Cigarette smoke causes inhibition of the immune response to intratracheally administered antigens

Chronic inhalation of cigarette smoke in rats preferentially inhibited the plaque-forming cell (PFC) response of lung-associated lymph nodes (LALN) to sheep red blood cells (SRBC), compared to anatomically distant lymph nodes. Inhibition of the antibody response in LALN of smoke-exposed animals was first detected at 21 weeks of smoke inhalation and was well established by the 27th week of smoke exposure. After prolonged exposure (greater than 34 weeks) to cigarette smoke, similar smoke-induced changes in PFC response took place in other lymphoid tissues as well. Cigarette smoke affected the response of LALN cells to a T cell-dependent antigen (SRBC). Exposure to cigarette smoke, however, did not alter the relative percentages of W3/13-positive (T cells) or Ig-positive (B cells) cells, nor did it alter the relative percentages of T cell subsets as scored by their surface phenotypes, i.e., T helper (W3/25+) or T suppressor/cytotoxic (OX-8+) cells. The percentage of phagocytic cells and the accessory cell functions of macrophages remained comparable between sham and smoke-exposed animals. Exposure to cigarette smoke did not significantly alter the response of LALN cells to T cell mitogens (concanavalin A and phytohemagglutinin). However, response to a T cell-independent antigen trinitrophenyl Brucella abortus was also significantly reduced. These results show that cigarette exposure in the rat results in a decreased antibody response and this exposure to cigarette smoke may primarily affect the B cell function.     

Ontogenic changes in hepatic glutathione and metallothionein in rats and the effect of a low-sulphur-containing diet

Metallothionein contains about 30% cysteine and is a major protein in newborn rat liver. This protein and glutathione constitute two major intracellular cysteine pools in newborn rat liver. When pregnant rats were fed on a soya-bean-protein diet, low in sulphur amino acids, the hepatic glutathione levels of the dams were decreased. However, this did not affect the levels of glutathione or metallothionein in the pups. The activity of the glutathione-degrading enzyme gamma-glutamyltransferase (EC 2.3.2.2) in the livers of pups was maximum at birth and gradually decreased with age when the hepatic glutathione was transported to the kidney. In the pups born from dams fed on soya-bean-protein diet the decline in the hepatic enzyme activity was delayed, suggesting a continued degradation of glutathione in the liver. These results suggest that even with a maternal nutritional deficiency of sulphur amino acids, the transfer of cysteine to the fetus is not impaired. However, the hepatic intra-organ degradation of glutathione is continued in these pups for a prolonged period after birth compared with pups born from control mothers. The increased degradation of glutathione in the liver may be essential to meet the requirement of cysteine in pups born from dams fed on the soya-bean-protein diet.     

Motility of the human ureter, with special reference to the effect of indomethacin

Ureteral motility was studied in isolated preparations obtained from 19 patients at surgery. Contraction was monitored in an organ bath and contraction recorded isometrically. In all but one patient rhythmic activity with a frequency of 2.0 +/- 0.3 contractions/min was recorded. In 6 patients contractions had to be elicited by stimulation with prostaglandin E2 or F2 alpha. In the remaining cases motility started spontaneously within 30 min. In patients with bilharzia nephropathy various pathological types of contraction were recorded. Motility was dose-dependently inhibited with indomethacin.     

Detergent induced lysis of erythrocytes in kwashiorkor

The effect of the non-ionic detergent Nonidet P40 on lysis of erythrocytes in children suffering from kwashiorkor was studied. The concentration of the detergent causing 50% haemolysis was significantly reduced in these patients. Detergent haemolysis was more sensitive than osmotic fragility (which was reduced). The abnormality was only slight in marasmic children.     

Tuberculosis in the elderly.

A study of 120 cases of tuberculosis in patients aged 65 years and above revealed that there were more males than females with the disease compared with the younger age group of 15 to 45 years old. The elderly group also had significantly more severe and more had bacteriologically positive disease. The majority of them were born outside Singapore and immigrated more than 30 years ago. Risk factors such as diabetes mellitus, past history of tuberculosis, malignancy and gastrectomy were more common in the elderly group. Standard 6-month regimens were well tolerated and adverse side effects to the drugs were negligible.     

Turnover of parenterally administered zinc and cadmium and the redistribution of metallothionein bound zinc in newborn rats

The whole body retention, tissue distribution and protein binding patterns of 65Zn were compared with 109Cd in newborn rats during postnatal development. One-day-old pups received a single injection of either 65Zn (2.5 microCi) or 109Cd (2.5 microCi plus 1 mg Cd/kg as CdCl2). During the 22 days of age, the whole body retention of 109Cd was higher than that for 65Zn. The biological half times were 466 and 46.3 days for 109Cd and 65Zn, respectively. There were marked differences in tissue deposition of these metals. Both liver and kidney accumulated more 109Cd than other tissues while the 65Zn showed a uniform distribution, with a gradual decrease in radioactivity with age. At the time of weaning, 109Cd had accumulated mainly in liver and kidney whereas, 65Zn was found predominantly in bone and skin. The specific binding of 109Cd to hepatic MT in newborn rats did not change with growth. Although a significant amount of 65Zn initially accumulated in the MT fractions in the liver, it was transferred gradually to high molecular weight protein fractions during development. The administration of these 2 metals had no effect on the body weight, liver weight and total hepatic zinc concentration. However, a significantly high content of MT and zinc in MT fractions was detected in the livers of Cd-treated rats at 22 days of age. The results show the transfer of the essential metal, zinc from hepatic MT to other proteins and the specific binding of cadmium, the non-essential metal to MT during postnatal development in rats.     

Metallothionein induction is not involved in cadmium accumulation in the duodenum of mice and rats fed diets containing high-cadmium rice or sunflower kernels and a marginal supply of zinc, iron, and calcium

Rats fed diets with cadmium (Cd) concentrations similar to that found in human diets, and nutritionally marginal with respect to iron (Fe), zinc (Zn), and calcium (Ca) retained 10 times more Cd in the duodenum than rats fed adequate mineral diets. In the current study, 2 experiments were performed to determine the role of intestinal metallothionein (MT) in the accumulation of duodenal Cd, and to determine whether endogenous rice grain Cd is as available as Cd exogenously incorporated into the grain. In Expt. 1, wild-type and MT-null mice were fed 40% rice diets containing marginal or adequate amounts of Fe, Zn, and Ca, and 240 mug Cd/kg. Duodenal Cd was 10 times higher in both wild-type and MT-null mice regardless of their mineral status. In Expt. 2, one group of rats was fed 40% rice diets in which Cd was incorporated into the rice during growth and maturation, and another group was fed 40% rice diets in which Cd was incorporated into the rice during cooking. Each group also was fed either marginal or adequate amounts of Zn, Fe, and Ca. After 5 wk, rats were given a single meal labeled with (109)Cd, and the amount of label retained after 7 d was determined by whole-body counting. Rats with marginal mineral status retained 10 times more (109)Cd than those with adequate status; however, there was no difference between rats fed endogenous or exogenous Cd rice. Although duodenal Cd concentration was 8 times higher in the marginally fed rats, MT concentration was unchanged. These 2 experiments indicate that MT induction is not involved in duodenal Cd accumulation in animals with marginal dietary status of Fe, Zn, and Ca. In addition, they support the hypothesis that marginal deficiencies of Fe, Zn, and Ca, commonly found in certain human populations subsisting on rice-based diets, play an important role in increasing the risk of dietary Cd exposure.