The σ* molecular orbitals of perfluoroalkanes as studied by inner-shell electron energy loss and electron transmission spectroscopies

Absolute oscillator strength spectra in the C 1s (280–340 eV) and F 1s (680–740 eV) regions of the perfluoro-n-alkanes from C2 to C6 and perfluorocycloalkanes from C3 to C6 have been determined from inner-shell electron energy loss spectra recorded under electric-dipole scattering conditions. The spectral features are interpreted in terms of spatially localized transitions terminating at orbitals of predominantly σ*(C—F) and σ*(C—C) character. When compared to the spectra of the perfluoro-n-alkanes, both the C 1s and F 1s spectra of the perfluorocycloalkanes exhibit additional low-lying bands which are assigned to transitions terminating at σ*(C—C) orbitals which are shifted to low energy by the combination of the strain of cyclization and the inductive effect of the fluorination. The electron transmission spectra of selected perfluorocycloalkanes (which provide information on their anion states) show as well that the electron affinities of the cyclic systems are substantially lower than those of the corresponding perfluoro-n-alkanes, again as a result of a low-lying σ* orbital in the cyclic species. Quantum chemical calculations of the alkane and perfluoroalkane ground-state orbital structures support the experimental results. The localized character of the inner-shell excitations, indicated by the constancy of both term values and oscillator strengths with increasing chain length, contrasts with the more delocalized character of the states accessed in ultraviolet excitation or negative ion formation.

Extension of the H-2 TLb molecular map. Isolation and characterization of T13, T14, and T15 from the C57BL/6 mouse

A region of the TLb locus encompassing T11 to T13 contains retroviral sequences TLev1 and TLev2. As part of a study to determine whether the retroviral elements are involved in the expression of TL genes, the genomic organization of this region was reexamined in greater detail. A result of these investigations is the extension of the H-2 TLb molecular map. Two additional TL genes have been isolated from C57BL/6 mice, T14 and T15. The genomic organization of T9 through T15 is presented. The nucleotide sequence has been determined for exons 4, 5, and 6 of T13. As a result of a C to T conversion, a termination codon is introduced into exon 4, indicating that T13 either encodes a secreted protein or is a pseudogene. T13 was found to be more homologous to the H-2 genes outside the TL region. T14 has been physically disrupted by the integration of TLev1, and the H-2 sequences appear to have diverged greatly. The relationship of the TL regions of the b and c haplotypes has been investigated using numerous low copy probes. The genome of BALB/c (TLc) is shown to lack a counterpart of the T13-T15b region. Homologous regions exist in the two haplotypes; yet considerable polymorphism is observed. TLb mice do not express TLa on the cell surface of normal thymocytes while TLc mice do; TLa expression is activated in many TLb leukemias. The diversity seen in the T13-T15 region may provide insights into the phenotypic expression or regulatory mechanisms of TL expression in these two haplotypes.

Childhood renal diseases in Korea. A clinicopathological study of 657 cases

Between June 1975 and March 1987, 662 renal biopsies were performed in 657 children at Seoul National University Children's Hospital. Nephrotic syndrome was the most indication for renal biopsy and accounted for 62% of all cases. Of these, 57% showed minimal change lesions and 21% showed focal segmental glomerular sclerosis. Nephropathy, associated with Australia-antigen-positive hepatitis, was the most prominent cause of secondary nephrotic syndrome, and of these patients membranous nephropathy was found in 86%. Diffuse proliferative glomerulonephritis was found in 60% of patients with acute nephritic syndrome. Fifty-eight percent of children with haematuria were found to have either IgA nephropathy or Henoch-Schönlein nephritis. Fifteen children with acute renal failure were biopsied, 2 of whom had haemorrhagic fever.

Epidural butorphanol or morphine for the relief of post-cesarean section pain: ventilatory responses to carbon dioxide

To determine the safety, efficacy, and the ventilatory responses to carbon dioxide (CO2) of epidurally administered butorphanol or morphine, 122 healthy women who underwent cesarean section with epidural anesthesia were studied. Patients were randomly assigned to receive one of four epidural regimens for the relief of postoperative pain: 5 mg morphine (n = 32), 4 mg butorphanol (n = 30), 2 mg butorphanol (n = 29), or 1 mg butorphanol (n = 31). Epidural morphine provided satisfactory analgesia with slow onset and long duration of approximately 21 hr. When butorphanol was administered, analgesia of rapid onset was seen with increasing duration and effectiveness observed with increasing dose; approximately 8 hr when using 4 mg. Sixty-two percent of the patients who received morphine had pruritus. Somnolence was the main side effect encountered in patients who received epidural butorphanol. The ventilatory response to CO2 was depressed after morphine and after 2 and 4 mg butorphanol, but the duration of depression was more prolonged after morphine. It is concluded that epidural butorphanol is effective in providing pain relief after cesarean section with minor side effects. However, patients must be observed closely because of possible respiratory depression.

