Characterization of nanoscale atomic motion of Si in polycrystalline Cu layer

Atomic migration of silicon through grain boundaries of a thin polycrystalline Cu film and island formation on the Cu surface were studied in the temperature range of 403-520 K. Samples used in these experiments was prepared on Si(111) wafers by room temperature magnetron sputtering and they consisted of amorphous Si layer (80 nm) and polycrystalline Cu layer (40 nm). The silicon layer served as the source layer of diffusion, while the copper surface was the accumulation surface. Detection of Si atoms on the accumulation surface after penetration through the Cu layer was made by low energy ion scattering spectroscopy and the grain boundary diffusion coefficient DGB was determined from the appearance time. The depth distribution of Si in the Cu film was analysed by secondary neutral mass spectroscopy. From this depth distribution, DGB was also determined. By scanning probe microscope and electron microscope measurements, it was experimentally detected that Si atoms on the Cu surface did not form a continuous layer. Instead, amorphous Si islands were formed at the accumulation surface with surface protrusions in their centres.

Structural Analysis of Si(OEt)4 Deposits on Au(111)/SiO2 Substrates at the Nanometer Scale Using Focused Electron Beam-Induced Deposition

The focused electron beam-induced deposition (FEBID) process was used by employing a GeminiSEM with a beam characteristic of 1 keV and 24 pA to deposit pillars and line-shaped nanostructures with heights between 9 nm and 1 μm and widths from 5 nm to 0.5 μm. All structures have been analyzed to their composition looking at a desired Si/O/C content measuring a 1:2:0 ratio. The C content of the structure was found to be ∼over 60% for older deposits kept in air (∼at room temperature) and less than 50% for later deposits, only 12 h old. Upon depositing Si(OEt)₄ at high rates and at a deposition temperature of under 0 °C, the obtained Si content of our structures was between 10 and 15 atom % (compositional percentage). The FEBID structures have been deposited on Au(111)/SiO₂. The Au(111) was chosen as a substrate for the deposition of Si(OEt)₄ due to its structural and morphological properties. With its surface granulation following a Chevron pattern and surface defects having an increased contribution to the changes in the composition of the final structure content, the Au(111) surface characteristic behavior at the deposition of Si(OEt)₄ is an increase in the O ratio and a reduction in the nanodeposit heights.

Tuning of the Titanium Oxide Surface to Control Magnetic Properties of Thin Iron Films

We describe the magnetic properties of thin iron films deposited on the nanoporous titanium oxide templates and analyze their dependance on nanopore radius. We then compare the results to a continuous iron film of the same thickness. Additionally, we investigate the evolution of the magnetic properties of these films after annealing. We demonstrate that the M(H) loops consist of two magnetic phases originating from the iron layer and iron oxides formed at the titanium oxide/iron interface. We perform deconvolution of hysteresis loops to extract information for each magnetic phase. Finally, we investigate the magnetic interactions between the phases and verify the presence of exchange coupling between them. We observe the altering of the magnetic properties by the nanopores as a magnetic hardening of the magnetic material. The ZFC-FC (Zero-field cooled/field cooled) measurements indicate the presence of a disordered glass state below 50 K, which can be explained by the formation of iron oxide at the titanium oxide-iron interface with a short-range magnetic order.

Tissue attenuation imaging and tissue scatter imaging for quantitative ultrasound evaluation of hepatic steatosis

