[Supracondylar humerus fracture in childhood--an efficacy study. Results of a multicenter study by the Pediatric Traumatology Section of the German Society of Trauma Surgery--II: Costs and effectiveness of the treatment]. / Die suprakondyläre Oberarmfraktur im Kindesalter--eine Effiziensztudie. Ergebnisse der multizentrischen Studie der Sektion Kindertraumatologie der Deutschen Gesellschaft für Unfallchirurgie--Teil II: Aufwand und Nutzen der Behandlung.

The following are the results and conclusions of a retrospective research study done on 886 patients with supracondylar fractures of the humerus. The study evaluates how effective the treatment procedures of the fractures are. The patients' fractures were categorized into four groups. It made it easier to differentiate between dislocated and undislocated fractures (see part I Weinberg A et al.). The following parameters were established to evaluate the treatment procedures and to create relevancy to the final outcome depending on the degree of difficulty of the fractures: Length of hospitalization, amount of repositioning procedures (including if an open or closed procedure was needed), amount of post repositioning procedures and the recommended change of therapy, method of retention and fixation, necessary metal removal, amount of check ups needed. The amount of x-ray exams could not be established due to insufficient documentation. The study showed a rather random pattern regarding length of hospitalization and the amount of check ups especially among type I and II patients. Open versus closed repositioning procedures did not seem to be advantageous. The implanted wires did not prevent infections. It just increased the treatment procedure by another hospitalization and anesthesia to remove the implanted wires. Physical therapy was not necessary and was only prescribed in cases of prolonged immobilization. The results of this study generated consequences regarding treatment procedures and developed a more efficient treatment protocol: Type I and II (dislocated and undislocated fractures in one plane) will be treated conservatively on an out-patient basis. Type I in a cast. Type II in a blount or plaster cast with flexed angle between 100 degrees and 130 degrees. Type III an IV (dislocated and undislocated fractures in two or three planes) will be treated if possible with a closed repositioning procedure. Otherwise a close repositioning procedure will be necessary and followed with some kind of KD-osteosynthese to capture the fracture. The patient will be hospitalized for a short period. The blount procedure will not be sufficient for this type of fracture. Therapy and procedure will be translated put in a perspective research study.

The role of corticosteroids in nicotine's physiological and behavioral effects.

This paper reviews evidence indicating that adrenal corticosteroids modulate the responsiveness of mice and rats to nicotine. Adrenalectomy increases, and both acute and chronic corticosteroid administration decrease, some of the physiological and behavioral effects of nicotine. One function of adrenal steroids may be to regulate stress-induced changes in nicotine sensitivity. Another is to mediate the development of chronic tolerance when nicotine is given intermittently, and when the resulting tolerance has a learned component. A role of glucocorticoids in the development of tolerance to nicotine is suggested by the findings that a conditioned elevation of plasma corticosterone, which anticipates nicotine delivery, accompanies the development of chronic tolerance and that environmental cues evoke a conditioned corticosterone response, but only after they have become associated with nicotine delivery. The mechanisms by which adrenal steroids modulate nicotine sensitivity are not known, although recent in vitro evidence suggests that steroids can rapidly and reversibly reduce nicotinic receptor function. While most of the data are consistent with the hypothesis that corticosteroids reduce nicotine responsiveness, and thus promote a learned form of tolerance, there are new findings that corticosteroids increase the development of sensitization to the locomotor-activating effects of nicotine. These data suggest that formulations postulating a unidirectional effect of corticosteroids on nicotine's actions (e.g. decreased sensitivity) must be revised to take into account interacting variables such as the specific nicotine effect being studied and whether that effect normally exhibits tolerance or sensitization. Finally, research is presented which indicates that the corticosterone-elevating effects of nicotine, previously reported for experimenter-administered drug, are also produced when nicotine administration is contingent on an operant response, and at a dose which sustains the development of nicotine self-administration in rats. These findings highlight the feasibility of using self-administration models in future explorations of the relationship between adrenal steroids and nicotine function.

The effects of nicotine on the immune system.

Although considerable work has been done on the potential health effects of smoking, little is known about the contribution of nicotine to those effects. This paper presents an overview of the immune system, and a discussion of the existing literature on the effects of tobacco smoke and nicotine on immunity. Treatment with nicotine has been shown to influence all aspects of the immune system, including alterations in humoral and cellular immunity. In addition, preliminary data suggest that gender and genetic factors impact on the immunological effects of nicotine. Finally, the possible mechanisms that might mediate the effects of nicotine are discussed.

Nicotine self-administration in rats.

