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Biomedical subjects

M Kaplan

Publications and source records attributed to M Kaplan.

At least 91 records · Page 5Linked to original sources
PubMed1999

Treatment of maxillary sinus carcinoma: a comparison of the 1997 and 1977 American Joint Committee on cancer staging systems.

BACKGROUND: This study was conducted to assess the effectiveness of the 1997 American Joint Committee on Cancer (AJCC) staging system to predict survival and local control of patients with maxillary sinus carcinoma and to identify significant factors for overall survival, local control, and distant metastases in patients with these tumors. METHODS: Ninety-seven patients with maxillary sinus carcinoma were treated with radiotherapy at Stanford University and the University of California, San Francisco between 1959-1996. The histologic type of carcinoma among the 97 patients were: 58 squamous cell carcinomas, 4 adenocarcinomas, 16 undifferentiated carcinomas, and 19 adenoid cystic carcinomas. All patients were restaged clinically according to the 1977 and 1997 AJCC staging systems. The T classification of the tumors of the patients was as follows: 8 with T2, 18 with T3, and 71 with T4 according to the 1977 system and 8 with T2, 36 with T3, and 53 with T4 according to the 1997 system. Eleven patients had lymph node involvement at diagnosis. Thirty-six patients were treated with radiotherapy alone and 61 received a combination of surgical and radiation treatments. The median follow-up for surviving patients was 78 months. RESULTS: The 5-year and 10-year actuarial survival rates for all patients were 34% and 31%, respectively. The 5-year survival estimate by the 1977 AJCC system (P = 0.06) was 75% for Stage II, 19% for Stage III, and 34% for Stage IV and by the 1997 AJCC system (P = 0.006) was 75% for Stage II, 37% for Stage III, and 28% for Stage IV. Significant prognostic factors for survival by multivariate analysis included age (favoring younger age, P<0.001), 1997 T classification (favoring T2-3, P = 0. 001), lymph node involvement at diagnosis (favoring N0, P = 0.002), treatment modality of the primary tumor site (favoring surgery and radiotherapy, P = 0.009), and gender (favoring female patients, P = 0.04). The overall radiation time was of borderline significance (favoring shorter time, P = 0.06). The actuarial 5-year local control rate was 43%. By the 1977 AJCC system (P = 0.78) it was 62% with T2, 36% with T3, and 45% with T4 and using the 1997 AJCC system (P = 0.29) it was 62% with T2, 53% with T3, and 36% with T4. The only significant prognostic factor for local control for all patients by multivariate analysis was local therapy, favoring surgery and radiotherapy over radiotherapy alone (P< 0.001). For patients treated with surgery, pathologic margin status correlated with local control (P = 0.007) and for patients treated with radiation alone, higher tumor dose (P = 0.007) and shorter overall treatment time (P = 0.04) were associated with fewer local recurrences. The 5-year estimate of freedom from distant metastases was 66%. The 1997 T classification, N classification, and lymph node recurrence were adverse prognostic factors for distant metastases on multivariate analysis. There were 22 complications in 16 patients, representing a 30% actuarial risk of developing late complications at 10 years. CONCLUSIONS: The 1997 AJCC staging system was found to be superior to the 1977 AJCC staging system in predicting both survival and local control in this patient population. Combined surgical and radiation treatment to the primary tumor yielded higher survival and local control than radiotherapy alone. Other significant prognostic factors for survival were patient age, gender, and lymph node (N) classification. Prolonged overall radiation time was associated with poorer survival and local control. Late severe toxicity from the treatment of these tumors was a significant problem in long term survivors. Improved radiotherapy techniques should lead to decreased injury to the surrounding normal tissues. (c) 1999 American Cancer Society.

Adenocarcinoma↗
PubMed1999

Reduction in T cell apoptosis in patients with HIV disease following antiretroviral therapy.

Patients with HIV infection manifest increased T lymphocyte apoptosis. This study investigated the influence of antiretroviral therapy (ART) upon lymphocyte apoptosis in 23 HIV-infected adults naive to protease inhibitors. Patients were enrolled in a treatment trial consisting of Nelfinavir (NFV), d4T, or NFV + d4T for 24 weeks, followed by triple therapy (NFV + reverse transcriptase inhibitors) for an additional 24 weeks. Spontaneous T cell apoptosis in cultured PBMC decreased by 23.67 +/- 18.2% (P < 0.006) at 48 weeks and plasma HIV RNA decreased by 1.79 +/- 0.59 log(10) RNA copies/ml (P < 0.001). The absolute decrease and slope of T cell apoptosis correlated with plasma virus load and with activated CD8 T cells and was inversely correlated with CD4 T cells. We conclude that reduction in chronic antigenic stimulation and the absence of cellular signals elicited by viral products contribute to the rescue of T lymphocytes from apoptosis, which facilitates immunologic recovery in ART-treated patients.

