A self-matched leaky-wave antenna for ultrahigh-field magnetic resonance imaging with low specific absorption rate.

The technology of magnetic resonance imaging is developing towards higher magnetic fields to improve resolution and contrast. However, whole-body imaging at 7 T or even higher flux densities remains challenging due to wave interference, tissue inhomogeneities, and high RF power deposition. Nowadays, proper RF excitation of a human body in prostate and cardiac MRI is only possible to achieve by using phased arrays of antennas attached to the body (so-called surface coils). Due to safety concerns, the design of such coils aims at minimization of the local specific absorption rate (SAR), keeping the highest possible RF signal in the region of interest. Most previously demonstrated approaches were based on resonant structures such as e.g. dipoles, capacitively-loaded loops, TEM-line sections. In this study, we show that there is a better compromise between the transmit signal [Formula: see text] and the local SAR using non-resonant surface coils generating a low electric field in the proximity of their conductors. With this aim, we propose and experimentally demonstrate a leaky-wave antenna implemented as a periodically-slotted microstrip transmission line. Due to its non-resonant radiation, it induces only slightly over half the peak local SAR compared to a state-of-the-art dipole antenna but has the same transmit efficiency in prostate imaging at 7 T. Unlike other antennas for MRI, the leaky-wave antenna does not require to be tuned and matched when placed on a body, which makes it easy-to-use in prostate imaging at 7 T MRI.

[Serious manifestation of primary hypothyroidism]. / Závazná manifestace primární hypotyreózy.

Thyroid gland diseases are the most frequent endocrinopathy and can be often seen in adult population. They occur at least by 5% of the population and the occurence increases with age, in females aging 45 and more, as thyroid gland diseases in this age group are represented approximately by 20%. Due to a complex influence of thyroid hormones in humans, diagnosis of thyroid disease may remain unsuspected under other disease with typical symptoms; the most serious of them is cardiogenic manifestation. When thyroid disease suspected, methods of diagnostics are very comprehensive and broad. Treatment on time can prevent serious complications. Case-study presenting a female patient with untreated primary hypothyroidism that had caused serious cardiac symptoms.

Secondary tumors in cancer patients after therapy.

Forty-five thousand three hundred thirteen patients treated in our Institute during the period 1949-1982 were retrospectively analyzed in regard to the appearance of secondary tumors after therapy. Eighty-seven (0.19%) tumors were found, 71 (81.6%) being secondary and 16 (18.4%) simultaneous. Fifty-one (71.8%) tumors were lymphoid, 20 (28.1%) nonlymphoid. Thirty-seven (52.1%) tumors appeared after radiotherapy, 13 (18.3%) after chemotherapy alone. Secondary tumors appeared mostly after 6 years. The prevalence of lymphoid secondary tumors may be explained as a compensatory proliferation of surviving cells progressing to neoplasia. Cytostatics and ionizing radiation as both the initiators and the promoters of malignancy, have besides person's susceptibility a triggering function. From these aspects before any treatment is started all possible carcinogenic factors should be taken into consideration and less carcinogenic procedures with keeping up a full effectiveness should be chosen.

Cytologic diagnosis of malignant melanoma.

Cytology in malignant melanoma of the skin is a useful method, which alone yields in many cases enough diagnostic informations for a therapeutical approach. It is of a special importance in cases with marked anisocytosis of cells and with large, sometimes polynuclear cells and with cells with melanotic pigment. In cases with middle-sized apigmented cells of epitheloid appearance it should be always completed by biopsy, which, in these cases predominates over cytology. Combination of both methods brings a more substantial elucidation of diagnosis.

Cytologic grading in relation to the clinical stage of the breast cancer.

Cytologic grading which may be performed at the same time as diagnostic cytology seems to be of a value in the pathobiology of the breast cancer. Other methods, such as mammography, termography, xenography, histological grading and some biological markers help to establish biological behavior of the tumor and appropriate treatment approach. In spite of the progress in diagnosis and therapy many problems remain to be clarified. In agreement with VORHERR a progress may be expected only from the development of novel approaches such as diagnosis before systematic spread has occurred or by the availability of efficient chemotherapy to kill all disseminated cancer cells.

