Levels of polychlorinated biphenyls (PCBs), DDE,and mirex in waterfowl collected in New York State, 1981–1982

The PCBs, DDE, and mirex levels were measured in the subcutaneous fat and breast muscle of fifty-five waterfowl collected in New York State during 1981 and 1982. Levels were obtained by electron capture gas chromatography (EC-GC) on wet weight, dry weight, and lipid weight bases; results were confirmed by gas chromatography-mass spectrometry (GC-MS). The mean PCB levels were 6.1 (g/g in fat and 0.25 g/g in breast muscle on a wet weight basis. The mean DDE and mirex levels were 0.10 g/g and 0.28 g/g in fat and 0.01 g/g and 0.002 g/g in breast muscle on a wet weight basis, respectively.The results of the present study confirm those of the previous study (Kimet al. 1984). The detailed comparison, however, shows that the levels of PCBs and DDE in fat continued to decline while the level of mirex increased slightly.     

Subtyping lymphocytes in peripheral blood by immunoperoxidase labeling and light scatter/absorption flow cytometry

Lymphocyte subpopulations in a whole-blood sample can be detected by adapting mouse monoclonal antibodies (MAbs) and peroxidase (EC 1.11.1.7) labeling to a flow cytometer equipped with a tungsten-halogen light source and scatter/absorption optics (Technicon H6000). In the optimized cytochemical conditions each cell population generates a distinct, well-separated cluster, for accurate "thresholding" of the surface-antigen negative and positive lymphocyte populations in the presence of other leukocytes. After reaction with MAb, the erythrocytes are lysed, and the lymphocytes and other leukocytes are fixed. Biotinylated anti-mouse IgG, used as a bridge, amplifies the response from the avidin-peroxidase label. Granulocytes and monocytes, which have high endogenous peroxidase activity, and the labeled lymphocytes are stained in a specific amount of hydrogen peroxide plus 4-chloro-1-naphthol in 4-(2-hydroxyethyl)-1-piperazine-ethanesulfonic acid buffer. Accuracy and precision are equivalent to those of flow cytometers that measure immunofluorescence (e.g., Ortho Spectrum III), as demonstrated with OKT3, OKT4, OKT8, OKT11, and Leu 12 MAbs.     

An explanation of renal hemodynamics in acute renal failure based on sequential CT in patients with Korean hemorrhagic fever

The pattern of renal enhancement and washout of contrast medium was observed on sequential follow-up CT in 12 patients with Korean hemorrhagic fever, in which acute renal failure is one of the most important clinical features. Renal contrast enhancement and contrast medium washout were delayed longer in patients with severe oliguric renal failure. The delayed washout peaked at 4-5 days and did not return to normal until 8-9 days in the patients with severe oliguria; in the patients without severe oliguria the times were 1-2 days and 3-4 days, respectively. A characteristic "cart-wheel" pattern was observed during the washout stage in patients without severe oliguria. This "cart-wheel" pattern of washout is thought to result from relief of vasoconstriction and repair of tubular function. Multifocal "wedge-shaped" nonenhanced areas of the kidney, seen on the 2 week follow-up postcontrast CT, are thought to be ischemic zones due to persistent vasoconstriction. On the 6 week follow-up postcontrast CT in one patient, scarring of the kidney was detected in the same area that did not enhance on the 2 week CT. This scarring is thought to be a result of permanent vasoconstriction.     

Modulation of the peritoneal clearance of liposomal cytosine arabinoside by blank liposomes

Summary Liposomes containing cytosine arabinoside (ara-C) release drug slowly and can be used to maintain a locally high concentration of ara-C in the peritoneal cavity for intracavitary chemotherapy. However, a significant amount of active drug does reach the systemic circulation and contributes to systemic toxicity. We have devised a novel method of decreasing toxicity and increasing intraperitoneal half-life by pretreatment with blank liposomes containing no active drug. This technique has resulted in prolongation of intraperitoneal half-life of the liposomal ara-C from 21 h to 165 h, enabling maintenance of a therapeutic drug concentration even at 11 days after initial injection. One hundred percent cures (60-day survival) were achieved with a single-dose therapy begun 1 day after i. p. implantation of 10⁶ L1210 leukemia cells.Supported in part by Public Health Service grants CA-01082, CA-35309, and CA 23100 from the National Cancer Institute, National Institute of Health, DHHS. This work was conducted in part by the Clayton Foundation for Research, California Division. Stephen B. Howell is a Clayton Foundation Investigator     

Studies on the development of enzyme linked immunosorbent assay (ELISA) for hepatitis B surface antigen(HBsAg) by monoclonal antibodies of different affinity constants

Mouse monoclonal antibodies to Hepatitis B surface antigen(HBsAg) were prepared and their functional capabilities tested by the method of solid phase enzyme linked immuno sorbent assay(ELISA). HBsAg binding studies indicated that one monoclonal antibody 6E-1-1 bound more HBsAg at a faster rate than the other monoclonal antibodies. Also, for the binding inhibition studies with the selected monoclonal antibody 6E-1-1, one monoclonal antibody 8D-3-6 didn’t exhibit binding inhibition for HBsAg. Then, a simultaneous ELISA method was developed for the immunodiagnosis of HBsAg. Different combinations of two monoclonal antibodies as solid phase and horseradish peroxidase(HRPO) labeled phase were studied. The combination of monoclonal antibody of higher affinity constant (6E-1-1) immobilized in a solid phase and monoclonal antibody of lower affinity constant (8D-3-6) as a HRPO labeled phase was more sensitive when two monoclonal antibodies of different affinity constants for HBsAg were prepared.     

