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G Bauman

Publications and source records attributed to G Bauman.

15 recordsLinked to original sources
PubMed1999

Pretreatment factors predict overall survival for patients with low-grade glioma: a recursive partitioning analysis.

PURPOSE: Three databases were pooled and analyzed to determine which groupings of prognostic factors best predicted overall survival for patients with low-grade gliomas treated with surgery and immediate or delayed radiotherapy. METHODS AND MATERIALS: Databases of patients with low-grade gliomas compiled at the London Regional Cancer Centre (LRCC), the Norwegian Radium Hospital (NRH), and the University of California, San Francisco (UCSF) were merged. Inclusion criteria for the pooled analysis included: age > or =18 years and histologically confirmed low-grade (World Health Organization Grade II) supratentorial fibrillary astrocytoma, oligodendroglioma or mixed oligoastrocytoma. Factors analyzed for prognostic significance included: age at diagnosis, gender, seizures at presentation, presence of enhancement on computed tomography (CT) or magnetic resonance imaging (MRI), Karnofsky Performance Status (KPS) at diagnosis, histology, extent of surgical resection, timing of radiotherapy, and treating institution. Univariate and multivariate analysis of overall survival for these factors was performed. Recursive partitioning was performed to generate prognostic groups using these factors. RESULTS: From the combined databases, 401 patients were eligible for analysis. Median survival for the entire group was 95 months/7.9 years. On univariate analysis age 18-40, presence of seizures at presentation, KPS > or =70, treating institution, and absence of contrast enhancement were associated with improved overall survival. On multivariate analysis, these factors remained independent predictors of improved overall survival. Recursive partitioning analysis yielded four prognostic groups with statistically different median survivals (MS): Group I (n = 41: KPS <70, age >40) MS 12 months; Group II (n = 34: KPS > or =70, age >40, enhancement present) MS 46 months; Group III (n = 138: KPS <70, age 18-40 or KPS > or =70 age >40, no enhancement) MS 87 months; Group IV (n = 188: KPS > or =70, age 18-40) MS 128 months. CONCLUSION: Clusters of pretreatment prognostic factors described subgroups of low-grade glioma patients with divergent overall survivals. Consideration of these prognostic subgroups may be important when considering timing of interventions for these patients and in the stratification of patients for clinical trials.

Adult↗
PubMed1999

Low grade glioma: a measuring radiographic response to radiotherapy.

PURPOSE: We set out to determine the rate of response of low-grade (WHO Grade II) gliomas to radiotherapy and analyze the relationship between radiographic response, symptom control and patient survival. METHODS: Patients were eligible for this study if they had received radiotherapy for pathologically confirmed, residual, supratentorial low-grade astrocytoma, oligodendroglioma, or mixed glioma, and imaging studies (baseline and follow-up) were available for review. Percent change in tumor size and rate and timing of response were determined by maximum linear measurement, area measurement, volume measurement using an ellipsoid model, and volume measurement by image segmentation. For each method, response to radiotherapy was defined firstly as a > or = 50% decrease in tumor size (partial response), and secondly as a decrease equivalent to a 50% area decrease (normalized partial response). Relationships between radiographic response, clinical improvement and progression-free survival were analyzed using a Cox Proportional Hazard's model. RESULTS: Twenty-one patients in a database (13 male, 8 female; ages 22-66 years) met the eligibility criteria. Twenty were imaged by computed tomography, 18 had an astrocytoma and 15 were irradiated soon after surgery. Responses were common and not felt to be due to a steroid effect. Use of normalized response criteria improved agreement between assessment of response as determined by the 4 methods. Median time to maximum radiographic improvement was 2.8 months (range, 1.5-11). Sixteen patients (76%) were improved neurologically, the median time to progression was 4.8 years and the 5-year progression-free survival rate was 43%. We did not detect a statistically significant association between response (as measured by any method), symptomatology and progression-free survival. CONCLUSIONS: Low-grade gliomas are moderately radioresponsive. Use of volume measurement may over-estimate the number of partial responses unless a volume reduction equivalent to a 50% area decrease is used to define response. The best way to measure response remains uncertain because neither visual, area, nor volume changes confidently predicted clinical outcomes.

Adult↗
PubMed1997

Supratentorial low-grade glioma in adults: an analysis of prognostic factors and timing of radiation.

PURPOSE: To review the outcomes of patients with low-grade glioma diagnosed by modern imaging and treated at a center where postponing radiotherapy was common practice. METHODS: We reviewed the records of patients (age > or = 18 years) with pathologically confirmed supratentorial low-grade fibrillary astrocytoma, oligodendroglioma, and mixed glioma treated at a regional cancer center in Canada between 1979 and 1995. RESULTS: Median survival for the entire group (N = 167; mean age 40.6 years) was 10.5 years with 5- and 10-year survival rates of 72% and 50%, respectively. Median progression-free survival was 4.9 years with 5- and 10-year progression-free rates of 50% and 12%, respectively. Overall and progression-free survivals were longer for patients with an oligodendroglioma or mixed glioma than with astrocytoma (median 13 v 7.5 years, P = .003; progression-free 5.6 v 4.4 years, p = .054). Age at diagnosis < or = 40 years, seizures at presentation, minimal residual tumor after surgery, Karnofsky performance status > or = 70, and oligodendroglioma or mixed glioma pathology were associated with significantly longer median survival on univariate and multivariate analyses. Radiotherapy deferred until tumor progression (v immediate radiotherapy) was associated with longer survival on univariate analysis, but an imbalance in other variables accounted for this advantage such that timing of radiotherapy was not an independent (favorable or adverse) prognostic factor on multivariate analysis. CONCLUSION: Patients with low-grade glioma diagnosed by modern imaging can be expected to live a long time; timing of radiotherapy may be a less important determinant of survival than nontreatment variables and residual tumor bulk.

