The effects of pentylenetetrazol on molluscan neurons. II. Voltage clamp studies

The effects of pentylenetetrazol (PTZ) upon the steady and transient outward ionic currents during PTZ-induced prolonged depolarizations were investigated using voltage clamp techniques. PTZ causes a 5-35% reduction in gL and a 40-60% reduction in steady-state gK. There is also a marked reduction in the activation of gA of Connor and Stevens6 at all clamp potentials; a shortening of the time constant for the inactivation of gA; and a 10-15 mV shift in the depolarizing direction of the curve relating the steady-state inactivation of gA to membrane potential. The equilibrium potentials for both gA and gK are depolarized by 20 mV in PTZ solution. Equation and voltage clamp data for normal repetitive firing were integrated with the normal and PTZ-alered data. Solution to these equations demonstrated: (1) normal repetitive firing in response to a constant current stimulus; and (2) PTZ-altered repetitive firing that was in the direction of, and for the most part, similar to the observed behavior.     

Renal toxicity. Tobramycin and gentamicin

To see if urinary 2-methyl-4-chlorophenoxyacetic acid (MCPA) excretion could be used to estimate MCPA exposure, four healthy males ingested 5 mg MCPA. The MCPA in the urine was extracted and anlyzed by high pressure liquid chromatography. About 50% of the ingested dose was detected in the urine within 48 h. On the fifth day after intake the MCPA concentration in the urine was below the level of detection, 0.2 microgram/ml. The MCPA did not increase those serum enzymes indicating liver cell damage (S-alanine-aminotransferase, S-alkaline-phosphate). Some creatine kinase (CK) and S-aspartate-aminotransferase (ASAT) values were pathological, but, as all CK values were normal in two persons and all ASAT values were normal in three persons, it not likely that MCPA had a toxic effect on muscle cells. MCPA in urine seems to be a useful indicator of MCPA intake in humans. All the urine passed within 48 h of MCPA exposure must be collected.     

Neonatal modification of endocrine functions and mammary carcinogenesis in the rat

Effects of neonatal androgenization or neonatal ovariectomy in female rats on endocrine functions and mammary tumourigenesis are examined. Pituitary gonadotrophin contents (both LH and FSH) are significantly lower in neonatally androgenized rats (TT) and significantly increased in neonatally ovariectomized rats (NO) when compared with controls of the same age. Plasma and pituitary prolactin levels are higher in TT rats than in the control rats of the same age, but the difference is not significant. Mammary tumours developing in TT rats after DMBA treatment are predominantly fibroadenomata, and lactogenesis in TT rats occurs almost entirely in those receiving DMBA treatment. Neonatal ovariectomy in female rats protects against subsequent induction of mammary cnacer by DMBA. The relationship between neonatal modification of endocrine functions and mammary tumourigenesis is discussed.     

Clinical pathway for enhanced parent and preterm infant interaction through parent education

The article discusses the importance of implementing a clinical pathway in the neonatal intensive care unit that emphasizes parent education. Through an extensive literature review, a clinical path was developed that incorporates parent education through an individualized, developmentally supportive model of interaction. The clinical path is designed to be utilized as a teaching tool from birth to discharge from the hospital. The path can serve as a guide for teaching and identifying learning objectives a long a time line as well as for providing consistent documentation.     

Biological properties of recombinant alpha-interferons: 40th anniversary of the discovery of interferons

IFNs were first described as potent antiviral agents 40 years ago, and recombinant IFN-alpha2a and IFN-alpha2b were approved for the treatment of hairy cell leukemia just 11 years ago. Today, alpha-IFNs are approved worldwide for the treatment of a variety of malignancies and virologic diseases. Although the exact mechanism of action of IFN-alpha in the treatment of such diseases is not fully understood, many advances have been made in the characterization of the physicochemical and diverse biological properties of this highly pleiotropic cytokine. Here we review recent developments in our understanding of the antiviral and immunoregulatory properties of IFN-alpha, the nature of the multisubunit IFN-alpha receptor, and the molecular mechanisms of signal transduction. Where available, we have included comparative data on recombinant alpha-IFNs derived from both naturally occurring and nonnaturally occurring synthetic genes. We also review clinical data and data on the side effects and antigenicity of different sources of recombinant alpha-IFNs in humans. These latter topics are of clinical interest, because they may potentially affect the efficacy of these various products. Hopefully, what is already known about IFN will prompt further exploration into the mechanism(s) of action of IFN-alpha and thus deliver new applications for this prototypic cytokine, whose full therapeutic potential is yet to be realized.