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Biomedical subjects

B Brown

Publications and source records attributed to B Brown.

At least 109 records · Page 6Linked to original sources
PubMed1997

Long-term outcome of treatment for Ann Arbor Stage I Hodgkin's disease: prognostic factors for survival and freedom from progression.

PURPOSE: The earliest stages of Hodgkin's disease are associated with excellent short-term survival with radiation therapy. This has led to controversies regarding pretreatment evaluation, the extent of irradiation, the role of chemotherapy, and the relative importance of prognostic factors. Long-term results were sought to address these controversies. METHODS AND MATERIALS: A retrospective study was conducted of patients with Stage I Hodgkin's disease treated at the M. D. Anderson Cancer Center from 1967 through 1987. The median age at presentation of 145 patients was 31 years, and the male-to-female ratio was 1.8. Pretreatment evaluation included lymphangiography and bone marrow aspiration and biopsy in all patients. Laparotomy was performed in 101 of the 145 patients (70%). There were 133 patients with supradiaphragmatic presentations; 12 patients had infradiaphragmatic adenopathy. Only five patients had B symptoms (3.5%). Histologic subtypes of the disease included lymphocyte predominance 17.9%, nodular sclerosis 40.7%, mixed cellularity 40.7%, and one unclassified Hodgkin's disease with primary splenic involvement. All patients were treated with radiotherapy, and 16 (11%) also received combination chemotherapy as part of their initial treatment. Radiotherapy techniques included involved/regional field in 49%, extended field in 42.7% (mantle or inverted Y), and subtotal nodal irradiation in 8.3%. Follow-up extended from a minimum of 30-339 months, with a median period of observation of 16.5 years. RESULTS: The median survival was 13.7 years. The 10- and 20-year survival rates were 83% and 66%, respectively. The only factor important for decreased survival was age >40 years at diagnosis (p < 0.0001). Out of 43 deaths, 11 were the result of Hodgkin's disease and the remaining 32 resulted from intercurrent disease, including treatment-related causes. Median freedom from progression was 10.5 years, and the 10- and 20-year freedom from progression were 76% and 69%, respectively. Out of 39 relapses, 5 (13%) occurred beyond 10 years. Women had higher freedom from progression (p = 0.0534) than men. Age, histology, bulk of disease, site of involvement including the mediastinal presentations, and the addition of chemotherapy did not influence the freedom of progression. Although very few patients (12 of 145) received subtotal nodal irradiation, the freedom from progression at 10 years was 91.7% for this group versus 64.7% for the group of patients who were treated with more limited techniques. CONCLUSION: Treatment with radiation therapy for patients with Stage I Hodgkin's disease leads to an excellent outcome, but patients require long-term surveillance as late relapses are not rare. Age is the only factor that affects survival, and gender marginally affects freedom from progression. Subtotal nodal irradiation may improve freedom from progression; further investigation of this treatment is justified.

Adolescent↗
PubMed1997

Herbicide/pesticide effects on intestinal epithelial growth.

The purpose of the present study was to examine the effects of some common herbicides and pesticides on the growth of normal intestinal and colonic epithelial cells. Preconfluent cultures of normal rat intestinal cells (IEC-6 cell line) and normal human colonic epithelial cells were treated with 0.05-50 microM doses of atrazine, diazinon, and endosulfan. After 3 days of treatment, the change in cell proliferation was quantified by cell counting or the MTT growth assay. Both intestinal and colonic epithelial cell cultures had increases in cell growth when treated with as little as 1.0 microM atrazine, diazinon, or endosulfan. The observed changes in both cultured intestinal and colonic cell growth rates were not due to the influence of the vehicle control dimethyl sulfoxide (DMSO). That is, the treatment of the cell cultures with concentrations of DMSO as high as 0.5% for 3 days resulted in no change in cell growth compared with untreated control cultures. A consistent observation with all three of the compounds was that the highest doses (50 microM) had the least "proliferative potential" in stimulating either IEC-6 cell or human colonic epithelial cell growth. Within the concentration range used, none of the herbicides or pesticides caused a decrease in cell proliferation below that of the untreated control cultures. Overall, treatment of IEC-6 cell cultures with atrazine, diazinon, or endosulfan produced a biphasic growth response, whereas the same treatment in the human colonic epithelial cell cultures produced a more sustained level of growth over the same period. This culture system may provide the basis for an in vitro model to further study the cellular and molecular basis of the effects of herbicides and pesticides on intestinal epithelial proliferation.

