The algorithmic complexity of neural spike trains increases during focal seizures.

The interspike interval spike trains of spontaneously active cortical neurons can display nonrandom internal structure. The degree of nonrandom structure can be quantified and was found to decrease during focal epileptic seizures. Greater statistical discrimination between the two physiological conditions (normal vs seizure) was obtained with measurements of context-free grammar complexity than by measures of the distribution of the interspike intervals such as the mean interval, its standard deviation, skewness, or kurtosis.

Chaotic behavior in transverse-mode laser dynamics.

We analyze chaotic behavior found in numerical simulations of the transverse pattern dynamics of a laser demonstrating that in some cases chaos originates in phase dynamics and is of low dimension. Investigations of both a Ginzburg-Landau equation for the complex field amplitude of the laser output and a Kuramoto-Sivashinsky-type equation for only the phase of that complex field equation find the same behavior. Both equations can be expanded in terms of spatial modes and in the chaotic regime the behavior of the modal amplitudes seems relatively independent.

The bone marrow in murine AIDS.

In order to increase the understanding of blood cytopenias in HIV infection we have investigated the bone marrow in murine AIDS. C57BL/6 mice infected with the LP-BM5 retrovirus show a decrease in cellularity, numerous haemophagocytic histiocytes, a reduction of all erythroid precursor cells, an increase in eosinophil number and an increase in lymphocytes. Immunostaining with an anti-Pr60gag antibody shows that the majority of bone marrow cells express the viral protein.

Sexual transmission of hepatitis C virus and HIV-1 infection in female intravenous drug users.

We examined the relationship between the presence of antibody to HCV and sexually transmitted diseases in 151 female, intravenous drug users aged 17-43 years. Anti-HCV was present in 49 of 66 HIV-1-negative women (74.2%), and 63 of 85 HIV-1-positive women (74.

In vitro and in vivo toxicity of 2',3'-dideoxycytidine in mice.

3T3 mouse embryo fibroblast cell growth was inhibited in a concentration dependent manner by 2',3'-dideoxycytidine (ddCyd), a strong inhibitor of human immunodeficiency virus. Cell growth inhibition was associated with an increased incorporation of ddCyd into cell DNA. In contrast SP2/0-Ag14 (a mouse myeloma) cell growth is not inhibited by 100 microM ddCyd both in the presence or absence of hypoxanthine and thymidine.

Prevalence of anti-HCV in subjects of various age groups.

812 serum samples from 382 males and 430 females from various age groups were examined. All the samples were tested for anti-HCV hepatitis C virus, anti-HBc and HBsAg with an enzymeimmunoassay. The total serum prevalence was 2.

Differential effect of the amino acid cystine in cultured mammalian and bacterial cells exposed to oxidative stress.

The effect of cystine in the cytotoxic response of cultured Chinese hamster ovary and Escherichia coli cells to challenge with hydrogen peroxide has been investigated. It was found that this amino acid could either protect or sensitize cells, depending on the cellular system. In fact, although a reduction in the growth-inhibitory effect of hydrogen peroxide was observed in mammalian cells, a marked increase in the susceptibility to oxidative stress was induced by cystine in bacteria.

[Cutaneous tumor metastasis. A possible first clinical event of visceral neoplasms].

Two cases of visceral malignant tumours due to cutaneous metastases (stomach adenocarcinoma and left pulmonary adenocarcinoma). Are reported in both cases the cutaneous lesions represent the first clinical phenomenon of the disease.

In vitro toxicity and metabolism of 2',3'-dideoxycytidine, an inhibitor of human immunodeficiency virus infectivity.

U937 human monoblastoid cell growth was inhibited in a concentration-dependent manner by 2',3'-dideoxycytidine (ddCyd) (an antiretroviral drug) up to 500 microM. Cell growth inhibition was associated with a pronounced increase in cell volume, however this was not due to cell ATP or NAD+ depletion that could effect osmotic balance or DNA repair. This ddCyd toxicity paralleled the accumulation of ddCyd into acid soluble material where 2',3'-dideoxycytidine-5'-triphosphate (ddCTP) was the predominant labelled nucleotide up to an extracellular ddCyd concentration of 150 microM.

Stress fracture of the first rib from serratus anterior tension: an unusual mechanism of injury.

Fracture of the first rib usually results from high-impact, direct trauma. Stress fractures are less common and are associated with minimal morbidity. The case of a patient with a stress fracture resulting from the use of an exercise machine is reported.

Yersinia enterocolitica and related species isolated in the Pesaro and Urbino area (Italy) from 1981 to 1986.

A total of 23 strains of yersinias, Y. enterocolitica (17), Y. frederiksenii (5) and Y.

The effect of K2Cr2O7 on the growth and morphology of Escherichia coli.

Treatment with 16 microM K2Cr2O7 results is a time-dependent loss of the clonogenicity of E. coli cells. Under the same experimental conditions, optical density values do not change significantly, since cells have the ability to replicate but not to septate.

Rectal diazepam in pediatric status epilepticus.

Status epilepticus is a neurologic emergency with an 8% to 12% mortality. Rapid ablation of seizure activity is imperative. Although intravenous administration of diazepam is the preferred immediate treatment, vascular access is often difficult to achieve.

Morphological changes in Escherichia coli cells exposed to low or high concentrations of hydrogen peroxide.

Escherichia coli cells challenged with low or high concentrations of hydrogen peroxide are killed via two different mechanisms and respond with morphological changes which are also dependent on the extracellular concentration of the oxidant. Treatment with low concentrations (less than 2.5 mM) of H2O2 is followed by an extensive cell filamentation which is dependent on the level of H2O2 or the time of exposure.

Lethality of hydrogen peroxide in wild type and superoxide dismutase mutants of Escherichia coli. (A hypothesis on the mechanism of H2O2-induced inactivation of Escherichia coli).

The toxicity of H2O2 in Escherichia coli wild type and superoxide dismutase mutants was investigated under different experimental conditions. Cells were either grown aerobically, and then treated in M9 salts or K medium, or grown anoxically, and then treated in K medium. Results have demonstrated that the wild type and superoxide dismutase mutants display a markedly different sensitivity to both modes of lethality produced by H2O2 (i.

Dynamics of brain electrical activity.

In addition to providing important theoretical insights into chaotic deterministic systems, dynamical systems theory has provided techniques for analyzing experimental data. These methods have been applied to a variety of physical and chemical systems. More recently, biological applications have become important.

Role of hydroxyl radicals in Escherichia coli killing induced by hydrogen peroxide.

Escherichia coli lethality by hydrogen peroxide is characterized by two modes of killing. In this paper we have found that hydroxyl radicals (OH.) generated by H2O2 and intracellular divalent iron are not involved in the induction of mode one lethality (i.