Considering the importance of self-administration models in determining mechanisms of drug maintained behavior, we attempted to replicate the findings of nicotine self-administration by Corrigall and Coen. Male, Sprague-Dawley rats, trained on food reinforcement, acquired relatively high and stable rates of self-administration of IV nicotine bitartrate (0.03 mg/kg, free base). Extinction and reacquisition followed substituting saline and then nicotine, respectively. Responses, infusions and intake decreased at 0.003 mg/kg, while intake increased at 0.06 mg/kg. This model of nicotine self-administration provides a reliable alternative to experimenter-administration models for examining the effects of nicotine.

Immunological effects of acute and chronic nicotine administration in rats.

We previously demonstrated that acute nicotine administration decreased the response of rat blood leukocytes (PBL) to concanavalin A (ConA). We now extend those findings to a comparison between the effects of acute and prolonged nicotine exposure (ten daily injections), on PBL and splenocytes (SL). A single injection suppressed the PBL response to ConA and phytohemagglutinin (PHA); tolerance developed by ten injections. In contrast, acute nicotine did not affect SL response to ConA and reduced the PHA response only at the highest concentration. Ten nicotine injections enhanced SL responsiveness to PHA. The only change in PBL subsets was an increase in CD8+ cells following ten injections.

Acute stress or corticosterone administration reduces responsiveness to nicotine: implications for a mechanism of conditioned tolerance.

We have shown that conditioned tolerance develops to some of the behavioral and endocrine effects of nicotine in rats. Other investigators have suggested that tolerance to multiple nicotine injections in mice may be due, in part, to elevated plasma corticosterone (CORT) levels, since repeated nicotine injections are associated with elevated CORT, chronically elevated CORT reduces nicotine responsiveness and adrenalectomy disrupts nicotine tolerance. Three experiments tested the feasibility of this hypothesis, as a mechanism for conditioned nicotine tolerance in rats, by determining whether acute administration of CORT or manipulations that increase adrenocortical activity reduce nicotine responsiveness. In experiment 1, male rats were injected IP with CORT (1 mg/kg), vehicle (ETOH + distilled water) or no injection 10 min before nicotine (0.75 mg/kg, SC) and tested for nicotine-induced analgesia every other day for 10 days. A significant reduction in withdrawal latencies was obtained for CORT pretreated rats compared to animals given only nicotine. A similar reduction was produced by the vehicle pretreatment, which itself induced an elevation of endogenous CORT. Experiments 2 and 3 established that similar effects could be produced by doses of CORT as low as 0.125 mg/kg or by exposure to a novel environment which also elevated CORT levels. Results also suggest that a conditioned release of endogenous CORT was triggered by stimuli associated with nicotine delivery. These data are consistent with the hypothesis that a conditioned release of CORT could contribute to the development of tolerance to some of nicotine's effects.(ABSTRACT TRUNCATED AT 250 WORDS)

One brief exposure to a psychological stressor induces long-lasting, time-dependent sensitization of both the cataleptic and neurochemical responses to haloperidol.

Rats were exposed for 10 minutes to one of several enclosures graded in novelty. In one experiment they were then simply sacrificed and plasma corticosterone determinations made in order to obtain an index of the relative stressfulness of these enclosures. In a second experiment the animals received haloperidol and were tested for catalepsy, 2 hours or two weeks following the novel experience. The most novel experience, exposure to a black box, resulted in the highest corticosterone levels and was the only one of our pre-treatments to induce significant enhancement of catalepsy as well as alteration of nucleus accumbens dopamine levels, 2 weeks--but not 2 hours--later. These findings indicate that brief exposure of adult animals to a psychological stressor can induce a long-term alteration in both behavioral and neurochemical responses to a drug and that this effect requires a minimum level of stress to get started and once triggered gets stronger with the passage of time.

Amphetamine or haloperidol 2 weeks earlier antagonized the plasma corticosterone response to amphetamine; evidence for the stressful/foreign nature of drugs.

We inquired whether a single exposure to amphetamine (AM) or haloperidol (HALO) could modify the plasma corticosterone (CORT) response to a second injection of AM 2 weeks later. Male rats were injected with 4 mg/kg d-AM sulfate and tested for water intake for 5 h before sacrifice. Overall, AM induced water intake but none of the pretreatments altered this effect. By contrast, preexposure to AM, HALO or its vehicle 2 weeks earlier prevented the elevation of plasma CORT obtained when AM was administered without pretreatment. A combined pretreatment of HALO or its vehicle with AM produced an even greater blockade of AM-induced CORT elevation. Manipulations which prevented AM-induced drinking reduced the effectiveness of AM pretreatment in attenuating AM-induced elevation in CORT, suggesting that the pretreatment may have been sensitizing the effectiveness of a coping response--drinking--in reducing the CORT effect. Our findings also indicate that a dopamine agonist (AM), a dopamine antagonist (HALO) and a nonspecific stressor (acidic vehicle) can all induce the same, long-lasting action on CORT. This strongly suggests that the effects of AM and HALO in this instance cannot be explained in terms of their pharmacological actions, which are opposite to one another, but instead relate to their properties as stressful/foreign agents to the organism.

