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Biomedical subjects

J Schachter

Publications and source records attributed to J Schachter.

At least 37 records · Page 2Linked to original sources
PubMed2000

Standard and nonstandard applications of sentinel node-guided melanoma surgery.

Identification and histologic study of the sentinel node (SN) is an acceptable, yet not firmly established, guide for treating intermediate-thickness melanoma. This study widens the range of applications of this technique. We included 97 patients with intermediate-thickness melanoma lesions or lesions for which there is no standard treatment. Fifty-six underwent preoperative lymphoscintigraphy, and all underwent intraoperative lymphatic mapping (IOLM) using blue dye, followed by frozen section study and total node processing by serial sections. Elective lymph node dissection was performed in cases of metastasis to the sentinel node or technical failures with high risk. Four categories were defined: (A) intermediate-thickness lesions (mean 2.27 mm) (n = 45); (B) thin lesions (mean 1.14 mm) with risk factors of regional failure (n = 27); (C) lesion thickness close to but more than 4 mm (n = 10); and (D) lesions of undetermined thickness (n = 15). Median follow-up was 30 months (range 13-51 months). Intraoperative lymphatic mapping successfully identified the sentinel node (SN) in 93% of basins explored. Metastases were detected in 11 SNs. There were three lymph basin recurrences in patients with previously negative SNs, all salvaged by therapeutic lymph basin dissection and are NED (no evidence of disease). Two SN(+) patients had systemic recurrences; one died of his disease, and the other is alive with disease. One SN(-) patient died NED owing to other cause. This technique spared 83% of category A patients from lymph node dissection. It allowed better staging and better decision making for treatment in categories B and D; and it prevented early regional recurrences in category C patients. Intraoperative lymphatic mapping with SN guidance is a novel, lo

Adult↗
PubMed2000

Applicability of the sentinel node technique to Merkel cell carcinoma.

BACKGROUND: Merkel cell carcinoma (MCC) resembles malignant melanoma in several ways. Both are cutaneous lesions of the same embryonic origin. Both have an unpredictable biologic behavior, early regional lymph node involvement, early distant metastases, and high recurrence rate. OBJECTIVE: To apply the sentinel node technique described for melanoma to MCC in light of the common biologic features of these two tumors. METHODS: Preoperative lymphoscintigraphy, intraoperative lymphatic mapping, and sentinel node biopsy and frozen section histology were performed to guide the surgical treatment of three patients with MCC. RESULTS: Application of this approach in patients with MCC is feasible, reproducible, and seems reliable. CONCLUSION: The use of the sentinel node technique for MCC will reduce the number of unnecessary lymphadenectomies, will enable identification of microscopic metastases to lymph nodes, and will improve the stratification and accrual of patients into adjuvant treatment protocols. It may even lead to a survival benefit.

Aged↗
PubMed2000

Chlamydia pneumoniae serology: interlaboratory variation in microimmunofluorescence assay results.

The lack of standardization in chlamydia serology has made interpretation of published data difficult. This study was initiated to determine the extent of interlaboratory variation of microimmunofluorescence (MIF) test results for the serodiagnosis of Chlamydia pneumoniae infections. Identical panels of 22 sera were sent to 14 laboratories in eight countries for the determination of IgG and IgM antibodies by MIF. Although there was extensive variation in the numeric titer values, the overall percentage agreement with the reference standard titers from the University of Washington was 80%. For results by serodiagnostic category, the best agreement was for four-fold rise in IgG titers, while the lowest agreement was for negative or low IgG titers. Agreement for IgM titers was 50%-95%. Four laboratories failed to discern false-positive IgM titers possibly because of the presence of rheumatoid factor. Further studies are underway to determine the source of interlaboratory variation for the MIF test.

Antibodies, Bacterial↗
PubMed2000

Oral etoposide for Merkel cell carcinoma in patients previously treated with intravenous etoposide.

