Cardiac physiologic-metabolic changes after chronic low-level heavy metal feeding

Female Long-Evans hooded rats received 0 or 5 parts per million Cd, Pb, or Cd + Pb in the drinking water from weaning to 20 mo. Growth, measured as body weight, and organ weights were comparable among heavy metal and control animals. Indirect blood pressure responses measured trimonthly are discussed. Analysis of His bundle electrograms (HBE) and electrocardiograms recorded in sodium pentobarbital-anesthetized animals at 20 mo demonstrated that Cd selectively depressed conduction system excitability proximal to the common His bundle (atrioventricular node region), whereas Pb and Pb + Cd impaired conductivity distal to the common His bundle (His-Purkinje system). Perchloric acid extracts of liquid N2-freeze-clamped isolated perfused hearts, derived from a subpopulation of control and Cd-fed rats in which HBE analyses were not performed, were analyzed by phosphorus-31 nuclear magnetic resonance (31P-NMR) spectroscopic techniques to quantitate [31P]phosphate metabolite profiles. Cardiac active tension and atrioventricular node excitability were depressed in the Cd group. High-energy phosphate and glycerol 3-phosphorylcholine concentrations were depressed. Results demonstrate potentially significant pathophysiological changes within cardiovascular tissues that develop in the absence of overt heavy metal toxicity manifestations.

Oedeme bleu: a reappraisal

The case-histories of four patients with self-induced lymphoedema show a distinctive organic syndrome, but the underlying mental mechanisms in these patients show no common thread other than an apparent wish to draw attention to an untreatable condition. A policy of non-intervention may reduce or limit the eventual disability.

Additional properties of a soluble polymer of glucose from cultures of Acetobacter xylinum

The results of differential, thermal analysis of a soluble, beta (1 leads to 2)-branched, beta (1 leads to 4)-D-glucan isolated from cultures of Acetobacter xylinum are consistent with previous conclusions about its structure. The O-acetyl content of the polymer is 8.3% which corresponds to a maximum substitution of one acetyl group per three glucose residues. Proton nuclear magnetic resonance spectra confirm that all the glycosidic bonds are beta linkages. Some preparations of the polymer are contaminated by another polymer containing mannose and rhamnose. No evidence was obtained to support a previous suggestion that the branched D-glucan is a precursor of bacterial cellulose and this suggestion is now withdrawn.

Histone deacetylation in nuclei isolated from hepatoma tissue culture cells. Inhibition by sodium butyrate

Nuclei from hepatoma tissue culture (HTC) cells were isolated by standard methods and incubated in media commonly used for nuclease digestions (DNAase I and micrococcal nuclease) and for in vitro RNA synthesis. During the incubation, histones can be deacetylated from both control cells and cells treated with 6 mM sodium butyrate to enhance the levels of histone acetylation. Deacetylation of histone is much more apparent in nuclei isolated from sodium butyrate-treated cells. Inclusion of 6 mM sodium butyrate in the incubation medium effectively inhibits the endogenous deacetylase activity acting on histones H3 and H4, whereas sodium acetate at the same concentration has very little inhibitory effect.

Technical aids as an economic alternative

Interest in technical aids is growing. Occupational therapists are beginning to play a role in this area. Four programs in which occupational therapists are involved in Canada are described. The programs are: 1. a province-wide, private agency supported program 2. a university based research project funded by a provincial government 3. a technical aids component of the rehabilitation program at a Regional Rehabilitation Centre. 4. a private consulting business. The economic implications of each program are examined to determine whether the program can be justified economically and whether the occupational therapist can justify economically, adding involvement with technical aids to their existing role.

Thyroid function in patients with breast cancer

Thyroid function has been assessed in 40 patients with breast cancer and compared with an age-matched control female population. The free thyroxine index was lower and the level of thyroid-stimulating hormone in the serum higher in the cancer group and these changes became more marked at 6 months. It is concluded that patients with breast cancer show more evidence of hypothyroidism as time progresses.

Malignant neoplasms in the families of patients with ataxia-telangiectasia

Ataxia-telangiectasia (A-T) is an autosomal recessive syndrome associated with a greatly increased incidence of malignant neoplasms in homozygous affected individuals. Heterozygotes for the gene for A-T are thought to comprise about 1% of the general population and, therefore, it is important to know whether this gene also predisposes the heterozygous carrier to cancers. Heterozygous carriers of this gene are common among the close relatives of patients with A-T, although individual carriers cannot be identified by any clinical criterion or laboratory test. For this reason, we compared the incidence of death from malignant neoplasms in 2 families of patients with A-T to that expected in a random sample of the general population. There were 59 deaths from malignant neoplasms in relatives dying before age 75, compared to 42.6 expected (p less than 0.02). For A-T heterozygotes younger than age 45, the risk of dying from a malignant neoplasm was estimated to be greater than 5 times the risk for the general population. A-T heterozygotes may comprise more than 5% of all persons dying from a cancer before age 45. The incidence of ovarian, gastric, and biliary system carcinomas and of leukemia and lymphoma was increased in these A-T families. Other neoplasms that may be associated with this gene in heterozygotes include pancreatic, basal cell, colonic, breast, and cervical carcinomas.

The chick embryo in studies of virulence and immunity with Neisseria Gonorrhoeae

Intravenous inoculation of 11-day old chick embryos with Neisseria gonorrhoeae has confirmed the original observation of Bumgarner and Finkelstein that T1 and T2 gonocci are significantly more virulent than T3 and T4. Pili do not seem to be solely responsible for this virulence, since elimination of pili did not effect either the viability or the virulence of N. gonorrhoeae. In neutralization studies, there was only one log difference between the ability of normal and hyperimmune rabbit serum to protect the embryo against gonoccocal infection. However, when mouse sera were used in the same chick embryo system a clear difference was noted between the protective activity of normal serum and that antisera elicited in mice by purified gonococcal antigens. It is suggested therefore that mouse antisera be used in this chick embryo model for the assay for gonococcal antigens.

Intestinal absorption following small-bowel resection

Proximal or distal small-bowel resection was performed on female Wistar rats. Water, glucose, electrolyte, and bile acid absorption from the perfusate was studied in bile-fistula sham-operated rats and in animals 3 months after intestinal resection, using an in-vivo recirculation perfusion system. The jejunum and caecum, but not the colon, showed adaptive increases in intestinal absorption after resection of the ileum, and supranormal bile acid absorption and enhanced glucose, water, and electrolyte absorption were demonstrated in the ileum after jejunal resection. The improvement in diarrhoea observed in some patients after right hemicolectomy may be due to compensatory changes in the residual colon; rectal mucosal thickness becomes significantly increased after right hemicoletomy.

Evaluation of breast tumour sex chromatin (Barr body) as an index of survival and response to pituitary ablation

In a retrospective study of 36 patients with advanced oreast cancer relationships were found between the cumour Barr body count and the response to pituitary ablation and the length of survival. High tumour Barr body counts were associated with long survival after treatment, and low counts with short survival. (P < 0.001). High counts were also associated with a good response to pituitary ablation, and low counts with a poor response (P < 0.01). The tumour Barr body count gave possibly better prediction than urinary steroid measurement.

Congenital duodenal diaphragm in the adult: review of the literature and report of a case

Images