One experience with 'lower' or 'higher' intensity stressors, respectively enhances or diminishes responsiveness to haloperidol weeks later: implications for understanding drug variability.

This laboratory has previously shown that acute exposure to a variety of brief stressful events can have a very long-lasting influence on subsequent responsiveness to pharmacological and non-pharmacological stressors. In some cases the response to these agents is enhanced, while in others it is diminished: the common denominator being that in each instance the influence of the initial stressor grows stronger with the passage of time. Here, we identify one factor that determines which time-dependent effect is manifest. In 3 separate experiments, male rats were subjected to a single exposure to stressors of either lower or higher intensity and their effects on haloperidol-induced catalepsy and dopamine and dihydroxyphenylacetic acid levels in the nucleus accumbens and medial frontal cortex, measured either 1-2 h or 2 weeks later. The stressors were either environmental (needle jab or 1 h of immobilization), metabolic (200 or 750 mg/kg, i.p. of 2-deoxy-D-glucose), or no effect on haloperidol-induced catalepsy when stressors preceded such behavioral testing by 1-2 h. By contrast, when the interval was 2 weeks, the lower-intensity stressors all increased haloperidol catalepsy, whereas the higher-intensity stressors decreased the same response. In other words, a process that progressed with the passage of time was observed regardless of whether sensitization or diminution of haloperidol's action occurred. In contrast to the uniform bipolar behavioral effects observed, depending on the intensity of the prestressor, the neurochemical findings failed to show any evidence of bipolarity whatever.(ABSTRACT TRUNCATED AT 250 WORDS)

Conditioned tolerance to the anorectic and corticosterone-elevating effects of nicotine.

We have shown that tolerance to the behavioral effects of nicotine is partially dependent on conditioned environmental cues that predict drug delivery. The present research extends this finding to physiological effects of nicotine by assessing both the appetite-suppressing and adrenocortical-activating effects of nicotine, as measured by plasma corticosterone (CORT). In the first study, male rats on a 22-h food deprivation schedule were injected daily with 0.33 or 0.66 mg/kg (free base) of nicotine bitartrate or saline in a distinctive environment and tested for milk intake. Nicotine initially suppressed milk intake and tolerance developed over 10 days. Changing cues associated with drug administration partially reversed tolerance since injection of nicotine in a new environment reduced milk intake of tolerant animals. Similarly, animals who repeatedly received nicotine in one environment exhibited CORT levels lower than rats injected for the first time, and this tolerance also was partially reversed when administration occurred in the new environment. The second experiment indicated that the increased CORT of Experiment 1 was not a stress response associated with injecting animals in a different environment. These results indicate that tolerance to both behavioral and neuroendocrine effects of nicotine is influenced by conditioning.

Plasma tranylcypromine: relationship to pharmacokinetic variables and clinical antidepressant actions.

Because the clinical actions of psychotherapeutic agents can be influenced by their pharmacokinetics, we investigated plasma tranylcypromine in relation to treatment outcome in 26 patients with bipolar depression. After oral administration of a tranylcypromine dose, plasma drug levels were measured hourly from 5-8 hours (N = 16) or 0-8 hours (N = 10) postdose, and pharmacokinetic parameters were calculated. Depressive symptoms were rated using the Hamilton Rating Scale for Depression (HAM-D), and subjects were categorized as responders, partial responders, or nonresponders, based on end-pair ratings. Twelve subjects were responders, seven were partial responders, and seven were nonresponders (mean scores = 3.2, 13.1, and 24.9, respectively); pretreatment HAM-D scores did not differ among the three groups. Tranylcypromine elimination (t1/2) was unrelated to clinical outcome. However, plasma tranylcypromine measured 5 hours postdose (5hTCP) was correlated with the end-pair HAM-D scores (r = 0.48, p less than 0.015) and was significantly higher in nonresponders than in responders (ANOVA, F = 4.7, p less than 0.02; Newman-Keuls test, p less than 0.05). For subjects who were studied from 0-8 hours postdose, the time to peak absorption (Tpeak), the area under the plasma tranylcypromine-versus-time curve, and the volume of distribution (Vd) were determined. Two subjects having delayed (3-4 hours) Tpeak also manifested elevated mean 5hTCP (63.9 vs. 34.1 ng/ml).(ABSTRACT TRUNCATED AT 250 WORDS)

Immobilization 12 days (but not one hour) earlier enhanced 2-deoxy-D-glucose-induced immunosuppression: evidence for stressor-induced time-dependent sensitization of the immune system.