We describe three patients with advanced Merkel cell carcinoma who were treated with etoposide given orally for recurrent regional lymph node involvement 18 to 30 months after exposure to etoposide given intravenously. Etoposide given orally (100 mg/day) was given for 10 to 14 consecutive days and repeated every 21 to 28 days for a median of three courses (range: two to four). Toxicity was minimal and mainly hematologic. Two patients showed a complete response and one a partial response, all of very rapid onset. All three patients are alive 6, 9, and 42 months from the start of oral treatment. Two remain progression free, and one had a recurrence 1 month after completion of chemotherapy. We suggest that orally administered etoposide, a topoisomerase II inhibitor, has a strong antitumor effect in advanced Merkel cell carcinoma, even in patients previously treated parenterally with the same drug. This action may be explained by the greater dependence of the drug's efficacy on the duration of administration rather than the dose intensity.

Administration, Oral↗
PubMed2000

Reexamining the prevalence of Chlamydia trachomatis infection among gay men with urethritis: implications for STD policy and HIV prevention activities.

BACKGROUND: Evidence of an STD-HIV interaction and the availability of noninvasive urine-based screening tests have resulted in an increased focus on chlamydial infections in men. GOAL: To evaluate the prevalence of chlamydial infections among men with urethritis at the San Francisco City Clinic (SFCC). STUDY DESIGN: In 1997, male SFCC patients diagnosed with urethritis were tested for chlamydia using urine-based ligase chain reaction and for gonorrhea using urethral culture. RESULTS: Gonorrhea was identified in 45% of men who have sex with men (MSM) versus 26% of men who have sex with women (MSW). Among men with gonorrhea, chlamydia coinfection was found among 15.2% of MSM and 8.4% of MSW. Among men with nongonococcal urethritis, 18% and 20% of MSM and MSW had chlamydial infection, respectively. Young age was associated with chlamydial infection in MSM. CONCLUSION: After a period of low chlamydial infection rates in MSM during the pre-AIDS era, infection rates are increasing among this population. SFCC's revised clinical practice guidelines include chlamydia testing of MSM with urethritis.

Adolescent↗
PubMed2000

Multicenter evaluation of AMPLICOR and automated COBAS AMPLICOR CT/NG tests for Neisseria gonorrhoeae.

The fully automated COBAS AMPLICOR CT/NG and semiautomated AMPLICOR CT/NG tests were evaluated in a multicenter trial for their ability to detect Neisseria gonorrhoeae infections. Test performance compared to that of culturing was evaluated for 2,192 matched endocervical swab and urine specimens obtained from women and for 1, 981 matched urethral swab and urine specimens obtained from men. Culture-negative, PCR-positive specimens that tested positive in a confirmatory PCR test for an alternative target sequence within the N. gonorrhoeae 16S rRNA gene were considered to be true positives. The overall prevalences of gonorrhea were 6.6% in women and 20.1% in men. The COBAS AMPLICOR and AMPLICOR formats yielded concordant results for 98.8% of the specimens and exhibited virtually identical sensitivities and specificities. The results that follow are for the COBAS AMPLICOR format. With the infected patient as the reference standard, the resolved sensitivities of PCR were 92.4% for endocervical swab specimens and 64.8% for female urine specimens. There were no significant differences in these rates between women with and without symptoms. Among symptomatic men, COBAS AMPLICOR sensitivities were 94.1% for urine and 98.1% for urethral swabs; for asymptomatic men, the results were 42.3 and 73.1%, respectively. In comparison, the sensitivities of culturing were 84.8% for endocervical specimens, 92.7% for symptomatic male urethral specimens, and only 46.2% for urethral specimens obtained from asymptomatic men. When PCR results were analyzed as if only a single test had been performed on a single specimen type, the resolved sensitivity was always higher. The resolved specificities of PCR were 99.5% for endocervical swab specimens, 99.8% for female urine specimens, 98.9% for male urethral swab specimens, and 99.9% for male urine specimens. The internal control revealed that 2.1% of specimens were inhibitory when initially tested. Nevertheless, valid results were obtained for 99.2% of specimens because 60.0% of the inhibitory specimens were not inhibitory when a second aliquot was tested. The COBAS AMPLICOR CT/NG test for N. gonorrhoeae exhibited high sensitivity and specificity with urethral swab and urine specimens from men and endocervical swab specimens from women and thus is well suited for diagnosing and screening for N. gonorrhoeae infection.