Animals↗
PubMed1997

Hospital costs and severity of illness in three types of elective surgery.

BACKGROUND: If patients who are more severely ill have greater hospital costs for surgery, then health-care reimbursements need to be adjusted appropriately so that providers caring for more seriously ill patients are not penalized for incurring higher costs. The authors' goal for this study was to determine if severity of illness, as measured by either the American Society of Anesthesiologists Physical Status (ASA PS) or the comorbidity index developed by Charlson, can predict anesthesia costs, operating room costs, total hospital costs, or length of stay for elective surgery. METHODS: The authors randomly selected 224 inpatients (60% sampling fraction) having either colectomy (n = 30), total knee replacement (n = 100), or laparoscopic cholecystectomy (n = 94) from September 1993 to September 1994. For each surgical procedure, backward-elimination multiple regression was used to build models to predict (1) total hospital costs, (2) operating room costs, (3) anesthesia costs, and (4) length of stay. Explanatory candidate variables included patient age (years), sex, ASA PS, Charlson comorbidity index (which weighs the number and seriousness of coexisting diseases), and type of insurance (Medicare/Medicaid, managed care, or indemnity). These analyses were repeated for the pooled data of all 224 patients. Costs (not patient charges) were obtained from the hospital cost accounting software. RESULTS: Mean total hospital costs were $3,778 (95% confidence interval +/- 299) for laparoscopic cholecystectomy, $13,614 (95% CI +/- 3,019) for colectomy, and $18,788 (95% CI +/- 573) for knee replacement. The correlation (r) between ASA PS and Charlson comorbidity scores equaled 0.34 (P < .001). No consistent relation was found between hospital costs and either of the two severity-of-illness indices. The Charlson comorbidity index (but not the ASA PS) predicted hospital costs only for knee replacement (P = .003). The ASA PS, but not the Charlson index, predicted operating room and anesthesia costs only for colectomy (P < .03). CONCLUSIONS: Severity of illness, as categorized by ASA PS categories 1-3 or by the Charlson comorbidity index, was not a consistent predictor of hospital costs and lengths of stay for three types of elective surgery. Hospital resources for these lower-risk elective procedures may be expended primarily to manage the consequences of the surgical disease, rather than to manage the patient's coexisting diseases.

Aged↗
PubMed1997

Variation of the multifocal visual evoked potential with eccentricity in isometropic amblyopes.

PURPOSE: To investigate the variation of visual function in different eccentricities of the visual field in isometropic amblyopes. METHOD: The stimulus matrix containing 61 hexagons was generated on a monitor. The diameter of the entire stimulating field was approximately 13.6 deg of arc; the frame rate of the monitor was 67 Hz. Every hexagon of the display contained a number of black and white small hexagonal patches which reversed during stimulation. These hexagons were simultaneously but independently modulated in time by the controlling computer program. The flashed elements were selected differently on each frame according to a computer-generated binary pseudo-random time series (m-sequence); the response contributions from each of the individual stimulus elements could be extracted from the cross corre-ation function. Subjects were asked to maintain fixation at the center of the stimulus pattern while each of the hexagons of the display reversed. The VERIS system extracted the local responses by cross-correlating the input (binary m-sequence) and output (evoked response) signals. The latencies and amplitudes of the responses from the central 8.6 deg of arc in the visual field were analyzed. RESULT: Mean latency is about 22 ms longer at the fovea, and 10 ms longer in the first ring for the isometropic amblyopes than for the normal (control) subjects. The differences are highly significant at the fovea and in the first ring. In the second ring and the third ring, the difference have reduced to 3 to 4 ms. The latencies at the second ring and the third ring are not significantly different. In isometropic amblyopes, the P1-N2 amplitude is about half of that in the normal subjects for the fovea and is similar to that for the normal subjects in the third ring. The P1-N2 amplitudes in the isometropic amblyopes are significant lower than the normal values from the center to the second ring. CONCLUSION: In isometropic amblyopia, the prolongation of latencies and the attenuation of the amplitudes of topographic VEPs are marked in the central region of the visual field and diminished in the periphery. The topographic VEP can objectively reflect the variation of visual response with eccentricity in the visual field.