Some remarks to the histological classification of malignant melanoma of the skin and its prognostic values.

Histological classification of human skin malignant melanoma as recommended by WHO melanoma group renders the first useful orientation in regard to the biological behavior of the tumor, but it cannot give any further clinical outlook. It would be therefore desiderable to complete the histological examinations with enzymatic and immunologic examinations performed during the treatment of the patient and thus try to gain a basis for a prognostic evaluation.

A freeze-etch study of occurrence of nuclear pores in normal and tumor cells.

A freeze-etch study of nuclear pores performed on human lymphocytes, epidermal and corneal cells, on hamster fibroblasts, on rat and hamster sarcoma cells and cells from a human malignant melanoma, revealed that the frequency of pores as a part of very important biological cellular structures increases in proliferating cells, and that there is a statistically significand difference between normal and tumor cells. Once produced the pores maintain and their frequency practically does not change. The pores are randomly distributed on the nuclear envelope. Markham rotating method revealed an octa- or nonaedric outside shape of the pores and round inner margin with eight or nine granules. One bigger granule was found in the center of the pores. The granule is with a great probability filamentously attached to the margin of the pore. Fibrillar structures running to the pores on inner surface of nuclear envelope as far as the chemical composition of granules need special cytochemical examinations.

Histologic changes in the human skin melanoma after intratumorous treatment with BCG.

Twenty six patients with malignant skin melanomas were treated with an intratumorous injection of 0.1 ml BCG applicated in certain time intervals. Histologic changes in tumor tissue starting with dystrophy and necrosis of the cells and ending with the formation of a granular tissue replacing the tumor are described. In one case the untreated satellite localized 2 cm from the injected tumor disappeared. The results indicate that the reaction of the cells on the applicated vaccine varied. In some tumors dystrophic changes and necroses were very large, in others they were of a lesser extent, but in all the process ended with the formation of a granular tissue. The mechanism of the action of BCG is discussed. For the time being, it seems that the intratumorous application of BCG is a useful adjuvant therapy.

Establishment of cell line derived from human malignant melanoma.

A new human cell line of malignant melanoma (MJM) was established with the use of the in vitro fragment technique. It has been maintained over 34 months of continuous cultivation. Three types of cells can be recognized by light microscope. The epitheloid elements predominate, less frequent are fibroblastoid and giant multinuclear cells. The pigment production is not macroscopically visible. Over 60 per cent of analyzed metabphases showed hyperdiploid number of chromosomes, the rest was mostly tetra and hexaploid. No marker chromosomes were detected. The growth studies indicate the MJM cells have 63-hr doubling time. Cytochemistry revealed positive pigment or propigment granules in 36 per cent of cells. Ultrastructural studies did not detect melanin granules but some particles resembling atypical premelanosomes and melanosomes were recognized in some sections.

Cytology in the diagnosis of malignant melanoma.

Some cytologic criteria useful for routine examinations in the diagnosis of malignant melanoma are reported and the diagnostic value of the pre-operatory cytologic smears is also emphasized.

[GBV-C/HGV, a new virus as one possible cause of hepatitis of unknown etiology]. / Nový virus GBV-C/HGV jako jeden z mozných puvodcu etiologicky nevyjasnených hepatitid.

