Arrangement of lambda light chain genes in mutant clones of the MOPC 315 mouse myeloma cells

The synthesis of lambda light chains and the arrangement of the lambda-chain genes was examined in cells of the mouse myeloma MOPC 315, which is an alpha lambda 2 producer, and in several mutants derived from it. The mutants produce lambda 2 chains only (MOPC 315.26, MOPC 315.34, and MOPC 315.37) or fail to produce alpha and lambda 2 chains (MOPC 315.25 and MOPC 315.36). Messenger RNA from the lambda 2 chain-producing cells directed the synthesis of a lambda 2 chain precursor and a fragment of the lambda 1 chain (lambda 1 F) in a wheat embryo cellfree system, whereas mRNA from the cells that do not produce lambda 2 chains directed the synthesis of lambda 1 F only. DNA from the parental MOPC 315 cells and from the lambda 2 chain-producing cells contained discrete EcoRI restriction fragments coding for rearranged lambda 1 and lambda 23 chain genes and their respective germ-line V and J-C regions. DNA from the no-Ig-producing cells contained fragments coding for the rearranged lambda 1 chain gene and the germ-line V lambda 2 region, but it lacked the sequences coding for the rearranged lambda 2 chain gene and the germ-line V lambda 1 and J-C lambda 1 regions. These results suggest that rearrangements of the lambda 1 and lambda 2 chain genes occur on different chromosomes in MOPC 315 cells and imply that rearrangements of the lambda 1 and lambda 2 chain genes on the same chromosome may be mutually exclusive.

The demonstration of lymphatic channels on wrist arthrography in rheumatoid disease with particular reference to associated lymphoedema

Delineation of lymphatic vessels is a frequent finding in arthrograms of rheumatoid joints. Arthrography of the rheumatoid wrist when associated with oedema of the upper limb reveals a characteristic pattern consistent with lymphatic obstruction. In our opinion, these findings may be regarded as further evidence in favour of lymphatic obstruction as the cause of peripheral oedema in rheumatoid arthritis. The syndrome appears to be a separate entity from idiopathic oedema of women.

Hyphema in the newborn: report of a case

This is a case report of an anterior chamber hemorrhage noted two days after spontaneous delivery in a full-term infant with perinatal asphyxia. There was probably vitreous hemorrhage in the same eye and extensive retinal hemorrhages in both eyes. By two weeks, the hyphema and vitreous hemorrhage had resolved and the retinal hemorrhages largely cleared.

Bilirubin mono- and diglucuronide formation by human liver in vitro: assay by high-pressure liquid chromatography

Bilirubin diglucuronide, the major pigment in human bile is formed in two steps. Bilirubin is converted to bilirubin monoglucuronide by transfer of the glucuronosyl moiety of uridine diphosphoglucuronic acid catalyzed by the microsomal enzyme, uridine diphosphoglucuronate glucuraonosyl transferase (UDP glucuronyl transferase, EC 2.4.1.17). Bilirubin monoglucuaronide is converted to bilirubin diglucuronide in vitro by two enzymatic mechanisms: (a) UDP glucuronyl transferase-mediated transfer of a second mole of glucuronic acid form UDP-glucuronic acid to bilirubin monoglucuronide; (b) dismutation of 2 moles of bilirubin monoglucuronide to 1 mole of bilirubin diglucuronide and 1 mole of unconjugated bilirubin, catalyzed by bilirubin monoglucuronide dismutase (bilirubin glucuronoside glucuronosyl transferase EC 2.4.1.95). Assay methods for the three enzymatic mechanisms in human liver homogenate by high-pressure liquid chromatography analysis of underivatized bilirubin tetrapyrroles have been developed. UDP glucuronyl transferase was activated in five human liver homogenates with digitonin, Triton X-100, or UDP-N-acetylglucosamine. Greatest activation was observed with Triton X-100. The pH optimum for conversion of bilirubin to bilirubin monoglucuronide was 7.4, and UDP glucuronyl transferase activity was 625 +/- 51 nmoles per 20 min per gm liver. At high initial bilirubin concentrations (342 microM), the product of UDP glucuronyl transferase assay with bilirubin as substrate was predominantly bilirubin monoglucuronide. At lower initial bilirubin concentrations (6.5 to 34 microM), up to 15% bilirubin diglucuronide was formed. Glucuronyl transferase-mediated UDP glucuronic acid-dependent conversion of bilirubin monoglucuronide to diglucuronide was assayed using UDP-14-C-glucuronic acid. The pH optimum was 7.4, and the rate was 21 +/- 7 nmoles per gm liver per 20 min. The rate of bilirubin diglucuronide formation by enzymatic dismutation of bilirubin monoglucuronide was 470 +/- 112 nmoles per gm liver per min. The pH optimum was 6.6. The products of enzymatic dismutation were of the IX alpha configuration.

THe hazards of injecting local anesthetic solutions with epinephrine into flaps: experimental study

In a study using paired longitudinal flaps on the back of the rat, we found evidence to support the findings of previous investigators regarding the toxic effects of injecting local anesthetic solutions containing epinephrine into delayed flaps. Epinephrine concentrations of 1:200,000 and 1:400,000 were demonstrated to significantly increase losses in these flaps. Epinephrine concentrations of 1:100,000, 1:200,000, and 1:400,000 were not demonstrated to be harmful to undelayed flaps, in the dosages used.

Auxin increases the hydraulic conductivity of auxin-sensitive hypocotyl tissue

The ability of water to enter the cells of growing hypocotyl tissue was determined in etiolated soybean (Glycine max (L.) Merr.) seedlings. Water uptake was restricted to that for cell enlargement, and the seedlings were kept intact insofar as possible. Tissue water potentials (ψ w) were measured at thermodynamic equilibrium with an isopiestic thermocouple psychrometer. ψ wwas below the water potential of the environment by as much as 3.1 bars when the tissue was enlarging rapidly. However, ψ w was similar to the water potential of the environment when cell enlargement was not occurring. The low ψ w in enlarging tissue indicates that there was a low conductivity for water entering the cells.The ability of water to enter the enlarging cells was defined as the apparent hydraulic conductivity of the tissue (L'p). Despite the low L'p of growing cells, L'p decreased further as cell enlargement decreased when intact hypocotyl tissue was deprived of endogenous auxin (indole-3-acetic acid) by removal of the hypocotyl hook. Cell enlargement resumed and L'p increased when auxin was resupplied exogenously. The auxin-induced increase in L'p was correlated with the magnitude of the growth enhancement caused by auxin, and it was observed during the earliest phase of the growth response to auxin. The increase in L'p appeared to be caused by an increase in the hydraulic conductivity of the cell protoplasm, since other factors contributing to L'p remained constant. The rapidity of the response is consistent with a cellular site of action at the plasmalemma, although other sites are not precluded.Because the experiments involved only short times, auxin-induced changes in cell enlargement could not be attributed to changes in cell osmotic potentials. Neither could they be attributed to changes in turgor, which increased when the rate of enlargement decreased. Rather, auxin appeared to act by altering the extensibility of the cell walls and by simultaneously altering the ability of water to enter the growing cells under a given water potential gradient. The hydraulic conductivity and extensibility of the cell walls appeared to contribute about equally to the control of the growth rate of the hypocotyls.

Velopharyngeal incompetence without overt cleft palate. A collective review and experience with 98 patients

Our experience in patients with velopharyngeal incompetence but without overt cleft palate is described, and the literature is reviewed.