Adolescent↗
PubMed1997

Comparative study of hyperacuity and retinometer tests for the evaluation of vision in patients with advanced cataract.

OBJECTIVE: To investigates the clinical application value of hyperacuity test for evaluating vision through dense cataracts. METHODS: Ten normal subjects (20 years) were tested both with Bailey-Lovie type chart and three points vernier acuity test (one of the hyperacuity test); and retinometer test were performed preoperatively and postoperatively in 30 patients (31 eyes) with senile cataract. These patients' lens opacity was classified with LOCS III system. RESULTS: The correlation of vernier acuity and visual acuity of normal subjects is significant. The result of difference compression of pre-surgical and post-surgical vernier acuity of 30 cataract patients is not significant. The correlation of retinometer findings with post-surgical visual acuity shows not statistically significant. Our result shows that there is good correlation between vernier acuity and post-surgical visual acuity. CONCLUSION: It appears that hyperacuity is a good test for foveal function behind dense cataract and other ocular opacities.

Adult↗
PubMed1997

Variation of topographic visually evoked potentials across the visual field.

We examined the variation of monocular pattern reversal topographic visually evoked potentials across a 13.6 degrees visual field and measured the parameters of the VEP waveforms in 37 locations across the field. Eighteen right and 20 left normal eyes were tested from 23 subjects. The mean response densities of the VEP decreased with increasing eccentricity; response densities are higher in the lower hemifield than in the corresponding mirror symmetric locations in the upper hemifield. The incidence of polarity reversal is higher in the upper hemifield, especially in more superior locations. The latency in the temporal field is shorter than that in the other locations. The coefficients of variations (CVs) of latencies are less than those of amplitudes in corresponding locations and the CVs of latencies of P1 and N2 components are less than those of the N1 component in corresponding locations. The CVs of amplitudes of the waveforms in mid-peripheral locations are larger than those of the other central areas. The parameters of the human topographic visually evoked potential are distributed regularly across the visual field and appear to reflect the underlying anatomy of the retina and visual cortex, and the placement of the recording electrode.

Adolescent↗
PubMed1997

Comparison of analytical performance and biological variability of three bone resorption assays.

We have compared the analytical performance and biological variability of three commercially available bone resorption assays: Pyrilinks-D, Osteomark, and CrossLaps, for the measurement of urinary free deoxypyridinoline (Dpd), cross-linked N-telopeptides of type I collagen (NTx), and linear C-telopeptides of type I collagen (CTx), respectively. The intraassay and interassay CVs for precision of the Dpd and NTx assays were < 10% for analyte concentrations greater than the second calibrator (i.e., 3 nmol/L Dpd or 30 nmol bone collagen equivalents/L NTx). The CTx assay demonstrated poor precision for analyte concentration lower than the third calibrator (i.e., 200 micrograms/L). The NTx assay exhibited nonlinear recovery for sample dilutions prepared in buffer; however, this nonlinear recovery could be corrected for sample dilutions made in urine at a low analyte concentration. Supplement recoveries of each of the three assays were within 100% +/- 10% on average. All three analytes showed stability through five freeze-thaw cycles. The mean day-to-day variations were 16% for Dpd, and 23% for both NTx and CTx. Similar diurnal rhythm was observed for all three assays on average, with the peak in the early morning and the nadir in the afternoon. Mean amplitude of the diurnal variation was 37% for Dpd and NTx, and 57% for CTx. Variations within the reference intervals for a healthy premenopausal population were 28% for Dpd, 57% for NTx, and 56% for CTx. Pyrilinks-D has demonstrated analytical precision and accuracy equal or superior to Osteomark and CrossLaps in all areas. Dpd exhibits the least biological variability day-to-day, within individuals across the diurnal cycle, and within a healthy premenopausal population.

Adult↗
PubMed1996

Elimination of n-butylated hydroxytoluene methylation during fatty acid analysis by gas chromatography.

