Establishing albumin levels in sheep serum by a specific fluoroimmunoassay.

A rapid and sensitive fluoroimmunoassay (FIA) was developed to measure albumin levels in sheep serum. The assay employed ovine albumin labelled with fluorescein as the tracer and a rabbit antiserum raised against sheep albumin. Separation of antibody-bound from free albumin was achieved using a second antiserum directed against the Fc component of rabbit IgG.

Connexin 43 expression in normal and irradiated mouse skin.

The expression of connexin 43 (Cx43) in normal and irradiated mouse skin was evaluated using immunofluorescence with polyclonal antisera to Cx43 on cryostat sections. One week after the start of daily irradiation with 3 Gy, enhanced immunoreactivity in basal cells and in the lower part of the spinous layer of the epidermis was detected. In hypertrophic and hyperplastic skin, about 3 weeks after irradiation, a further increase in the expression of Cx43 was found in the epidermis as well as in the dermis.

Modified low density lipoprotein is a potent stimulus for smooth muscle cell outgrowth from rat aortic explant in vitro.

Outgrowth of vascular wall cells from rat aortic tissue explant was studied. In addition to fresh rat serum (3%), the complete culture medium contained either low density lipoprotein (LDL) separated from rat plasma (n-LDL, 100 microg/ml) or rat LDL modified either by activated rat polymorphonuclear leucocytes (pmn-LDL) or by exposure to UV light (uv-LDL). Compared to n-LDL, pmn-LDL significantly increased the start of cell outgrowth and the further rate of growth.

Evidence for nitric oxide participation in down-regulation of CYP2B1/2 gene expression at the pretranslational level.

Septic or inflammatory stimuli suppress drug metabolism by cytochrome P-450 in the liver, presumably at the pretranslational level. We have shown previously that nitric oxide is responsible at least in part for the inhibition by bacterial lipopolysaccharide of phenobarbital-induced CYP2B1/2 activity in vivo. This was attributed to the interaction of nitric oxide with heme in the active-center of cytochrome P450, leading to enzyme inactivation.

Changes in keratinocyte differentiation during accelerated repopulation of the irradiated mouse epidermis.

Epidermal stem cells accelerate their repopulation rate during fractionated irradiation. To study the changes in keratinocyte differentiation associated with radiation-induced repopulation, we investigated the expression of a panel of 14 monoclonal or polyclonal antibodies against keratins, involucrin and others, as well as the expression of 15 lectins in the irradiated mouse leg skin. Tissue samples were collected after 1, 2, and 3 weeks of daily irradiation with 3 Gy per fraction.

Exposure to ultraviolet B radiation increases the tolerance of mouse skin to daily X irradiation.

Based on the hypothesis that acceleration of repopulation in skin during fractionated irradiation is triggered by an inflammatory response of the dermis to radiation-induced epidermal hypoplasia, we produced a mild erythema by exposure to UVB radiation before applying different X-irradiation schedules. At different times ranging from 6 h to 14 days after a single exposure to UVB radiation which caused a distinct erythema, a 2-cm skin field on the legs of mice was irradiated with either different single doses or five daily fractions of 3 Gy followed by different single top-up doses of 300 kV X rays. Skin reactions were scored daily for 4 weeks and the occurrence of moist desquamation was taken to construct dose-response curves and to calculate ED50 values.

Rheumatology and medical education in Great Britain.

Rheumatology has been relatively under-represented in UK medical school curricula to date. The incidence of rheumatic disease in the community is not reflected by the amount of time spent on it in undergraduate medicine. In addition, the emphasis in medical colleges is on the less common conditions like systemic lupus erythematosus and vasculitis, rather than the commoner treatment of sore shoulders and backs.

Changes in network composition among the very old living in inner London.

This article examines changes over time in social network composition among a sample of people aged 85 and over at baseline interview in 1987, who were followed-up two and a half to three years later. Almost half of respondents at follow-up had smaller networks than in 1987, with 19% having fewer relatives in their networks, 30% having fewer friends, and 26% also having fewer confidants. However, for most (84%) there was no change in whether they could name a main helper.

Modulation of heme oxygenase activity in rat brain and spleen by inhibitors and donors of nitric oxide.

The capacity of nitric oxide to activate or inhibit metalloprotein-containing enzymes underlies many of its biological actions. Heme oxygenase, involved in a variety of biological processes, does not contain heme but utilises it as a substrate. The substrate for nitric oxide, L-arginine (0.

[The effect of x-rays on experimental arthritis in the rat].

Aims: We investigated the therapeutic efficacy of low doses of X-rays on different in-vivo models of monoarticular arthritis which have been developed for the investigation of anti-inflammatory drugs.

Material And Methods: Zymosan or heat-inactivated mycobacterium tuberculosis was injected into 1 knee joint of Wistar rats to produce, via different pathogenetic mechanisms, an acute monoarticular arthritis. Five days later, the amount of joint swelling, bone destruction and cartilage catabolism were measured.

Epidermal morphology, cell proliferation and repopulation in mouse skin during daily fractionated irradiation.

In mouse, a 2 cm long field of both legs was irradiated daily with 3 Gy, five fractions per week for up to 3 weeks. Epidermal morphology, the circadian variation of the labelling index, and repopulation were determined at the end of each week. After a decrease of epidermal cellularity in the first week, excessive regeneration led to hyperplasia and hypertrophy, which continued throughout the experimental period while the residual tolerance of the epidermis to top-up irradiation decreased progressively.

