Structural changes of proteins in fish red blood cells after copper and mercury treatment

Exposure of fish red blood cells to increased concentrations (0.05–0.3 mmol/L) of copper and mercury ions may initiate structural changes in cells as detected by spin labeling method. Both heavy metals decreased membrane fluidity as indicated by methyl 5-doxylpalmitate and methyl 12-doxylstearate spectra. Furthermore, copper and mercury have been found to induce conformational alterations of internal peptides and proteins as determined by using 4-maleimido-2,2,6,6-tetramethylpiperidine-1-oxyl. Both heavy metal ions changed the internal viscosity of red blood cells. These results suggest that the possible cause of the damage of cells may be metal-protein interactions in the cells, but may exclude the oxidative mechanism of such damage.     

Application of the Minnesota Code in evaluating electrocardiographic features of ischemic heart disease in patients exposed to carbon disulphide

Summary We examined 81 men exposed for a long time to carbon disulphide (CS₂) and tested the possible electrocardiographic (ECG) changes of ischemic heart disease (I.H.D.). The subjects were examined twice in two years. In order to make the ECG evaluation more objective, the Minnesota Code was applied. Two obligatory ECG examinations and only one submaximal effort test were carried out. For comparative evaluation, the control group was examined once. We proved that, in spite of the accepted opinion concerning the atheromatous action of CS₂, this compound does not cause ECG symptoms of I.H.D. in a higher percentage of exposed persons. It also does not cause any significant increase in I.H.D. symptoms in dynamic ECG observations.     

A retrospective comparative study of surgery followed by chemotherapy vs. non-surgical management in limited-disease small cell lung cancer.

OBJECTIVE: The role of surgery in limited SCLC is still a matter of controversy. Even though the response rates to chemotherapy are very high, prognosis of SCLC patients has remained poor with a median survival of only 12-14 months for limited disease. High incidence of local relapses after chemotherapy in limited-stage SCLC led to reassessment of the role of local treatment in the multimodality management of this tumor. METHODS: We performed retrospective comparative analysis of survival in a series of 134 limited-stage SCLC patients treated between 1984 and 1996 with either complete resection followed by chemotherapy (67 patients), or with conventional non-surgical management (67 patients). In all patients who underwent resection, the diagnosis of SCLC was established only postoperatively. The control (non-surgical) group was selected using 'pair-matched case-control' methodology, out of 176 limited-stage patients potentially suitable for surgery (i.e. with no pleural effusion or other local advancement, no supraclavicular lymph node involvement and good performance status), but treated without resection. The major prognostic factors were well balanced between these two groups. Total series included 109 males and 25 females, 20 patients with T1 and 114 patients with T2 disease, 51 N0, 43 N1 and 40 N2 disease. RESULTS: Median survival in patients treated with and without surgery was 22 months and 11 months, respectively, (P < 0.001). The two-year and five-year survival probabilities were 43 and 27%, respectively, in the surgical group, and 17 and 4%, respectively, in the non-surgical group. Subset analysis confirmed significantly longer survival with surgery in all T and N categories, except for N2 disease. Local relapse occurred in 15 and 55% of patients treated with and without surgery, respectively, (P < 0.001). Distant relapse probabilities were similar in both groups (36 and 40%, respectively). The most common site of metastases in the entire series was brain, followed by liver, lymph nodes, bone, lung and skin. CONCLUSIONS: Our results suggest a possible role of surgery in limited-stage SCLC. Thus, a randomised study addressing this issue seems to be justified.     

Translocation t(12;22)(q13;q12.2–12.3) in a clear cell sarcoma of tendons and aponeuroses

Cytogenetic analysis of a short-term culture from a clear cell sarcoma revealed a complex karyotype with the mainline of 49,XY,t(7;18)(p11.2;q21.3), + der(7)t(7;18)(p11.2;q21.3), + 8, + der(8;17)(q10;q10),t(12;22)(q13;q12.2–12.3),add(13)(p13). An apparently identical translocation t(12;22) has been described recently in four clear cell sarcomas, indicating that this constitutes a primary cytogenetic change specific for this type of tumor. In our case, the breakpoint on chromosome 22 could be assigned to band 22q12.2 or 22q12.3. Together with the present case, trisomy or tetrasomy 8 has been found in six of nine clear cell sarcomas, suggesting that, as in Ewing's sarcoma and myxoid liposarcoma, trisomy/tetrasomy 8 represents a nonrandom secondary aberration. We conclude that the finding of the specific translocation t(12;22) may prove to be an important marker in the differential diagnosis of clear cell sarcoma from some other soft tissue sarcomas and malignant melanoma. © 1993 Wiley-Liss, Inc.     

