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Biomedical subjects

C Geyer

Publications and source records attributed to C Geyer.

At least 19 recordsLinked to original sources
PubMed2005

[Motivational interviewing for patients with comorbid schizophrenia and substance abuse disorders: a review].

Patients with schizophrenia and substance abuse disorders [dually diagnosed patients (DD)] show an unfavourable course of the illness and little interest in participating on specific integrated treatment programmes. Motivational interviewing (MI) has been shown to be effective among other substance abuse disorders and it aims to enhance intrinsic motivation to change problem behaviour. MI has been adapted for DD. The present paper reviews the empirical evidence for the efficacy of MI in DD. A search in the databases MEDLINE, EMBASE, PsycINFO was conducted and the methodological quality of the identified trials was assessed according to the Cochrane Collaboration and to the JADAD Scale. We identified 4 randomised studies with a total of 346 participants, in which MI interventions of 1 to 3 sessions were compared with various control conditions over a follow-up period of up to 6 months. With regard to the main outcome measures "subsequent participation at integrated treatment programme" (1 x positive, 2 x negative) and "substance use" (1 x positive, 1 x negative,) the studies gained contradictory results. In all 4 studies, there were relevant general methodological limitations (randomisation, blindness of raters, description of the reasons for drop-outs) and specific methodological shortcomings (sample size and sample homogenity, numbers of MI sessions, assessment of motivational status). Hence, at present the evidence for supporting MI in DD is not clear. This may be due to the methodological problems mentioned above or it may be that there is, in fact, no effect. Therefore, there is an urgent need for further research of MI in DD.

Diagnosis, Dual (Psychiatry)↗
PubMed2003

Marked inactivation of O6-alkylguanine-DNA alkyltransferase activity with protracted temozolomide schedules.

Temozolomide, an oral DNA methylator that inactivates the DNA repair enzyme O(6)-alkylguanine-DNA alkyltransferase (AGAT), has demonstrated anticancer activity on protracted schedules. Protracted schedules may lead to an 'autoenhancement' of temozolomide's inherent cytotoxic potential by cumulative reduction of the cell's capacity for AGAT-mediated DNA repair and resistance. This study was undertaken to characterise AGAT inactivation and regeneration in the peripheral blood mononuclear cells (PBMCs) of patients treated on two protracted temozolomide schedules. O(6)-alkyl guanine-DNA alkyltransferase activity was measured in the PBMCs of patients treated on two phase I protracted temozolomide studies. Patients were treated daily for either 7 days every 2 weeks (Schedule A) or 21 days every 4 weeks (Schedule B). The effects of various temozolomide doses (75-175 mg m(-2)), treatment duration (7-21 days), and temozolomide plasma levels on AGAT inactivation and regeneration, as well as the relation between AGAT inactivation and toxicity, were studied. O(6)-alkyl guanine-DNA alkyltransferase activity in PBMCs was measured serially in 52 patients. Marked inactivation of AGAT occurred following 7 days of temozolomide treatment, with mean AGAT activity decreasing by 72% (P<0.0001). Similarly, mean AGAT activity decreased by 63 and 73% after 14 and 21 days of treatment, respectively (P<0.001 for both comparisons). O(6)-alkyl guanine-DNA alkyltransferase inactivation was greater after 7 days of treatment with higher doses of temozolomide than lower doses and remained markedly reduced 7 days post-treatment. However, AGAT inactivation following temozolomide treatment for 14 and 21 days was similar at all doses. On the continuous 21-day schedule, AGAT inactivation was significantly greater in patients who experienced severe thrombocytopenia than those who did not (90.3+/-5.5 vs 72.5+/-16.1%, P<0.045). In conclusion, protracted administration of temozolomide, even at relatively low daily doses, leads to significant and prolonged depletion of AGAT activity, which may enhance the antitumour activity of the agent.

Antineoplastic Agents, Alkylating↗
PubMed2000

Comparison of the prognostic value of left ventricular filling and peak oxygen uptake in patients with systolic heart failure.

