Optical second-harmonic generation with coupled surface plasmons from a multilayer silver-quartz grating

We report a theoretical and experimental study of enhanced optical second-harmonic generation due to excitation of coupled surface plasmons from a thin silver grating bounded by two quartz crystals. With incident radiation from a Nd:YAG laser, diffracted second-harmonic generation in the n = 1, 0, and -1 modes is observed for the coupled surface plasmon fundamental modes. Nonlinear reflectance ratios calculated by using the reduced Rayleigh equations are in good agreement with the experimental results. Enhancement of the second-harmonic generation is limited by the scattering of the long-range surface plasmon mode in the thinnest silver films studied.

Molecular cloning of a 5' segment of the genomic phl gene defines a new breakpoint cluster region (bcr2) in Philadelphia-positive acute leukemias

Molecular rearrangements of Ph1 chromosome, the hallmark of CML, are clustered in a 5.8-kb DNA segment, the so-called breakpoint cluster region (bcr) of the phl gene that is localized to chromosome 22q11. In Ph1-positive (Ph1+) ALLs, the rearrangements have been shown to involve either the 5.8-kb bcr (called bcr+) or a region upstream of bcr in the 5' end of the phl gene (bcr-). To gain insight into the rearrangements occurring in Ph1+ acute leukemias, a 64-kb DNA fragment from the 5' end of phl was analyzed in order to generate molecular probes covering 40 kb of the phl gene first intron. A panel of seven cases of bcr-Ph1+ acute leukemia (three nonlymphocytic and four lymphocytic) was investigated with these intron 1-derived probes. Strikingly, in six of the seven leukemias, the breakpoints were located in a 10.8-kb DNA segment, defining a new bcr which appears to be specific for Ph1+ acute leukemias. By analogy with the CML bcr region located in the 3' part of the phl gene, we propose to designate this 10.8-kb fragment bcr2.

The V gamma locus of the human T cell receptor gamma gene. Repertoire polymorphism of the first variable gene segment subgroup

Southern blot analysis using a genomic probe of the human TCR-gamma chain first variable gene subgroup (V gamma I) was performed on DNA samples from both parents of 36 healthy Caucasian families. Two types of polymorphisms were found in these 72 unrelated DNA samples: three repertoire polymorphisms and two restriction fragment length polymorphisms (RFLP). In all cases, Mendelian inheritance of these polymorphisms was demonstrated. The most frequent repertoire polymorphism consists in the lack of the V gamma 4 and V gamma 5 segments. In 16% of chromosomes, the Eco RI and Taq I restriction fragments corresponding to V gamma 4 and V gamma 5 were lacking, with no additional bands. In these cases, a decrease of 10 kb was observed in the Bam HI fragment containing all V gamma I segments as compared with samples containing V gamma 4-V gamma 5 segments. To better understand this polymorphism, which takes place in a previously incompletely defined region, the central part of the V gamma I region, including the polymorphic V gamma 4-V gamma 5 segments, was cloned. This allowed us to localize precisely the V gamma 5 segment and thus complete the description of the V gamma I region. A striking homology of DNA and deduced amino acid sequences is present between V gamma 2 and V gamma 4 and between V gamma 3 and V gamma 5, much higher than that observed between V gamma 2 and V gamma 3 and between V gamma 4 and V gamma 5. The differences in nucleotide sequence occur mainly in the intron and three hypervariable regions. These results strongly suggest a gene duplication relationship between the segments V gamma 2-V gamma 3 and the segments V gamma 4-V gamma 5. The most frequent RFLP documented in this study is due to the combined absence of the Eco RI and the Taq I sites located in the noncoding region between V gamma 3 and V gamma 4. The haplotypic frequence of this RFLP is 6.9% of the general population. As the gamma/delta receptor may play an important role in immunological response, the biological relevance of the high degree of polymorphism occurring in the V gamma I region, as well as its possible association with some immune disturbances, should be further explored.

