Delayed-type hypersensitivity responses to murine cytomegalovirus in genetically resistant and susceptible strains of mice.

The delayed-type hypersensitivity (DTH) response in mice infected with murine cytomegalovirus (MCMV) was measured by ear swelling following a challenge with heat-treated MCMV. DTH was dose-dependent and could be detected as early as 3 days post-infection with peak responses occurring between days 15 and 21 post-infection. The DTH response was found to be specific for MCMV since it could not be elicited by either herpes simplex virus type 1 or influenza A virus in MCMV-primed mice.

The crystal structure of trp aporepressor at 1.8 A shows how binding tryptophan enhances DNA affinity.

Comparison of the crystal structure of inactive unliganded trp aporepressor with that of trp repressor shows that binding tryptophan activates the dimer a thousandfold by moving two symmetrically-disposed flexible bihelical motifs. These flexible 'DNA-reading heads' flank a highly inflexible core domain formed by an unusual arrangement of interlocking alpha-helices from both subunits.

An immunohistochemical study of differentiation in malignant fibrous histiocytoma.

Immunohistochemistry was used to examine 10 cases of malignant fibrous histiocytoma. Malignant cells in all cases expressed vimentin and in eight there was co-expression of either desmin or neurofilament, both of these being present in four cases. In addition, cytokeratin was found in one case.

Influence of dietary fats on blood coagulation and prostaglandin production in the common marmoset.

Common marmosets were fed a standard marmoset diet (REF) or diets supplemented with 12% (wt/wt) sunflower seed oil (SSO) or sheep fat (SF) for a period of 90 weeks. The values for coagulation indices, clotting time, and Russel viper venom time were consistent with decreased thrombotic tendency of platelets from animals on the SSO diet relative to the low fat, REF diet animals, while an increased tendency to thrombosis was observed with SF-fed marmosets. The SSO- and SF-supplemented marmosets showed a significantly reduced thromboxane (TXB2) generation from platelets aggregating to collagen (ASC) relative to the REF group, while at 50 micrograms/ml ASC this difference was maintained only by the SSO group.

Hydrolysis of 2-hydroxy-4-(methylthio)butanoic acid dimer in two model systems.

Hydrolysis of 2-hydroxy-4-(methylthio)butanoic acid (HMB) dimer was observed in two model systems that were designed to emulate in vivo conditions. A physiologically feasible rate of hydrolysis of this methionine precursor has not previously been demonstrated in vivo. In the first model, simulated intestinal fluid (SIF) was used, and in the second model, sections of chick small intestine were incubated in vitro with the compound under study.

Leukotriene B4 and 20-hydroxyleukotriene B4 contract guinea-pig trachea strips in vitro.

In contrast to its established myotropic effect on guinea-pig lung parenchyma, the myotropic action of leukotriene B4 on the trachea is uncertain. Our characterization of its effects on the latter organ indicates that leukotriene B4 contracts guinea-pig trachea zig-zag strips in a concentration-dependent manner from 5 X 10(-9) to 5 X 10(-7) M. Leukotriene B4 was at least 10 times more potent than histamine, but 10 times less potent than leukotriene C4.

Effect of Piriprost, a 5-lipoxygenase inhibitor, on leukocyte accumulation during thioglycollate-induced acute inflammation.

We evaluated the effect of a prototype 5-lipoxygenase enzyme inhibitor, Piriprost [6,9-deepoxy-6,9-(phenylimino-)delta 6,8-prostaglandin I1], on the leukocyte accumulation induced by intraperitoneal injection of thioglycollate in rats. Piriprost, at 40 mg/kg, i.p.

Tremors in Samoyed pups with oligodendrocyte deficiencies and hypomyelination.

Over a 3-year period a breeder of Samoyed dogs observed six litters in which one or more pups at 3 weeks of age showed generalized tremors and an inability to stand. One affected pup, a 5-week-old male, was referred for clinical and pathological evaluation. Gross and microscopic studies including immunocytochemical demonstration of myelin basic protein, revealed a lack of myelin throughout the central nervous system.

The three-dimensional structure of trp repressor.