We aimed to assess the feasibility of ultrasound-based tissue attenuation imaging (TAI) and tissue scatter distribution imaging (TSI) for quantification of liver steatosis in patients with nonalcoholic fatty liver disease (NAFLD). We prospectively enrolled 101 participants with suspected NAFLD. The TAI and TSI measurements of the liver were performed with a Samsung RS85 Prestige ultrasound system. Based on the magnetic resonance imaging proton density fat fraction (MRI-PDFF), patients were divided into ≤5%, 5-10%, and ≥10% of MRI-PDFF groups. We determined the correlation between TAI, TSI, and MRI-PDFF and used multiple linear regression analysis to identify any association with clinical variables. The diagnostic performance of TAI, TSI was determined based on the area under the receiver operating characteristic curve (AUC). The intraclass correlation coefficient (ICC) was calculated to assess interobserver reliability. Both TAI (rs = 0.78, P < .001) and TSI (rs = 0.68, P < .001) showed significant correlation with MRI-PDFF. TAI overperformed TSI in the detection of both ≥5% MRI-PDFF (AUC = 0.89 vs 0.87) and ≥10% (AUC = 0.93 vs 0.86). MRI-PDFF proved to be an independent predictor of TAI (β = 1.03; P < .001), while both MRI-PDFF (β = 50.9; P < .001) and liver stiffness (β = -0.86; P < .001) were independent predictors of TSI. Interobserver analysis showed excellent reproducibility of TAI (ICC = 0.95) and moderate reproducibility of TSI (ICC = 0.73). TAI and TSI could be used successfully to diagnose and estimate the severity of hepatic steatosis in routine clinical practice.

Abstract 3741: Folic acid combined chemotherapy has an immediate effect on C1 methionine cycle and consequential DNA methylation in liquid biopsy samples of colorectal cancer patients

The main function of the single-carbon metabolic cycle is maintaining nucleotide pool and DNA methylation which is highly influenced by the chemotherapy protocols. This study aimed to evaluate the ultrashort effect of reduced folate combined anticancer treatment on peripheral blood parameters of colorectal cancer (CRC) patients. Post-operative CRC patients were treated with chemotherapy using the combination of oxaliplatin, 5-FU, leucovorin, and capecitabine. Blood samples were taken until the beginning of the treatment and immediately after the therapy. Plasma fractions were separated and the levels of S-adenosylmethionine (SAM), S-adenosyl homocysteine (SAH) and the simultaneous quantification of nucleotides (adenine, cytosine, thymine, guanine and uracil) were detected by HPLC-MS/MS. Homocysteine (HCY) was also determined from plasma specimens. Cell-free DNA (cfDNA) was isolated from plasma and DNA methylation was analyzed by LINE-1 bisulfite pyrosequencing. Moreover, LINE-1 methylation statuses were also examined from PBMC cells that were separated from whole blood by a density gradient centrifugation. In each patient, the HCY level of plasma was decreased by an average of 17% after oxaliplatin treatment with the combination of capecitabine (XELOX) and also with 5-FU + leucovorin (FOLFOX) agents. Our study also confirmed that cancer patients have an elevated cfDNA level (avg. 20ng/plasma mL); however, its concentration decreased significantly (p=0.02) on average by 50% after treatment compared to the baseline. The same tendency was observed in the case of SAM after XELOX and FOLFOX adjuvant therapy in plasma samples (p=0.03). Moreover, mostly elevated SAM/SAH ratios were observed in parallel with reduced SAH level after the therapy. Significant (p=0.0001) mean LINE-1 hypomethylation was detected in PBMC (81.84%) compared to cfDNA of plasma (73.76%), furthermore, slightly DNA hypermethylation was noticed in CpG1 position of LINE-1 after chemotherapy in both mononuclear cells and circulating DNA. Lower level of plasma nucleotides was identified in case of adenine, cytosine and uracil after treatment, while thymine and guanine were below the detection limit. The present study demonstrates that the DNA-damaging chemotherapy results in a detectable decrease in cfDNA immediately after the treatment, that was supported by the decrease in the level of the nucleotides measured in the plasma fraction. The methionine cycle is responsible for the DNA methylation maintenance, and though the amount of members of this pathway was reduced, only a moderately increased DNA methylation could be detected even in such a short period time. Co-administration of high dose leucovorin as a folate derivative and a methyl donor with further chemotherapeutic agents may actively contribute to genome alterations.

Citation Format: Zsófia Brigitta Nagy, Barbara Kinga Barták, Tamás Fodor, Gellért Balázs Karvaly, Sára Zsigrai, Krisztina Andrea Szigeti, Alexandra Kalmár, Magdolna Dank, István Takács, Béla Molnár. Folic acid combined chemotherapy has an immediate effect on C1 methionine cycle and consequential DNA methylation in liquid biopsy samples of colorectal cancer patients [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3741.