Animals↗
PubMed2000

Evaluation of nucleic acid amplification tests as reference tests for Chlamydia trachomatis infections in asymptomatic men.

Urine ligase chain reaction (LCR) and PCR tests and urethral swab culture were compared for their abilities to detect Chlamydia trachomatis infection in 3,639 asymptomatic men by using one-, two-, and three-test reference standards. Frozen urine at four of five participating centers was also tested by a transcription-mediated amplification assay which was used as a reference test. LCR increased the yield of positive results by 27% and PCR increased the yield of positive results by 26% over the yield of positive results by culture (n = 295). LCR and PCR sensitivities were similar, ranging from 80.4 to 93.5%, depending on the reference standard. Culture sensitivity was substantially less. A multiple-test standard yielded LCR, PCR, and culture specificities of 99.6%, with or without discrepant analysis. Test performance varied among centers partly due to different interpretations of the testing protocols. The study confirms that urine LCR and PCR for the detection of C. trachomatis have substantially improved sensitivities over that of urethral swab culture for testing of asymptomatic men, enabling screening of this important target group. These tests, perhaps in combination, are also candidate reference tests for the conduct of test evaluation studies.

Animals↗
PubMed2000

Multicenter evaluation of the AMPLICOR and automated COBAS AMPLICOR CT/NG tests for detection of Chlamydia trachomatis.

The fully automated COBAS AMPLICOR CT/NG and semiautomated AMPLICOR CT/NG tests were evaluated in a multicenter trial for the ability to detect Chlamydia trachomatis infections. Test performance compared to that of culture was evaluated for 2,236 matched endocervical swab and urine specimens obtained from women and for 1,940 matched urethral swab and urine specimens obtained from men. Culture-negative, PCR-positive specimens that tested positive in a direct fluorescent-antibody test or in a confirmatory PCR test for an alternative target sequence were resolved as true positives. The overall prevalences of chlamydia were 2.4% in women and 7.2% in men. The COBAS AMPLICOR and AMPLICOR formats yielded concordant results for 98.1% of the specimens. With the infected patient as the reference standard, the resolved sensitivities of COBAS AMPLICOR were 89.7% for endocervical swab specimens, 89.2% for female urine specimens, 88.6% for male urethral swab specimens, and 90.3% for male urine specimens. When results were analyzed as if only a single test had been performed on a single specimen type, the resolved sensitivity was always higher. The resolved specificities of PCR were 99.4% for endocervical swab specimens, 99.0% for female urine specimens, 98.7% for male urethral swab specimens, and 98.4% for male urine specimens. The internal control revealed that 2.4% of the specimens were inhibitory when initially tested. Nevertheless, valid results were obtained for 98.6% of the specimens because 59.1% of the inhibitory specimens were not inhibitory when a second aliquot was tested. The COBAS AMPLICOR and AMPLICOR CT/NG tests for C. trachomatis exhibited equally high sensitivity and specificity with both urogenital swab and urine specimens and thus are well suited for screening for C. trachomatis infection.

Automation↗
PubMed2000

Paclitaxel versus doxorubicin as first-line single-agent chemotherapy for metastatic breast cancer: a European Organization for Research and Treatment of Cancer Randomized Study with cross-over.

