Photochemically induced binding of Rh(phen)2Cl2+ to DNA

The photoinduced covalent binding of the title compound to native and heat denatured DNA is described. The level of binding has been measured by UV (for DNA) and atomic absorption (for Rh) analysis. Quantum efficiencies of 6.4 x 10(-4) mol Rh per mol photons and 1.6 x 10(-3) mol Rh per mol photons have been determined for binding to native and denatured calf thymus DNA, respectively. Levels of bound rhodium as high as 1 molecule per five bases have been achieved. There is no binding of the complex in the absence of light, and there is evidence that at least a portion of the binding may be due to the photolytic conversion of the complex into one or more stable intermediates. Studies with polyribonucleotides indicate a strong preference for binding to the purine bases.

Survival rates among patients with cancer in Alberta in 1974-78

We calculated 5-year crude and relative survival rates, by age and sex, for patients in Alberta in whom cancer was diagnosed between 1974 and 1978. Cancers with low overall 5-year relative survival rates (less than 35%) included stomach cancer, cancer of the pancreas, lung cancer, brain cancer, multiple myeloma and myeloid leukemia. Cancers with high overall 5-year relative survival rates (more than 70%) included melanoma, breast cancer, cancer of the uterus, cancer of the bladder and Hodgkin's disease. Five-year relative survival rates were generally lower in the highest age group (75 years or more). A strong inverse relation between age and survival was noted for brain cancer, non-Hodgkin's lymphoma, Hodgkin's disease and myeloid leukemia.

HLA haplotype A1 B8 DR3 as a risk factor for HIV-related disease

Of 32 patients exposed to a single batch of factor VIII contaminated with human immunodeficiency virus (HIV), 18 became antibody positive. Serial T cell subset analyses over the succeeding four years have shown a progressive decline in circulating T4 cells in those 18 but no change in the 14 who remain seronegative. 2 of the seroconverters have died and a further 7 have symptoms attributable to HIV infection. In the group as a whole, the HLA haplotype A1 B8 DR3 was weakly associated with an increased risk of seroconversion on exposure to the virus while, in those who seroconverted, it was strongly associated with a rapid decline in T4 cells and development of HIV-related symptoms within four years of infection.

MR imaging of portal venous thrombosis: correlation with CT and sonography

Fourteen patients with portal venous thrombosis (PVT) diagnosed by CT and/or sonography were studied with MR. Three of the 14 had portal hypertension. The MR findings were compared with those of eight patients with portal hypertension, but without CT or sonographic evidence of PVT. MR imaging showed portal venous thrombosis in all 14 PVT cases. Intraluminal thrombi of less than 5 weeks duration appeared markedly hyperintense relative to liver and muscle on both T1- and T2-weighted images. Older thrombi appeared hyperintense relative to liver and muscle in eight of 11 cases, but only on T2-weighted images. MR showed thrombi in 11% more portal vessels than did CT (MR = 30, CT = 27) and in 28% more vessels than did sonography (MR = 32, sonography = 25). MR also showed 24% more collateral vessels than did CT (MR = 31, CT = 25) and 50% more vessels than did sonography (MR = 33, sonography = 22). Third-echo images (echo time = 96 msec, repetition time = 1500-2150 msec) verified the presence of venous thrombi in 28 (93%) of 30 PVT vessels, and they differentiated flow-related intravascular signal from true thrombi in six (17%) of 36 portal hypertension vessels. We conclude that MR is a valuable tool for imaging portal vein thrombosis. MR is a good substitute for CT and can be more informative than sonography.