Acute toxicity in the guinea pig and in vitro "dioxin-like" activity of the environmental contaminant 1,2,4,5,7,8-hexachloro (9H)xanthene

A number of sites in the state of Missouri have been contaminated with polychlorinated dibenzodioxins and dibenzofurans as a result of improper waste-oil application for dust control. In addition to these compounds, relatively high levels of 1,2,4,5,7,8-hexachloro(9H)xanthene (1,2,4,5,7,8-HCX), a by-product of hexachlorophene manufacture, were also detected. Unlike the dibenzodioxins and dibenzofurans, no animal toxicity data are available on the chlorinated xanthenes. In view of the potential importance of this novel class of environmental contaminants, studies were conducted to examine the acute oral toxicity in guinea pigs and in vitro "dioxin-like" activity of 1,2,4,5,7,8-HCX. Animals administered a single oral dose of 0.02, 0.1, 0.5 or 2.5 mg 1,2,4,5,7,8-HCX/kg in corn oil and sacrificed 42 d later exhibited no treatment-related pathology. Guinea pigs given 12.5 mg/kg displayed mild to moderate distension and histologically observable subserosal edema of the urinary bladder, in addition to mild fatty vacuolization of pancreatic acinar cells. The alterations were considered to be of minimal toxicological significance. No compound- or dose-related mortality, body weight loss, or organ weight changes were noted at any dose level. Results using an in vitro bioassay for "dioxin-like" activity confirmed preliminary data suggesting that 1,2,4,5,7,8-HCX is about 10(6) times less potent than 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD) in this assay system. These findings indicate that 1,2,4,5,7,8-HCX may represent a relatively low environmental hazard compared to 2,3,7,8-TCDD.     

Acetylcholinesterase and manometry in the diagnosis of the constipated child

We studied 309 constipated infants and children who underwent rectal manometry (n = 261) and/or punch rectal biopsy, in which acetylcholinesterase histochemistry (n = 124) was compared with routine histologic examination (n = 93) for diagnostic accuracy. A 99% diagnostic accuracy was achieved with acetylcholinesterase histochemistry compared with 61% accuracy with routine hematoxylin-eosin staining on punch rectal biopsy. We recommend screening cooperative, quiet patients with rectal manometry. Most patients with abnormal manometric studies or those on whom manometry cannot be performed should have superficial punch biopsy (except those ill infants who require urgent operative intervention). This plan of management provides the least invasive but the most accurate evaluation of the constipated child. Deep rectal biopsy can be avoided except in the very rare child with hypoganglionosis or "skip-area" aganglionosis, which can be detected by manometry.     

Effect of phenothiazine derivatives on the thermotropic phase transition of liposomal phospholipid membrane

The effect of phenothiazine derivatives on the thermotropic transition of liposomal lipid bilayer made of dipalmitoyl phosphatidylcholine and dipalmitoyl phosphatidic acid was investigated with differential scanning calorimetry. The thermograms of the liposomal bilayer incorporated with levomepromazine, chlorpromazine, prochlorperazine, perphenazine and fluphenazine were obtained and the size of cooperative unit of the transition were calculated from the ratio of the van’t Hoff enthalpy change to the calculated enthalpy change of the transition. The results showed that incorporation of phenothiazine derivatives into the liposomal bilayer reduced the transition temperature at which the transition from solid state to liquid-crystalline state occurs, and broadened the thermogram peaks. Phenothiazine derivatives also significantly reduced the size of cooperative unit of the transition. The effect of the drugs was proportional to the concentration of the drug in the bilayer. This means that phenothiazine derivatives might have significant fluidizing effects on the biomembrane. The sizes of cooperative unit were successfully correlated with pharmacological activities of the drugs and the surface pressure increases of lipid monolayer by these drugs. These correlations might be ascribed to a possible hydrophobic nature of interaction between the biomembrane and the drugs involved in their pharmacology.     

Stereochemical aspects of diels-alder reaction of substituted penta-2,4-dienols and maleic anhydride derivatives

Reaction of diene alcohol5 and maleic anhydride in benzene at either room temperature or reflux proceeds probably through a intermolecular Diels-Alder cycloaddition followed by lactone formation to give adduct6.     

流行性脑脊髓膜炎的流行趋势变化与其疫苗接种

在过去几十年,随着疫苗的广泛使用,不同国家和区域引起流行性脑脊髓膜炎(简称流脑)病原体的血清群也发生了变迁。本文将脑膜炎球菌疫苗免疫接种、感染人群、不同区域和国家流脑的流行趋势及其内在机制研究进展进行综述,为进一步了解流脑流行趋势变化与其疫苗接种和后续制定免疫策略提供参考。