Changes in dehydrodolichyl diphosphate synthase during spermatogenesis in the rat

The levels of dolichyl phosphate and 2,3-dehydrodolichyl diphosphate synthase were determined in seminiferous tubules of prepuberal rats to assess any changes occurring during early stages of spermatogenesis. Dolichyl phosphate increased in concentration two- to threefold from Day 10 to Day 23 after birth. A method was optimized to measure dehydrodolichyl diphosphate synthesis from delta 3-[14C]isopentenyl diphosphate and t,t-farnesyl diphosphate in homogenates of seminiferous tubules. Both dehydrodolichyl mono- and diphosphates were observed as products of the in vitro assay. The specific activity of tubular synthase increased twofold between Day 7 and Day 23 and decreased similarly between Day 23 and Day 60. Since there was a parallel increase in the concentration of tubular dolichyl phosphate and dehydrodolichyl diphosphate synthase activity during early stages of spermatogenesis, it is proposed that the level of dolichyl phosphate may be controlled at least in part by the regulation of de novo dehydrodolichyl diphosphate biosynthesis. The synthase was also solubilized from tubular membranes with deoxycholate and partially purified by chromatography.

The human T-cell V gamma gene locus: cloning of new segments and study of V gamma rearrangements in neoplastic T and B cells

The authors have analyzed the involvement of V gamma and J gamma segments in TRG gamma rearrangement from a series of 40 acute lymphoblastic leukemia (ALL), including 25 T- and 15 B-lineage cases, in which TRG gamma are rearranged. Sixty-five rearranged alleles were studied. The authors first describe the cloning and sequencing of two variable segments, V gamma 11 and psi V gamma 12, which rearrange in T- and B-neoplastic cells. To date three subgroups of translatable V gamma segments have been described. The authors show that V gamma 11 is the unique member of a new fourth V gamma subgroup that also rearranges in normal polyclonal T cells and that psi V gamma 12 is located at 5-kilobase (kb) downstream to V gamma 11. As shown by DNA sequence analysis, V gamma 11 shares a 60% homology with V gamma 10 (third subgroup) and a 50% homology with V gamma 9 (second subgroup) but no appreciable homology with the V gamma segments from the first family. In contrast to psi V gamma 12, V gamma 11 is translatable. In this paper the authors have also attempted to determine which V gamma segments were rearranged in the ALL cases by hybridization with a J gamma probe and genomic probes specific of the four subgroups. In the 54 instances in which the rearrangement was consistent with J gamma 1 or J gamma 2 involvement, the authors have identified the corresponding V gamma segments and have not found any other rearrangements suggestive of the existence of further V regions. The V gamma segments, belonging to the first subgroup, were the most frequently used (41 alleles). V gamma 9, V gamma 10, V gamma 11, and psi V gamma 12 were found rearranged in cases 3, 4, 5, and 1, respectively. No cases using the pseudo psi V gamma 1, psi V gamma 5, and psi V gamma 6 segments were found. Pseudo V gamma segments were not found rearranged in T cells, while V gamma 2 and V gamma 4, segments are frequently used. In contrast to the V gamma I gene rearrangement, the involvement of the V gamma II, V gamma III, and V gamma IV subgroups was most frequently observed in T-ALL with stage II differentiation (CD7+, CD4+, and/or CD8+, CD3-), than in those with stage I (CD7+, CD4-, CD8-, CD3-), than in those with stage I (CD7+, CD4-, CD8-, CD3-) and stage III (CD7+, CD4+/-CD8+/-CD3+).(ABSTRACT TRUNCATED AT 400 WORDS)

Increased subjective symptom prevalence among workers exposed to trichloroethylene at sub-OEL levels

Over 100 workers exposed to trichloroethylene (TRI) mostly at less than 50 ppm during the production or vapor degreasing operation and about an equal number of the non-exposed control workers were examined for subjective symptoms, hematology, serum biochemistry, and sugar, protein and occult blood in urine. Essentially all the clinico-laboratory tests stayed normal, and there was no significant differences in the findings between the exposed and the controls. Thus, no clinically significant effects of TRI exposure were found in the blood and liver functions among the exposed workers as compared with the controls. The prevalence of the subjective symptoms was, however, significantly higher in the exposed group than in the controls, and dose-response relationship could be established in some selected symptoms such as nausea, heavy feeling in the head, forgetfulness, tremor in extremities, cramp in extremities and dry mouth, although the exposure was low. The findings warrant further attention to the effects of TRI especially on the central nervous system at the concentration lower than e.g., 50 ppm.

