Cardiac myosin phenotype remodeling following chronic spinal transection.

Spinal transection results in profound neural and functional changes of the heart. However, phenotypic alterations in cardiac myosin heavy chains (MyHC) as a result of spinal transection have not been explored. Hearts were removed from 180 day old rats who had their spinal cords transected between T6 and T9 (ST; n = 10) and intact controls (IN; n = 9). Myosin was isolated from the left and right ventricles and separated into its respective heavy chain components (designated as alpha and beta) by SDS-PAGE. The resulting gels were scanned with a laser scanning densitometer to obtain relative concentrations of these two heavy chains. The left ventricles of the ST rats had a significantly higher (p < 0.05) alpha to beta ratio (10.89) than the intact controls (4.20), while the right ventricle of the ST rats had a significantly lower (p < 0.05) alpha to beta ratio (7.49) relative to intact controls (13.62). The left and right ventricular weight to body weight ratios were not different in ST compared to IN. Additionally, there were significant within group differences (p < 0.05) between the alpha and beta MyHC ratios for the left and right ventricles. These data suggest that 1) spinal transection causes remodeling of the right and left ventricles and 2) the two ventricles do not remodel as a unit.

Central GABA activation and behaviors evoked by tail-pinch stress in the rat.

Experiments were conducted to evaluate the possibility that central GABA(A) receptors are involved in the stress response of rats. Separate groups of animals were implanted bilaterally with cannulae in the lateral cerebral ventricle, substantia nigra, and anterior to the rostral margin of the substantia nigra. Microinjections of the GABA(A) agonist muscimol into each of these areas augmented the stress response evoked by moderate tail pinch. Although consistent changes in the amount of food eaten in response to stress were not observed, stress-evoked gnawing was significantly increased by muscimol at all three sites. Additionally, intraventricular muscimol resulted in an enhancement of stress-evoked oral stereotypy, revolution (escape behavior), and vocalization. The data suggest that a GABAergic component exists in the central mediation of stress. The results are discussed in regard to possible interactions between GABA and central dopamine systems.

Kappa opioid-mediated behavioral sensitization in the preweanling rat: relationship to Fos immunoreactivity.

When given acutely, drugs that stimulate kappa opioid receptors (e.g., U-50,488) enhance the locomotor activity of preweanling rats and induce regional increases in Fos immunoreactivity (IR). In contrast, the effects of chronic treatment with kappa opioid agonists are unknown. The purpose of the present study was two-fold: first, to determine whether repeated treatment with a kappa opioid agonist would sensitize the locomotor activity of preweanling rats and, second, to determine whether changes in Fos IR correspond with the occurrence of locomotor sensitization. To test these hypotheses, rats were injected with U-50,488 (5 mg/kg, s.c.) or saline on either postnatal days (PD) 5-9 or PD 11-15. For rats pretreated on PD 5-9, a test day injection of U-50,488 or saline was given after either 1 or 7 abstinence days (i.e., at PD 11 or PD 17). For rats pretreated on PD 11-15, a test day injection of U-50,488 or saline was given after 1 abstinence day (i.e., at PD 17). In two additional experiments, the acute and chronic effects of U-50,488 treatment were assessed in adult rats. As expected, repeated treatment with U-50,488 produced locomotor sensitization at both PD 11 and PD 17, but only when the test day occurred 1, and not 7, days after cessation of drug pretreatment. Thus, the persistence of the sensitized response was very brief. Test day treatment with U-50,488 stimulated Fos IR in various brain regions of the preweanling rat, including the medial striatum, nucleus accumbens, lateral habenula, and septal area. Chronic treatment with U-50,488 depressed Fos expression in a number of brain regions (relative to acutely treated rats); however, these changes in Fos IR did not necessarily coincide with the occurrence of behavioral sensitization. Repeated treatment with U-50,488 did not produce locomotor sensitization in adult rats, so Fos IR was not assessed in this age group. Therefore, while acute treatment with U-50,488 both increased locomotor activity and stimulated Fos IR in preweanling rats, chronic U-50,488 treatment produced behavioral changes that did not correspond with Fos expression.

Ontogeny of dopamine agonist-induced sensitization: role of NMDA receptors.