PURPOSE: To compare the efficacy of paclitaxel versus doxorubicin given as single agents in first-line therapy of advanced breast cancer (primary end point, progression-free survival ¿PFS) and to explore the degree of cross-resistance between the two agents. PATIENTS AND METHODS: Three hundred thirty-one patients were randomized to receive either paclitaxel 200 mg/m(2), 3-hour infusion every 3 weeks, or doxorubicin 75 mg/m(2), intravenous bolus every 3 weeks. Seven courses were planned unless progression or unacceptable toxicity occurred before the seven courses were finished. Patients who progressed within the seven courses underwent early cross-over to the alternative drug, while a delayed cross-over was optional for the remainder of patients at the time of disease progression. RESULTS: Objective response in first-line therapy was significantly better (P =.003) for doxorubicin (response rate ¿RR, 41%) than for paclitaxel (RR, 25%), with doxorubicin achieving a longer median PFS (7.5 months for doxorubicin v 3.9 months for paclitaxel, P <.001). In second-line therapy, cross-over to doxorubicin (91 patients) and to paclitaxel (77 patients) gave response rates of 30% and 16%, respectively. The median survival durations of 18.3 months for doxorubicin and 15.6 months for paclitaxel were not significantly different (P =.38). The doxorubicin arm had greater toxicity, but this was counterbalanced by better symptom control. CONCLUSION: At the dosages and schedules used in the present study, doxorubicin achieves better disease and symptom control than paclitaxel in first-line treatment. Doxorubicin and paclitaxel are not totally cross-resistant, which supports further investigation of these drugs in combination or in sequence, both in advanced disease and in the adjuvant setting.

Adenocarcinoma↗
PubMed1999

Azithromycin in control of trachoma.

BACKGROUND: Trachoma is the leading cause of preventable blindness. Programmes to prevent blindness due to trachoma are based on community-wide treatment with topical tetracycline. We assessed the potential of community-wide azithromycin treatment for trachoma control. METHODS: Pairs of villages in trachoma endemic areas of Egypt, The Gambia, and Tanzania were matched on trachoma rates in 1-10-year-old children. Villages were randomly assigned community-wide oral azithromycin treatment (three doses with intervals of 1 week) or treatment with 1% topical tetracycline (once daily for 6 weeks). Clinical examinations were done at baseline, 2-4.5 months, and 12-14 months after treatment. Chlamydia trachomatitis was identified by ligase chain reaction (LCR). Analyses were by intention to treat. Univariate comparisons and multivariate analyses were used to compare outcomes. FINDINGS: LCR positivity was correlated with clinical severity, but about 30% of Egyptian and Gambian villagers with no active disease were LCR positive. Village-wide LCR positivity ranged from 16.5% (Tanzania) to 43.6% (Egypt). Treatment compliance was over 90% except in the tetracycline treatment village in Egypt. Of the participants initially LCR positive, 866 (95%) of 924 who received at least one azithromycin dose and 482 (82%) of 587 who received 28 days or more topical tetracycline, were negative at follow-up. At 1 year, village-wide LCR positivity rates were substantially lower than at baseline with both treatments; the decreases were greater with azithromycin than with tetracycline (93% vs 77% in Egypt, 78 vs 66% in The Gambia, 64 vs 55% in Tanzania). Similarly, greater reduction in clinical activity occurred after azithromycin. In multivariate analyses, factors associated with being LCR positive at 1 year were: not receiving azithromycin; age under 10 years; and LCR positivity at baseline. INTERPRETATION: Community-wide treatment with oral azithromycin markedly reduces C. trachomatis infection and clinical trachoma in endemic areas and may be an important approach to control of trachoma.

Administration, Oral↗
PubMed1999

Is the routine pelvic examination needed with the advent of urine-based screening for sexually transmitted diseases?