Abstract 3738: Monitoring chemotherapy response status of colorectal cancer patients using liquid biopsy samples

Background and aims: The early detection of colorectal cancer (CRC) recurrence and the monitoring of therapeutic response are crucial steps in the determination and modification of treatment strategies. The currently used gold standard tumor markers such as CEA and CA 19-9 and the different imaging techniques have several limitations in many cases. Therefore, we aimed to establish a liquid biopsy-based approach for tracking tumor dynamics in post-operative non-metastatic (n=32) and metastatic (n=23) CRC patients.

Methods: Blood samples were collected from each patient before and during chemotherapy, and finally, patients were classified according to disease outcome. Longitudinal investigations of the total amount, global and local (SFRP2 and SDC2 genes) DNA methylation pattern of cell-free DNA (cfDNA) fraction were performed. The plasma concentration of homocysteine was also determined, as it is one of the main components of the DNA methylation process, and its level defines the methylation potential. We examined how the parameters mentioned above were affected depending on the different therapy responses.

Results: The average cfDNA amount was significantly higher (p&lt;0.05) in patients with recurrent cancer (30.4±17.6ng) and progressive disease (PD) (44.3±34.5ng) than individuals who achieved remission (REM) (13.2±10.0ng). More than 10% elevation of cfDNA from first to last sample collection was detected in 92% of PD patients, while reduced cfDNA concentration was observed in 67% of the non-metastatic CRC patients with REM. An effective differentiation was detected between patients achieving remission and showing tumor progression based on cfDNA level with 94% sensitivity and 81% specificity. The average global cfDNA methylation was determined by bisulfite pyrosequencing analysis of long interspersed nuclear element-1 (LINE-1), and it was significantly lower (p&lt;0.05) in the PD group compared to people with remission (71.0±6.7% vs. 78.9±2.0%). Methylation level changes between the study beginning and end indicated a decline (75.5±3.4% vs. 68.2±8.4%) in PD; in contrast, we found a reverse change in remission. The mean relative change of homocysteine concentration revealed an opposite trend with the global DNA methylation suggesting a linkage between these parameters, as it showed an increase (+12.5%) in the case of PD and a decrease (-15.8%) in patients with REM. Regarding local DNA methylation, SFRP2 and SDC2 genes revealed higher promoter hypermethylation in the PD set compared to patients with remission.

Conclusion: Our study offers the possibility to monitor the therapeutic response during chemotherapy with a minimally-invasive blood-based method that combines the analysis of cfDNA, its global and local DNA methylation pattern, and homocysteine level.

Citation Format: Barbara Kinga Bartak, Tamás Fodor, Alexandra Kalmár, Zsófia Brigitta Nagy, Sára Zsigrai, Krisztina Andrea Szigeti, William Kothalawala, Gábor Valcz, Péter Igaz, István Takács, Magdolna Dank, Béla Molnár. Monitoring chemotherapy response status of colorectal cancer patients using liquid biopsy samples [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3738.

Dithallium(III)-Containing 30-Tungsto-4-phosphate, [Tl2Na2(H2O)2(P2W15O56)2]16-: Synthesis, Structural Characterization, and Biological Studies

Here we report on the synthesis and structural characterization of the dithallium(III)-containing 30-tungsto -4-phosphate [Tl₂Na₂(H₂O)₂{P₂W₁₅O₅₆}₂]^16- (1) by a multitude of solid-state and solution techniques. Polyanion 1 comprises two octahedrally coordinated Tl³⁺ ions sandwiched between two trilacunary {P₂W₁₅} Wells-Dawson fragments and represents only the second structurally characterized, discrete thallium-containing polyoxometalate to date. The two outer positions of the central rhombus are occupied by sodium ions. The title polyanion is solution-stable as shown by ³¹P and ^203/205Tl NMR. This was also supported by Tl NMR spectra simulations including several spin systems of isotopologues with half-spin nuclei (²⁰³Tl, ²⁰⁵Tl, ³¹P, ¹⁸³W). ²³Na NMR showed a time-averaged signal of the Na⁺ counter cations and the structurally bonded Na⁺ ions. ^203/205Tl NMR spectra also showed a minor signal tentatively attributed to the trithallium-containing derivative [Tl₃Na(H₂O)₂(P₂W₁₅O₅₆)₂]^14-, which could also be identified in the solid state by single-crystal X-ray diffraction. The bioactivity of polyanion 1 was also tested against bacteria and Leishmania.