1. Prior exposure to a stressor can either increase or decrease subsequent behavioral, neurochemical, and endocrine reactivity to stress, depending on the pattern of stress exposure. 2. Massed or frequent exposures typically induce a reduction in reactivity whereas intermittent or widely spaced exposures increase subsequent reactivity. 3. In the present study, the authors examined whether a single presentation of a temporally remote stressor would increase the immunosuppressive effects of a subsequent stressor. Specifically, the authors investigated the effectiveness of 2-deoxy-D-glucose (2-DG) in suppressing the responsiveness of splenic lymphocytes in male, Sprague-Dawley rats that received either no prior treatment, or immobilization either one hour or 12 days earlier. 4. Splenic lymphocyte responsiveness to the T-cell mitogens, Concanavalin A (Con-A) and phytohemagglutinin (PHA) was suppressed following a single injection of 2-DG. 5. The group exposed to the stress of immobilization one hour prior to 2-DG demonstrated a comparable level of immune suppression. 6. In contrast, animals immobilized 12 days prior to the administration of 2-DG showed a more pronounced suppression of immune responsiveness which was significantly greater than the other groups injected with 2-DG. 7. Neither the stress-induced elevation in corticosterone, nor the suppression of blood lymphocyte reactivity to Con-A and PHA was enhanced by prior immobilization. 8. The results indicate that the immunosuppressive effects of an acute stressor can sensitize with the passage of time.

Effects of the beta 2-adrenoceptor agonist clenbuterol on tyrosine and tryptophan in plasma and brain of the rat.

The beta 2-adrenoceptor agonist, clenbuterol (initially 5 mg/kg), was found to significantly reduce plasma tyrosine and raise brain tryptophan levels (P less than 0.01). By comparison, decreases in plasma tryptophan and increases in brain tyrosine were small and often nonsignificant. Amino acid levels measured in different brain regions revealed that the elevations were similar among the cerebellum, striatum, and cortex. These effects were partially blocked by propanolol but not by atenolol. The ED50 was estimated from dose-response curves to be about 0.05 mg/kg for both the decrease in plasma tyrosine and the increase in brain tryptophan. The effects of low doses of clenbuterol were prevented completely by propranolol. Peripheral organs displayed strikingly different patterns of change in amino acid concentrations. Only the spleen had any accumulation of tryptophan, but that was much less than in brain. In contrast, tyrosine and tryptophan were decreased in heart and unaltered in liver; tyrosine was decreased in lung. The elevation in brain tryptophan levels was attenuated by the beta 2-antagonist, ICI 118,551, but not by the beta 1-antagonist, betaxolol; but the reduction in plasma tyrosine was unaffected by either drug. The serotonin antagonist, methysergide, failed to block the effects of clenbuterol. We conclude that changes in amino acid concentrations produced by clenbuterol are mediated by beta 2-adrenoceptor stimulation. Although the increases in brain tyrosine and tryptophan were similar to increases in the plasma ratios of these amino acids to the sum of the other large neutral amino acids competing for transport into the brain, the disparity between the effects of ICI 118,551 in brain and plasma suggests that clenbuterol may also have a direct action in brain to regulate levels of aromatic amino acids. Since clenbuterol has been purported to have an antidepressant effect and since other antidepressants also increase brain tryptophan, this may be a common feature of antidepressant drug action.

Anticonvulsant and other effects of diazepam grow with time after a single treatment.

The hypothesis was tested that some of the effects in rats of the prototypical benzodiazepine, diazepam, would grow (i.e., sensitize) with the passage of time after acute administration as we had previously observed following stimulants, antidepressants, neuroleptics and other compounds. Our principal findings indicate that: 1) A single pretreatment with 0.5 mg/kg of diazepam significantly enhances the anticonvulsant effect of this same dose administered again two weeks later. 2) One injection of 2.5 mg/kg of diazepam significantly sensitizes the catalepsy and ptosis observed following the administration of haloperidol two weeks but not two hours later. These data provide the first evidence for time-dependent sensitization after benzodiazepines and perhaps by implication, of GABA neurons. They may also suggest that acute stimulation of GABA neurons triggers the progressive development of a long-term, antidopaminergic influence. Finally, they raise the question of whether the progressive anxiolytic influence seen during the first week or so of benzodiazepine therapy depends on the passage of time rather than repeated drug treatment.