AIM: The aim of this prospective study was to compare the prognostic value of the mitral inflow pattern and peak oxygen uptake in patients with systolic heart failure. BACKGROUND: Peak oxygen uptake is a major prognostic parameter in heart failure. It is not known whether a restrictive mitral inflow pattern has similar prognostic value. METHODS: One hundred heart failure patients (ejection fraction <45%) underwent exercise testing after Doppler evaluation; prognosis was assessed after a mean follow-up of 17 months. RESULTS: The ejection fraction was larger in group 1 (non-restrictive pattern: E/A mitral wave ratio <1 or between 1 and 2 with E wave deceleration time >/=140 ms, n=45) than in group 2 (restrictive pattern: E/A ratio >2 or between 1 and 2 with E deceleration time <140 ms, n=40) (29+/-9 vs 22+/-10%, P<0.05). Peak oxygen uptake was lower in group 2 (17+/-4 vs 22+/-5 ml. min(-1). kg(-1)57+/-11 vs 75+/-15% of predicted values;P<0.05 for both comparisons). Univariate analysis showed that the deceleration time (r=0.65), E/A ratio (r=-0.50) and heart rate increment (r=0.47) correlated best with peak oxygen uptake. A third group of patients with persistent fusion of the E and A waves (n=15) had exercise responses similar to those of group 2 patients. A short deceleration time (P=0.006), a restrictive or a fusion pattern (P=0.04) were associated with a poor outcome; the prognostic value of these Doppler variables was greater than that of ejection fraction, but remained less than peak oxygen uptake indexed by predicted values (P=0.0004). CONCLUSION: The left ventricular filling pattern is a strong predictor of exercise capacity, and outcome, in patients with systolic heart failure and is independent of the left ventricular ejection fraction. Peak oxygen uptake remains a more powerful prognostic variable.

Aged↗
PubMed2000

Predicting cancer development in oral leukoplakia: ten years of translational research.

Our 10-year translational study of the oral premalignant lesion (OPL) model has advanced the basic understanding of carcinogenesis. Although retinoids have established activity in this model, a substantial percentage of our OPL patients progress to cancer, especially after treatment is stopped. On the basis of our 10-year OPL study, we have developed the first comprehensive tool for assessing cancer risk of OPL patients. This cancer risk assessment tool incorporates medical/demographic variables, epidemiological factors, and cellular and molecular biomarkers. Between 1988 and 1991, 70 advanced OPL patients were enrolled in a chemoprevention trial of induction with high dose isotretinoin (1.5 mg/kg/day for 3 months) followed by 9 months of maintenance treatment with either low dose isotretinoin (0.5 mg/kg/day) or beta-carotene (30 mg/d; total treatment duration, 1 year). We assessed the relationship between cancer risk factors and time to cancer development by means of exploratory data analysis, logrank test, Cox proportional hazard model, and recursive partitioning. With a median follow-up of 7 years, 22 of our 70 patients (31.4%) developed cancers in the upper aerodigestive tract following treatment. The overall cancer incidence was 5.7% per year. The most predictive factors of cancer risk are OPL histology, cancer history, and three of the five biomarkers we assessed (chromosomal polysomy, p53 protein expression, and loss of heterozygosity at chromosome 3p or 9p). In the multivariable Cox model, histology (P = 0.0003) and the combined biomarker score of chromosomal polysomy, p53, and loss of heterozygosity (P = 0.0008) are the strongest predictors for cancer development. Retinoic acid receptor beta and micronuclei were not associated with increased cancer risk. We have demonstrated a successful strategy of comprehensive cancer risk assessment in OPL patients. Combining conventional medical/demographic variables and a panel of three biomarkers can identify high risk patients in our sample. This result will need to be validated by future studies. With the identification of high risk individuals, more efficient chemoprevention trials and molecular targeting studies can be designed.

Alcohol Drinking↗
PubMed1999

[Brain natriuretic peptide (BNP) in coronary insufficiency: relationship with left ventricular filling and exercise tolerance].

Brain natriuretic peptide (BNP) is a recently discovered peptide, secreted by the atria and ventricles in response to parietal distension. It was recently proposed as a screening test for left ventricular failure. The authors assayed this peptide at rest in 37 patients with chronic heart failure due to left ventricular systolic dysfunction and another 20 patients with various diseases (respiratory failure, cirrhosis, heart transplantation, "diastolic" heart failure) but normal left ventricular systolic function. A significant increase compared to normal values was observed not only in the group of heart failure patients, but also in patients with all other diseases. BNP was significantly higher in NYHA class IV patients. The relationship between plasma BNP levels and ejection fraction was not significant. On the other hand, a good correlation was observed between BNP and left ventricular filling parameters evaluated by cardiac Doppler: E wave deceleration time (r = -0.53, p = 0.001), E/A ratio: r = 0.57 p = 0.005) or VO2 max (r = -0.55, p < 0.005).

Aged↗
PubMed1998

Chemoprevention in head and neck cancer: basic science and clinical application.

The concept of field cancerization and the multistep carcinogenesis theory are the premises on which the development of chemoprevention efforts has been based. The first concept underlies the fact that patients who have been cured of a cancer in the aerodigestive tract are still at risk of developing additional primary tumors in the same field, and the multistep carcinogenesis theory implies that the conceivable arrest of one of the steps by chemoprevention might be enough to impede the development of cancer. There is ongoing research for development of new candidate-chemopreventive substances in most areas of oncology. Most of the clinical experience in chemoprevention of head and neck cancer is based on the use of retinoids. Retinoids in high doses have demonstrated activity in treating oral premalignant lesions (OPLs) but with frequent side effects and early relapse after cessation of therapy. Subsequent trials showed better tolerability of retinoids in lower doses. Ongoing trials are currently evaluating whether chemoprevention over 3 years might have longer-lasting effect both on OPLs and in the prevention of second primary tumors.