Combined Treatment of MCF-7 Cells with AICAR and Methotrexate, Arrests Cell Cycle and Reverses Warburg Metabolism through AMP-Activated Protein Kinase (AMPK) and FOXO1

Cancer cells are characterized by metabolic alterations, namely, depressed mitochondrial oxidation, enhanced glycolysis and pentose phosphate shunt flux to support rapid cell growth, which is called the Warburg effect. In our study we assessed the metabolic consequences of a joint treatment of MCF-7 breast cancer cells with AICAR, an inducer of AMP-activated kinase (AMPK) jointly with methotrexate (MTX), a folate-analog antimetabolite that blunts de novo nucleotide synthesis. MCF7 cells, a model of breast cancer cells, were resistant to the individual application of AICAR or MTX, however combined treatment of AICAR and MTX reduced cell proliferation. Prolonged joint application of AICAR and MTX induced AMPK and consequently enhanced mitochondrial oxidation and reduced the rate of glycolysis. These metabolic changes suggest an anti-Warburg rearrangement of metabolism that led to the block of the G1/S and the G2/M transition slowing down cell cycle. The slowdown of cell proliferation was abolished when mitotropic transcription factors, PGC-1α, PGC-1β or FOXO1 were silenced. In human breast cancers higher expression of AMPKα and FOXO1 extended survival. AICAR and MTX exerts similar additive antiproliferative effect on other breast cancer cell lines, such as SKBR and 4T1 cells, too. Our data not only underline the importance of Warburg metabolism in breast cancer cells but nominate the AICAR+MTX combination as a potential cytostatic regime blunting Warburg metabolism. Furthermore, we suggest the targeting of AMPK and FOXO1 to combat breast cancer.

[Tl(III)(dota)](-): An Extraordinarily Robust Macrocyclic Complex

The X-ray structure of {C(NH2)3}[Tl(dota)]·H2O shows that the Tl(3+) ion is deeply buried in the macrocyclic cavity of the dota(4-) ligand (1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetate) with average Tl-N and Tl-O distances of 2.464 and 2.365 Å, respectively. The metal ion is directly coordinated to the eight donor atoms of the ligand, which results in a twisted square antiprismatic (TSAP') coordination around Tl(3+). A multinuclear (1)H, (13)C, and (205)Tl NMR study combined with DFT calculations confirmed the TSAP' structure of the complex in aqueous solution, which exists as the Λ(λλλλ)/Δ(δδδδ) enantiomeric pair. (205)Tl NMR spectroscopy allowed the protonation constant associated with the protonation of the complex according to [Tl(dota)](-) + H(+) ⇆ [Tl(Hdota)] to be determined, which turned out to be pK(H)Tl(dota) = 1.4 ± 0.1. [Tl(dota)](-) does not react with Br(-), even when using an excess of the anion, but it forms a weak mixed complex with cyanide, [Tl(dota)](-) + CN(-) ⇆ [Tl(dota)(CN)](2-), with an equilibrium constant of Kmix = 6.0 ± 0.8. The dissociation of the [Tl(dota)](-) complex was determined by UV-vis spectrophotometry under acidic conditions using a large excess of Br(-), and it was found to follow proton-assisted kinetics and to take place very slowly (∼10 days), even in 1 M HClO4, with the estimated half-life of the process being in the 10(9) h range at neutral pH. The solution dynamics of [Tl(dota)](-) were investigated using (13)C NMR spectroscopy and DFT calculations. The (13)C NMR spectra recorded at low temperature (272 K) point to C4 symmetry of the complex in solution, which averages to C4v as the temperature increases. This dynamic behavior was attributed to the Λ(λλλλ) ↔ Δ(δδδδ) enantiomerization process, which involves both the inversion of the macrocyclic unit and the rotation of the pendant arms. According to our calculations, the arm-rotation process limits the Λ(λλλλ) ↔ Δ(δδδδ) interconversion.