Cis-urocanic acid, a product formed by ultraviolet B irradiation of the skin, initiates an antigen presentation defect in splenic dendritic cells in vivo

Urocanic acid (UCA, deaminated histidine) is a major ultraviolet-absorbing component of the stratum corneum. On UV irradiation, the naturally occurring trans form converts to the cis isomer. We have previously postulated that UV-induced systemic suppression is initiated by cis-UCA by way of an antigen-presenting cell defect. To test this hypothesis further, we have investigated the antigen-presenting cell (APC) function of splenic dendritic cells (DC). Splenic DC were prepared from mice 7 days after 1 h UV irradiation (27 kJ/m2) or i.v. administration of 50-200 micrograms/mouse of cis- or trans-UCA. Dendritic cells from UV-irradiated or cis-UCA-treated mice had a significantly impaired (APC) ability, assessed by the proliferative response of purified T cells from mice immune to DNP6 OVA to DC pulsed with this antigen. Dendritic cells from mice given trans-UCA had normal APC ability. The number of FcR+ cells was the same in DCs from all four treatment groups, and the number of IAd+ cells and the intensity of IAd expression were not decreased in DCs from UV-irradiated or cis-UCA-treated mice. Mixture of DCs from UV- or cis-UCA-treated mice with DCs from normal mice did not suppress APC activity. Dendritic cells taken 3 days after UV or cis-UCA treatment, in contrast to DC taken 7 days after treatment, had normal APC ability, indicating a time delay in the generation of the APC defect. In contrast, addition of cis-UCA or trans-UCA (66 micrograms/ml) directly to an in vitro proliferation assay had no effect, suggesting that cis-UCA may be activated in vivo. These results support our original hypothesis that cis-UCA has a natural role as a modulator of immune function.

Analysis of WAGR deletions and related translocations with gene-specific DNA probes, using FACS-selected cell hybrids

We used the fluorescence-activated cell sorter (FACS) to select a series of somatic cell hybrids with deleted or translocated chromosome 11 segregated from its normal homolog. Analysis of these cell hybrids with gene-specific probes and for cell-surface marker expression has allowed us to order the markers and define a smallest region of overlap (SRO) for deletions associated with the WAGR (Wilms' tumor, aniridia, genitourinary abnormalities, and mental retardation) region of chromosome 11. Two translocation breakpoints in 11p13 (one associated with familial aniridia and one with a sporadic case of congenital renal dysfunction resulting from urethral and ureteral atresia) map within this SRO.

Risk factors for hypertension: results from a cross-sectional survey

A case-control study of hypertension was conducted, using as a sampling frame a cross-sectional survey of Canadian Federal civil servants. Three case groups were selected, based on prior knowledge of hypertensive status and measured blood pressure. A 3-to-1 matching scheme was employed. Data was analysed using a logistic regression model. Statistically significantly elevated odds ratios, in excess of 3.0, were noted for overweight or obese status. Other odds ratios associated with a significantly increased risk of hypertension were maternal and paternal history of hypertension and current cigarette smoking.

Adoptive immunotherapy for stage IV renal cell carcinoma: a novel protocol utilizing periodate and interleukin-2-activated autologous leukocytes and continuous infusions of low-dose interleukin-2

In a pilot study involving 13 patients with advanced stage IV renal cell carcinoma, anti-tumor effects and toxicity of a novel form of adoptive immunotherapy were determined. The protocol utilizes infusions of autologous mononuclear leukocytes treated with the oxidizing mitogen sodium periodate (IO4-) and cultured in medium containing human recombinant interleukin-2 (IL-2), and continuous infusions of low-dose IL-2 (mean +/- SD dose = 39.5 +/- 8.6 X 10(3) U/kg/24 hours). Leukocytes (5 to 10 X 10(9] were removed by leukapheresis three times per week, mononuclear cells were separated, activated with IO4- and cultured in medium containing IL-2 (500 U/ml) for 48 to 72 hours. The cells were re-infused following the next leukapheresis procedure. IL-2 was administered five days per week. Treatment was continued for two three-week cycles. An increase in peripheral blood mononuclear cells bearing the natural killer cell (NK) surface marker, Leu 11, an increase in NK- and antibody-dependent cell-mediated cytotoxicity, and a slight increase in spontaneous cytotoxicity for non-NK targets were noted. Regressions (more than 50 percent decrease in tumor mass) of pulmonary, liver, bone, or soft tissue metastases were induced in six patients. Severe fluid retention did not develop in any patient and no patient required treatment in the intensive care unit. Five of the patients who showed a response have experienced a relapse at 5.2 +/- 1.0 (mean +/- SD) months. These observations indicate that IO4-/IL-2-activated killer cells plus continuous infusions of low-dose IL-2 can result in regression of metastatic renal cell carcinoma.