Differential modulation of Ca(v)2.1 channels by calmodulin and Ca2+-binding protein 1

Ca(v)2.1 channels, which mediate P/Q-type Ca2+ currents, undergo Ca2+/calmodulin (CaM)-dependent inactivation and facilitation that can significantly alter synaptic efficacy. Here we report that the neuronal Ca2+-binding protein 1 (CaBP1) modulates Ca(v)2.1 channels in a manner that is markedly different from modulation by CaM. CaBP1 enhances inactivation, causes a depolarizing shift in the voltage dependence of activation, and does not support Ca2+-dependent facilitation of Ca(v)2.1 channels. These inhibitory effects of CaBP1 do not require Ca2+, but depend on the CaM-binding domain in the alpha1 subunit of Ca(v)2.1 channels (alpha12.1). CaBP1 binds to the CaM-binding domain, co-immunoprecipitates with alpha12.1 from transfected cells and brain extracts, and colocalizes with alpha12.1 in discrete microdomains of neurons in the hippocampus and cerebellum. Our results identify an interaction between Ca2+ channels and CaBP1 that may regulate Ca2+-dependent forms of synaptic plasticity by inhibiting Ca2+ influx into neurons.     

CD80 and CD86 expression on LPS-stimulated monocytes and the effect of CD80 and CD86 blockade on IL-4 and IFN-gamma production in nonatopic bronchial asthma

CD80 and CD86 seem to play an important role in the allergen-induced secretion of interleukin (IL)-5 and IL-13. Up to now, the expressions of CD80 (B7.1) and CD86 (B7.2) on monocytes and the kinetics of the expression of these molecules on lipopolysaccharide-stimulated monocytes in nonatopic asthma have not been defined. Using monoclonal antibodies, we have compared the expressions of CD80 (B7.1) and CD86 (B7.2) on the monocytes of healthy persons and nonatopic asthmatic patients. We have also assessed the effect of CD80 and CD86 inactivation on IL-4 and interferon (IFN)-gamma production in nonatopic asthmatics and healthy subjects. We found that a low expression of CD80 (1.64 +/- 0.65 vs. 3.53 +/- 1.43%) and a moderate expression of CD86 (41.25 +/- 13.4 vs. 49.46 +/- 11.49%) on the studied monocytes were characteristic for asthma. In nonatopic asthma patients inactivation of CD80 or CD86 blockade significantly reduced IFN-gamma production by T lymphocytes (p < 0.02; p < 0.03). In both the studied groups, anti-CD80 antibodies did not diminish T lymphocyte production of IL-4. However, anti-CD86 antibodies significantly (p < 0.04) reduced the IL-4 concentration in culture supernatants. Our results confirm that both the CD80 and CD86 molecules play an important role in the maintenance and amplification of the inflammatory process. It suggests that in the inflammatory process that occurs in nonatopic bronchial asthma, Th1 as well as Th2 lymphocytes are equally important.     

Development of a simple method for rapid isolation of polymorphonuclear leukocytes from human blood

Polymorphonuclear leukocytes (PMNs; commonly known as neutrophils) play essential roles in innate immunity and inflammation. Although there are standardized methods for the isolation of human neutrophils, they are time consuming and demand considerable technical expertise, making them unfeasible for many clinical applications. Here, we describe a simple and time-efficient technique for the isolation of human neutrophils, which adapts a readily available commercial cell preparation tube (CPT) currently in use for isolation of peripheral blood mononuclear cells (PBMC) and plasma and is now adapted to also yield neutrophils. The total time required for neutrophil isolation was less than 1 hr. Neutrophils isolated by this method were highly purified (> or =97%) as assessed by surface expression of the neutrophil specific marker, CD66b. Neutrophils isolated by this method were functional as demonstrated by their ability to secrete interleukin-1 receptor antagonist (IL-1RA). Neutrophils isolated using this new technique secreted significant amounts of soluble IL-1RA (929.3+/-197 pg/10(6)cells/mL) in response to lipopolysaccharide (LPS). Use of this adapted CPT method allows simultaneous isolation of functional human neutrophils as well as PBMC and plasma. Adoption of this new method will allow the conduct of different neutrophil assays at any clinical site without requiring trained laboratory personnel or a large staff time commitment.     

Crystalline and disordered state of poly(dihexylsilylene) copolymers

A systematic comparison of random copolymers, derived from poly(dihexylsilylene) (PDHS) by incorporation of monomeric units with shorter unbranched alkyl side chains, has been carried out based on calorimetry, variable temperature UV spectroscopy, and ²⁹Si MAS (magic angle spinning) solid state NMR investigations. Also, hexylmethylsilylene units and branched monomers have been copolymerized. Up to 10% comonomer with shorter linear side chains (i. e., pentyl to propyl) could be incorporated into PDHS without impeding the all-trans order of the crystalline phase. In this case, the UV absorption maximum of the crystalline low-temperature phase was affected only slightly according to the length and fraction of the comonomer side chains. A less ordered crystal structure (λ_max = 345–355 nm) was observed when the content of comonomers with shorter side chains was about 20%. Yet, all these materials form conformationally disordered mesophases. A clear disordering transition and corresponding thermochromism was not observed any more when 50% of propyl side chains were incorporated. The order of the crystalline and the mesophase is also strongly perturbed if only a small fraction (4%) of the side chains are branched at C².