Poly(ADP-ribose) polymerases as modulators of mitochondrial activity

Mitochondria are essential in cellular stress responses. Mitochondrial output to environmental stress is a major factor in metabolic adaptation and is regulated by a complex network of energy and nutrient sensing proteins. Activation of poly(ADP-ribose) polymerases (PARPs) has been known to impair mitochondrial function; however, our view of PARP-mediated mitochondrial dysfunction and injury has only recently fundamentally evolved. In this review, we examine our current understanding of PARP-elicited mitochondrial damage, PARP-mediated signal transduction pathways, transcription factors that interact with PARPs and govern mitochondrial biogenesis, as well as mitochondrial diseases that are mediated by PARPs. With PARP activation emerging as a common underlying mechanism in numerous pathologies, a better understanding the role of various PARPs in mitochondrial regulation may help open new therapeutic avenues.

Silencing the KCNK9 potassium channel (TASK-3) gene disturbs mitochondrial function, causes mitochondrial depolarization, and induces apoptosis of human melanoma cells

TASK-3 (KCNK9 or K2P9.1) channels are thought to promote proliferation and/or survival of malignantly transformed cells, most likely by increasing their hypoxia tolerance. Based on our previous results that suggested mitochondrial expression of TASK-3 channels, we hypothesized that TASK-3 channels have roles in maintaining mitochondrial activity. In the present work we studied the effect of reduced TASK-3 expression on the mitochondrial function and survival of WM35 and A2058 melanoma cells. TASK-3 knockdown cells had depolarized mitochondrial membrane potential and contained a reduced amount of mitochondrial DNA. Compared to their scrambled shRNA-transfected counterparts, they demonstrated diminished responsiveness to the application of the mitochondrial uncoupler [(3-chlorophenyl)hydrazono]malononitrile (CCCP). These observations indicate impaired mitochondrial function. Further, TASK-3 knockdown cells presented reduced viability, decreased total DNA content, altered cell morphology, and reduced surface area. In contrast to non- and scrambled shRNA-transfected melanoma cell lines, which did not present noteworthy apoptotic activity, almost 50 % of the TASK-3 knockdown cells exhibited strong Annexin-V-specific immunofluorescence signal. Sequestration of cytochrome c from the mitochondria to the cytosol, increased caspase 3 activity, and translocation of the apoptosis-inducing factor from mitochondria to cell nuclei were also demonstrated in TASK-3 knockdown cells. Interference with TASK-3 channel expression, therefore, induces caspase-dependent and -independent apoptosis of melanoma cells, most likely via causing mitochondrial depolarization. Consequently, TASK-3 channels may be legitimate targets of future melanoma therapies.

Picolinate-containing macrocyclic Mn2+ complexes as potential MRI contrast agents

We report the synthesis of the ligand Hnompa (6-((1,4,7-triazacyclononan-1-yl)methyl)picolinic acid) and a detailed characterization of the Mn(2+) complexes formed by this ligand and the related ligands Hdompa (6-((1,4,7,10-tetraazacyclododecan-1-yl)methyl)picolinic acid) and Htempa (6-((1,4,8,11-tetraazacyclotetradecan-1-yl)methyl)picolinic acid). These ligands form thermodynamically stable complexes in aqueous solution with stability constants of logKMnL = 10.28(1) (nompa), 14.48(1) (dompa), and 12.53(1) (tempa). A detailed study of the dissociation kinetics of these Mn(2+) complexes indicates that the decomplexation reaction at about neutral pH occurs mainly following a spontaneous dissociation mechanism. The X-ray structure of [Mn2(nompa)2(H2O)2](ClO4)2 shows that the Mn(2+) ion is seven-coordinate in the solid state, being directly bound to five donor atoms of the ligand, the oxygen atom of a coordinated water molecule and an oxygen atom of a neighboring nompa(-) ligand acting as a bridging bidentate carboxylate group (μ-η(1)-carboxylate). Nuclear magnetic relaxation dispersion ((1)H NMRD) profiles and (17)O NMR chemical shifts and transverse relaxation rates of aqueous solutions of [Mn(nompa)](+) indicate that the Mn(2+) ion is six-coordinate in solution by the pentadentate ligand and one inner-sphere water molecule. The analysis of the (1)H NMRD and (17)O NMR data provides a very high water exchange rate of the inner-sphere water molecule (kex(298) = 2.8 × 10(9) s(-1)) and an unusually high value of the (17)O hyperfine coupling constant of the coordinated water molecule (AO/ℏ = 73.3 ± 0.6 rad s(-1)). DFT calculations performed on the [Mn(nompa)(H2O)](+)·2H2O system (TPSSh model) provide a AO/ℏ value in excellent agreement with the one obtained experimentally.