Adult↗
PubMed1999

Expression and characterization of Sapporo-like human calicivirus capsid proteins in baculovirus.

Sapporo-like caliciviruses reveal typical calicivirus morphology and cause acute gastroenteritis. This study describes the expression in baculovirus of capsid proteins of two Sapporo-like calicivirus strains (Hou/86 and Hou/90). Eight different constructs of the capsid genes were compared for production of the proteins. Constructs containing short (9 or 19 nt) upstream sequences failed to produce capsid proteins but extension of the upstream sequence to 73 nt resulted in production of capsid proteins. Expressed capsid protein with the MEG tri-peptide as the N-terminus self-formed virus-like particles (VLPs). Expressed protein with an upstream AUG failed to form VLPs. Addition of His-tag to the N-terminus of capsid protein also blocked VLP formation. Of three Norwalk-Hou/90 chimeric capsid gene constructs, one resulted in production of chimeric capsid and the protein did not form VLPs. Recombinant capsid proteins for each of Hou/86 and Hou/90 were further characterized. The expressed capsid antigens of the two strains were antigenically distinct but shared a common epitope(s). Further study of these proteins should allow development of immunologic assays for diagnosis and should help to clarify the epidemiology of Sapporo-like caliciviruses in humans.

Adult↗
PubMed1999

Methotrexate improves biochemical tests in patients with primary biliary cirrhosis who respond incompletely to ursodiol.

BACKGROUND & AIMS: Primary biliary cirrhosis (PBC) is a chronic cholestatic liver disease of presumed autoimmune etiology. Ursodeoxycholic acid (UDCA), methotrexate, and colchicine each have shown promise in its treatment. The value of combining 2 or 3 of these drugs is uncertain. The aim of this study was to determine whether addition of methotrexate to the treatment regimen improves results of liver biochemical tests in patients with antimitochondrial antibody-positive PBC who responded incompletely to treatment with UDCA and colchicine. METHODS: Methotrexate was added to the treatment regimen of 10 consecutive patients with antimitochondrial antibody-positive PBC who had an incomplete response to therapy with UDCA alone or in combination with colchicine. The primary end point was biochemical response. Symptoms and histological changes were also recorded. RESULTS: Addition of methotrexate to the UDCA plus colchicine regimen was associated with a significant reduction in serum alkaline phosphatase (ALP) levels beyond those found with UDCA and colchicine alone or in combination. Median ALP concentration was 389 IU (range, 247-1013 IU) at baseline, 300 IU (range, 155-467 IU) after treatment with UDCA plus colchicine, and 120 IU (range, 66-351 IU) after treatment with methotrexate. CONCLUSIONS: Addition of methotrexate to a regimen of UDCA and colchicine may be beneficial for patients with PBC who respond incompletely to treatment with UDCA and colchicine.

Adult↗
PubMed1999

Amelioration of ischemia-reperfusion injury in rat intestine by pentoxifylline-mediated inhibition of xanthine oxidase.

BACKGROUND: Intestinal ischemia-reperfusion (IR) injury results in cell destruction, which may be mediated by the generation of reactive oxygen species, potentially toxic metabolites of xanthine oxidase. Pentoxifylline (PTX) possesses a variety of biochemical and antioxidant properties that can improve capillary flow and tissue oxygenation. Because of these combined effects, it has been hypothesized that pentoxifylline would protect against intestinal IR. METHODS: Young adult rats were randomly assigned to one of four experimental groups: IR/Placebo (n = 12) in which superior and inferior mesenteric arteries were clamped for 45 minutes and then reopened; IR/PTX (n = 11) in which IR was induced as in the Placebo group, but with 25 mg/kg PTX at 0, 30, and 60 minutes; No IR/Placebo (n = 12); and No IR/PTX (n = 6) in which placebo and PTX were applied with no IR. Blood and intestinal samples were taken for serial thiobarbituric acid-reducing substances (TBARS; index of lipid peroxidation), for xanthine oxidase-xanthine dehydrogenase ratios, glutathione, myeloperoxidase, and histopathology. RESULTS: Animals in the IR/PTX group had lower TBARS and the least severe histopathologic injury. Xanthine oxidasexanthine dehydrogenase ratios were elevated only in IR/ Placebo (0.67+/-0.22 vs. 0.45+/-0.14 in IR/PTX; 0.42+/-0.22 in No IR/Placebo; and 0.40+/-0.11 in No IR/PTX; p = 0.0009). Reduced glutathione was diminished in IR/PTX animals (38.9 +/-1.35 vs. 46.1+/-7.0 in IR/Placebo; 41.1+/-2.5 in No IR/ Placebo; 43.6+/-1.0 in No IR/PTX; p = 0.048). No differences were recorded in myeloperoxidase levels among groups. CONCLUSIONS: Pentoxifylline ameliorates histopathologic signs of injury and decreases lipid peroxidation (TBARS). Normal xanthine oxidase-xanthine dehydrogenase ratios in the treated compared with IR-only animals imply that the protective effect of PTX is at least partially mediated through inhibition of xanthine oxidase.