Does folic acid harm people with vitamin B12 deficiency?

Oral folic acid given before and during pregnancy can prevent about 75% of fetal neural tube defects. Even in large dose (20 mg daily) folic acid has never been shown to harm normal people, but it has acquired a bad reputation in pernicious anaemia. Before 1930, if untreated patients survived the anaemia, they succumbed to peripheral neuritis, subacute combined degeneration of the spinal cord, and death.

Translocation of particulates across the gut wall--a quantitative approach.

The translocation of latex particles across the epithelium of the rat small intestine and their transfer to internal organs was determined and quantified. The rate of particle uptake was also established. Particle uptake from the gut lumen to internal tissues was rapid as they were detected in all tissues examined within 30 minutes of oral administration.

Inhibition of ETB receptors limits the efficacy of nonselective endothelin antagonists in vivo.

Endothelin-1 (ET-1) produces vasoconstriction via activation of ETA and ETB receptors on vascular smooth muscle, and vasodilatation via ETB receptors on endothelial cells. Here we have used the selective ETA receptor antagonist BQ-123, the selective ETB receptor antagonist BQ-788 and the nonselective ETA/ETB receptor antagonist PD 145065 to study the role of these receptors in mediating the hemodynamic changes induced by an infusion of ET-1 to the anesthetised, ganglion-blocked rat. ET-1 (10 pmol/kg/min) infused for 70 min induced an increase in the mean arterial pressure (MAP) and total peripheral resistance (TPR), as well as a fall in cardiac output (CO).

Activation of the phagocytic system increases intimal proliferation in hypercholesterolemic rabbits.

The effect of in vivo stimulation of the phagocytic system (neutrophils, monocytes and hepatic Kupffer-cells) by inducing phagocytosis of intravenously administered latex particles on lipid peroxidation and aortic intimal proliferation was tested in cholesterol-fed rabbits. Three weeks after starting the diet, aortic intimal proliferation was measured by the intimal to medial ratios and by the incorporation of [3H]thymidine, infused into the circulation for the preceding 14 days. Intimal to medial ratios were increased (0.

Clonal heterogeneity in the progeny of HeLa cells which survive X-irradiation.

Clones of HeLa cells that had survived 9 Gy X-rays were investigated for plating efficiency, radiosensitivity, the proportion of giant cells, and chromosome numbers. A significant decrease in plating efficiency was observed that persisted for > 20 population doublings. The reduced plating efficiency was associated with an increased proportion of giant cells in the colonies.

Assessing possible hazards of reducing serum cholesterol.

Objective: To assess whether low serum cholesterol concentration increases mortality from any cause.

Design: Systematic review of published data on mortality from causes other than ischaemic heart disease derived from the 10 largest cohort studies, two international studies, and 28 randomised trials, supplemented by unpublished data on causes of death obtained when necessary.

Main Outcome Measures: Excess cause specific mortality associated with low or lowered serum cholesterol concentration.

By how much and how quickly does reduction in serum cholesterol concentration lower risk of ischaemic heart disease?

Objective: To estimate by how much and how quickly a given reduction in serum cholesterol concentration will reduce the risk of ischaemic heart disease.

Design: Data on the incidence of ischaemic heart disease and serum cholesterol concentration were analysed from 10 prospective (cohort) studies, three international studies in different communities, and 28 randomised controlled trials (with mortality data analysed according to allocated treatment to ensure the avoidance of bias).

Main Outcome Measure: Decrease in incidence of ischaemic heart disease or mortality for a 0.

Dietary fat induces changes in factor VII coagulant activity through effects on plasma free stearic acid concentration.

Previous studies have demonstrated activation of the contact system of coagulation and an increase in factor VII coagulant activity (VIIc) when citrated plasma is incubated in the presence of micellar stearate. The products of contact activation, factors XIIa and IXa, were responsible in this system for the activation of factor VII, thereby increasing factor VIIc. To obtain evidence that these in vitro interactions also operate in vivo, factor VIIc was examined in relation to plasma free fatty acid concentrations in five healthy individuals during the consumption of isocaloric high-saturated fat, high-unsaturated fat, and low-fat diets, each taken for 4 weeks in random order and separated by intervals of 12 weeks.

Therapeutic effects of low radiation doses.

Purpose: This editorial explores the scientific basis of radiotherapy with doses of < 1 Gy for various non-malignant conditions, in particular dose-effect relationships, risk-benefit considerations and biological mechanisms.

Methods: A review of the literature, particularly clinical and experimental reports published more than 50 years ago was conducted to clarify the following problems. 1.

Tumour stem cells: the biological concept and its application in cancer treatment.

Experiments in different transplantable mouse tumours suggest that a proportion ranging from 0.1% to 100% of all tumour cells in these different tumours meet the functional definition criteria of tumour stem cells, i.e.

Radiation risks from imaging of intestinal and abdominal inflammation.

Most abdominal imaging procedures involve some radiation dose to the patient. The types of radiation-induced harm from these techniques are described. The dose received from each of these techniques in clinical practice is thought to be below the threshold required to cause developmental abnormalities in pregnancy.