Deletion of PARP-2 induces hepatic cholesterol accumulation and decrease in HDL levels

Poly(ADP-ribose) polymerase-2 (PARP-2) is acknowledged as a DNA repair enzyme. However, recent investigations have attributed unique roles to PARP-2 in metabolic regulation in the liver. We assessed changes in hepatic lipid homeostasis upon the deletion of PARP-2 and found that cholesterol levels were higher in PARP-2(-/-) mice as compared to wild-type littermates. To uncover the molecular background, we analyzed changes in steady-state mRNA levels upon the knockdown of PARP-2 in HepG2 cells and in murine liver that revealed higher expression of sterol-regulatory element binding protein (SREBP)-1 dependent genes. We demonstrated that PARP-2 is a suppressor of the SREBP1 promoter, and the suppression of the SREBP1 gene depends on the enzymatic activation of PARP-2. Consequently, the knockdown of PARP-2 enhances SREBP1 expression that in turn induces the genes driven by SREBP1 culminating in higher hepatic cholesterol content. We did not detect hypercholesterolemia, higher fecal cholesterol content or increase in serum LDL, although serum HDL levels decreased in the PARP-2(-/-) mice. In cells and mice where PARP-2 was deleted we observed decreased ABCA1 mRNA and protein expression that is probably linked to lower HDL levels. In our current study we show that PARP-2 impacts on hepatic and systemic cholesterol homeostasis. Furthermore, the depletion of PARP-2 leads to lower HDL levels which represent a risk factor to cardiovascular diseases.

Analysis of tuberculosis surveillance in Hungary in 2000

SETTING

Hungary, Central Europe, with a population of 10.3 million living in 20 administrative districts (19 counties and the capital).

OBJECTIVE

To summarize the results of the first year of the revised National Tuberculosis Surveillance System.

DESIGN

Retrospective survey of the National Tuberculosis Surveillance Center (NTSC) database.

METHODS

Analysis of data on all tuberculosis cases reported to the NTSC in 2000. Drug susceptibility results were evaluated in line with WHO and IUATLD definitions.

RESULTS

During 2000, a total of 3598 patients with tuberculosis were reported. Only 40% of these were bacteriologically confirmed. Although susceptibility testing has been required for previously untreated culture-positive cases, only 801 (67.8% of the bacteriologically confirmed cases) were tested in 2000. Drug resistance was detected in 10.7% of previously untreated and in 23.5% of previously treated patients. Multidrug-resistant (MDR) cases were not common: only 1.5% of the isolates from previously untreated patients and 4.9% of those from previously treated patients were MDR.

CONCLUSIONS

The results suggest that the NTSC should work towards increasing the numbers of cases that are bacteriologically confirmed. In addition, some form of surveillance system should be instituted to ensure that mandatory susceptibility testing is performed on all isolates from previously untreated tuberculosis patients.