Animals↗
PubMed1999

Neonatal bilirubin production, reflected by carboxyhaemoglobin concentrations, in Down's syndrome.

AIM: To determine whether increased bilirubin production, reflected by blood carboxyhaemoglobin (COHb) values, is responsible for hyperbilirubinaemia in cases of Down's syndrome with no obvious cause for excessive jaundice. METHODS: Blood was sampled on the third day of life for COHb, total haemoglobin (tHb), and serum total bilirubin, from 19 consecutively born neonates with Down's syndrome (a subset of 34 term babies), who had developed hyperbilirubinaemia (serum bilirubin >/= 256 micromol), and from 32 term controls. COHb, measured by gas chromatography, was corrected for inspired CO (COHbc) and expressed as a percentage of tHb. RESULTS: Significantly more of the Down's syndrome subset developed hyperbilirubinaemia than the controls (10/19 (52%) vs 7/32 (22%), relative risk 2.4, 95% confidence intervals (CI) 1.10 to 5.26). Third day serum bilirubin values (mean (SD)) were higher in the Down's syndrome neonates than in controls (214 +- 63 micromol/l vs 172 +- 54 micromol/l, respectively, p=0.015). Mean (SD) COHbc values were significantly higher in the Down's syndrome neonates than in controls (0.92 +- 0. 24% vs 0.63 +- 0.17%; p<0.0001). However, Down's syndrome neonates who became hyperbilirubinaemic had similar COHbc values to those who did not (0.87 +- 0.26% and 0.95 +- 0.23%, respectively). These values contrast with those of the controls, in whom a significant increase in COHbc was associated with hyperbilirubinaemia (0.74 +- 0. 15% vs 0.60 +- 0.16%, respectively; p<0.05). tHb values were similar in both groups. CONCLUSIONS: Down's syndrome neonates had a greater risk of hyperbilirubinaemia, and higher COHbc values, than controls. However, excessive bilirubin production could not be exclusively responsible for the hyperbilirubinaemia. By inference, decreased bilirubin elimination probably plays a greater part in its pathogenesis than in controls. Down's syndrome neonates may have abnormal erythropoiesis, leading to increased haem turnover.

Bilirubin↗
PubMed1999

Oxidized low density lipoprotein: atherogenic and proinflammatory characteristics during macrophage foam cell formation. An inhibitory role for nutritional antioxidants and serum paraoxonase.

Oxidative stress and inflammatory processes are of major importance in atherogenesis because they stimulate oxidized LDL (Ox-LDL)-induced macrophage cholesterol accumulation and foam cell formation, the hallmark of early atherosclerosis. Under oxidative stress, both blood monocytes and plasma lipoproteins invade the arterial wall, where they are exposed to atherogenic modifications. Oxidative stress stimulates endothelial secretion of monocyte chemoattractant protein 1 (MCP-1) and of macrophage colony stimulating factor (M-CSF), leading to monocyte adhesion and differentiation, respectively. LDL binds to extracellular matrix (ECM secreted by endothelial cells, smooth muscle cells and macrophages) proteoglycans, in a process that contributes to the enhanced susceptibility of the lipoprotein to oxidation by arterial wall macrophages. ECM-retained Ox-LDL is taken up by activated macrophages via their scavenger receptors. This leads to cellular cholesterol accumulation and enhanced atherogenesis. Protection of LDL against oxidation by antioxidants that can act directly on the LDL, or indirectly on the cellular oxidative machinery, or conversion of Ox-LDL to a non-atherogenic particle by HDL-associated paraoxonase (PON-1), can contribute to attenuation of atherosclerosis.