Chemoprevention↗
PubMed1998

Reduced central serotonin transporters in alcoholism.

OBJECTIVE: Dysfunction of monoamine uptake mechanisms has been implicated in the pathogenesis of alcohol dependence. The authors explored whether serotonergic dysfunction is associated with anxiety and depression, which increase the risk of relapse in alcoholics. METHOD: The availability of serotonin and dopamine transporters in 22 male alcoholics and 13 healthy male volunteers was measured with the use of [123I] beta-CIT and single photon emission computed tomography, and psychopathological correlates were assessed. RESULTS: A significant reduction (a mean of about 30%) in the availability of brainstem serotonin transporters was found in the alcoholics, which was significantly correlated with lifetime alcohol consumption and with ratings of depression and anxiety during withdrawal. CONCLUSIONS: The findings support the hypothesis of serotonergic dysfunction in alcoholism and in withdrawal-emergent depressive symptoms.

Adult↗
PubMed1996

Familial basis of exertional rhabdomyolysis in quarter horse-related breeds.

OBJECTIVES: To trace pedigrees from affected horses, identify likely contributing founder horses, and determine the conditional probability of founder genotypes. DESIGN: Muscle biopsy records from the Neuromuscular Disease Laboratory at the University of California-Davis and the University of Minnesota were searched to identify horses with a polysaccharide storage myopathy and exercise intolerance/rhabdomyolysis. Pedigrees containing 5 to 6 generations were obtained where possible. ANIMALS: 13 Quarter Horses, 4 American Paint Horses, 3 Appaloosas, and 3 Quarter Horse crossbreds (16 mares, 4 geldings, and 3 stallions) were identified with polysaccharide storage myopathy. Pedigrees were available for 18 horses. PROCEDURE: Inbreeding coefficients, founder contributions, and conditional probability of founder genotypes were calculated. RESULTS: Three stallions (A, B, and C) were featured prominently in the pedigrees. Stallions A and B descended from a common sire. On average, A contributed 8.8% (range, 0 to 23%) of the genes in affected horses, B contributed 4.2% (range, 0 to 14%), and C contributed 3.0% (range, 0 to 14%). The sire and dam of 4 horses were descendants of stallion A, the sire and dam of 1 horse were descendants of stallion B, and the sire and dam of 11 horses were descendants of a combination of stallions A and B. The pattern of inheritance resembled an autosomal recessive disorder. Assuming this pattern of inheritance, the conditional probability that these founders were carriers or recessive for the trait was > 99.29% for stallions A and B and 92% for stallion C. CONCLUSIONS: Results support a familial basis for polysaccharide storage myopathy and associated exertional rhabdomyolysis in Quarter Horse-related breeds. The strong contribution of particular founder stallions to the gene pool in some lines of Quarter Horses may explain the high incidence of exertional rhabdomyolysis in these horses.

Animals↗
PubMed1996

[Indications for heart transplantation (excluding emergencies)].

The improved diagnosis in chronic cardiac failure and the lack of donor hearts have lead to a reexamination of the indications of cardiac transplantation. In the absence of a contraindication, the indication is straightforward in class IV of the NYHA to improve quality of life. In less sympatomatic patients, the primary objectives are to improve the prognosis and prevent sudden death: the indication should be considered with respect to a range of criteria (the VO2 max and arrhythmogenic potential are important features) and the rate of progression of the disease (resistance to treatment, repeated episodes of decompensation). This indication may and should be reevaluated to optimise the distribution of the race donor hearts for the benefit of patient with the most to gain.

Age Factors↗
PubMed1995

Increasing patient involvement in choosing treatment for early breast cancer.

BACKGROUND: This investigation examined factors affecting patient involvement in consultations to decide local treatment for early breast cancer and the effectiveness of two methods of preconsultation education aimed at increasing patient participation in these discussions. METHODS: Sixty patients with Stage I or II breast cancer (1) were pretested on their knowledge about breast cancer treatment and optimism for the future, (2) were randomly assigned to one of two methods for preconsultation education: interactive multimedia program or brochure, (3) completed knowledge and optimism measures, (4) consulted with a medical oncologist, radiation oncologist, and general surgeon, and (5) completed self-report measures assessing their involvement in the consultations and control over decision-making. The consultations were audiorecorded and analyzed to identify behavioral indicators of patient involvement (question-asking, opinion-giving, and expressing concern) and physician utterances encouraging patient participation. RESULTS: College-educated patients younger than 65 years of age were more active participants in these consultations than were older, less educated patients. In addition, patients showed more involvement when they interacted with physicians who encouraged and facilitated patient participation. The method of education did not affect patient involvement although patients tended to learn more about breast cancer treatment after using the multimedia program than after reading the brochure. CONCLUSIONS: Although patients vary in their expressiveness, physicians may be able to increase patient participation in deciding treatment by using patient-centered behavior. Also, preconsultation education appears to be an effective clinical strategy for helping patients gain an accurate understanding of their treatment options before meeting with physicians.