The crystal structure of the Escherichia coli trp repressor has been solved to atomic resolution. The dimeric protein has a remarkable subunit interface in which five of each subunit's six helices are interlinked. The binding of L-tryptophan activates the aporepressor indirectly by fixing the orientation of the second helix of the helix-turn-helix motif and by moulding the details of the repressor's structure near the DNA binding surface.

The sex distribution of children in care.

It is shown that there is a substantial and sustained disparity, both on a national and on a regional basis, between the numbers of males and the numbers of females in care. The disparity is analysed by examining the reasons for entering care, and the legal status of those in care. It is shown that in the aggregate the disparity is caused by imbalances in admissions, particularly in certain key legal and administrative categories.

The influence of dietary fats on plasma lipids, blood pressure and coagulation indices in the rat.

Male Hooded Wistar rats were fed a commercial rat diet supplemented 12% by weight with sheep fat, sunflower seed oil and fish oil (tuna) over a period of 8 months. The influence of these diets on plasma fatty acids, triglycerides and cholesterol, blood pressure, body weight and coagulation indices was assessed. The sheep fat (SF)-fed rats showed a significant increase in body weight over the reference group (C) of 18%, and systolic blood pressure increased by 9.

Spectral and other physicochemical properties of submicron powders of hematite (alpha-Fe2O3), maghemite (gamma-Fe2O3), magnetite (Fe3O4), goethite (alpha-FeOOH), and lepidocrocite (gamma-FeOOH).

Spectral and other physicochemical properties were determined for a suite of submicron powders of hematite (alpha-Fe2O3), maghemite (gamma-Fe2O3), magnetite (Fe3O4), goethite (alpha-FeOOH), and lepidocrocite (gamma-FeOOH). The spectral reflectivity measurements were made between 0.35 and 2.

Haematological characteristics of the common marmoset (Callithrix jacchus jacchus).

Blood cell indices and parameters of haemostasis were studied in the common marmoset. The majority of the results were similar to those found in man. Differences from man were that the prothrombin time was shorter in the marmoset, higher concentrations of aggregating stimuli were required to cause platelet aggregation, and marmoset platelets did not aggregate under the influence of adrenalin.

Alterations in the dopaminergic system and behaviour in rats reared on iodine-deficient diets.

Male rats raised on an iodine-deficient diet were found to be retarded in growth rate, to have lowered body temperature, and to have poorer memory retention of a passive avoidance task than rats raised on a similar diet but with adequate iodine concentration. In addition, the iodine deficient rats showed increased locomotor activity and sniffing frequency after the dopamine agonist, apomorphine; while their operant performance was inhibited to a greater degree after apomorphine. However, the hypothermic effects of apomorphine were comparable in both iodine-deficient and normal rats.

Fiber-optic diaphragm-curvature pressure transducer.

A novel fiber-optic sensor that determines pressure from diaphragm curvature is discussed. This sensing technique exhibits a high degree of sensitivity and linearity and is less susceptible to environmental perturbations than previous intensity-modulating techniques. Experimental results are presented for a miniature pressure transducer suitable for in vivo medical applications.

Pocket-sized device for measuring forced expiratory volume in one second and forced vital capacity.

An inexpensive pocket-sized instrument--the turbine spirometer--has been developed that measures and gives a direct digital display of the forced expiratory volume in one second and forced vital capacity. The instrument is as accurate as and considerably cheaper than spirometers in general use. Condensation does not affect the calibration.

Ossification of the laryngeal cartilages as it relates to computed tomography.

Ossification of adult laryngeal cartilages was studied using cross sections cut in planes parallel to those used in computed tomography (CT). The percentage of ossification of surfaces of thyroid laminae was calculated and marked variations were found. There was no correlation between ossification and age (all subjects were 50 years or older).

Antiphase domains and reverse thermoremanent magnetism in ilmenite-hematite minerals.

Examination of synthetic ilmenite-hematite samples by transmission electron microscopy has for the first time revealed the presence of well-defined antiphase domains and antiphase domain boundaries in this mineral system. Samples quenched from 1300 degrees C have a high density of domain boundaries, whereas samples quenched from 900 degrees C have a much lower density. Only the high-temperature samples acquire reverse thermoremanent magnetism when cooled in an applied magnetic field.