In contrast to adults, preweanling rats exhibit behavioral sensitization for only a few days after cessation of dopamine (DA) agonist treatment. The reasons for this ontogenetic difference are uncertain, but maturational changes in the N-methyl-D-aspartate (NMDA) receptor may be responsible, since stimulation of these receptors is necessary for the development of DA agonist-induced sensitization in adult rats. The purpose of the present study was to examine the relationship between NMDA receptor functioning and DA agonist-induced sensitization during the preweanling period. To that end, 17-day-old rats were injected (i.p.) on 4 consecutive days with saline or 0.3 mg/kg dizocilpine (a non-competitive NMDA receptor antagonist) followed, 30 min later, by an injection of saline, 2.5 mg/kg amphetamine (an indirect DA agonist), or 1.0 mg/kg NPA (a direct DA agonist). Sensitization was tested 2 days later (i.e., at 22 days of age), with rats receiving a challenge injection of saline, amphetamine, NPA, or dizocilpine. Results showed that the NMDA antagonist had adult-like effects on the behavioral sensitization of preweanling rats, as amphetamine- and NPA-induced sensitization were eliminated by dizocilpine pretreatment. When given alone, dizocilpine substantially increased the locomotor activity (i.e., line-crosses) of preweanling rats, an effect that became sensitized with repeated drug treatment. Lastly, preweanling rats already sensitized to dizocilpine did not exhibit cross-sensitization to amphetamine or NPA. Thus, with few exceptions, NMDA receptor stimulation appears to modulate sensitization in a similar fashion across ontogeny. This finding suggests that maturational differences in the NMDA receptor system are not responsible for the lack of long-term sensitization in the younger animal.

Paradoxical effects of kappa-opioid stimulation on the locomotor activity and Fos immunoreactivity of the preweanling rat: role of dopamine receptors.

The kappa-opioid agonist U-50,488 increases the locomotor activity of preweanling rats. The authors attempted to determine whether this effect was modulated by dopamine (DA) system functioning. Surprisingly, U-50,488's locomotor activating effects were attenuated by both the DA receptor antagonist flupenthixol and the DA receptor agonist R(-)-propylnorapomorphine (NPA). In order to determine those brain areas stimulated by U-50,488, Fos immunoreactivity was assessed in 17- and 80-day-old rats. U-50,488 not only enhanced the locomotor activity of the younger rats, but it also enhanced Fos expression in various brain areas, including the nucleus accumbens and medial striatum. NPA blocked U-50,488-induced Fos expression in the latter region. When considered together, these results indicate that U-50,488 does not increase locomotion by stimulating a DA mechanism. Instead, either agonizing or antagonizing DA receptors is sufficient to disrupt U-50,488's locomotor activating effects in the preweanling rat.

Ontogeny of behavioral sensitization in the rat: effects of direct and indirect dopamine agonists.

In the present study, the abilities of NPA (a direct DA receptor agonist) and amphetamine (an indirect DA receptor agonist) to induce short- and long-term behavioral sensitization were assessed in 11- and 17-day-old rats (age at initial injection). Rats were injected on 4 consecutive days with amphetamine (1.0, 2.5, or 5.0 mg/kg), NPA (1.0 mg/kg), or saline. A final test day occurred either 2 days (experiment 1) or 8 days (experiment 2) later. On the test day, rats given successive agonist injections received a single injection of the same agonist again; whereas rats given successive saline injections received either amphetamine or NPA for the first time. Five minutes after injection, locomotor activity (line-crosses), stereotyped sniffing, and vertical activity were measured during a 30-min testing session. The results showed that 11- and 17-day-old rats exhibited behavioral sensitization when tested with NPA or amphetamine after a 2-day interval. In contrast, neither NPA nor amphetamine was able to sensitize the behaviors of preweanling rats when measured 8 days after initial drug treatments. Therefore, these results show that both direct and indirect DA agonists are able to induce short-term behavioral sensitization in preweanling rats, but that the mechanisms responsible for mediating long-term behavioral sensitization have not yet matured.

Caloric needs of adolescent patients with burns.

