Background: Genomic prediction of tumoral chemosensitivity might also predict residual nodal stat... more Background: Genomic prediction of tumoral chemosensitivity might also predict residual nodal status after neoadjuvant chemotherapy (NC). This information could assist in selecting patients for axillary-conserving surgery. Methods: We developed a microarray-based genomic predictor of pathologic response after sequential taxane-anthracycline chemotherapy from 227 patients with HER2-negative breast cancer, and tested this in an independent, multicenter cohort of 113 patients who received neoadjuvant taxane-anthracycline chemotherapy containing paclitaxel or docetaxel. Predicted response from a diagnostic needle biopsy before NC was compared to pathologic nodal status after NC. Results: Predicted chemotherapy responders (20%) were significantly more likely to be node-negative after treatment (positive predictive value [PPV] 83%, 95% confidence interval [CI] 61%-95%), compared to 57% overall. In 68 clinically node-positive patients, 37% converted to node-negative status after NC, and thi...
ABSTRACT Since the advent of the first IEEE 802.11 standard, several papers have proposed means o... more ABSTRACT Since the advent of the first IEEE 802.11 standard, several papers have proposed means of providing QoS to IEEE 802.11 networks and evaluate various traffic-prioritization mechanisms. Nevertheless, studies on the assignment of AIFS times defined in IEEE 802.11e reveal that the various priority levels work in a synchronized manner. The studies show that, under large loads of high-priority traffic, EDCA starves low-priority frames, which is undesirable. We argue that QoS traffic needs to be prioritized, but users sending best-effort frames should also obtain the expected service. High-priority traffic can also suffer performance degradation when using EDCA because of heavy loads of low-priority frames. Thus, we have proposed a mechanism based on desynchronizing the IEEE 802.11e working procedure. It prevents stations that belong to different priority classes from attempting simultaneous transmission, prioritizes independent collision groups and achieves better short-term and long-term channel access fairness. We have evaluated the proposal based on extensive analytical and simulation results. It prevents the strangulation of low-priority traffic, and, moreover, reduces the degradation of high-priority traffic with the increased presence of low-priority frames. Peer reviewed
The prevalence of BRCA1 and BRCA2 mutations among breast cancer patients in Peru has not yet been... more The prevalence of BRCA1 and BRCA2 mutations among breast cancer patients in Peru has not yet been explored. We enrolled 266 women with breast cancer from a National cancer hospital in Lima, Peru, unselected for age or family history. DNA was screened with a panel of 114 recurrent Hispanic BRCA mutations (HISPANEL). Among the 266 cases, 13 deleterious mutations were identified (11 in BRCA1 and 2 in BRCA2), representing 5% of the total. The average age of breast cancer in the mutation-positive cases was 44 years. BRCA1 185delAG represented 7 of 11 mutations in BRCA1. Other mutations detected in BRCA1 included: two 2080delA, one 943ins10, and one 3878delTA. The BRCA2 3036del4 mutation was seen in two patients. Given the relatively low cost of the HISPANEL test, one should consider offering this test to all Peruvian women with breast or ovarian cancer.
Since the advent of the first IEEE 802.11 standard, several papers have proposed means of providi... more Since the advent of the first IEEE 802.11 standard, several papers have proposed means of providing QoS to IEEE 802.11 networks and evaluate various traffic-prioritization mechanisms. Nevertheless, studies on the assignment of AIFS times defined in IEEE 802.11e reveal that the various priority levels work in a synchronized manner. The studies show that, under large loads of high-priority traffic, EDCA starves low-priority frames, which is undesirable. We argue that QoS traffic needs to be prioritized, but users sending best-effort frames should also obtain the expected service. High-priority traffic can also suffer performance degradation when using EDCA because of heavy loads of low-priority frames. Thus, we have proposed a mechanism based on desynchronizing the IEEE 802.11e working procedure. It prevents stations that belong to different priority classes from attempting simultaneous transmission, prioritizes independent collision groups and achieves better short-term and long-term channel access fairness. We have evaluated the proposal based on extensive analytical and simulation results. It prevents the strangulation of low-priority traffic, and, moreover, reduces the degradation of high-priority traffic with the increased presence of low-priority frames.
The 13th IEEE Workshop on Local and Metropolitan Area Networks, 2004. LANMAN 2004., 2004
This paper is focused on the study of WLAN performance in IEEE 802.11 networks that are in a situ... more This paper is focused on the study of WLAN performance in IEEE 802.11 networks that are in a situation of asymmetric traffic, where the access point (AP) transmits much more than the user stations (US). This situation is very different from the symmetric one, wherein all the stations have the same traffic load. The paper also presents a discussion of the different mechanisms in order to increase AP priority under the asymmetric traffic situation.