[The role of bacteriology in the treatment of tuberculosis; the Hungarian program]

A positive result of the bacteriological examination of Mycobacterium tuberculosis is signal to start treatment. The response to antituberculosis chemotherapy in patients with positive bacteriology is best evaluated by repeated examinations. The recommendation of the Hungarian National Tuberculosis Programme for the initial intensive phase of chemotherapy of previously untreated patients is based on the frequency of primoresistance determined by the National Reference Laboratory. The treatment of multidrug resistant tuberculosis can be supported by the result of previous susceptibility test and/or by the outcome of multicenter validated Bactec 460 susceptibility test of second-line antimicrobial drugs. The presence of a mutation within a gen is predictive of rifampicin resistance of M. tuberculosis. The results are available within 48 h. 92.4% of rifampicin resistant and nearly 100% of pyrazinamid resistant isolates in the Reference Laboratory were resistant to isoniazid. On the other hand streptomycin resistant strains were susceptible to amikacin in a rate of 38:1. Some rifampicin resistant strains are susceptible to rifabutin. The Reference Laboratory observed among the first that some ofloxacin resistant strains are susceptible to ciprofloxacin. It was the first which demonstrated effectivity of amikacin in the treatment of pulmonary tuberculosis. It was drawn attention to the importance of the PAS infusion therapy of multidrug resistant tuberculosis cases by observing bacteriological conversion.

Drug-resistant tuberculosis in Budapest

SETTING

Sixteen districts of Budapest, Hungary.

OBJECTIVE

To determine the frequency of primary and secondary drug resistance, and to recommend treatment regimens.

DESIGN

A retrospective survey.

METHODS

Mycobacterium tuberculosis isolates were collected from 264 newly diagnosed and 147 previously treated patients. All strains were tested against isoniazid (INH), rifampicin (RIF), streptomycin (SM) and ethambutol (EMB) using the proportion method. Bacteriologic examinations were performed in the Diagnostic Laboratory of the Koranyi National Institute for Tuberculosis and Pulmonology in Budapest.

RESULTS

Primary resistance to INH alone was 4%, to SM alone 2%, to RIF alone 0.4%, to INH and SM 1%, and to INH, RIF, SM and EMB 0.4%. Of the isolates of 78 relapse cases, six (8%) were resistant to INH alone, one (1%) to INH and RIF, two (3%) to INH, RIF, SM and EMB. Of the isolates of 69 patients notified with active tuberculosis for over a year, 51 (74%) were susceptible to the drugs tested.

CONCLUSION

Based on the level of primary drug resistance as well as on the resistance pattern of relapse cases, it is recommended to start the treatment of newly detected and relapse cases with four drugs. The high rate of chronic cases with susceptible strains can be explained by poor compliance. To prevent development of resistant cases and to achieve good compliance, it is necessary to apply direct observation of treatment in all types of patients.

Detection of mycobacteria in sputum smears prepared by cytocentrifugation and sedimentation

The efficacy of sedimentation combined with cytocentrifugation of sputa was examined by preparing smears for the detection of mycobacteria. The detection of acid-fast bacilli from sputum sediment by cytocentrifugation yielded 32 smears positive for acid-fast bacilli, out of which in 26 cases better results were obtained than by the conventional method. More bacilli were found in 20 cases and on 6 occasions solely the cytospin method was positive. The differences in the number of bacilli were 100-200-fold in 5 cases and 10-fold in 12 paired cases. The technique applied is suitable for making culture and smear from the same sediment. The sedimentation combined with cytocentrifugation increases the effectiveness of the detection of acid-fast bacilli in smears.

[Which patients are dying of tuberculosis in the 90-s?]

Medical and social characteristics of 27 patients deceased in tuberculosis in the Korányi National Institute for Tuberculosis and Pulmonology, Budapest, were analysed and evaluated. M. tuberculosis strains sensitive to all antituberculotic drugs were isolated from all cases. Characteristics of patients: males over 40 years of age (17 cases), single (9 cases), alcoholics (16 cases) who were transferred from another hospital (13 cases). All patients had pulmonary tuberculosis, in 3 cases together with extrapulmonary lesions. Sputum direct smear examination revealed acid-fast bacteria in 9 cases. There were 8 relapses. It is proposed to consider possibility of tuberculosis in the presence of the above mentioned "risk factors".

Bulk staining of sputum by the Ziehl-Neelsen method

A trial of the Ziehl-Neelsen staining method employing bulk decolorization, rinsing and counter staining yielded reliable results. Of 110 patients who proved to be positive by direct microscopy, cross-contamination could not be proved in any. The advantage of the mass method is its economy.