore City Health Department between the period November 1, 1988, and December 31, 1989. The health department conducted case investigations to identify factors important to the development of control measures. Immunoglobulin was given to appropriate contacts, and an educational campaign was initiated. Of the 607 reported cases, 63% were white and 57% were male. Cases were geographically clustered within 5 of Baltimore's 23 zip codes. Among the 242 adults interviewed, 43% self-reported drug use and 44% were unemployed. Twenty-one percent of the adults and 56% of the children reported contact with either a suspected or confirmed case of hepatitis. Despite control efforts, the epidemic continued through 1990. Barriers to implementing traditional control measures resulted in continuing transmission of hepatitis A in the community.

Adolescent↗
PubMed1992

Effect of HIV posttest counseling on STD incidence.

OBJECTIVE: To evaluate the effectiveness of human immunodeficiency virus (HIV) testing and posttest counseling in reducing subsequent high-risk behavior. METHODS: The incidence of sexually transmitted diseases (STDs) in the Baltimore, Md, public STD clinic population after HIV testing and counseling was determined by chart review and was compared in two groups, 868 HIV-seropositive patients and 1104 HIV-seronegative patients, matched by age, sex, and month in which HIV test was conducted. Patients were observed for incident STDs at intervals of 6 through 23 months. Patients with incident STDs were classified hierarchically after being notified of the HIV test result and receiving posttest counseling. RESULTS: Of HIV-seropositive patients, 615 (71%) returned for their test results and received posttest counseling; 694 HIV-seronegative patients (63%) returned. Of all those who returned for results and posttest counseling, 60 (9.7%) of 615 HIV-seropositive patients and 61 (8.8%) of 694 HIV-seronegative patients were diagnosed at least once with definite STD (syphilis, gonorrhea, or trichomoniasis) (P, not significant). Twenty-four HIV-seropositive patients (3.9%) and 71 HIV-seronegative patients (10.2%) returned with probable STD (nongonococcal urethritis or pelvic inflammatory disease) (P less than .001). Nine HIV-seropositive patients (1.5%) and 23 HIV-seronegative patients (3.3%) returned having had an STD-infected sexual partner (P less than .03). Age, sexual orientation, and drug use behavior did not predict return with STD. CONCLUSIONS: Both HIV-seropositive and HIV-seronegative patients showed high rates of repeat STDs after posttest counseling, an important public health challenge in creating effective high-risk behavior prevention strategies.

Counseling↗
PubMed1991

Twice-daily tapering dexamethasone treatment during cranial radiation for newly diagnosed brain metastases.

Twenty evaluable patients with newly diagnosed brain metastases underwent treatment with a novel dose/schedule of dexamethasone aimed at reducing steroid toxicity during palliative radiation therapy. All patients received twice daily dexamethasone starting at 8 mg bid for four days then 4 mg bid for four days then 2 mg bid until the last day of radiation therapy. The radiation prescriptions were not standardized varying from 2000 cGy/5 fractions to 5800 cGy/29 fractions. Fourteen patients received dexamethasone for a minimum of 24 hours before their first radiation treatment and 7 (50%) experienced improvement in neurologic symptoms/signs prior to starting radiation treatments. Fourteen patients completed the planned course of radiation and dexamethasone. Only 1 patient needed to restart dexamethasone within 30 days of finishing radiation because of steroid reversible neurologic deficits. Steroid toxicity was mild including hyperglycemia (1), candida esophagitis (1), steroid pseudorheumatism (2), peripheral edema (1) and steroid withdrawal syndrome (1). Only two toxic events were recorded in patients receiving steroids less than 21 days. Twice daily dexamethasone appears to provide good clinical results with minimal morbidity.

Administration, Oral↗