Confusion of identification of o,p′-Kelthane as heptachlor in orange rind extractives

Conclusions Both the glc and the tlc data prove that the unknown compound in the rind of Kelthane-treated oranges was not heptachlor. While the characterization is not absolutely conclusive, there can be no reasonable doubt that it iso,p′-Kelthane, known to be present in technical grade Kelthane. Other workers, using glc, reportedp,p′- ando,p′-Kelthane in the ratio of 100∶1 in 21 market fruit samples from different areas of Southern California. By analogy with DDT, if technical grade Kelthane is assumed to contain up to 20% of theo,p′-isomer this ratio found on fruits treated months previously means that on and in oranges theo,p′-isomer has much the longer half-life (RL₅₀) of the two isomers. On the other hand, approximately equal half-lives are indicated for the two isomers in soil. This brief study emphasizes the need for checking on gas chromatographic data by a more specific method and clearly demonstrates again that improper interpretation of data may be avoided by using at least two columns possessing different retention characteristics for the compounds of interest.     

Comparison of intramural 5-fluorouracil and more conventional routes of drug administration on concentrations in gastric regional lymph nodes: a potential for trans-endoscopic adjuvant chemotherapy.

Intramural injection of 20 muCi (2-14C) 5-fluorouacil (5-FU) into the gastric submucosa of dogs and baboons was employed to evaluate the kinetics of 5-FU distribution following this route of administration and to compare these results with those following intraluminal, intravenous, and local intraarterial injections. Measurements of radioactivity taken over a six-hour period after injections demonstrated that the greatest concentration of isotope in samples of gastric wall and perigastric lymph nodes was found after administration of the drug directly into the stomach wall. Clinical application of intramural injections of 5-FU into the stomach wall under direct gastroscopic visual control, may be worthy of trial in patients with gastric cancer.     

Possible nonspecific immunopotentiation by 2,4-dinitrochlorobenzene sensitization in patients with Hodgkin's disease.

Various immunological parameters were evaluated in untreated Hodgkin's patients before and after sensitization with dinitrochlorobenzene (DNCB). The ratio (r) of these parameters after/before DNCB sensitization for patients and second/first samples in the controls were calculated. There were significantly more patients in the r greater than 1.1 group for PHA and Con A responses and for peripheral blood T cell percentages. These data suggest that DNCB sensitization may have a nonspecific immunopotentiation effect.     

Variations in the initial formation of pellicle and plaque on enamel in vivo.

Four subjects wore acrylic baseplates with small pieces of enamel from unerupted teeth for periods of 24 and 48 hours. The rate of colonization of the pellicle with bacteria varied among the subjects in 2 of whom bacteria were not seen on the surface at 24 hours. Etching the enamel did not enhance the rate of colonization. Chlorhexidine treatment did not prevent bacterial adherence after 2 days, but etched enamel retained the antibacterial effect of chlorhexidine longer than normal enamel.     

Biochemical and metabolic function of the canine liver after four hours preservation

Canine livers were stored for four hours with either hypothermia alone, hypothermia and low flow electrolyte perfusion, hypothermia low flow plasma perfusion, or normothermic dilute blood perfusion. The livers were evaluated by a subsequent two hour normothermic dilute blood test perfusion. Pressure flow relationships were of value in assessing the adequacy of the storage, and correlated well with glucose production and ultrastructural appearances. Livers stored with plasma perfusion seemed to be the most satisfactory. Anaerobic utilization of fructose was a more sensitive index of cellular damage than oxygen uptake in manometric studies. Bromsulphthalein clearance during the test perfusion was of limited value.     

Hematopoietic Stem Cell Regulation. II. Chronic Effects of Hypoxic-Hypoxia on CFU Kinetics

Hypobaric-hypoxia, an established stimulator of erythropoiesis, was used to perturbnormal steady-state hematopoiesis andthereby to facilitate an analysis of stemcell kinetics. BDF₁ male mice were exposed to a simulated altitude of 22,000 ftfor 1-15 days. The following parameterswere assessed at daily intervals: packedred cell volumes (PCV), femoral and splenicnucleated cellularity, the relative concentration and total number of colony-formingunits (CFU, i.e., stem cells) in the femoralshaft and whole spleen, as well as theturnover of this population of cells usingthe "³H-thymidine-killing" technique. By10 days of hypoxia the PCV had risen to65% and by a fortnight was elevated to,and stabilized at, 70%-75%. After anevanescent increase, the femoral cellularitybecame slightly hypocellular but returnedto normal by 3 days, thence becominghypercellular from days 5 to 15. The spleenwas markedly depleted of cells for 48 hrand recovered to hypercellular levelsbetween 4 and 6 days. It then oscillatedfrom hypercellular to normal levels with aperiod interval of 5 days. Both femoraland splenic CFU demonstrated oscillations,as did the estimations made on the stateof CFU turnover. The femoral and splenicCFU did not decrease in number duringthe 15 days of hypoxia, indeed, they bothrevealed cyclic increases. These resultsare discussed in terms of CFU kinetics andhumoral mediation.

Submitted on October 25, 1972 Revised on December 12, 1972 Accepted on December 15, 1972