Biomedical subjects

L Rob

Publications and source records attributed to L Rob.

At least 19 recordsLinked to original sources

PubMed2006

HESS observations of the galactic center region and their possible dark matter interpretation.

The detection of gamma rays from the source HESS J1745-290 in the Galactic Center (GC) region with the High Energy Spectroscopic System (HESS) array of Cherenkov telescopes in 2004 is presented. After subtraction of the diffuse gamma-ray emission from the GC ridge, the source is compatible with a point source with spatial extent less than 1.2;{'}(stat) (95% C.L.). The measured energy spectrum above 160 GeV is compatible with a power law with photon index of 2.25+/-0.04(stat)+/-0.10(syst) and no significant flux variation is detected. It is finally found that the bulk of the very high energy emission must have non-dark-matter origin.

Journal Article↗

PubMed2006

Fast variability of tera-electron volt gamma rays from the radio galaxy M87.

The detection of fast variations of the tera-electron volt (TeV) (10(12) eV) gamma-ray flux, on time scales of days, from the nearby radio galaxy M87 is reported. These variations are about 10 times as fast as those observed in any other wave band and imply a very compact emission region with a dimension similar to the Schwarzschild radius of the central black hole. We thus can exclude several other sites and processes of the gamma-ray production. The observations confirm that TeV gamma rays are emitted by extragalactic sources other than blazars, where jets are not relativistically beamed toward the observer.

Journal Article↗

PubMed2006

A low level of extragalactic background light as revealed by gamma-rays from blazars.

The diffuse extragalactic background light consists of the sum of the starlight emitted by galaxies through the history of the Universe, and it could also have an important contribution from the 'first stars', which may have formed before galaxy formation began. Direct measurements are difficult and not yet conclusive, owing to the large uncertainties caused by the bright foreground emission associated with zodiacal light. An alternative approach is to study the absorption features imprinted on the gamma-ray spectra of distant extragalactic objects by interactions of those photons with the background light photons. Here we report the discovery of gamma-ray emission from the blazars H 2356 - 309 and 1ES 1101 - 232, at redshifts z = 0.165 and z = 0.186, respectively. Their unexpectedly hard spectra provide an upper limit on the background light at optical/near-infrared wavelengths that appears to be very close to the lower limit given by the integrated light of resolved galaxies. The background flux at these wavelengths accordingly seems to be strongly dominated by the direct starlight from galaxies, thus excluding a large contribution from other sources-in particular from the first stars formed. This result also indicates that intergalactic space is more transparent to gamma-rays than previously thought.

Journal Article↗

PubMed2006

Discovery of very-high-energy gamma-rays from the Galactic Centre ridge.

The source of Galactic cosmic rays (with energies up to 10(15) eV) remains unclear, although it is widely believed that they originate in the shock waves of expanding supernova remnants. At present the best way to investigate their acceleration and propagation is by observing the gamma-rays produced when cosmic rays interact with interstellar gas. Here we report observations of an extended region of very-high-energy (> 10(11) eV) gamma-ray emission correlated spatially with a complex of giant molecular clouds in the central 200 parsecs of the Milky Way. The hardness of the gamma-ray spectrum and the conditions in those molecular clouds indicate that the cosmic rays giving rise to the gamma-rays are likely to be protons and nuclei rather than electrons. The energy associated with the cosmic rays could have come from a single supernova explosion around 10(4) years ago.

Journal Article↗

PubMed2006

Longitudinal study of patients after surgical treatment for cervical lesions: detection of HPV DNA and prevalence of HPV-specific antibodies.

