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Biomedical subjects

B Bernhardt

Publications and source records attributed to B Bernhardt.

At least 19 recordsLinked to original sources
PubMed2004

Jarosite and hematite at Meridiani Planum from Opportunity's Mossbauer Spectrometer.

Mossbauer spectra measured by the Opportunity rover revealed four mineralogical components in Meridiani Planum at Eagle crater: jarosite- and hematite-rich outcrop, hematite-rich soil, olivine-bearing basaltic soil, and a pyroxene-bearing basaltic rock (Bounce rock). Spherules, interpreted to be concretions, are hematite-rich and dispersed throughout the outcrop. Hematitic soils both within and outside Eagle crater are dominated by spherules and their fragments. Olivine-bearing basaltic soil is present throughout the region. Bounce rock is probably an impact erratic. Because jarosite is a hydroxide sulfate mineral, its presence at Meridiani Planum is mineralogical evidence for aqueous processes on Mars, probably under acid-sulfate conditions.

Extraterrestrial Environment↗
PubMed2004

Mineralogy at Gusev Crater from the Mössbauer spectrometer on the Spirit Rover.

Mössbauer spectra measured on Mars by the Spirit rover during the primary mission are characterized by two ferrous iron doublets (olivine and probably pyroxene) and a ferric iron doublet (tentatively associated to nanophase ferric iron oxide). Two sextets resulting from nonstoichiometric magnetite are also present, except for a coating on the rock Mazatzal, where a hematite-like sextet is present. Greater proportions of ferric-bearing phases are associated with undisturbed soils and rock surfaces as compared to fresh rock surfaces exposed by grinding. The ubiquitous presence of olivine in soil suggests that physical rather than chemical weathering processes currently dominate at Gusev crater.

Extraterrestrial Environment↗
PubMed2004

[Intraoperative laparoscopic cholangiography -- when is it useful?].

Since the introduction of laparoscopic cholecystectomy (LC), a decrease in the practice of intraoperative cholangiography (IOC) has been reported. Are there actually reasons for carrying on IOC during LC? Depending on the management of common bile duct (CBD) stones treatment a different IOC regime is recommended. If the single-stage laparoscopic extraction of ductal calculi during LC is preferred, routine IOC is generally necessary to detect all CBD stones for desobstruction via ductus cysticus or choledochotomy. When therapeutic splitting is favoured, including two-stage management with endoscopic desobstruction and later LC, routine IOC can be foregone. However, selective practice of IOC can help to reduce the rates of unnecessary preoperative investigations from 40-60 % to 20 % when postoperative endoscopic desobstruction demonstrates similar success rates of about 95 %. Regarding the preventive character of laparoscopic IOC to CBD injuries, a routine investigation should be adopted by institutions with injury rates > 0.4 % and in the learning phase of young surgeons. For all other institutions a selective practice should be recommended when difficult intraoperative conditions render recognition of the anatomical situation more difficult or for identification of dissected non-bleeding ducts near the triangle of Calot.

Cholangiography↗
PubMed1998

Sequence analysis of BRCA1 and BRCA2: correlation of mutations with family history and ovarian cancer risk.

PURPOSE: Previous studies of mutations in BRCA1 or BRCA2 have used detection methods that may underestimate the actual frequency of mutations and have analyzed women using heterogeneous criteria for risk of hereditary cancer. PATIENTS AND METHODS: A total of 238 women with breast cancer before age 50 or ovarian cancer at any age and at least one first- or second-degree relative with either diagnosis underwent sequence analysis of BRCA1 followed by analysis of BRCA2 (except for 27 women who declined analysis of BRCA2 after a deleterious mutation was discovered in BRCA1). Results were correlated with personal and family history of malignancy. RESULTS: Deleterious mutations were identified in 94 (39%) women, including 59 of 117 (50%) from families with ovarian cancer and 35 of 121 (29%) from families without ovarian cancer. Mutations were identified in 14 of 70 (20%) women with just one other relative who developed breast cancer before age 50. In women with breast cancer, mutations in BRCA1 and BRCA2 were associated with a 10-fold increased risk of subsequent ovarian carcinoma (P = .005). CONCLUSION: Because mutations in BRCA1 and BRCA2 in women with breast cancer are associated with an increased risk of ovarian cancer, analysis of these genes should be considered for women diagnosed with breast cancer who have a high probability of carrying a mutation according to the statistical model developed with these data.

Adult↗
PubMed1994

Phonological intervention techniques for syllable and word structure development.