2005 IEEE 16th International Symposium on Personal, Indoor and Mobile Radio Communications, 2005
Abstract-Most studies about the performance of IEEE 802.11 consider scenarios of ad-hoc topology ... more Abstract-Most studies about the performance of IEEE 802.11 consider scenarios of ad-hoc topology and networks where all stations have the same traffic load (symmetric traffic conditions). This paper presents a study of performance parameters of more realistic networks. We focus ...
It is known that hair can accumulate environmental toxics and excrete foreign chemical or biologi... more It is known that hair can accumulate environmental toxics and excrete foreign chemical or biological substances. In this context, we hypothesized that foreign DNA could be found in the hair of an infected organism, and thus, be detected by Real Time PCR in the hair of Leishmania infantum naturally infected dogs. A population of 28 dogs living in Leishmania endemic areas was divided into two groups: A (13 Leishmania infected dogs) and B (15 healthy dogs). Blood, lymph node and ear hair samples from all of them were tested for the presence of parasite kinetoplast DNA (kDNA). For the same purpose, hair of several body areas and hair sections of two infected dogs were also analyzed. Epidermal keratinocytes from an infected animal were also analyzed for reactivity against Leishmania antigens by ELISA and for the presence of kDNA. Regarding to dogs from group A, parasite kDNA was detected in the 100% of lymph node samples. The sensitivity of Real Time PCR in ear hair was similar to that obtained in blood (9 positive out of 13 versus 8 positive out of 13, respectively). Moreover, the presence of L. infantum kDNA was also detected in the hair of all the analyzed body zones, in all hair sections and in epidermal keratinocytes. In infected dogs, parasite kDNA could be detected and quantified from just one single hair, whereas it was not detected in any of the samples of the healthy dogs. This work describes a new method for a reliable and non-invasive diagnosis of canine leishmaniosis using hair samples of infected animals. The data presented also provide some insights for the understanding of the physiology of keratinocytes and the role of hair as a specialized tissue in the kidnapping and removal of foreign DNA.
The protective potential against Leishmania infection of the Leishmania chimerical Q protein admi... more The protective potential against Leishmania infection of the Leishmania chimerical Q protein administered as a single (Q) or double dose (Q+Q) without adjuvant was analyzed in a double-blind placebo controlled experiment in dogs. During vaccination the protein induced an intense early anti-Q response but no reactivity against total Leishmania infantum proteins was detected. Several end-points were taken into consideration. In the vaccinated animals the amount and intensity of clinical symptoms was lower than in the control group. Pathological signs of disease were observed in liver, kidney and spleen of all dogs from the control group in contrast to the normal appearance of the organs of the vaccinated animals. Vaccination was able to induce parasite clearance in most dogs. Only 1/7 dog was parasite DNA positive in skin in the Q group in contrast to 6/7 dogs in control and 4/7 in Q+Q. Significant anti-SLA clearance was observed in the vaccinated animals at the end of the study. Differences between control and vaccinated animals were also observed at the biochemical level, DTH and nitrite oxide production.
... DOI: 10.1080/02331934.2010.507273 John Cotrina a , Elizabeth W. Karas b * , Ademir A. Ribeiro... more ... DOI: 10.1080/02331934.2010.507273 John Cotrina a , Elizabeth W. Karas b * , Ademir A. Ribeiro b , Wilfredo Sosa a c & Jin Y. Yuan b Available online: 09 Aug 2011. ...
ABSTRACT Retrospective evaluation of the clinical behavior, treatment and prognosis in five cases... more ABSTRACT Retrospective evaluation of the clinical behavior, treatment and prognosis in five cases of primary breast lymphoma. From 1999 to 2003, five patients with primary breast lymphoma were diagnosed in our department. Primary breast lymphoma (PBL) was diagnosed in five patients, whose median age was 63.4 (41-79) years. In four out of five patients, a diagnosis of lymphoma was made after the evaluation of a palpable breast mass measuring 1.5 to 6 cm. All of them were classified as non-Hodgkin's B cell lymphomas and three of five cases were diffuse large cell lymphomas. All patients were submitted to chemotherapy; in only one patient was surgery performed. A relatively high rate of PBL was observed in our department compared with other oncology centers. Beyond its scarce appearance, PBL is very difficult to distinguish from primary breast carcinoma. Histology remains the major diagnostic tool.