The principal aims of this study were to test whether persistence of human papillomavirus (HPV) DNA is predictive of recurrent disease in women after surgical treatment for cervical lesions, to distinguish between persistent and newly acquired HPV infection, and to observe the effect of surgical treatment on levels of HPV-specific antibodies. A group of 198 patients surgically treated for low-grade and high-grade squamous intraepithelial lesions and 35 age-matched controls were monitored for 18 months at 6-month intervals. The presence of HPV DNA in cervical smears was detected by means of consensus polymerase chain reaction, and serum levels of HPV-specific antibodies to HPV types 16, 18, 31, 33, and 45 were measured. In ten patients positive for HPV type 16 in consecutive samples, the HPV 16 variants were identified using a polymerase chain reaction specific for the long control region. Data regarding demographics, risk factors for cervical cancer, and risks related to HPV exposure were collected through a patient questionnaire. Subjects persistently positive for HPV DNA were more likely to present with cytological and/or colposcopical abnormalities. A higher reactivity to HPV-specific antibodies was observed in these women at the 18-month follow-up visit. All ten patients with HPV 16 infection detected in consecutive samples showed persistence of either the same prototype or the same variant during the follow-up period. Risky sexual behavior and smoking were more common in patients than in controls. Persistent HPV infection as demonstrated by both HPV DNA detection and antibody detection appears to be a risk factor for the recurrence of pathological findings in women after surgery. An individually based approach to surgical treatment is an important factor in the outcome of disease at follow-up.

Adolescent↗

PubMed2006

[New method for detection of nonpalpable breast cancer].

OBJECTIVE: The objective of the study was to evaluate the feasibility of radio guided occult lesion localization (ROLL) in the cases of nonpalpable breast cancers with sentinel lymph node biopsy. DESIGN: Prospective clinical study SETTING: Department of Gynecology and Obstetrics, 2nd Medical Faculty and Teaching Hospital, Praha METHODS: Thirty-eight patients with nonpalpable breast cancer diagnosed by core cut biopsy underwent an injection of the radiopharmaceutical 18-20 hours before surgery. The dose of the radiopharmaceutical was 45 MBg into tumor and 15 MBg subdermaly. Surgical excision of radioactive breast tissue with nonpalpable tumor was carried out using the hand held gamma probe and the same technique was performed for biopsy of sentinel lymph node. Standard localization technique with hook-wire was performed in the control group of fifty-one patients. RESULTS: Radioguided surgery of nonpalpable tumor was successful in all cases. Surgical margins were clear in all cases, in four cases (10.5%) the margins were only 2 mm. The sentinel node was identified in all cases, in 3 patients (7.9%) the sentinel node was involved by tumor and axillary lymphadenectomy was performed. Infiltrating carcinomas were diagnosed in the "hook-wire" group in 21 cases (41.2%), all with clear margins over 3mm. Proportion of margins status between ROLL and hook-wire was the same. It seems that the health tissue loss around the tumor is in hook-wire technique bigger but it requires next study. CONCLUSION: Simultaneous performance of ROLL and sentinel node biopsy is useful and practicable methods in the management of nonpalpable breast cancer. In comparison to hook-wire, radioguided removal allows reduced excision volume and better lesion centering within the specimen.

Adult↗

PubMed2006

[Guideline for gynecological malignant tumors I. Standard--a complex therapy of ovarian epithelial malignant tumors].

OBJECTIVE: Elaboration of guideline for primary and secondary treatment of ovarian cancer. DESIGN: Review, consensus between proposers and opponents. METHOD: A retrospective review of published data, analysis of Czech statistics and consensus between proposers and opponents. RESULTS: We underline importance of comprehensive approach in therapy of ovarian cancer. We notice importance of expert ultrasound and CA 125 level in diagnostic algorithm. Extension of surgery depends on result of frozen section. All departments which want to perform surgery for ovarian resistance must have possibility to do peroperative histopathology. We can perform conservative fertility sparing surgery in patient with wishing of pregnancy and low stage disease. The effort of maximal debulking with radical surgery including lymphadenectomy is the standard procedure. When we diagnose ovarian cancer during laparoscopy, we have to convert on laparotomy procedure. We define the role of the neoadjuvant chemotherapy followed by surgery after 3-4 cycles of chemotherapy. We define adequate surgery treatment, indication for adjuvant chemotherapy and indication for second line therapy. CONCLUSION: Guideline for the treatment of epithelial ovarian cancer should become directions for clinicians and others, who participate in the process of treatment of the ovarian cancer. The guidelines include all parts of the process from diagnosis, treatment to follow up. All topics of the guidelines arose from a voting of the proposers and opponents.