Persistent sensitization of clonidine-induced hypokinesia following one exposure to a stressor: possible relevance to panic disorder and its treatment.

Based on previous findings of this laboratory that a single exposure to a stressful stimulus can induce a very long-lasting, sensitizing influence on the actions of drugs of multiple clinical and structural classes, the hypothesis was tested that a single stressful event might exert such an action on the alpha-2 norepinephrine agonist clonidine. Male rats received a single injection of the highly stressful convulsant stimulant pentylenetetrazole (PTZ; 40 mg/kg, IP) and were tested for locomotion after treatment with clonidine (25 micrograms/kg, IP) 1 h, 1 week or 2 weeks later. As expected, clonidine itself induced the hypokinesia typically associated with low doses of this compound. More importantly, all groups pretreated with PTZ showed a significant enhancement of this effect. The influence of PTZ 1 or 2 weeks prior to clonidine cannot be explained as simply due to a lingering impairment of locomotion by PTZ, since no hypokinesia was observed when activity in these groups was examined immediately prior to clonidine administration. Such impairment appears, however, to have been a factor in the heightened hypokinesia observed in the group receiving PTZ only 1 h before clonidine. Mass spectrometric analysis of norepinephrine and 3-methoxy-4-hydroxyphenylglycol levels in hippocampus and cortical areas failed to reveal any changes which could explain the persistent behavioral sensitization we observed. Plasma corticosterone determinations confirmed the stressful nature of PTZ but similarly failed to provide an explanation for the observed behavioral sensitization. The major finding of a long-term sensitizing influence on clonidine of an acute stressful experience is consistent with what is known of the precipitants and treatment of panic disorder.

Prior stress attenuates the analgesic response but sensitizes the corticosterone and cortical dopamine responses to stress 10 days later.

This study demonstrates that pre-exposure to stress influences subsequent effects of stress on pain sensitivity (stress-induced analgesia) and on plasma corticosterone and brain catecholamine activity. Animals exposed to a 30 min shock session (S1 = 8, 5.0 s shocks) 10 days earlier showed a significant attenuation of shock-induced analgesia, as measured by increased latency of tail withdrawal from a hot water bath immediately after a 40 s, 1.6 mA footshock (S2). Animals exposed to shock 10 days before testing also exhibited a higher plasma corticosterone response to testing than did all other groups. Norepinephrine (NE) levels in the frontal cortex and dopamine (DA) and dihydroxyphenylacetic acid (DOPAC) levels in the frontal cortex and nucleus accumbens were not altered in any group. However, the DOPAC/DA ratio in the frontal cortex was increased by analgesia testing, and this increase was enhanced only by the combination of shock 10 days before testing and shock immediately before the test (S1 + S2). These results are consistent with previous reports from this laboratory which indicate that an animal's acute response to stress is strongly influenced by its past history of stress.

One stressful event blocks multiple actions of diazepam for up to at least a month.

Based on recent findings of this laboratory, the hypothesis was tested that a single stressful encounter might have a persistent antidiazepam influence. Our results indicate that one exposure to a brief stressful event up to at least one month earlier prevented completely the effect of diazepam on pentylenetetrazole-induced changes in dopamine in the rat frontal cortex, elevations of plasma corticosterone levels and seizures.

Stimulation of cell membrane sodium transport activity by lithium: possible relationship to therapeutic action.

Because lithium is extruded from cells by means of coupled exchange for external sodium (Na+-Li+ countertransport), we hypothesized that clinical treatment with this agent could lead to significant augmentation of net cellular sodium influx. We therefore directly measured sodium influx in vitro using erythrocytes (RBCs) from 27 depressed bipolar patients. When cells were loaded with sufficient lithium to maximally stimulate Na+-Li+ countertransport activity (5.1 mmoles/1 RBCs), there was a significant 44% increase in mean sodium influx. To approximate clinical conditions more closely, we also studied sodium influx in a subset of eight subjects after loading cells with 0, 0.40, 0.66, and 1.55 mmoles lithium/1 RBCs. Over this range of lithium concentrations, sodium influx increased progressively. In separate experiments, we found that RBC sodium content measured in eight subjects did not change significantly during a 4-week course of lithium treatment. Thus, excess cellular sodium during such treatment may be extruded by increased activity of the membrane Na+-K+ pump, which has electrogenic properties and thereby could augment the membrane potential. In the nervous system, such an effect could stabilize cell membranes electrophysiologically, and possibly affect processes, such as behavioral sensitization or kindling, proposed to have a role in the development of recurrent affective disorders.