An improved method for fatty acids analysis with optimum recovery of highly polyunsaturated fatty acids methyl esters in biological systems is presented. The method is based on transesterification of phospholipid and triacylglycerols to fatty acid methyl esters using a commercially available reagent, Methyl-Prep II. Without proper precautions, as much as 50% of n-butylated hydroxytoluene (BHT) added to prevent oxidation of polyunsaturated fatty acids, could be methylated during the transesterification step. Methylated BHT elutes close to 14:0 (myristic acid) and no longer functions as an antioxidant, but the modified conditions virtually eliminate the methylation of BHT. Sample extraction and methylation was completed in 30 min at room temperature. A chelator (diethylenetriamine-pentaacetic acid; DTPA) is also added to prevent peroxidation of metal catalyzed free radical chain reactions. The standard deviations of the major fatty acids from multiple human plasma samples prepared on different days were less than 5%. The recovery of arachidonic acid, 20:4, from plasma was improved using the new method, and the recovery for docosahexaenoic acid, 22:6, spiked to human plasma was found to be 99%.

Butylated Hydroxytoluene↗
PubMed1996

Dual metalloprotease inhibitors. 6. Incorporation of bicyclic and substituted monocyclic azepinones as dipeptide surrogates in angiotensin-converting enzyme/neutral endopeptidase inhibitors.

A series of substituted monocyclic and bicyclic azepinones were incorporated as dipeptide surrogates in mercaptoacetyl dipeptides with the desire to generate a single compound which would potently inhibit both angiotensin-converting enzyme (ACE) and neutral endopeptidase (NEP). Many of these compounds displayed excellent potency against both enzymes. Two of the most potent compounds, monocyclic azepinone 2n and bicyclic azepinone 3q, demonstrated a high level of activity versus ACE and NEP both in vitro and in vivo.

Amino Acid Sequence↗
PubMed1996

Clinical and laboratory findings in four patients with the non-progressive hepatic form of type IV glycogen storage disease.

The classic clinical presentation for type IV glycogen storage disease (branching enzyme deficiency, GSD IV) is hepatosplenomegaly with failure to thrive occurring in the first 18 months of life, followed by progressive liver failure and death by age 5 years. Although there have been two patients without apparent liver progression previously reported, no long-term follow-up clinical data have been available. We present here the clinical spectrum of the non-progressive liver form of GSD IV in four patients, and long-term follow-up of the oldest identified patients (ages 13 and 20 years). None has developed progressive liver cirrhosis, skeletal muscle, cardiac or neurological involvement, and none has been transplanted. Branching enzyme activity was also measured in cultured skin fibroblasts from patients with the classic liver progressive, the early neonatal fatal, and the non-progressive hepatic presentations of GSD IV. The residual branching enzyme activity in the patients without progression was not distinguishable from the other forms and could not be used to predict the clinical course. Our data indicate that GSD IV does not always necessitate hepatic transplantation and that caution should be used when counselling patients regarding the prognosis of GSD IV. Patients should be carefully monitored for evidence of progression before recommending liver transplantation.

1,4-alpha-Glucan Branching Enzyme↗
PubMed1996

Interaction, language and the "narrative turn" in psychotherapy and psychiatry.

The traditional emphasis in psychiatry about "listening to patients" has recently been added to by the development of what we call the "narrative turn" in mental health care where clients' narratives are emphasised. We shall argue however that both approaches tend to embody similar assumptions about therapeutic transactions and roles, and that much work emphasising narratives reveals little about how therapists and researchers work to reconstruct the clients' accounts. It is therefore vital that the emphasis on narratives be supplemented by a more thoroughgoing approach to shared structures of knowledge which act to prefigure clients' distress, how professional records are a profoundly transformative medium, and how therapeutic encounters work to co-construct clients' narratives, rather than simply reflect or explore them. The radical implications of thinking about therapy in terms of narrative and language need to be more fully discussed in the therapy literature, so the narrative turn does not simply reproduce the common-sense assumptions of more conventional approaches.

Communication↗
PubMed1996

Effect of fluorescein on the tear stability of Hong Kong-Chinese.