This article has two purposes: to outline aspects of nonlinear phonological theory that refer to syllable, word, and phrase structure, and to provide some examples of phonological intervention techniques for development of these structures. A variety of restricted child productions of syllable, word, and phrase structures are described in nonlinear terms. Intervention targets are defined for each of the restrictions, and both general and specific interventions are suggested, the majority of which have been clinically evaluated. Clinicians are encouraged to try various alternatives to discover which techniques that facilitate syllable- and word-building strategies are most productive for an individual child. Rationales, purposes, activities, and procedures are presented to assist the clinician in developing appropriate and individualized intervention strategies.

Articulation Disorders↗
PubMed1994

Nonlinear phonology: introduction and clinical application.

The purpose of this tutorial is to introduce a recent advance in phonological theory, "nonlinear phonology," which differs fundamentally from previous theories by focusing on the hierarchical nature of relationships among phonological units. We first introduce the basic concepts and assumptions of nonlinear phonological theory and then demonstrate clinical applications of the theory for assessment and intervention. Data from a child with a severe phonological disorder are used to illustrate aspects of nonlinear theory. The data are first analyzed in terms of phonological processes in order to provide the readers with a familiar starting point for comprehension and comparison. The nonlinear frameworks are shown to provide a deeper analysis of the child's phonological system than the phonological process analyses and to lead to a more clearly defined intervention plan.

Articulation Disorders↗
PubMed1993

A randomized clinical trial comparing melphalan/prednisone with or without interferon alfa-2b in newly diagnosed patients with multiple myeloma: a Cancer and Leukemia Group B study.

PURPOSE: This clinical trial was designed to compare the effectiveness of the standard melphalan and prednisone regimen to that of melphalan, prednisone, and interferon in patients with untreated multiple myeloma. PATIENTS AND METHODS: Between October 1985 and March 1988, 278 patients were accrued to a multi-institutional, randomized clinical trial. Responding patients were treated for 2 years before termination of therapy. RESULTS: After a median follow-up of 23 months, the overall remission rate for the melphalan/prednisone treatment group was 44% compared with 33% for the group receiving melphalan/prednisone/interferon alfa-2b. The durations of response and survival were identical for the two treatment groups. Median survival was 3.17 years on melphalan/prednisone treatment and 3.0 years on melphalan/prednisone/interferon alfa-2b treatment. Both hematologic and nonhematologic toxicities were greater in the melphalan/prednisone/interferon alfa-2b treatment group, but were usually of a mild or moderate degree and did not interfere with the completion of therapy. The frequency of deaths in the two treatment groups attributable to the treatment itself was similar. CONCLUSION: This study shows no advantage to the concomitant delivery of interferon alfa-2b with standard melphalan and prednisone as initial treatment for patients with multiple myeloma.

Adult↗
PubMed1988

Clonal immunoglobulin gene rearrangements in chronic lymphocytic leukemia: a correlative study.

Forty-two patients with chronic lymphocytic leukemia (CLL) were studied for immunoglobulin gene and T-cell receptor gene rearrangements. Immunoglobulin heavy chain gene rearrangements were demonstrable in 41 cases. One rearrangement of the T-cell receptor beta chain gene was detected. Quantification of the relative intensities of germline and rearranged DNA bands suggests that a significant component of the lymphocytosis may be due to cell populations other than the malignant clonal population, particularly in earlier stages of the disease. A direct relationship was found between severity of disease and the relative amount of clonal immunoglobulin heavy chain gene rearrangement. Preliminary data for 12 patients followed sequentially indicated that clinical deteriorations or improvements are reflected in an increase or decrease, respectively, in the proportion of cells with rearranged immunoglobulin genes. Change in the relative proportion of cells with germline versus rearranged genes may provide an additional useful criterion for staging CLL, for more precisely defining the abnormal lymphocyte population, and for monitoring progression of the disease and efficacy of treatment.

Adult↗
PubMed1988

COPBLAM III: infusional combination chemotherapy for diffuse large-cell lymphoma.

COPBLAM III, a polychemotherapy regimen consisting of cyclophosphamide, infusional vincristine, prednisone, infusional bleomycin, doxorubicin, and procarbazine, was administered to 51 patients with diffuse large-cell lymphoma. Ninety-six percent of patients age 60 or younger achieved a complete response (CR); none have relapsed. Overall, 88% of patients are alive and well and potentially in the survival plateau. For patients greater than 60 years, CR was obtained in 73%, with 42% potentially in the survival plateau, the difference resulting in part from four relapses, three toxic deaths, and one presumed unrelated death. These results in the elderly were paralleled by a relatively reduced ability to tolerate therapy. Toxicity was primarily pulmonary, occurring in 39% of patients, two of whom died. With an overall CR rate of 84%, of which 92% are sustained at a median follow-up of 40 months, COPBLAM III represents a highly effective treatment in a sizeable cohort of patients.

Adult↗
PubMed1988

The location of breakpoints within the breakpoint cluster region (bcr) of chromosome 22 in chronic myeloid leukemia.