Formulas for estimating the caloric requirements of pediatric and adult patients with burns have been suggested. However, the needs of adolescent patients with burns have not been specifically addressed. This study was undertaken to determine the calorie intake required to maintain weight of adolescent patients with burns over more than 35% of the total body surface area. The 29 patients studied were divided into two groups according to sex. Caloric requirements were determined with the use of the Galveston surface area formula and the Curreri formula. The comparison of these estimations with the actual intake required to maintain weight indicated that there is a significant difference between the calories indicated by the formulas and the actual intake. A surface area formula that also correlates with the results of indirect-calorimetry studies is suggested for this adolescent population with burns.

Reassessing caloric requirements in pediatric burn patients.

New formulas for estimating the caloric requirements of burned children have been suggested. These formulas appeared to exceed the caloric estimates made by the Galveston Shriners Burns Institute formula. This study was undertaken to compare the Curreri Junior formulas and the Galveston Shriners Burns Institute formula with the actual intake required by pediatric patients with burns greater than 30% total body surface area to maintain weight. The 121 patients studied were divided into three age groups to coincide with those in the Curreri Junior formulas and calorie requirements as estimated by both formulas were determined. The comparison of these estimations with the actual intake required to maintain weight indicated that there is a significant difference in the caloric requirement per m2 burn between the age three and under group and the older age group. The results also suggest that overfeeding may occur with the historic formulas.

Nutritional intake from food sources of high school football athletes.

Male high school football athletes served as subjects (no. = 134; age = 15.0 +/- 1.2 years, range = 12 to 18 years; weight = 67.7 +/- 13.9 kg) (mean +/- standard deviation) in a dietary survey project to characterize nutritional intake from food sources. Dietary intake data were collected using the recall method for 1 weekday during the summer when athletes participated in unsupervised, informal conditioning. Subjects were grouped by age as junior high (JR-HI: 12 to 14 years) or senior high (SR-HI: 15 to 18 years) students. Absolute mean energy and nutrient intakes, except for vitamin A, were statistically greater for SR-HI relative to JR-HI (p less than .02). These findings are consistent with age-related growth on nutritional intake. Mean nutritional intakes from food sources for SR-HI met or exceeded the RDAs. For JR-HI, mean intakes met or exceeded the RDAs except for energy (94% RDA) and zinc (87% RDA). Mean intakes exceeded those of a representative sample of same-age boys in the larger American population.

A modified immunoperoxidase method for rapid diagnosis of herpes simplex I keratitis.

To study the possibility of establishing a rapid diagnosis of herpes simplex keratitis, corneas of 10 rabbits, a total of 20 eyes, were inoculated with herpes simplex virus (HSV), type I, strain PH. Epithelial keratitis developed within three days of inoculation in all the animals used. Scraping of infected corneas were smeared and examined, using a modified indirect immunoperoxidase technic. One hundred percent of the smears prepared from these corneas demonstrated positive cells. Negative findings in corneas inoculated with adenovirus 19 suggest the specificity of the reaction. To test the possibility of blockage of staining by the presumed development of circulating endogenous anti-HSV I antibodies, the corneas of eight consecutive patients who presented to the Albany Medical Center Hospital with known recurrent dendritic keratitis also were scraped and stained, using a similar procedure. Positive cells present in each of these scrapings suggest against the blocking of this immunoperoxidase method by the development of circulating anti-HSV antibodies.

Bacterial infection of a neurotrophic cornea in an immunocompromised subject.

The following is a case report of a 61-year-old woman with a 10-year history of pemphigus vulgaris, successfully treated with steroids and cytotoxic agents. The patient developed severe herpes zoster ophthalmicus, complicated by a staph-indolent corneal ulcer. This case illustrates several of the many unfortunate ophthalmological complications that may develop in the immunocompromised patient.

A new rapid immunoperoxidase diagnostic staining of herpes simplex virus 1 indolent corneal ulcer.

A tear film aspirate, from the lower fornix of a 64-year-old man with the clinical diagnosis of a herpes simplex indolent corneal ulcer, was examined via a new, rapid immunoperoxidase staining technique. This 4-hour modified immunoperoxidase stain is both sensitive and specific for herpes simplex virus type 1. The corneal epithelial cells shed in the tear film from the indolent ulcer were strongly positive for herpes simplex type 1 viral antigen using this new technique. This case report supports the theory that the pathogenesis of indolent herpetic corneal ulcers involves both a hypersensitivity response to viral antigen and an active viral infection.