Philadelphia-positive acute leukemia: lineage promiscuity and inconsistently rearranged breakpoint cluster region

Six patients with Philadelphia-positive (Ph1+) acute nonlymphocytic leukemia (ANLL) were studied by morphological, immunological, cytogenetic, and molecular techniques. Seven Ph1+ acute lymphocytic leukemia (ALL) cases were also studied for comparison. Three of ANLL cases were classified in M1, M2, and M4 groups of the FAB nomenclature, while the three other cases do not fit with any FAB subgroup and are described as M0. Immunophenotypical marker studies, double immunolabeling, and combined immunological and cytogenetic studies of metaphases showed that these ANLL expressed several lineage differentiation antigens. Rearrangements of immunoglobulin heavy chain gene (C mu) were detected in the six ANLL cases and in the seven ALL cases studied, as well as, in most cases, rearrangement of T cell receptor beta chain genes and/or T cell rearranging gamma genes. The results favored the assumption that the Ph1 translocation originated from a multipotent stem cell in Ph1+ ANLL. A common t(9;22) translocation was found in all cases, and additional chromosomal abnormalities were present in the six ANLL cases and in five of the seven ALL cases. Molecular studies of bcr gene configuration and c-abl transcription allowed two groups of Ph1+ ANLL to be distinguished. Three cases had bcr rearrangement and c-abl mRNA expression comparable to those reported in Ph1+ chronic myeloid leukemia, while three others had not detectable bcr rearrangement and a 7.2-7.5 kb c-abl mRNA. The existence of Ph1+ ALL with and without classical bcr rearrangement was confirmed.

Missense Mutation in the Chlamydomonas Chloroplast Gene that Encodes the Rubisco Large Subunit

The 69-12Q mutant of Chlamydomonas reinhardtii lacks ribulose-1,5-bisphosphate carboxylase activity, but retains holoenzyme protein. It results from a mutation in the chloroplast large-subunit gene that causes an isoleucine-for-threonine substitution at amino-acid residue 173. Considering that lysine-175 is involved in catalysis, it appears that mutations cluster at the active site.

Modern high resolution computed tomography (CT) diagnosis of longitudinal fractures of the petrous bone

High resolution computed tomographic (HRCT) examinations were performed in 14 patients with clinically suspected fractures of the temporal bone (TBF). HRCT were performed previously by a sophisticated, but not the latest, generation CT scanner. No fractures were demonstrated. The patients were re-examined by the latest generation CT scanner which demonstrated unilateral hair-line longitudinal fractures of the petrous bone in all of the patients. All the cases were associated with partial aeration of the mastoid cells on the affected side. The importance of this symptom is discussed.

Treatment of the thalassemia syndrome with splenectomy

Splenectomy was performed on 152 patients with thalassemia (thal), including 90 cases with Hb H disease, 48 cases with homozygous beta-thal, and 14 cases with Hb E-beta-thal. The therapeutic effect in Hb H disease was 83.3%, and 32.3% in Hb E-beta-thal and beta-thal. In Hb H disease, the hemoglobin (Hb) level increased 30 g/l in 14 of 29 cases. After splenectomy, the life-span (T1/2) of 51Cr RBC in Hb H and Hb E-beta-thal increased to 18.2 +/- 2.6 and 18.2 days, respectively. The number of inclusion (Heinz) bodies attached to the RBC membrane increased after surgery. The interdermal delayed supersensitivity reaction became negative in seven of 26 cases of Hb H disease; the IgG also decreased after surgery. The number of PAS positive foam cells in the spleen correlated to Hb level after surgery. Infection is a common complication.

T cell rearranging gene gamma: diversity and mRNA expression in fresh cells from T cell acute lymphoblastic leukemia

Rearrangement and in most cases expression of the T cell rearranging genes gamma (TRG gamma) and T cell antigen receptor beta chain (TCR beta) genes were studied in 19 cases of T cell acute malignancies where the surface phenotype is representative of the different stages of thymic maturation. TCR alpha gene transcription was also studied. TRG gamma and TCR beta genes were found to be rearranged in all but one case. The TRG gamma rearrangement pattern seen in most cases is compatible with biallelic rearrangement by loop excision involving the J gamma 2 regions. The sizes of all but two rearranged bands were identical to those of the rearranged bands seen in polyclonal T lymphocytes also studied in this work. One identical-sized band was found in 11 of the 18 rearranged cases. The expression of TRG gamma mRNA (transcripts of 1.6 kilobases [kb]) was highly variable from case to case and did not correlate with the stage of differentiation of the malignant cells, the expression of the molecules CD4 and CD8, the expression and size of the transcripts of the TCR beta genes, and the transcription of TCR alpha genes. In one CD3 + case, strong expression of the TRG gamma transcripts coexisted with the exclusive presence of TCR beta mRNA of 1.0 kb. The cells from this case did not react with anti-Ti antibody and exhibited no natural killer activity. These findings are suggestive of a malignancy that may express the recently isolated CD3-TRG gamma complex.