For etiologically obscure (some 4%) viral hepatitis agents are sought and tested to make elucidation of their cause possible. One of the candidates is since 1995 the newly discovered virus GBV-C/HGV. Despite intense research its relationship to viral hepatitis of obscure origin (VHN) has not been elucidated so far. In the submitted paper the authors attempted to contribute to the elucidation of etiological associations of GBV-C/HGV infection and VHN by comparing the dynamics of markers of the infection in a group of 59 patients with VHN, two control groups exposed to a high risk of parenteral operations and a third comparative group. The first control group comprised 64 patients in a long-term haemodialyzation programme (HD), the second group was formed by 82 patients with haematooncological disease (BD). The third comparative group comprised 22 patients coinfected (CI) with virus of hepatitis C (VHC), or possibly hepatitis B (VHB). The patients with VHN were HBsAg, anti HCV and anti HEV negative. In the majority in the first blood sample transaminases were elevated which was one of the main reasons for examination of GBV-C/HGV RNA. Prevalence of GBV-C/HGV infection, proved by the presence of at least one of the two markers of current or past infection (GBV-C/HGV RNA, antiGBV-C/HGV) was in the compared VHN, HD and BD groups as follows: 88.1%, 59.4% and 43.9%. The frequency of GBV-C/HGV positivity was highest in VHN-76.3%. In control groups HD and BD GBV-C/HGV RNA positivity was substantially lower, 18.8% and 25.6% resp. Long-term continuous viraemia was recorded in patients with VHN in 18.6%. In groups HD and BD it was half that value: 9.3% and 9.18%. In patients with VHN surprisingly after 6.5 months a marked rise of negative findings occurred (5.6x) without the expected increase of antibodies. A similar finding was recorded also in the other groups (HD and BD), incl. CI patients. Disappearance of viraemia was observed most frequently in VHN (55.9%). In groups HD and BD GBV-C/HGV RNA disappeared only in 7.8% and 12.1% resp. In treated patients of the CI group viral RNA was present in 45.5% and it disappeared in 36.4%. On the other hand, seroconversion to antibodies was comparable in VHN, HD and BD (11.9%, 9.4%, 8.5%), only in group CI it was higher (18.2%), obviously in conjunction with treatment of concurrent HCV or HBV infection. Disappearance of viraemia without subsequent seroconversion occurs in GBV-C/HGV infection frequently, the highest rate was observed by the authors in patients with VHN. Disappearance of viraemia does not necessarily imply clearance of GBV-C/HGV but may be due to a change of GBV-C(HGV into a state of persistence without positive laboratory markers of the infection. Persistence of the virus could also be the reason of the assumed conditioned pathogenicity of the virus, and the effect of frequent disappearance of both markers could explain some controversial epidemiological observations when in studies only static data without dynamic associations were used.

[Mucosal candidiasis]. / Sliznicní kandidóza.

The authors demonstrate the case of a female patient with a prolonged mucosal form of candidosis caused by different biotypes of Candida albicans. Despite the fact the long-term and repeated treatment with Nizoral and transfer factor was applied, relapses of the disease developed. Marked improvement of clinical manifestations occurred only after a change of the dietary habits and long-term administration of immunomodulating agents. The authors discuss therapeutic and diagnostic aspects of the disease.

[Candida sepsis. I. Risk factors, pathogenesis and the clinical picture]. / Kandidové sepse. I. Rizikové faktory, patogeneze a klinický obraz.

Candida sepsis is a serious and ever increasing complication in patients with a reduced defense capacity. At the intensive care unit of the infectious department in 1978-1990 from a total of 430 patients with the diagnosis of sepsis 20 (4.7%) had a Candida aetiology. Candida sepsis is suspected in particular in leukaemic patients with neutropenia, in organ transplantations and in patients given intensive care on account of a serious primary disease, bacterial infection or after surgery. The risk of deep candidosis is increased by venous catheters, hyperalimentation, antibiotic treatment, invasive operations. Diagnosis is supported by endophthalmitis and skin lesions; signs of affection of the liver, lungs, kidneys and cardiac valves are sought. Analysis of risk factors, pathogenesis and the clinical picture of invasive Candida infections is based on ample data in the literature.

[Candida sepsis. II. Laboratory methods and their clinical importance]. / Kandidové sepse. II. Laboratorní metody a jejich klinický význam.

The authors present experience assembled at the septic station of the infectious department and mycological laboratory as regards interpretation of results of laboratory examinations in invasive Candida infections and they summarize the most important data from the literature on the correct collection of material, evaluation of microscopic and cultivation findings, the importance of examinations and haemocultures, venous catheters, urine, faeces and sputum. They analyze problems of serological examination and direct detection of antigen, they recommend mycological monitoring of patients at risk. In the conclusion they summarize the most frequent mistakes as regards the evaluation of laboratory results and indications of treatment.

[Takayasu's disease. Detection of the early systemic stage of the disease in a pregnant woman]. / Takayasuova choroba. Záchyt casné systémové fáze nemoci u tehotné zeny.

