Effects of isradipine, a dihydropyridine-class calcium channel antagonist, on d-methamphetamine-induced reduction in hunger

1. The authors studied the effects of isradipine, a dihydropyridine-class calcium channel antagonist, on d-methamphetamine-induced changes in somatic and psychological perceptions of hunger state using a placebo-controlled, double-blind, Latin Square, cross-over design in 18 healthy volunteers. 2. D-methamphetamine significantly decreased these subjective ratings of hunger, presumably by increasing monoaminergic turnover. 3. Effects on hunger are hypothesized to be mediated by norepinephrine primarily, while dopamine plays only a modest role. Isradipine alone, an inhibitor of dopamine release, had no significant effect on the hunger measures. Additionally, isradipine pretreatment did not significantly alter d-methamphetamine's anorexic effects. 4. Isradipine may, therefore, not significantly modify the control of hunger in humans.

Lesser metatarsal stress fractures

Stress fractures continue to be a fact of military life. With appropriate attention to training issues, shoe gear, and physical training activities, however, their effect can be minimized.

Multidimensional chemotopic responses to n-aliphatic acid odorants in the rat olfactory bulb

In an effort to understand the means by which similar chemical odorants are encoded in the mammalian brain, we exposed rats to a homologous series of n-aliphatic acids and mapped the response of the entire olfactory bulb glomerular layer by using a high-resolution [14C]-2-deoxyglucose uptake technique. We found that these similar odorants evoked spatially clustered but distinct responses in the bulb that changed systematically with carbon chain length. In addition to these chemotopic responses, different odorants within the series evoked systematic differences along two other dimensions: amount of deoxyglucose uptake and extent of the glomerular layer showing high activity. Increases along these two dimensions also were correlated with increasing carbon number. The focal glomerular responses were mirrored by responses in deeper bulb layers. Decreasing the odorant concentration decreased the deoxyglucose uptake within focal regions. The focal regions of activity occurred in pairs involving both medial and lateral representations in the bulb, perhaps reflecting the paired medial and lateral projections of olfactory sensory neurons expressing specific types of odorant feature receptor proteins. The observed spatial pattern of response also may explain both the failure of some bulb lesions to interfere with behavioral olfactory responses and the success of other lesions in blocking olfactory responses. These data support a model of parallel, distributed processing of odorants along multiple dimensions. They also support the notion that analyses of the spatial relationships among odorant responses in the olfactory bulb can demonstrate aspects of the mechanism for odor chemical coding.

Upstream elements bestow T-cell and haemopoietic progenitor-specific activity on the granzyme B promoter

Cytotoxic T cells and early haemopoietic progenitors share the expression of a number of specific genes. Of these, granzyme B has attracted particular interest because of its role in inducing apoptosis during cytotoxic T cell-mediated target cell killing, and its potential role in the mobilisation and homeostasis of haemopoietic stem cells. Studies of granzyme B regulation should therefore yield valuable information concerning the molecular control of these processes, and also identify elements capable of directing gene expression to two cell types of relevance to gene therapy. Here we show that proximal regulatory elements already known to direct promoter activity in T cells are similarly active in haemopoietic progenitors. However, this activity is not strictly specific, since the promoter regions also direct low levels of reporter gene expression in fibroblasts. More importantly, we also report the presence of two previously unidentified clusters of DNaseI hypersensitive sites upstream from the murine granzyme B gene, and show that these regions impart both increased transcriptional activity and the appropriate cell type specificity on the granzyme B promoter. These upstream regulatory regions are therefore likely to play a key role in the coordination of granzyme B expression in vivo.

4-chloro-m-cresol triggers malignant hyperthermia in susceptible swine at doses greatly exceeding those found in drug preparations

BACKGROUND

Chlorocresols are used as preservatives in numerous commercial drugs that have been shown to induce myoplasmic Ca2+ release; the most potent isoform is 4-chloro-m-cresol. The aims of this study were to (1) examine the in vivo effects of 4-chloro-m-cresol on swine susceptible to malignant hyperthermia and (2) contrast in vivo versus in vitro dose-response curves.