Antioxidants↗
PubMed1999

Neonatal hyperbilirubinemia in glucose-6-phosphate dehydrogenase-deficient heterozygotes.

OBJECTIVES: We assessed the incidence of hyperbilirubinemia, defined as serum total bilirubin >/=15 mg/dL (256 micromol/L), in a cohort of Sephardic Jewish female neonates at risk for glucose-6-phosphate dehydrogenase (G-6-PD) deficiency with especial emphasis on the heterozygotes. We studied the roles of hemolysis by blood carboxyhemoglobin (COHb) determinations and of the variant promoter of the gene for the bilirubin-conjugating enzyme uridine 5'-diphosphate glucuronosyltransferase 1 (UGT1A1) seen in Gilbert's syndrome in the pathogenesis of the hyperbilirubinemia. METHODS: Consecutively born, healthy, term, female neonates were screened for G-6-PD deficiency and observed clinically with serum bilirubin evaluations as indicated for hyperbilirubinemia. On day 3, blood was sampled for COHb, total hemoglobin (tHb), and a mandatory serum bilirubin determination. COHb, determined by gas chromatography, was expressed as percentage of tHb and corrected for inspired carbon monoxide (COHbc). DNA was analyzed for the G-6-PD Mediterranean563T mutation and for the variant UGT1A1 gene. RESULTS: The cohort included 54 G-6-PD-deficient heterozygotes, 19 deficient homozygotes, and 112 normal homozygotes. More heterozygotes (12/54, 22%; relative risk: 2.26; 95% CI: 1.07-4.80) and deficient homozygotes (5/19, 26.3%; relative risk: 2.68; 95% CI: 1.05-6.90) developed hyperbilirubinemia, than did normal homozygotes (11/112, 9.8%). Third-day serum bilirubin values that were obtained from 144 neonates were significantly higher in both heterozygotes (11.2 +/- 3. 7 mg/dL [192 +/- 64 micromol/L]) and G-6-PD-deficient homozygotes (12.0 +/- 3.0 mg/dL [206 +/- 52 micromol/L]) than in the G-6-PD normal homozygotes (9.4 +/- 3.4 mg/dL [160 +/- 58 micromol/L). In contrast, COHbc values were higher only in G-6-PD-deficient homozygotes (0.74% +/- 0.14%) and not in heterozygotes (0.69% +/- 0. 19%, not statistically significant), compared with control values (0. 63% +/- 0.19%). High COHbc values were not a prerequisite for the development of hyperbilirubinemia in any of the G-6-PD genotypes. A greater incidence of hyperbilirubinemia was found among the G-6-PD-deficient heterozygotes, who also had the variant UGT1A1 gene, in both heterozygous (6/20, 30%) and homozygous (4/8, 50%) forms, than was found in their counterparts with the normal UGT1A1 gene (2/26, 7.7%). This effect was not seen in the G-6-PD normal homozygote group. A color reduction screening test for G-6-PD deficiency identified only 20.4% (11/54) of the heterozygotes. CONCLUSIONS: We showed that G-6-PD-deficient heterozygotes, categorically defined by DNA analysis, are at increased risk for neonatal hyperbilirubinemia. The screening test that was used was unable to detect most heterozygotes. Increased bilirubin production was not crucial to the development of hyperbilirubinemia, but presence of the variant UGT1A1 gene did confer increased risk.

Case-Control Studies↗
PubMed1998

The ability of lumbar medial branch blocks to anesthetize the zygapophysial joint. A physiologic challenge.

STUDY DESIGN: Randomized, controlled, single blinded study. OBJECTIVES: To determine the physiologic effectiveness of lumbar medial branch blocks. SUMMARY OF BACKGROUND DATA: Zygapophysial joint pain can be diagnosed by anesthetization of the joint or its nerve supply (the medial branch divisions of the dorsal rami). The physiologic effectiveness of lumbar medial branch blocks has been assumed but not proven. METHODS: Eighteen asymptomatic individuals were randomly assigned to either L4-L5 or L5-S1 zygapophysial joint injections with contrast medium until capsular distention elicited pain without extracapsular contrast spread. One week later, 15 blinded individuals underwent two randomized saline or 2% lidocaine medial branch injections that correlated to the innervation of the previously injected joint. Medical branch injections were performed such that inadvertent venous uptake was avoided in 14 individuals. Thirty minutes after medial branch injections, these 14 individuals underwent repeat capsular distention of the same zygapophysial joint provoked the prior week in an attempt to elicit another painful response. RESULTS: All five control individuals who received saline medial branch injections felt pain on repeat capsular distention. Nine individuals received 2% lidocaine medial branch blocks; eight felt no pain, and one felt pain on repeat capsular distention. CONCLUSIONS: There was a significant effect of 2% lidocaine (versus saline) medial branch injections on anesthetization of the zygapophysial joint when venous uptake was avoided during these injections. When properly performed, lumbar medial branch blocks successfully inhibit pain associated with capsular distention of the lumbar zygapophysial joints at a rate of 89%.

