Neutropenia, fever, and infection

With the advances in the management of various neoplastic diseases and subsequent improvement in "disease-free" states, complications of therapy--particularly, infectious complications--have evolved as stumbling blocks to survival. Among neutropenic (absolute neutrophil count below 1,000/mm3) patients with cancer, infection is the major autopsy-determined cause of death. With expected "cure rates" of childhood leukemia approaching 60 to 70 percent, it seems unreasonable to lose such patients to an infectious cause of death, yet this, indeed, happens. The purpose of this review is to (1) define the magnitude of the problem; (2) describe the various agents responsible for infections in neutropenic patients; (3) attempt to more sharply define degrees of neutropenia and mechanical defenses; and (4) consider various approaches to studying and treating these infections.     

Osmoregulatory changes during the aquatic-to-terrestrial transition in the rough-skinned newt, Taricha granulosa: the roles of temperature and ACTH

Aquatic breeding-condition newts kept at 5, 11, or 18 degrees showed temperature-dependent changes in body weight (BW), tail height, plasma [Na+], hematocrit, integumental osmotic permeability, urine production, and transepithelial potential. Net urine production could account for the change in weight observed in animals kept at 11 and 18 degrees, suggesting that initial weight change results from a reduction in extracellular volume. Weight loss was correlated with increased hematocrit and plasma [Na+]. In another experiment, newts were sham-hypophysectomized (sham-HX) or hypophysectomized (HX) and injected with saline, ovine prolactin (PRL), ovine growth hormone (GH), or porcine adrenocorticotropic hormone (ACTH) and maintained at 5 degrees for 13 days. All animals lost 3-7% of their initial BW. Plasma [Na+] was reduced in animals injected with hormone compared with both sham-operated and saline-injected controls. Following an increase in water temperature to 11 degrees for 13 days, weight loss in sham-operated and ACTH-injected newts increased to 16% of BW compared with a total of 4-8% in newts injected with PRL, GH, or saline. In this experiment also, loss of body weight was correlated with increased plasma [Na+]. Although measurements of plasma Na+ concentrations indicated that ACTH caused "sodium retention," estimates of changes in total extracellular Na+ revealed that both sham-operated and ACTH-injected newts experienced a net sodium loss. In Taricha granulosa, warm temperatures and ACTH (presumably acting via interrenal hormones) appear necessary for the fluid and electrolyte loss which accompanies the transition from the aquatic to the terrestrial condition.     

Pituitary pigmentary hormones. Relationship of melanocyte-stimulating hormone to lipotropic hormone.

Pituitary control of pigmentation has known for more than 60 years. Since 1969, beta-melanocyte-stimulating hormone (beta-MSH) has been accepted as the main pituitary pigmentary hormone in man. Its "constant companionship" with adrenocorticotrophic hormone (ACTH) has also been repeatedly demonstrated. Current investigations challenge both of these concepts. Human beta-MSH immunoreactivity has been shown to be actually due to beta-lipotropic hormone (beta-LPH), a larger molecule that within itself contains the entire amino acid sequence of beta-MSH. Human beta-MSH does not exist in vivo; it is merely an extraction artifact formed by enzymatic degradation of beta-LPH. It would appear likely that beta-LPH, not beta-MSH, is the constant companion of ACTH.     

Marijuana,alcohol, and combined drug effects on the time course of glare recovery

The time course of light adaptation after intense light exposure is significantly delayed by alcohol, marijuana, and a combined dose of alcohol and marijuana. These effects were found in a double blind experiment, using 10 subjects. The experimental treatements were placebo, 0.75 ml/kg of 95% ethanol, 8 and 15 mg of ⁹ tetrahydrocannabinol (THC), and 0.75 ml/kg of 95% ethanol together with 15 mg of THC. The marijuana-induced delay in recovery is doserelated. Both drugs produce delayed recovery for at least 2 h after drug ingestion. The combined alcohol and marijuana treatment produces little more than the effect produced by either drug alone, suggesting some antagonism between the drugs — a suggestion supported by a significantly lower blood alcohol level for the alcohol dose when combined with marijuana than when taken alone.     

Variability in the stereotaxic position of cerebral points in the albino rat

An analysis of variability in the stereotaxic position of five cerebral points in rats revealed:

1. (1) that variability was less from the bregma skull point than from ear-bar-zero or the lambda skull point,

2. (2) that high correlations exist between the position of skull points and cerebral structures, and

3. (3) that the use of two external landmarks for predicting the position of cerebral targets produces a greater than 40% reduction in errors over that resulting from the use of single (ear-bar-zero or skull landmark) predictors.

Local cerebral blood flow following transient cerebral ischemia. II. Effect of arterial PCO2 on reperfusion following global ischemia

Following 5 minutes of global ischemia, local cerebral blood flow (LCBF) was shown to have an initial reactive hyperemia that was followed, within the first hour, by persistent hypoperfusion (Part I). Intracranial pressure (ICP) was never elevated during the period of poor reperfusion. These experiments attempted to reverse the state of subnormal LCBF by inducing hypercarbia or hyocarbia or maintaining normocarbia. Although hypocarbia did increase LCBF at several electrode sites, neither the intracerebral steal syndrome nor the "squeeze" syndrome are a dominant consequence of hypercarbia in this model of global ischemia. Hypercarbia was consistently more effective in elevating LCBFs and in recovery of the electrocorticogram. It appears that, in the absence of raised ICP, hypercarbia may be preferred to normal or low PACO2,. Even though hypercarbia was superior to normocarbia or hypocarbia, hypercarbia was not a completely satisfactory regimen for reversing the state of poor reperfusion.