Relationships among New World species of Hibiscus section furcaria (Malvaceae)

Seventeen species ofHibiscus sectionFurcaria are native to the New World, of which 12 (one diploid, nine tetraploids, one octoploid and one decaploid) have been studied cytotaxonomically. New chromosome counts (2n=4x=72) are reported forH. cucurbitaceus, H. flagelliformis, H. kitaibelifolius, andH. laxiflorus. Seventeen types of tetraploid interspecific hybrids (seven new to this study) all showed complete meiotic chromosome homology (genome formulaGGPP) and normal floral development. That all hybrids were nevertheless almost completely sterile suggests a cytoplasmic component to the genetic differentiation of the species. The diversification of the tetraploid species in habits, habitats and geographical ranges is considerable, despite their similar genome constitutions. A key to 17 native and four introduced African species is presented.Hibiscus cerradoensis sp. nov. is described.     

An enzymatic assay for acetate in spent bacterial culture supernatants

A method is presented for the rapid enzymatic determination of acetate in spent bacterial culture supernatants. The assay is based on a previously published assay for acetate kinase [Bergmeyer et al. (1974) in Methods of Enzymatic Analysis (Bergmeyer, H. V., ed.), Vol. 1, pp. 425-426, Verlag Chemie-Academic Press, New York/London], and is sufficiently sensitive to detect acetate levels of 50 microM. The assay is cheaper than commercially available assays and is particularly useful for occasional use by laboratories not equipped for routine acetate analysis using gas chromatography. The application of the assay to the measurement of acetate in bacterial cultures is described, though it should also be applicable to other biological fluids and foodstuffs.     

Activation of Na+/H+ exchange in lymphocytes by osmotically induced volume changes and by cytoplasmic acidification

After swelling in hypotonic solutions, peripheral blood mononuclear cells (PBM) shrink toward their original volumes. Upon restoration of isotonicity, the cells initially shrink but then regain near-normal size again. This regulatory volume increase (RVI) is abolished by removal of Na+o or Cl-o or by addition of amiloride. RVI is unaffected by removal of K+o or by ouabain and is only partially inhibited by 1 mM furosemide. As a result of increased influx, the cells gain both Na+ and K+ during reswelling. In contrast, only Na+ content increases in the presence of ouabain. Amiloride largely eliminates the changes in the content of both cations. Using diS-C3-(5), no significant membrane potential changes were detected during RVI, which suggests that the fluxes are electroneutral. The cytoplasmic pH of volume-static cells was measured with 5,6-dicarboxyfluorescein. After acid loading, the addition of extracellular Na+ induced an amiloride-inhibitable alkalinization, which is consistent with Na+/H+ exchange. Cytoplasmic pH was not affected by cell shrinkage itself, but an internal alkalinization, which was also amiloride sensitive and Na+ dependent, developed during reswelling. In isotonic lightly buffered solutions without HCO-3, an amiloride-sensitive acidification of the medium was measurable when Na+ was added to shrunken PBM. K+ was unable to mimic this effect. The observations are compatible with the model proposed by Cala (J. Gen. Physiol. 1980. 76:683-708), whereby an electroneutral Na+o/H+i exchange is activated by osmotic shrinking. Cellular volume gain occurs as Cl-o simultaneously exchanges for either HCO-3i or OH-i. Na+i is secondarily replaced by K+ through the pump, but this step is not essential for RVI.     

Irradiation as an Alternative to Mastectomy for Early Breast Cancer—An Important Consideration Because of Changes in Laws

Between May 1973 and December 1980 there were 76 patients (78 breasts) with clinical stage I or II breast carcinoma treated by biopsy and definitive radiotherapy at Stanford University Medical Center. Local-regional control has been achieved thus far in 76 of 78 cases (97 percent) with a median follow-up time of 26 months. Transient lymphedema of the breast, arm edema and breast fibrosis were the most commonly noted complications. The cosmetic result was analyzed and scored as excellent in 78 percent, satisfactory in 18 percent and unsatisfactory in 4 percent. The three unsatisfactory results occurred in patients in whom severe fibrosis developed as a result of suboptimal radiation techniques. Interdisciplinary cooperation among surgical, medical and radiation oncologists is important. The 97 percent local-regional control and the 96 percent excellent-to-satisfactory results support the use of primary radiotherapy in early stage breast carcinoma.     

Poliovirus type 3: molecular cloning of the genome and nucleotide sequence of the region encoding the protease and polymerase proteins.

Overlapping cDNA clones representing the entire genome of poliovirus type 3 have been prepared in E. coli by two separate methods. Cloning of RNA . cDNA hybrids produced a more comprehensive set of clones with generally larger cDNA inserts than cloning of double - stranded cDNA. A restriction map of the entire genome and the nucleotide sequence of 2003 bases from the 3' terminus, comprising the region encoding the protease and polymerase proteins, are presented.     

Vagotomy and Pyloroplasty for Gastric Ulcer

In a series of 68 patients with gastric ulcer who were treated by vagotomy and pyloroplasty there were no operative deaths, though one patient who received massive transfusions died 14 weeks later from hepatic necrosis probably associated with serum hepatitis. Four patients developed recurrent peptic ulceration requiring further surgical treatment. The clinical condition of all but three of the remainder was satisfactory after an average follow-up period of three years and two months. Of the 14 patients who presented with an acutely bleeding gastric ulcer, one subsequently required gastrectomy for continued bleeding; in all the others the immediate and long-term results were satisfactory. Of 21 patients with a “high” ulcer and 29 with combined gastric and duodenal ulceration one (4·8%) and three (10%) respectively suffered recurrences. We conclude that vagotomy and pyloroplasty is a satisfactory form of treatment for a high or bleeding gastric ulcer, but that for all other gastric ulcers some form of gastric resection is preferable.     

Hemagglutination Inhibition with Arboviruses: Relationship Between Titers and Source of Erythrocytes

Antigens for Grand Arbaud, Hazara, and California arboviruses were able to agglutinate goose and either dog, hamster and guinea pig, or hamster red blood cells (RBC) to the same titer at the same pH; in hemagglutination-inhibition (HI) tests, titers for homologous and related sera were the same with these different types of RBC or occasionally one dilution higher with the mammalian cells. Antigens for St. Louis encephalitis and Eastern equine encephalitis viruses required use of lower antigen dilutions with human, guinea pig, and hamster RBC than with goose RBC. The results of comparative HI testing with these latter antigens and types of RBC indicate that HI titer is not directly related to the antigen dilution used with different types of RBC.     

Stomatal movement in Zea mays: Shuttle of potassium and chloride between guard cells and subsidiary cells

Summary When stomates of Zea mays open K and Cl migrate from the subsidiary cells into the guard cells; when the stomates close both elements return to the subsidiary cells. Subsidiary cells function as reservoirs for K and Cl. Import of K and Cl into the guard cells and loss of both elements from the guard cells become observable 1 or 2 min after light is turned on or off, both when histochemical methods and the electron-probe microanalyzer are used for detection. Each stomatal complex of maize contains on the average 10±3×10^-13 gram equivalents (eq) of K and 4±1×10^-13 eq of Cl. Guard cells accumulate K in the light and CO₂-free air at an average rate of 10×10^-15 eq K per minute, and Cl at approximately half that rate.