Adult↗
PubMed1998

Behavioral changes in autistic individuals as a result of wearing ambient transitional prism lenses.

A double-blind crossover design was used to assess the efficacy of wearing ambient lenses to reduce the behavioral symptoms of autism. Eighteen autistic individuals, ranging in age from 7 to 18 years, participated in the study. Behavior, attention, and orientation were evaluated at 1 1/2 months, 2 months, 3 months, and 4 months. Compared to the placebo condition, the results showed a decrease in behavior problems at the 1 1/2 and 2 month assessment periods and a slight loss of these benefits at the 3 and 4 month assessment periods. These findings support the prediction that ambient lenses, worn without engaging in visual-motor exercises, have positive effects on autistic individuals.

Adolescent↗
PubMed1998

Combination of ABO blood group incompatibility and glucose-6-phosphate dehydrogenase deficiency: effect on hemolysis and neonatal hyperbilirubinemia.

The incidence (%) of hyperbilirubinemia (serum bilirubin > or = 257 micromol/l) was similar in neonates with a combination of ABO incompatibility and glucose-6-phosphate dehydrogenase (G-6-PD) deficiency (45%), with ABO incompatibility (54%) or G-6-PD deficiency (37%), alone (ns). Carboxyhemoglobin values, corrected for inspired CO, were similarly elevated in all three groups (0.87 +/- 0.32%, 0.82 +/- 0.29%, 0.76 +/- 0.18%, respectively, ns), but correlated with bilirubin only in those with ABO incompatibility alone. ABO-incompatible/G-6-PD-deficient neonates, compared with those with either condition alone, are not at increased risk for hemolysis or hyperbilirubinemia.

ABO Blood-Group System↗
PubMed1998

Effect of vitamin K1 on glucose-6-phosphate dehydrogenase deficient neonatal erythrocytes in vitro.

AIM: To determine whether vitamin K1, which is routinely administered to neonates, could act as an exogenous oxidising agent and be partly responsible for haemolysis in glucose-6-phosphat-dehydrogenase (G-6-PD). METHODS: G-6-PD deficient (n = 7) and control (n = 10) umbilical cord blood red blood cells were incubated in vitro with a vitamin K1 preparation (Konakion). Two concentrations of Vitamin K1 were used, both higher than that of expected serum concentrations, following routine injection of 1 mg vitamin K1. Concentrations of reduced glutathione (GSH) and methaemoglobin, indicators of oxidative red blood cell damage, were determined before and after incubation, and the mean percentage change from baseline calculated. RESULTS: Values (mean (SD)) for GSH, at baseline, and after incubation with vitamin K1 at concentrations of 44 and 444 microM, respectively, and percentage change from baseline (mean (SD)) were 1.97 + 0.31 mumol/g haemoglobin, 1.89 +/- 0.44 mumol/g (-4.3 +/- 13.1%), and 1.69 +/- 0.41 mumol/g (-14.5 +/- 9.3%) for the G-6-PD deficient red blood cells, and 2.27 +/- 0.31 mumol/g haemoglobin, 2.09 +/- 0.56 mumol/g (-7.2 +/- 23.2%), and 2.12 +/- 0.38 mumol/g (-6.0 + 14.1%) for the control cells. For methaemoglobin (percentage of total haemoglobin), the corresponding values were 2.01 +/- 0.53%, 1.93 +/- 0.37% (-0.6 +/- 17.4%) and 2.06 +/- 0.43% (5.7 +/- 14.2%) for the G-6-PD deficient red blood cells, and 1.56 +/- 0.74%, 1.70 +/- 0.78% (12.7 +/- 21.9%), and 1.78 +/- 0.71% (20.6 +/- 26.8%) for the control red blood cells. None of the corresponding percentage changes from baseline was significantly different when G-6-PD deficient and control red blood cells were compared. CONCLUSIONS: These findings suggest that G-6-PD deficient red blood cells are not at increased risk of oxidative damage from vitamin K1.

Biomarkers↗