Increased rates of illness and death from asthma in Canada

Recent rates of illness and death from asthma in Canada and rates of hospital admission/separation for asthma were examined by age group and region. The death rates were higher in 1982-84 than in 1970-72, especially among those aged 15 to 34 years. Increases were also noted in hospital admission/separation rates, especially among those less than 15 years of age. Hospital admission/separation rates were highest in the Maritime provinces and Saskatchewan, whereas death rates were highest in Alberta and Saskatchewan. Examination of death certificates for coding errors and recoding of certificates to a single (8th) revision of the International Classification of Diseases indicated that changes in disease coding and errors in coding did not account for the significant increase in rates of death from asthma for those aged 15 to 34 years. These increases in rates of illness and death from asthma are unexplained and warrant further investigation.

Perirenal spaces: CT evidence for communication across the midline

The perirenal spaces may communicate across the midline, anterior to the lower aorta and vena cava. The connecting channel has a relatively narrow anteroposterior dimension on computed tomographic (CT) scans, both in vivo and in injected cadavers. It may therefore be difficult to visualize on abdominal radiographs and may be mistaken for unopacified bowel on CT scans. The midline extension of perirenal fluid is usually contiguous to the lower abdominal great vessels anteriorly but does not surround them completely, possibly because of fibrous septa within the perivascular fat. Hematomas from ruptured aortic aneurysms extend mainly into the perirenal spaces. Thus, the lower abdominal great vessels are located, in effect, within the midline extension of these spaces. Superiorly, the perirenal spaces extend to the diaphragm, abutting the lateral and anterior margins of the psoas and quadratus lumborum muscles and the bare area of the liver. Inferiorly, perirenal collections appear to diverge into the pelvis, along the psoas muscles, ureters, and iliac vessels.

Stereospecific inhibition of human epidermal cell interleukin-1 secretion and HLA-DR expression by cis-urocanic acid

UV radiation is known to photoisomerize trans-urocanic acid (trans-UCA) into a stable isomer, cis-urocanic acid (cis-UCA). To study the possible immunomodulatory effects of cis-UCA, the two isomers were added separately to different in vitro assays employing human epidermal cell suspensions or purified human peripheral T lymphocytes, supplemented with epidermal cells. Cis-UCA but not trans-UCA suppressed interleukin-1 (IL-1) production by epidermal cell suspensions in a dose-dependent fashion and diminished the number of HLA-DR positive epidermal cells to 61% of control values. An inhibitory effect on epidermal cell accessory function could be demonstrated with both isomers of UCA, but only if UVB-irradiated epidermis was used as a source for the epidermal cells. Taken together, the findings of our study lend indirect support to the concept of cis-UCA as a possible mediator of UV-radiation-induced immunosuppression.

Important risk factors for death in adults: a 10-year follow-up of the Nutrition Canada survey cohort

Data on mortality among over 8000 Canadians aged 35 to 79 years who participated in the Nutrition Canada survey are presented. The effects of various risk factors on mortality were assessed with a multivariate Poisson regression analysis. Factors associated with a significantly increased risk of death over a 10-year follow-up period ending in 1981 included cigarette smoking, hypertension and diabetes mellitus. A shallow U-shaped mortality pattern was observed for body mass index and for serum cholesterol level. No statistically significant increases in risk were associated with alcohol consumption. The population attributable risks for smoking, hypertension and diabetes were 39%, 8% and 6% respectively for men and 21%, 12% and 7% respectively for women.