The authors describe the case of Takayasu's disease detected in the non-obliterating systemic stage. The disease developed in a 24-year-old woman in the 8th month of gestation and was associated with severe pain of the back and upper extremities, subfebrile temperatures, later fever and tachycardia. The authors describe the difficult diagnosis of the disease and discuss the relationship of the case with so-called fever of unknown aetiology and the development of the disease during pregnancy.

[Intradermal method of vaccination with a human diploid cell tissue culture vaccine for preexposure antirabies immunization]. / Intradermální zpusob ockování vakcínou z tkánové kultury lidských diploidních bunek v preexpozicní antirabické imunizaci.

The authors provide evidence of seroconversion in 16 subjects (100%) following intradermal administration of antirabies vaccine from a tissue culture of human diploid cells [Rabivac, Behring, FRG] for the purpose of pre-exposure immunization. The immunomodulating preparation Levamisol [Decaris Richter, Hungary] did not influence the mean antibody titre during administration by the intradermal route.

[Thrombosis of the superior vena cava as a complication of permanent cardiac pacing]. / Trombóza horní duté zíly jako komplikace trvalé kardiostimulace.

The authors present an account of thrombosis of the superior vena cava which developed in two patients with permanent cardiac pacing and led to the development of superior vena cava syndrome. The cause was loosening of the impaired stimulating electrode from fixation and its penetration into the superior vena cava with subsequent formation of a thrombus on the bare surface of the spiral. Contemporary therapeutic procedures are reviewed.

[Is antibiotic prophylaxis necessary in patients on chronic dialysis and with recurrent endocarditis?]. / Je antibiotická profylaxe chronicky dialyzovaných nemocných s recidivujícími endokarditidami nutná?

The authors present a group of 77 patients with chronic dialysis treatment during the period from 1/92 to 4/95 with regard to the prevalence of infectious endocarditis. This disease was detected in 8 instances in 6 patients whereby one patient had three relapses. In 75% staphylococci were the infectious agent. The main risks of the disease are according to the authors impaired immunity, repeated cannulation, degenerative valvular changes. In the conclusion the authors state that the risk of developing infectious endocarditis and relapses of the disease can be reduced by careful diagnosis and antibiotic therapy. The authors do not consider lifelong antibiotic prophylaxis of these patients necessary.

[Captopril in the treatment of congestive heart failure in acute myocardial infarct]. / Captopril v lécení mestnavé srdecní slabosti u akutního infarktu myokardu.

The extent of affection of the heart muscle by infarction with subsequent left-ventricular dilatation, remodelling and congestive failure is the decisive prognostic indicator of mortality. Inhibitors of ACE influence congestive heart failure in a favourable way and captopril reduces the morbidity and mortality in patients with still asymptomatic left ventricular dysfunction. The authors administered to a group of 23 patients with acute myocardial infarction and congestive heart failure (grade II according to Killip) small doses of captopril (4 x 6.25 mg/day)for a period of 10 days from the 1st-4th day after the onset of the disease). From ACE serum levels the effectiveness of these doses was assessed in keeping with data in the literature. As compared with a control group of 26 patients with similar haemodynamic conditions the authors did not find significant differences as regards improvement of the decompensation and in the mortality (à 3 patients in both groups). As to undesirable effects, arterial hypotension was recorded three times, twice minor proteinuria, once asymptomatic thrombocytopenia. Decisive for future therapeutic decision making are above all the results of the SAVE study which prefers captopril in patients with a yet asymptomatic left ventricular dysfunction. The authors are not quite convinced on the necessity to administer larger doses of captopril (up to 3 x 50 mg/day) in this indication.

[Long-term prognosis of patients after successful embolectomy in the upper mesenteric artery]. / Príspevek k dlouhodobé prognóze nemocných po úspesné embolektomii z horní mezenterické tepny.

The authors describe case-histories of two patients after successful embolectomy from the mesenteric artery, in one combined with resection of the small intestine with survival of 1 and 13 years resp. without sings of malnutrition. The authors discuss the prognosis of embolectomised patients with regard to the basic disease, relapsing embolization and nutritional disorders.