Background: Genomic prediction of tumoral chemosensitivity might also predict residual nodal stat... more Background: Genomic prediction of tumoral chemosensitivity might also predict residual nodal status after neoadjuvant chemotherapy (NC). This information could assist in selecting patients for axillary-conserving surgery. Methods: We developed a microarray-based genomic predictor of pathologic response after sequential taxane-anthracycline chemotherapy from 227 patients with HER2-negative breast cancer, and tested this in an independent, multicenter cohort of 113 patients who received neoadjuvant taxane-anthracycline chemotherapy containing paclitaxel or docetaxel. Predicted response from a diagnostic needle biopsy before NC was compared to pathologic nodal status after NC. Results: Predicted chemotherapy responders (20%) were significantly more likely to be node-negative after treatment (positive predictive value [PPV] 83%, 95% confidence interval [CI] 61%-95%), compared to 57% overall. In 68 clinically node-positive patients, 37% converted to node-negative status after NC, and thi...
ABSTRACT Since the advent of the first IEEE 802.11 standard, several papers have proposed means o... more ABSTRACT Since the advent of the first IEEE 802.11 standard, several papers have proposed means of providing QoS to IEEE 802.11 networks and evaluate various traffic-prioritization mechanisms. Nevertheless, studies on the assignment of AIFS times defined in IEEE 802.11e reveal that the various priority levels work in a synchronized manner. The studies show that, under large loads of high-priority traffic, EDCA starves low-priority frames, which is undesirable. We argue that QoS traffic needs to be prioritized, but users sending best-effort frames should also obtain the expected service. High-priority traffic can also suffer performance degradation when using EDCA because of heavy loads of low-priority frames. Thus, we have proposed a mechanism based on desynchronizing the IEEE 802.11e working procedure. It prevents stations that belong to different priority classes from attempting simultaneous transmission, prioritizes independent collision groups and achieves better short-term and long-term channel access fairness. We have evaluated the proposal based on extensive analytical and simulation results. It prevents the strangulation of low-priority traffic, and, moreover, reduces the degradation of high-priority traffic with the increased presence of low-priority frames. Peer reviewed
The prevalence of BRCA1 and BRCA2 mutations among breast cancer patients in Peru has not yet been... more The prevalence of BRCA1 and BRCA2 mutations among breast cancer patients in Peru has not yet been explored. We enrolled 266 women with breast cancer from a National cancer hospital in Lima, Peru, unselected for age or family history. DNA was screened with a panel of 114 recurrent Hispanic BRCA mutations (HISPANEL). Among the 266 cases, 13 deleterious mutations were identified (11 in BRCA1 and 2 in BRCA2), representing 5% of the total. The average age of breast cancer in the mutation-positive cases was 44 years. BRCA1 185delAG represented 7 of 11 mutations in BRCA1. Other mutations detected in BRCA1 included: two 2080delA, one 943ins10, and one 3878delTA. The BRCA2 3036del4 mutation was seen in two patients. Given the relatively low cost of the HISPANEL test, one should consider offering this test to all Peruvian women with breast or ovarian cancer.
Since the advent of the first IEEE 802.11 standard, several papers have proposed means of providi... more Since the advent of the first IEEE 802.11 standard, several papers have proposed means of providing QoS to IEEE 802.11 networks and evaluate various traffic-prioritization mechanisms. Nevertheless, studies on the assignment of AIFS times defined in IEEE 802.11e reveal that the various priority levels work in a synchronized manner. The studies show that, under large loads of high-priority traffic, EDCA starves low-priority frames, which is undesirable. We argue that QoS traffic needs to be prioritized, but users sending best-effort frames should also obtain the expected service. High-priority traffic can also suffer performance degradation when using EDCA because of heavy loads of low-priority frames. Thus, we have proposed a mechanism based on desynchronizing the IEEE 802.11e working procedure. It prevents stations that belong to different priority classes from attempting simultaneous transmission, prioritizes independent collision groups and achieves better short-term and long-term channel access fairness. We have evaluated the proposal based on extensive analytical and simulation results. It prevents the strangulation of low-priority traffic, and, moreover, reduces the degradation of high-priority traffic with the increased presence of low-priority frames.
The 13th IEEE Workshop on Local and Metropolitan Area Networks, 2004. LANMAN 2004., 2004
This paper is focused on the study of WLAN performance in IEEE 802.11 networks that are in a situ... more This paper is focused on the study of WLAN performance in IEEE 802.11 networks that are in a situation of asymmetric traffic, where the access point (AP) transmits much more than the user stations (US). This situation is very different from the symmetric one, wherein all the stations have the same traffic load. The paper also presents a discussion of the different mechanisms in order to increase AP priority under the asymmetric traffic situation.