Conjugation of organic compounds in isolated hepatocytes from a marine fish, the plaice, Pleuronectes platessa

A method is described for the preparation of viable hepatocytes from a marine fish, the plaice. Their ability to detoxify organic compounds was measured by the formation of glucuronic acid and sulphate conjugates with the model substrates 1-naphthol and phenolphthalein. 1-Naphthol was conjugated three- to four-fold faster than phenolphthalein and glucuronidation predominated with both substrates. Strong substrate inhibition of glucuronidation was observed with 200 microM 1-naphthol or phenolphthalein. No measurable sulphate conjugation was detected with phenolphthalein. Treatment of fish with 3-methylcholanthrene induced formation of both glucuronide and sulphate conjugates by two- to three-fold. Compared with rat hepatocytes, the extent of sulphation was 100-fold lower in plaice hepatocytes whereas glucuronide formation was only 10-fold lower. The observations indicate that isolated plaice hepatocytes provide a suitable system for studies of the detoxication of xenobiotic pollutants in fish liver.

Induction of cell damage by menadione and benzo(a)pyrene-3,6-quinone in cultures of adult rat hepatocytes and human fibroblasts

The cytotoxicity of menadione (2-methyl-1,4-naphthoquinone) and benzo(a)pyrene-3,6-quinone (BP-3,6-Q) was tested in cultures of adult rat hepatocytes and human fibroblasts. Menadione induced DNA strand breaks, cell membrane damage and depletion of reduced glutathione (GSH) in both hepatocytes and fibroblasts. In fibroblasts, effects on both DNA and membrane integrity were potentiated by the presence of dicoumarol, a specific inhibitor of the 2-electron reduction of quinones by DT-diaphorase, whereas in hepatocytes only the cell membrane damage was sensitive to dicoumarol. Results indicate that menadione toxicity is mediated via 1-electron reduction, although in hepatocytes different reactive species may be responsible for damage to DNA and to the membrane. BP-3,6-Q induced DNA strand breaks in fibroblasts at concentrations as low as 1 microM. The extent of DNA damage was insensitive to dicoumarol. Even after GSH depletion and inhibition of glucuronidation and sulphate conjugation, BP-3,6-Q caused no DNA damage in hepatocytes. In contrast to menadione, BP-3,6-Q did not induce cell membrane leakage or decrease in GSH levels in either hepatocytes or fibroblasts. These studies show the complexity of the metabolic pathways involved, in terms of activation and detoxification processes, in the toxicity of quinones.

Photochemistry and photobiology of urocanic acid

E-Urocanic acid is a metabolite of histidine which accumulates in the skin and is excreted in sweat. It has been of interest to photobiologists and photodermatologists because of its intense absorption band at approximately 270 nm, a feature suggestive of a role as a natural photoprotecting agent for DNA. Early work concentrated on the E----Z isomerization resulting from UV excitation. Recent studies have revealed additional, potentially significant, photobiological properties, i.e. photochemical binding to DNA and an apparent involvement of the Z isomer in the phenomenon of photoimmunosuppression.

Induction of DNA damage by menadione (2-methyl-1,4-naphthoquinone) in primary cultures of rat hepatocytes

The cytotoxicity of menadione (2-methyl-1,4-naphthoquinone) had been investigated using primary cultures of rat hepatocytes. Menadione was found to induce DNA strand breaks which were actively repaired by the cells. Dicoumarol, an inhibitor of DT diaphorase, did not potentiate menadione-induced DNA strand breaks. Neither had metyrapone, an inhibitor of cytochrome P-450 dependent monooxygenases, any effect on the extent of DNA damage. Covalent binding of menadione metabolite(s) to DNA was detected in the cultured hepatocytes and, in addition, hepatic microsomes were also found to metabolize menadione to DNA-binding products. The extent of binding of menadione to DNA in vitro, was markedly decreased by inclusion of the hepatic cytosol fraction, or reduced glutathione, in the incubations. In the presence of dicoumarol, menadione was also found to induce cell membrane damage. It also caused a rapid loss in cellular glutathione which was augmented by the presence of dicoumarol. The results suggest that both the cell membrane damage and DNA damage induced by menadione are mediated by one-electron reduction of the quinone to free radical intermediate(s). DT diaphorase appears to protect the cell from membrane damage, whereas reduced glutathione may have an important role in the prevention of DNA damage.