We used the noninvasive tear break-up time (NITBUT) technique to measure the tear stability of 24 asymptomatic Hong Kong (HK)-Chinese before and after instillation of fluorescein. One eye was used as the test eye while the fellow eye served as control. We compared the NITBUT of the test eyes pre- and postinstillation of fluorescein, and compared the NITBUT of the test eyes measured postinstillation of fluorescein with the NITBUT of the control eyes. After instillation of fluorescein, both longer and shorter NITBUT were recorded in the test eyes; similar results were observed for the control eyes (no fluorescein instilled) between the first and second measurement. The median NITBUT of the test eye pre- and postfluorescein instillation were 13.3 and 13.0 s, respectively. Fluorescein did not cause any significant change in the NITBUT of HK-Chinese and the instillation of fluorescein in one eye does not affect the NITBUT of the fellow eye. Fluorescein did not appear to affect the locations of tear break up (tear defects) observed using the NITBUT test. Tear defects are most frequent near the inferior periphery of the cornea.

Adult↗
PubMed1996

Genetic and phylogenetic clustering of enteroviruses.

Genetic and phylogenetic analysis of enteroviruses showed that in the 5'NCR enteroviruses formed three clusters: polioviruses (PVs), coxsackievirus A type 21 (CAV21), CAV24 and enterovirus type 70 (ENV70) formed one cluster; coxsackievirus B isolates (CBVs), CAV9, CAV16, ENV71, echovirus type 11 (EV11), EV12 and all partially sequenced echoviruses and swine vesicular disease virus (SVDV) belonged to another cluster and bovine enteroviruses (BEVs) formed the third cluster. In the capsid coding region five clusters were seen: PVs, CAV21 and CAV24 formed one cluster (PV-like); ENV70 formed a cluster of its own; all CBVs, CAV9, EV11, EV12 and SVDV formed the third cluster (CBV-like); CAV16, CAV2 and ENV71 belonged to the fourth cluster (CAV16-like) and BEVs formed their own cluster (BEV-like). In the 3'NCR the same clusters were seen as in the coding region suggesting a close association of the 3'NCR with viral proteins while the cellular environment may be more important in the evolution of the 5'NCR. Secondary structures were predicted in the 3'NCR, which showed two different patterns among the five clusters. A potential pseudoknot region common in all five clusters was identified. Although the BEV-like viruses formed a separate cluster in all genomic regions, in the coding region they seem to be phylogenetically related to the CAV16-like viruses.

Animals↗
PubMed1996

Pelvic abscesses: transvaginal US-guided drainage with the trocar method.

The effectiveness of the trocar technique of catheter placement for transvaginal sonographically guided drainage of pelvic abscess was assessed in seven women who presented with pelvic pain, fever, and presumed pelvic abscess. Endovaginal ultrasound was performed to document fluid collection before drainage. All procedures were performed in less than 1 hour, without complications. Catheters were left in place for 1-3 days. Catheter placement was curative in six of seven patients (86%).

Abscess↗
PubMed1996

The effects of a 4-year program promoting bicycle helmet use among children in Quebec.

OBJECTIVES: This study assessed the effectiveness of a 4-year program of bicycle helmet promotion that targeted elementary school children in one region of Quebec. The program revolved primarily around persuasive communication and community organization, combining standard educational activities and activities to facilitate helmet acquisition and use. METHODS: Helmet use was compared between more than 8000 young cyclists in municipalities exposed or not exposed to the program. Factors influencing helmet use were controlled through the use of multivariate analyses. RESULTS: Helmet use increased from 1.3% before program implementation to 33% in 1993. The program was clearly effective in most cycling circumstances and for various groups of children. However, the benefits of the program were unequally distributed; the program was one third as effective in poorer municipalities as in "average-rich" ones. CONCLUSIONS: This community-based program that combined various types of activities appeared to be effective. New intervention models are needed to ensure an equitable distribution of benefits.

Accidents, Traffic↗
PubMed1996

Sonographic appearance and distribution of normal cervical lymph nodes in a Chinese population.

In 100 normal subjects who had a sonographic examination of the neck, 1211 lymph nodes were detected. In all the subjects, at least five lymph nodes were seen. The distribution, number, echogenicity, shape, presence or absence of echogenic hilus, and the sharpness of nodal borders of normal cervical lymph nodes were determined. The usefulness of these sonographic features in understanding the normal distribution and characteristics of the nodes in the Chinese population is discussed. The relationship between the shape and size of lymph node also was assessed.

Adolescent↗