Actuarial Analysis↗
PubMed1995

Stereotactic radiosurgery in children.

The role of stereotactic radiosurgery in the treatment of pediatric patients is still being explored. We report the Gamma Knife treatment of 33 patients under the age of 21, at the University of California, San Francisco, between the years 1991 and 1993. Treatment-related toxicity has been low. 10/14 patients treated for arteriovenous malformation (AVM) with follow-up > 1 month have shown partial or complete AVM obliteration. No patient has had a new hemorrhage after AVM treatment. In children with malignant tumors, treatment was well tolerated, although most patients, ultimately, had progressive disease. Stereotactic radiosurgery is logistically possible in the pediatric population. Its use in selected patients with AVMs seems appropriate, although its role in the treatment of malignant brain tumors remains to be defined.

Adolescent↗
PubMed1993

Current concepts in polishing composite resins.

The aesthetic appearance of composite resin is based upon shape, color, and gloss of the restoration, achieved by finishing and polishing. The smaller the composite resin filler and the more resin polymer present in the restorative material, the higher the attainable luster. This article examines the recent changes and improvements in materials and techniques of polishing and finishing the macrofill, hybrid, and microfill restorations.

Adolescent↗
PubMed1990

Molecular approaches to leucotoxin as a virulence component in Actinobacillus actinomycetemcomitans.

A strategy has been developed to examine the hypothesis that leucotoxin is a critical virulence factor of Actinobacillus actinomycetemcomitans in a non-human primate (Macaca fascicularis). Firstly the leucotoxin gene from A. actinomycetemcomitans was cloned and sequenced. This DNA contained a functional leucotoxin gene, as protein extracts of Escherichia coli with the cloned sequences lysed appropriate human cell lines. The protein encoded by lktA shared at least 42% identity with P. haemolytica leucotoxin and with the alpha-haemolysins from E. coli and A. pleuropneumoniae. The lktA gene of A. actinomycetemcomitans was linked to another gene, lktC, which is thought to be related to the LktC proteins from these other bacteria and with which it shared at least 49% amino acid identity. Despite the overall homology to the other leucotoxins/haemolysins, the LktA from A. actinomycetemcomitans has several unique properties including a very basic pI of 9.7, as compared to pIs approx. 6.2 for lktA proteins in other bacteria. Using the cloned genes as probes produced evidence that a TOX- strain contains the leucotoxin gene but fails to transcribe it at high levels. The second avenue of investigation was to develop methods for examining the humoral immune responses in the monkey to bacterial toxins such as lktA. A. actinomycetemcomitans was detected in subgingival plaque samples from approx. 40% of the animals. A. actinomycetemcomitans comprised less than 1% to 9% of the flora. Most A. actinomycetemcomitans isolates were serotype b and each of the monkeys had serum IgG antibody to A. actinomycetemcomitans serotype b (generally considered to be lktA-producing strains). An ELISA was developed to examine the isotype/subclass distribution, level and avidity of serum antibody in the monkey following parenteral immunization with a prototype bacterial exotoxin (tetanus toxoid). IgG1 and IgG3 antibody predominated over IgG2 and IgG4 after primary immunization. Secondary immunization elicited enriched IgG1 and IgG4 responses. Primary immunization increased avidity indices of IgG to tetanus toxoid from approx. 0.9 (baseline) to a mean of 1.72 and secondary immunization significantly increased the avidity index to 2.56.

Actinobacillus↗
PubMed1976

An effect of change in patient status on marital interaction.

In the treatment of couples and families, even more so than of individuals, therapists invariably are forced to face the problem of assessment of change in the marital or family "system." The purpose of the present study was to investigate changes in marital interaction for a special population, that is, in which one member of each married pair had been, but was no longer, a hospitalized psychiatric patient. The primary question we addressed was whether changes in marital interaction could be amply detected and whether these changes could be attributed to the particular role shift that had occurred in one spouse--from "patient" to "nonpatient." Utilizing a technique called Interaction Testing, which the senior authors devised in 1960, we found that such alterations in marital interaction do indeed arise when one member of the couple moves out of a patient role and that our instrument is useful in elucidating the nature of such effects. In addition, it can be expected that a study of this kind will be of theoretical and methodological value in dealing with the general issues of problem-solving interaction in couples and families. The clinical aspect of the study may also be expected to stimulate useful thinking regarding family theapy in hospital settings, patient management, and aftercare.

Decision Making↗