2005 IEEE 16th International Symposium on Personal, Indoor and Mobile Radio Communications, 2005
Abstract-Most studies about the performance of IEEE 802.11 consider scenarios of ad-hoc topology ... more Abstract-Most studies about the performance of IEEE 802.11 consider scenarios of ad-hoc topology and networks where all stations have the same traffic load (symmetric traffic conditions). This paper presents a study of performance parameters of more realistic networks. We focus ...
It is known that hair can accumulate environmental toxics and excrete foreign chemical or biologi... more It is known that hair can accumulate environmental toxics and excrete foreign chemical or biological substances. In this context, we hypothesized that foreign DNA could be found in the hair of an infected organism, and thus, be detected by Real Time PCR in the hair of Leishmania infantum naturally infected dogs. A population of 28 dogs living in Leishmania endemic areas was divided into two groups: A (13 Leishmania infected dogs) and B (15 healthy dogs). Blood, lymph node and ear hair samples from all of them were tested for the presence of parasite kinetoplast DNA (kDNA). For the same purpose, hair of several body areas and hair sections of two infected dogs were also analyzed. Epidermal keratinocytes from an infected animal were also analyzed for reactivity against Leishmania antigens by ELISA and for the presence of kDNA. Regarding to dogs from group A, parasite kDNA was detected in the 100% of lymph node samples. The sensitivity of Real Time PCR in ear hair was similar to that obtained in blood (9 positive out of 13 versus 8 positive out of 13, respectively). Moreover, the presence of L. infantum kDNA was also detected in the hair of all the analyzed body zones, in all hair sections and in epidermal keratinocytes. In infected dogs, parasite kDNA could be detected and quantified from just one single hair, whereas it was not detected in any of the samples of the healthy dogs. This work describes a new method for a reliable and non-invasive diagnosis of canine leishmaniosis using hair samples of infected animals. The data presented also provide some insights for the understanding of the physiology of keratinocytes and the role of hair as a specialized tissue in the kidnapping and removal of foreign DNA.
The protective potential against Leishmania infection of the Leishmania chimerical Q protein admi... more The protective potential against Leishmania infection of the Leishmania chimerical Q protein administered as a single (Q) or double dose (Q+Q) without adjuvant was analyzed in a double-blind placebo controlled experiment in dogs. During vaccination the protein induced an intense early anti-Q response but no reactivity against total Leishmania infantum proteins was detected. Several end-points were taken into consideration. In the vaccinated animals the amount and intensity of clinical symptoms was lower than in the control group. Pathological signs of disease were observed in liver, kidney and spleen of all dogs from the control group in contrast to the normal appearance of the organs of the vaccinated animals. Vaccination was able to induce parasite clearance in most dogs. Only 1/7 dog was parasite DNA positive in skin in the Q group in contrast to 6/7 dogs in control and 4/7 in Q+Q. Significant anti-SLA clearance was observed in the vaccinated animals at the end of the study. Differences between control and vaccinated animals were also observed at the biochemical level, DTH and nitrite oxide production.
... DOI: 10.1080/02331934.2010.507273 John Cotrina a , Elizabeth W. Karas b * , Ademir A. Ribeiro... more ... DOI: 10.1080/02331934.2010.507273 John Cotrina a , Elizabeth W. Karas b * , Ademir A. Ribeiro b , Wilfredo Sosa a c & Jin Y. Yuan b Available online: 09 Aug 2011. ...
ABSTRACT Retrospective evaluation of the clinical behavior, treatment and prognosis in five cases... more ABSTRACT Retrospective evaluation of the clinical behavior, treatment and prognosis in five cases of primary breast lymphoma. From 1999 to 2003, five patients with primary breast lymphoma were diagnosed in our department. Primary breast lymphoma (PBL) was diagnosed in five patients, whose median age was 63.4 (41-79) years. In four out of five patients, a diagnosis of lymphoma was made after the evaluation of a palpable breast mass measuring 1.5 to 6 cm. All of them were classified as non-Hodgkin's B cell lymphomas and three of five cases were diffuse large cell lymphomas. All patients were submitted to chemotherapy; in only one patient was surgery performed. A relatively high rate of PBL was observed in our department compared with other oncology centers. Beyond its scarce appearance, PBL is very difficult to distinguish from primary breast carcinoma. Histology remains the major diagnostic tool.
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Papers by J. Cotrina