Adult↗
PubMed1992

Immunohistochemical and ultrastructural investigation of granular cell tumours in dog, cat, and horse.

Six canine, one feline and one equine granular cell tumours (GCTs) were investigated electron microscopically and immunohistochemically. The tumours were tested for reactivity with monoclonal antibodies against vimentin and desmin and with polyclonal antibodies against cytokeratin, S-100 protein, glial fibrillary acidic protein (GFAP) and neuron specific enolase (NSE). All GCTs were characterized by their PAS positive cytoplasmic granules in light microscopy, which in electron microscopy appeared as lysosome-like granules. In each case two canine GCTs were stained by the antibody against cytokeratin, vimentin and S-100 protein. Cells of the equine GCT showed reactivity with the antiserum against S-100 protein. In the feline GCT no reactivity with any of the antibodies tested was observed. These differences of the immunohistochemical reactions of GCTs suggest a nonuniform histogenesis of GCTs in domestic animals. The reactivity of the tumour cells with the antiserum against NSE is discussed.

Animals↗
PubMed1991

Differential expression of bcl2 protooncogene in neuroblastoma and other human tumor cell lines of neural origin.

The bcl2 protooncogene was originally discovered because of its involvement in t(14;18) chromosomal translocations frequently found in non-Hodgkin's lymphomas. The expression of this gene is reported to be highly tissue specific, with bcl2 mRNAs being readily detectable only in hematolymphoid tissues and brain. To explore the possible involvement of bcl2 in neural tumors, we surveyed a variety of tumor cell lines for the presence of the p26-BCL2 protein by immunoprecipitation and immunoblotting methods. Very high levels of BCL2 protein were found in three of nine neuroblastoma (NB) cell lines examined; these levels of p26-BCL2 were comparable to lymphoma cell lines that contain a t(14;18). Despite the impressive relative amounts of BCL2 protein, however, no structural alterations or changes in the methylation status of bcl2 genes were detected in these NB cell lines by conventional Southern blotting. Of the other NB cell lines surveyed, three contained intermediate levels of BCL2 and another three cell lines had little or no detectable BCL2 protein, raising the possibility that determination of relative levels of BCL2 protein may help to segregate neuroblastomas into groups with different biological and clinical characteristics. BCL2 protein levels were not influenced by induction of neuronal differentiation with nerve growth factor in two of the two cell lines examined [SH-SY5Y (high BCL2); GICAN (low BCL2)] and did not correlate with N-MYC gene amplification or expression of nerve growth factor receptors. NB cell lines that contained little or no detectable BCL2 protein, however, tended to contain significant proportions of flat epithelioid cells, whereas bcl2-expressing cell lines were composed primarily of neuronal-like cells, suggesting that expression of this protooncogene correlates with the differentiation characteristics of these tumor cell lines. In addition to NBs, lower levels of BCL2 protein were also found in a variety of other neural crest-derived tumors and tumor cell lines, including some neuroepitheliomas, Ewing's sarcomas, neurofibromas, and melanomas. With regard to tumors of central nervous system origin, bcl2 expression was absent from most medulloblastomas but was detected at moderate to low levels in a retinoblastoma and some glioblastoma multiforme cell lines. Taken together, these findings imply that bcl2 protooncogene expression is differentially regulated within the various lineages of cells that give rise to the nervous system.

Blotting, Southern↗
PubMed1991

[Malignant meningioma with lung metastases in a Boxer].

The rare case of a meningioma with pulmonary metastases in a dog is described. Clinically, the ten-year-old boxer bitch showed generalized seizures, strabismus and deficient proprioception. The post-mortem examination revealed a basically localized meningeal tumor, having the light- and electron-microscopic appearance of a malignant meningotheliomatous meningioma. Immunohistochemically, the tumor cells did not show any positive reaction with antibodies to GFAP, S-100 protein, NSE, vimentin, cytokeratin, desmin, and von Willebrand factor (factor VIII related antigen). Immunohistochemical examination of seven other canine meningiomas showed an identical pattern. The results and the relevant literature are discussed.

Animals↗