METHODS

Susceptible swine (weight: 38.5 kg+/-3.55 kg) were anesthetized and monitored for variations in physiological responses, including end-tidal CO2, heart rate, blood pressure, blood chemistry, and temperatures. In the first animals studied, 4-chloro-m-cresol, at equivalent cumulative doses of 0.14, 0.28, 0.57, 1.14, 2.27, 4.54, and 9.08 mg/kg (n = 3; 12.5, 25, 50, 100, 200, 400, and 800 micromol) were administered, and in a second group, larger doses were used: 1.14, 3.41, 7.95, 17.04 (n = 4), and/or 35.22 (n = 1) mg/kg (100, 300, 700, 1,500, and/or 3,100 micromol). For comparison, in vitro rectus abdominis muscle preparations obtained from normal and susceptible swine were exposed to 4-chloro-m-cresol, at cumulative concentrations of 6.25, 12.5, 25, 50, 100, 200, 400, 800, and 1,600 micromol; standard caffeine and halothane contracture testing was also performed.

RESULTS

Episodes of malignant hyperthermia were not triggered in response to administration of low doses of 4-chloro-m-cresol, but transient cardiovascular reactions (e.g., tachycardia, arrhythmias, and hypotension) were observed. Subsequently, episodes in these animals were triggered when halothane (0.87; 1 MAC) and succinylcholine (2 mg/kg) were given. Animals administered the higher doses of 4-chloro-m-cresol all had fulminant episodes of malignant hyperthermia that were fatal, when equivalent cumulative concentrations were greater than 1,500 micromol. The levels of 4-chloro-m-cresol in the plasma rapidly decreased: e.g., 5 min postadministration of the 1,500-micromol dose, the mean plasma level was only 52+/-18 micromol (n = 4). Hemolysis was detected following 4-chloro-m-cresol administration at concentrations > 200 micromol. In vitro, muscle from susceptible animals elicited contractures > 200 mg at 50-micromol bath concentrations of 4-chloro-m-cresol (n = 29), whereas normal muscle did not elicit such contractures until bath concentrations were > 800 micromol (n = 10).

CONCLUSIONS

4-chloro-m-cresol is a trigger of malignant hyperthermia in susceptible swine, but only when serum concentrations are far above those likely to be encountered in humans. A relatively low concentration of 4-chloro-m-cresol, 50 micromol, is sufficient to activate sarcoplasmic [Ca+2] release in vitro (e.g., contractures); this same bolus dose administered in vivo (0.57 mg/kg) has minimal effects due to the rapid decrease in its plasma levels.

Isradipine, a dihydropyridine-class calcium channel antagonist, attenuates some of d-methamphetamine's positive subjective effects: a preliminary study

RATIONALE

Dopamine (DA) pathways in the midbrain mediate d-methamphetamine's rewarding effects associated with its abuse liability. Isradipine, a dihydropyridine-class calcium channel antagonist, reduces the rewarding effects of psychostimulants such as cocaine and d-amphetamine, presumably by antagonizing these central DA pathways. This is the first experiment to test the hypothesis that the rewarding effects of d-methamphetamine, like other psychostimulants, can be reduced by isradipine.

OBJECTIVE

We studied the effects of high dose isradipine (0.21 mg/kg orally), on the positive subjective effects associated with the abuse liability of low and high dose d-methamphetamine (0.21 mg/kg and 0.42 mg/kg orally, respectively).

METHODS

Using a double-blind, double-dummy, placebo-controlled, Latin-Square, cross-over design, 18 healthy male and female volunteers received each of the following six treatments separated by a rest period of 2-7 days: a) placebo+placebo; b) low-dose d-methamphetamine+placebo); c) high-dose d-methamphetamine+placebo; d) high dose isradipine+placebo); e) low-dose d-methamphetamine+high dose isradipine, and f) high-dose d-methamphetamine+high dose isradipine.

RESULTS

d-Methamphetamine produced orderly increases in positive subjective measures of both stimulation and mood. Pre-treatment with isradipine significantly reduced some of these positive subjective effects and craving for d-methamphetamine.

CONCLUSION

Isradipine as an anti-reward or craving reducing medication is a promising therapeutic agent for the treatment of d-methamphetamine dependence.

Relationships of plasma tryptophan availability to course of illness and clinical features of alcoholism: a preliminary study

RATIONALE

Serotonergic (5-HT) mechanisms may be involved in impulse control (including antisocial behavior) across psychiatric syndromes. Age of onset may differentiate alcoholics on psychopathological characteristics associated with impulse control, especially mood disturbance, hostility, and a broad range of antisocial behaviors. Thus, there may be a predictable relationship between markers of 5-HT function and age of onset-related characteristics.