Carcinoma↗

PubMed2006

Radioguided occult lesion localisation in combination with detection of the sentinel lymph node in non-palpable breast cancer tumours.

PURPOSE OF THE INVESTIGATION: The aim of study was to determine the efficacy of radioguided occult lesion localisation (ROLL) for non-palpable invasive breast cancer combined with sentinel lymph node biopsy (SLNB) and to compare the amount of tissue excised by radioguided navigation versus the hook-wire technique. METHODS: We injected 45 MBq of radiolabelled technetium intratumourally and 15 MBq subdermally 18 hours before surgery in 21 women with bioptically verified non-palpable breast cancer. We identified by gamma probe non-palpable tumours, which were excised, followed by identification and excision of the sentinel lymph node. We compared our results with a group of 12 women with non-palpable lesions marked by hook-wire localisation. RESULTS: ROLL combined with SLNB was successful in 100%; volume of excised tissue was smaller in the hook-wire group but expressed higher variability in volume than in the ROLL group although the difference was not statistically significant. CONCLUSION: The method of ROLL combined with SLNB is technically possible and safe, resulting in minimisation of the surgical intervention and a decrease in postoperative morbidity. ROLL was more precise than the hook-wire procedure even though the amount of tissue excised was the same in both groups.

Adult↗

PubMed2006

[Sentinel lymph nodes identification in vulvar cancer--methods and technique].

OBJECTIVE: To evaluate detection of sentinel lymph nodes (SLN) in squamous vulvar cancer with blue dye and 99mTc. The study describes technique of application, timing, management, detection rate (DR), specific side detection rate (SSDR) and false negative rate. DESIGN: Prospective clinical study. SETTING: Department of Obstetrics and Gynecology, Charles University Prague, 2nd Medical Faculty, Teaching Hospital Motol. PATIENTS AND METHODS: 46 women with squamous cell carcinoma tumors stage I or II, <4 cm with no clinical suspect lymph nodes were included. Blue dye alone was used in 16 women and the combination of 99mTc and blue dye was used in 30 women. Radiocoloid 99mTc was applied 3-5 hours and blue dye 3-5 minutes prior to ingvinal incision. RESULTS: We detected 88 SLN in 61 inguinal spaces. The detection rate in the blue dye group was 68.8 % (11 cases). One false negative SLN (6.3 %) appeared in this group. In blue dye+ 99mTc group detection rate was 100 % with no false negative SLN. CONCLUSION: Detection of SLN in squamous vulvar cancer with the combination of 99mTc and blue dye was statistically significantly more effective than using the blue dye alone.

Adult↗

PubMed2006

[Fertility sparing surgery in early cervical cancer today and tomorrow].

OBJECTIVE: Describtion and evaluation of proposed protocol for conservative, fertility sparing surgeries in the treatment of early stages of cervical cancer and its comparison to most frequently used protocols regarding its reproductive and oncological outcomes. DESIGN: Prospective clinical study. SETTING: Department of Obstetrics and Gynecology, Charles University Prague, 2nd Medical Faculty, University Hospital Motol. PATIENTS AND METHODS: 24 patients that fitted into the inclusion criteria were recruited in the study (6 in stage T1A2 and 18 T1B1). Inclusion criteria were: tumor less than 20 mm in largest diameter, less than 1/2 of the stromal invasion, SCC serum levels within normal range, signed informed consent. Minimum follow up was 24 months. Described therapeutic protocol, evaluation of oncological and reproductive outcomes and comparison with different fertility sparing regimens were performed. RESULTS: In four cases (16.7%) peroperative histopatghological evaluation (frozen section: FS) detected metastatic involvement of lymphatic nodes. In one case (4.1%) following 14 months since initial surgery, reccurent disease in uterine isthmus was detected. The patient underwent chmotherapy and she is 36 months in complete remission. In the series of 15 women planning pregnancy 11 subjects become pregnant so far. Eight deliveries occurred (one in 24th week of gestation--650g, one in 34w--2240g, one in 36w--2700g and five between 37-39w). Only one newborn was delivered in the cathegory of extreme prematurity. CONCLUSION: Sentinel node detection involving peroperative histopathological evaluation followed by subsequent serial processing and together with 2-step therapeutic management increases efectivity of fertility sparing surgeries. Less radical surgery on uterine cervix: reconisaton (in stage IA2) or simple trachelectomy (in early stage T1B1) with negative finding after laparoscopic lymph node dissection has comparative results with radical trachelectomy and abdominal radical trachelectomy. Pregnancy rates and pregnancy outcomes particularly regarding in term delivery is the best after treatment of early stages of cervical cancer using proposed protocol, while very promising results are published in studies with radical vaginal trachelectomy as well. Results published for the patients treated with abdominal radical trachelectomy are unsatisfactory.