Quantitative analysis of collagen, protein and DNA in fixed, paraffin-embedded and sectioned tissue

Modifications and adaptations of chemical techniques have been used to quantitate hydroxyproline (collagen), total protein and DNA in fixed, paraffin-embedded and sectioned tissue. The assays are rapid and sensitive to between 0.1 and 1.0 micrograms of each of the three components. Values for the ratio of collagen to total protein or collagen per DNA obtained from sectioned material are the same as values derived from fresh or fixed starting material. Depending on the tissue and the sample size, as little as three to five 5 micron thick sections can be analysed for these three components. The ratios of collagen per total protein or collagen per DNA are given for several murine tissues. The assay of these components in tissue sections will allow a more precise correlation between histological appearance and the quantitative biochemical changes that may accompany many pathological disorders. The techniques are particularly useful in retrospective studies where the experimental material may be en bloc.

Association of simian virus 40 T antigen with the nuclear matrix of infected and transformed monkey cells

The subnuclear distribution of simian virus 40 large T antigen within nuclei of transformed Cos and C6 monkey cells was examined. Cos cells express wild-type T antigen but lack viral sequences required for DNA replication, whereas C6 cells contain a functional viral origin but express a replication-defective mutant T antigen which is unable to bind specifically to viral DNA. Discrete subpopulations of T antigen were isolated from the soluble nucleoplasm, chromatin, and nuclear matrix of both cell lines. Although only a small quantity (2 to 12%) of the total nuclear T antigen from Cos cells was associated with the nuclear matrix, a high proportion (25 to 50%) of C6 T antigen was bound to this structure. Results obtained from lytically infected monkey cells showed that early in infection, before viral replication was initiated, a higher proportion (22%) of T antigen was found associated with the nuclear matrix compared with amounts found associated with this structure later in infection (5 to 8%). These results suggest that an increased association of T antigen with this structure is not correlated with viral replication. T antigen isolated from the C6 nuclear matrix was more highly phosphorylated than was soluble C6 T antigen and was capable of binding to the host p53 protein. C6 DNA contains three mutations: two corresponding to N-terminal changes at amino acid positions 30 and 51 and a third located internally at amino acid position 153. By analysis of the subnuclear distribution of T antigen from rat cells transformed by C6 submutant T antigens, it was determined that one or both of the mutations at the NH2 terminus are responsible for the increased quantity of C6 T antigen associated with the nuclear matrix. These results suggest that neither a functional viral DNA replication origin nor the origin binding property of T antigen is required for association of this protein with the nuclear matrix.

Genetic load and viability variation in korean natural populations of Drosophila melanogaster

Natural populations of Drosophila melanogaster from Anyang and Susac (suburbs of Seoul) have been analyzed with respect to viability variation on the second chromosome. Homozygotes as well as random heterozygotes for wild chromosomes were studied. The frequency of lethal factors was about 16 per cent, that of drastics 26 per cent. The average viability of homozygotes was 0.650 including lethal lines and 0.858 for quasinormals; that for random heterozygotes was 1.125. Allelism tests have been performed for the lethals. The allelism rate turned out to be as high as 0.036 and 0.0214, respectively. Using a formula by Nei, the effective population size can be estimated from these data. Korean D. melanogaster populations proved as small as 2000 to 3000 individuals. No correlation between homozygous and heterozygous viabilities could be found. According to these observations, along with the fact that partly big clusters of identic lethals could be found in the allelism tests, it is concluded that in Korean populations quite a large part of the hard genetic load is balanced. The connection between population size, population structure and associative or genuine overdominance is discussed.

Effect of glycodiazine on blood sugar in diabetes mellitus

Clinical trials were made with glycodiazine, N.(5(2-Methoxyethoxy)-2-Pyrimidinyl) benzenesulfonamide by a technic in which the effects of the drug were compared statistically to those of a placebo in a group of patients with the adult onset type of diabetes mellitus. Glycodiazine was active orally at two dosage levels 0.5 gm. b.i.d. and 0.5 grn. once a day although onset of antihyperglycemic response was slower with the smaller dose. No untoward side effects were noticed. The findings indicate that glycodiazine may be an effective oral antihyperglycemic agent.