OBJECTIVE: To determine the most cost-effective method of screening for chlamydia and gonorrhea to prevent pelvic inflammatory disease (PID) in asymptomatic sexually active adolescent females. DESIGN: Cost-effectiveness decision analysis comparing pelvic examination with cervical screening (the current national standard) with a model of urine screening with ligase chain reaction testing for Chlamydia trachomatis and Neisseria gonorrhoeae. METHODS: Four strategies using decision analysis were compared for a potential cohort of 100000 asymptomatic sexually active young women: (1) pelvic examination screening in 100%; (2) urine screening in 100%; (3) actual predicted pelvic examination screening in 70%; and (4) actual predicted urine screening in 90%. Assumptions and costs were generated from published sources. MAIN OUTCOME MEASURES: Cases of PID prevented per year and cost to prevent a case of PID. RESULTS: A total of 1750 cases of PID would be predicted to occur per year with no screening. Strategy 1 would prevent the most cases of PID (1283) at a mean cost of $10230. Strategy 2 would prevent 1215 cases of PID at a mean cost of $5093. The marginal cost to prevent an additional case of PID by strategy 1 is $101454. Strategy 3 would prevent 898 cases of PID and 1093 cases of PID would be prevented with urine screening in strategy 4. CONCLUSION: Urine-based ligase chain reaction screening is the most cost-effective strategy to detect chlamydial and gonococcal genital infection in asymptomatic sexually active adolescent females and, owing to ease of implementation, the most likely to prevent the greatest number of cases of PID.

Adolescent↗
PubMed1999

Sexually transmitted diseases in a health maintenance organization teen clinic: associations of race, partner's age, and marijuana use.

OBJECTIVE: To determine the role of sociodemographic risk markers and behavioral risk factors associated with sexually transmitted diseases (STDs) in sexually experienced youth seeking care at an urban, general health maintenance organization teen clinic. DESIGN: Cross-sectional. PARTICIPANTS: A consecutive, racially and ethnically diverse sample of 285 sexually experienced youth who were preponderantly female (58.6%) and who were aged 16.7 years on average. METHODS: All participants completed a self-report questionnaire and were screened for Chlamydia trachomatis using the ligase chain reaction technique and for Neisseria gonorrhoeae and other STDs using conventional methods. RESULTS: Many of these youth were at high risk for STDs, having a self-reported history of sex with multiple partners (49.1%), sex with a new partner (42.5%), inconsistent use of condoms (71.9%), and frequent substance use (24.5% used marijuana 1-2 times per week or more). Sexually transmitted disease screening revealed that 11.6% of the participants had 1 or more STDs. A logistic regression analysis to determine the best model for predicting STDs indicated that youth who are African American (odds ratio, 3.34; 95% confidence interval, 1.52-7.35), had sexual partners who were 2 or more years older (odds ratio, 2.63, 95% confidence interval, 1.22-5.67), and used marijuana 1 to 2 times or more per week (odds ratio, 2.27; 95% confidence interval, 1.01-5.13) were more likely to have STDs at screening. CONCLUSIONS: A brief sociodemographic and behavioral risk assessment that includes these factors may be useful for clinicians in deciding when to screen for STDs in sexually active youth seeking care for reasons not related to reproductive health.

Adolescent↗
PubMed1999

Cervical secretory immunoglobulin A in adolescent girls.

PURPOSE: To determine whether there are differences in levels of cervical secretory immunoglobulin A (sIgA) between adolescent girls in the secretory and proliferative phases of their menstrual cycle. METHODS: Sexually active adolescent girls (n = 117) at health maintenance organization (HMO) based adolescent medical clinic were recruited into the study. In addition to demographic and clinical data, cervical specimens were collected for sIgA measurement and gonorrhea culture, urine for chlamydia ligase chain reaction, and blood for progesterone levels. Subjects were classified as being in the proliferative phase or secretory phase of the menstrual cycle on the basis of their progesterone levels. RESULTS: The mean age of the subjects was 17.2 years old. There was no difference in the sIgA levels between those in the proliferative phase of their cycle (n = 45; mean sIgA level, 0.0055 mg/mL) and those in the secretory phase (n = 40; mean sIgA level, 0.0032 mg/mL) (p > .10). CONCLUSIONS: The secretory phase of the menstrual cycle does not appear to be associated with higher levels of sIgA in adolescent girls. These results suggest that adolescents with anovulatory cycles, i.e., those who lack a secretory phase, may not be at increased risk for genital tract infections such as chlamydia or gonorrhea.

Adolescent↗