Adult↗

PubMed2005

Discovery of very high energy gamma rays associated with an x-ray binary.

X-ray binaries are composed of a normal star in orbit around a neutron star or stellar-mass black hole. Radio and x-ray observations have led to the presumption that some x-ray binaries called microquasars behave as scaled-down active galactic nuclei. Microquasars have resolved radio emission that is thought to arise from a relativistic outflow akin to active galactic nuclei jets, in which particles can be accelerated to large energies. Very high energy gamma-rays produced by the interactions of these particles have been observed from several active galactic nuclei. Using the High Energy Stereoscopic System, we find evidence for gamma-ray emission of >100 gigaelectron volts from a candidate microquasar, LS 5039, showing that particles are also accelerated to very high energies in these systems.

Journal Article↗

PubMed2005

A new population of very high energy gamma-ray sources in the Milky Way.

Very high energy gamma-rays probe the long-standing mystery of the origin of cosmic rays. Produced in the interactions of accelerated particles in astrophysical objects, they can be used to image cosmic particle accelerators. A first sensitive survey of the inner part of the Milky Way with the High Energy Stereoscopic System (HESS) reveals a population of eight previously unknown firmly detected sources of very high energy gamma-rays. At least two have no known radio or x-ray counterpart and may be representative of a new class of "dark" nucleonic cosmic ray sources.

Journal Article↗

PubMed2005

[Abdominal hysterectomy--risk factor in development of urinary incontinence? Results of a questionnaire study].

OBJECTIVE: To evaluate the risk of urinary incontinence development after abdominal hysterectomy for benign gynecological disease. DESIGN: Retrospective questionnaire study. SETTING: Obstetrics and Gynecology Department, Charles University 2nd Medical Faculty and Teaching Hospital Motol, Prague. METHODS: Questionnaire study of women in which abdominal hysterectomy for benign gynecological disease was performed from January till December 2001 at our Department of Gynecology and Obstetrics. The questionnaire included questions about symptoms of stress, urge and mixed urinary incontinence. They were evaluated in connection with age, parity, hormonal status and body mass index. Student t-test was used for the statistical analysis. RESULTS: 114 (59.7%) from all sent-out questionnaires were obtained. In 15.8% cases (18 from 114) de novo urinary incontinence after surgery developed. 77.8% (14 from 18) from these patients suffered from genuine stress incontinence. The rest (4 from 18) of the women had symptoms of mixed incontinence. Study results draw attention to 13.1% women (15 from 114) in which preoperative stress incontinence persisted even after hysterectomy. Preoperative stress incontinence was cured in 6.1% (7 from 114) cases after hysterectomy. Age, parity, hormonal status and body mass index were not statistically different in all groups after surgery. CONCLUSIONS: The results of the study show relatively high risk of urinary incontinence development after abdominal hysterectomy in previously continent women. The results also show high persistence of the stress incontinence symptoms in women who did not inform about their incontinence even if they were asked about it. Higher quality of further health education of the women with drawing their attention to both the possibility of surgical treatment of urinary incontinence simultaneously with hysterectomy are the most important aspects how to make the current gynecological surgical therapy more effective.

Adult↗

PubMed2005

[Sentinel lymphatic node biopsy for breast cancer in practice].