Wrist disarticulation of a deformed hand: appropriate prosthesis and the habilitation of a severely retarded young man

A 24-year-old man, who was late attaining developmental milestones and tested in the severely mentally retarded range, had incurred third- and fourth-degree burns at 2.5 years that resulted in a deformed, anesthetic, and useless distal left upper limb. Following wrist disarticulation, he was fitted with a cosmetic prosthesis that he accepted enthusiastically. It permitted him to use his left upper limb as an effective assister. Attempts to wear and use a functional prosthesis were not successful because the bulbous stump was covered with abnormal skin that ulcerated whenever he wore the prosthesis. At present, he resides at home with his mother and has all self-care skills. He attends a day treatment program and helps his mother with household chores as well as neighborhood errands. The prognosis for continued functional improvement is good, even though he remains severely mentally retarded.

Status of reduced glutathione in primary cultures of rat hepatocytes and the effect on conjugation of benzo[a]pyrene-7,8-dihydrodiol-9,10-oxide

The intracellular level of reduced glutathione (GSH) and GSH conjugation have been investigated in primary cell cultures of hepatocytes isolated from control rats, phenobarbitone (PB) and 3-methylcholanthrene (MC) treated rats. The data demonstrate that in all cell cultures the GSH concentrations show a triphasic pattern: (i) within 1 h of culture an initial marked decrease to 50% of the levels found in fresh hepatocytes; (ii) recovery of GSH concentrations to above the levels observed in fresh cells. This occurs after 6 h in culture with control cells and after 10-24 h with cells from either PB or MC treated rats and was most prominent in cells from PB-treated rats. (iii) A slow decline to between 30 and 40 nmol GSH/mg protein from 24 to 96 h in culture. Synthesis of GSH was slower in cultured cells from PB treated rats and this was confirmed by the resynthesis rates when diethylmaleate (DEM) was used to deplete GSH. The formation of GSH conjugates with racemic 7 beta,8 alpha-dihydroxy-9 alpha,10 alpha-epoxy-7,8,9,10-tetrahydrobenzo[a]pyrene (BPDE) was measured in control cells in suspension and after 3 and 24 h in culture. Despite the decrease in GSH concentrations observed between 1 and 4 h after culture, the conjugation rates were not decreased.

Thyrotropin releasing hormone: antagonism of pentobarbital narcosis in the monkey

The effect of TRH on pentobarbital narcosis in 21 rhesus monkeys was examined. Vital signs monitored included respiration rate, heart rate, temperature, sleeping time,and time of reappearance of certain reflexes. Blood samples were obtained for pentobarbital assay. Two dose schedules for TRH administration were used. One group of 6 animals received a single dose of 20 mg/kg 30 min after barbiturate administration, while the other group were received 3 injections of 20 mg/kg spaced at 30, 40 and 50 min after injection of pentobarbital. Both groups were sex balanced. TRH administration resulted in dramatically increased respiration and heart rates and arrested the progress of barbiturate induced hypothermia. The extended dose schedule prolonged increased respiration rate and a differential effect of TRH on pentobarbital induced hypothermia across sexes was observed. All animals regained reflexes sooner and sleeping time was reduced by 22%. No differences in pentobarbital blood levels with TRH were observed. These results extend earlier work in rodents to primates and suggest a possible use of TRH in cases of acute barbiturate intoxication.