Rearrangement of the breakpoint cluster region (bcr) was demonstrated by Southern blot analysis in the DNA in each of 68 patients with Ph chromosome-positive CML and in 3 of 7 patients with apparent Ph chromosome-negative CML. In contrast, no bcr rearrangement could be found in DNA from 17 normal individuals and 28 patients with various hematologic disorders other than CML or ALL. An analysis of the location of the breakpoints within the bcr indicated that 3' breakpoints were significantly more common in patients in blast crisis or accelerated phase disease compared to those with chronic phase disease. Patients with chronic phase disease and 3' breakpoints had shorter average disease duration than that for chronic phase patients with 5' breakpoints, although the difference between these two groups of patients was not statistically significant. For patients who had progressed to accelerated disease or blast crisis, a statistically significant difference in chronic phase disease duration could be demonstrated between 11 patients with 3' breakpoints (average chronic phase 30.2 months) and 15 patients with 5' breakpoints (average chronic phase 50.6 months). For 8 patients studied in both chronic phase and accelerated or blast crisis, the location of the breakpoint did not change. We suggest that the bcr-abl fusion protein associated with a 3' breakpoint could result in more rapid progression to acute disease, and this may account for differences in the relative frequency of 3' and 5' breakpoints at different disease stages. Although more studies are required, identifying CML patients with a higher propensity for early blast transformation may eventually prove to be of some clinical value.

Blast Crisis↗
PubMed1987

Malignant schwannoma in siblings with neurofibromatosis.

Three brothers with neurofibromatosis (NF) died of sarcoma. The proband tumor had malignant schwannoma. The histologic nature of the sarcoma in the other two brothers was not known, but it seemed likely to be similar to that of the proband. However, the sarcomatous lesions in these two siblings developed in the patients' right lower limbs which showed clinical and radiological evidence of anterior bowing of the tibia. Their mother and two other siblings have neurofibromatosis, but have not developed malignant tumors. The unaffected father died at age 61 of carcinoma of the common bile duct. An unaffected sister developed adenocarcinoma of both colon and lung. Although it is known that patients with NF are at a high risk of developing malignant sarcoma and second primary malignancies, it is not clear whether this association is genetically determined. The family we report has some of the features of a "cancer family" and suggests that sarcomatous transformation in patients with NF may be genetically influenced. This report raises the possibility that the presence of congenital malformation and exposure to irradiation may predispose patients with neurofibromatosis to develop malignant schwannoma.

Adult↗
PubMed1987

Induction of proliferation and differentiation of leukaemic B cells from patients with chronic lymphocytic leukaemia by anti-mu and conditioned medium.

We investigated the growth and differentiation of leukaemia B cells from patients with B-cell chronic lymphocytic leukaemia (CLL) in response to proliferation and differentiation factors present in conditioned medium and to anti-immunoglobulin antibodies. Highly purified E-rosette negative (E-) B cells from 5 out of 15 patients with CLL exhibited moderate proliferative responses to 10 or 50 micrograms/ml of F(ab)'2 fragments of rabbit anti-human mu-chain specific antibody. Conditioned medium (CM), derived by stimulating human peripheral blood mononuclear leucocytes with PHA, induced significant proliferative responses of purified E- cells in 13 out of 14 patients examined. The extent of these proliferative responses varied substantially, and was in the range of 2.6- to 91-fold. Stimulation of purified E- cells from patients with CLL with both anti-mu and CM resulted in significant proliferation in all 15 patients examined. These responses were significantly higher than those induced by CM alone (P less than 0.02). Synergism between CM and anti-mu in inducing proliferative responses was observed in 11 out of 15 patients. Largely leukaemic B cell populations expressing on the cell surface more than one immunoglobulin heavy-chain isotype, exhibited significantly higher (P less than 0.009) proliferative response to CM and anti-mu than those expressing IgM only. Highly purified E-peripheral blood or tonsil lymphocytes from all normal donors examined responded by proliferation to anti-mu alone or to CM alone. Synergism in inducing proliferative responses was also observed when the cells were stimulated with both CM and anti-mu. In addition to inducing proliferative responses, culture with CM of purified E-rosette negative, largely leukaemic, B cells from patients with CLL for 6 days at 37 degrees C resulted in differentiation into immunoglobulin synthesizing and secreting cells. Synthesis and secretion of IgM were observed in 7 out of 10 patients examined. A switch to IgG production was observed in three patients. Morphological examination of E- cells from patients with CLL after treatment with CM demonstrated that these cells were differentiated into plasma-like cells. These results suggest that leukaemic B cells from patients with CLL can be induced to proliferate and differentiate in response to growth and differentiation factors derived by mononuclear leucocytes, in a manner similar to that of normal B cells.

Antibodies, Anti-Idiotypic↗