OBJECTIVE: This paper reviewed the feasibility and accuracy of sentinel lymph node status in women with breast cancer. DESIGN: Clinical retrospective study. SETTING: Dept. of Obstetrics and Gynecology, 2nd Medical School, Teaching Hospital Motol, Praha. METHODS: Our trial involved 169 patients with breast cancer in the T1 and T2 stage without suspicion for axillary lymph node involvement. Lymphatic mapping was performed by sub dermal or subareolar injection of 99mTc labeled collodial human albumin (Senti-Scint) in the dose of 15 MBg one day before surgery. During the operation lymphatic mapping with vital blue dye (patent blau) was performed. Then the hand-held gamma-ray detector probe was used to locate the sentinel node. From a small axillary incision the blue-stained sentinel node was removed. Both methods of detection were compared, the sentinel lymph node has to be hot-radioactive and blue-stained. Complete axillary lymphadenectomy was then done. All removed lymph nodes were prepared for histopathological examination. RESULTS: Failures of sentinel lymph node detection were in 9 cases (5.3%) of the 169 patients. There was one case of false negative sentinel lymph node biopsy (0.6%). Most failures occurred during the learning phase of lymphatic mapping and were associated with excessive tumor involvement of axillary lymph nodes. Success of sentinel lymph node detection was in 160 cases (94.7%) and in our trial both methods of lymphatic mapping were equally effective. Tumor involvement of sentinel lymph nodes were in 43 patients (26.9%), in 19 (11.9%) of them, the sentinel nodes were the only metastasis nodes, whereas in the remaining 24 (15%) patients other axillary nodes were positive. The concordance between negative sentinel node and axillary lymph node status was in 117 (73.1%) cases. CONCLUSION: The introduction of sentinel lymph node biopsy allows directed and accurate assessment of axillary involvement with minimal morbidity. Sentinel node accurately predicts the status of all axillary nodes in more than 94.7% of cases.

Adult↗

PubMed2005

Squamous intraepithelial lesion-microinvasive carcinoma of the cervix during pregnancy.

OBJECTIVE: The objective of this work was to assess proper management of squamous intraepithelial lesion (SIL) and microinvasive carcinoma during and after pregnancy, to assess risks of punch biopsy and conization in pregnancy and to assess regression, persistence and risk of progression with low-grade (L) and high-grade (H) SIL. METHODS: We carried out a prospective study of 167 pregnant women from our colposcopic unit who were referred to us for abnormal cytological findings between 1997 and 2002. The diagnosis of precancerosis was verified in all of the women by punch biopsy, suspect microinvasive carcinoma needle or LETZ conization up to the 20th week of pregnancy. All women were followed-up during the pregnancy and 24 months after their deliveries. RESULTS: In 23 women with suspect early invasion we performed conization during the pregnancy (weeks 13-23). There were six cases (26.1%) of microinvasive carcinoma and 17 cases (73.9%) of HSIL. One pregnancy aborted two days after the conization. No other obstetrical complications were recorded and there were no premature deliveries. Sixty-two women with HSIL were only followed-up during their pregnancy. We observed complete regression of HSIL during the study in 14 patients (22.6%), regression to LSIL in 17 patients (27.4%), persistence in 25 patients (40.3%) and progression to microcarcinoma in six cases (9.7%). Eighty-two patients were followed up for LSIL. Complete regression of LSIL was observed during the study in 40 cases (48.8%), persistence in 24 cases (29.2%) and progression to HSIL in 18 cases (22.0%). CONCLUSION: For LSIL and HSIL during pregnancy the above follow-up is a sufficient and safe protocol. Suspect microinvasive carcinoma should be treated by conization, which is a safe procedure until the 24th week of pregnancy.

Adult↗

PubMed2004

High-energy particle acceleration in the shell of a supernova remnant.

A significant fraction of the energy density of the interstellar medium is in the form of high-energy charged particles (cosmic rays). The origin of these particles remains uncertain. Although it is generally accepted that the only sources capable of supplying the energy required to accelerate the bulk of Galactic cosmic rays are supernova explosions, and even though the mechanism of particle acceleration in expanding supernova remnant (SNR) shocks is thought to be well understood theoretically, unequivocal evidence for the production of high-energy particles in supernova shells has proven remarkably hard to find. Here we report on observations of the SNR RX J1713.7 - 3946 (G347.3 - 0.5), which was discovered by ROSAT in the X-ray spectrum and later claimed as a source of high-energy gamma-rays of TeV energies (1 TeV = 10(12) eV). We present a TeV gamma-ray image of the SNR: the spatially resolved remnant has a shell morphology similar to that seen in X-rays, which demonstrates that very-high-energy particles are accelerated there. The energy spectrum indicates efficient acceleration of charged particles to energies beyond 100 TeV, consistent with current ideas of particle acceleration in young SNR shocks.

Journal Article↗

PubMed2004

[Abdominal sacral colpopexy in the treatment of posthysterectomy vaginal vault prolapse].

OBJECTIVE: To evaluate the safety and efficacy of the abdominal sacral colpopexy in the treatment of posthysterectomy vault prolapse. DESIGN: Retrospective clinical trial. SETTING: Obstetric and Gynecologic Department, The Charles University 2nd Medical School and Faculty Hospital Motol, Prague. METHODS: A group of 18 patients with vaginal vault prolapse after hysterectomy who underwent abdominal sacral colpopexy between July 2001 and June 2003 was studied. Ten women had undergone previous abdominal and 8 previous vaginal hysterectomy. All patients were operated on by one surgeon. Preoperative evaluation consisted of physical examination, age, parity, body mass index, history of previous pelvic surgery and hormonal status. The cure rate and complications were evaluated in follow-up. RESULTS: The mean age was 59.5 (41-72) years, the median parity was 2.05 (1-5). Seven (38.9%) patients were slightly overweight (BMI 25-30 kg/m2), one (5.6%) patient was obese (BMI 33.4 kg/m2) and 10 (55.5%) had normal weight (20-25 kg/m2). The average period of follow-up was 14.9 months (6-24). The cure rate was 94.4% (17 of 18 patients). No serious intraoperative complications occurred. Postoperative complications occurred in 2 (11.2%) cases (one urgent and one stress urinary incontinence). The complications were resolved and the patients were free of negative postoperative symptoms in the time of the last follow-up visit. CONCLUSIONS: Vaginal vault prolapse is an infrequent complication after both vaginal and abdominal hysterectomy. The study shows that abdominal sacral colpopexy is an effective and safe surgical procedure in the treatment of posthysterectomy vault prolapse. The operative technique is simple but the surgery should be performed by experienced pelvic surgeons able to resolve intraoperative complications.

Adult↗

PubMed2004

[Sentinel lymph node mapping in early-stage cervical cancer].

OBJECTIVE: The aim of this study was to determine the utilization and usefulness of intraoperative lymphatic mapping and sentinel node identification with Patent blau in early stage cervical cancer. DESIGN: Prospective case observational study. SETTING: Department of Obstetrics and Gynecology, Charles University, 2nd Medical Faculty, Faculty Hospital Motol, Prague. METHODS: From February 2000 to July 2002, 100 patients undergoing surgery for early cervical cancer were included, 21 patients undergoing SNI (sentat laparoscopy and 79 patients undergoing SNI at the time of radical abdominal hysterectomy after installation of blue dye (PatentBlau V 2.5%). We carefully inspected the lymphatic channels and sentinel nodes and performed a preoperative frozen section of sentinel nodes. Finally, complete lymphadenectomy was done. RESULTS: There was one false-negative result in the group of 100 women. In the group of tumors less than 20 mm the detection rate was 90.5% when laparoscopic detection was performed and 91.7% in laparotomic detection. In tumors more than 20 mm the detection rate was 80% and in the group of 25 women with "bulky" tumors IB2 after neoadjuvant chemotherapy the detection was 60% only. We analysed locoregional distribution of 176 sentinel lymph nodes in 75 women not undergoing neoadjuvant chemotherapy and distribution of 20 positive sentinel nodes. CONCLUSION: Detection of sentinel nodes in early stages of cervical carcinomas using patent blue dye is a easy-to-perform, feasible and cheap method. Additional studies are necessary using radioisotope to improve detection rate. Another prospective studies should evaluate the role of SNI in reduction in surgical radicality.

Adult↗