OBJECTIVE

We tested the hypothesis that there would be a predictable relationship between the ratio of plasma tryptophan to large neutral amino acids (i.e. TRYP/LNAA ratio), a marker of 5-HT function, age of onset and related psychopathological characteristics associated with impulse control.

METHODS

Fifty-eight male and female DSM-IV diagnosed alcoholics attending an outpatient treatment center completing a comprehensive psychopathological assessment, and from whom blood samples were obtained.

RESULTS

Plasma TRYP/LNAA ratio was positively correlated with symptoms of dysphoria, and negatively associated with harm avoidance on Cloninger's Temperament and Character Inventory. Low tryptophan availability was associated with antisocial-type personality characteristics. Interestingly, the few (nine) subjects who had both early onset alcoholism and antisocial personality disorder had a higher plasma tryptophan but similar TRYP/LNAA ratio to the others.

CONCLUSIONS

These data suggest that a low plasma TRYP/LNAA ratio is associated with susceptibility to anxiety, antisocial-type personality characteristics, and an early age of onset for alcoholism. In contrast, a high plasma TRYP/LNAA ratio is associated with a later onset of alcoholism and dysphoria.

Results of a JCAHO accreditation survey in a university student health center

This article describes the results of our initial accreditation survey by the Joint Commission on the Accreditation of Healthcare Organizations (JCAHO). Strengths, as well as supplemental recommendations in our clinic and laboratory programs, were identified during the accreditation survey. Mechanisms for addressing the supplemental recommendations are described in this report. Direct and indirect costs of the accreditation process also are discussed.

Epidurography and therapeutic epidural injections: technical considerations and experience with 5334 cases

BACKGROUND AND PURPOSE

Even in experienced hands, blind epidural steroid injections result in inaccurate needle placement in up to 30% of cases. The use of fluoroscopy and radiologic contrast material provides confirmation of accurate needle placement within the epidural space. We describe our technique and experience with contrast epidurography and therapeutic epidural steroid injections, and review the frequency of systemic and neurologic complications.

METHODS

Epidural steroid injections were performed in 5489 consecutive outpatients over a period of 5 1/2 years by three procedural neuroradiologists. In 155 cases (2.8%), the injections were done without contrast material owing to either confirmed or suspected allergy. The remaining 5334 injections were performed after epidurography through the same needle. Patients and referring clinicians were instructed to contact us first regarding complications or any problem potentially related to the injection. In addition, the referring clinicians' offices were instructed to contact us regarding any conceivable procedure-related complications.

RESULTS

Only 10 patients in the entire series required either oral (n = 5) or intravenous (n = 5) sedation. Four complications (0.07%) required either transport to an emergency room (n = 2) or hospitalization (n = 2). None of the complications required surgical intervention, and all were self-limited with regard to symptoms and imaging manifestations. Fluoroscopic needle placement and epidurography provided visual confirmation of accurate needle placement, distribution of the injectate, and depiction of epidural space disease.

CONCLUSION

Epidurography in conjunction with epidural steroid injections provides for safe and accurate therapeutic injection and is associated with an exceedingly low frequency of untoward sequelae. It can be performed safely on an outpatient basis and does not require sedation or special monitoring.

Flexible sigmoidoscopy: screening for colorectal cancer

Flexible sigmoidoscopy is an important screening procedure because of its ability to detect early changes in the distal colon. The 60-cm flexible sigmoidoscope provides excellent visualization with minimal discomfort to patients. Successful sigmoidoscopy requires adequate patient preparation, proper equipment and an experienced examiner who can recognize both normal and abnormal findings. Complications arising from sigmoidoscopy are rare, but patients may experience some cramping, gas or watery stools. Screening and primary preventive measures, including regular exercise and increased dietary fiber intake, can lower the morbidity and mortality associated with colorectal cancer.

The rapid assessment of fatigue severity in cancer patients: use of the Brief Fatigue Inventory

BACKGROUND

Fatigue is a major disease and treatment burden for cancer patients. Several scales have been created to measure fatigue, but many are long and difficult for very ill patients to complete, or they are not easy to translate for non-English speaking patients. The Brief Fatigue Inventory was developed for the rapid assessment of fatigue severity for use in both clinical screening and clinical trials.

METHODS

The study enrolled 305 consecutive, consenting adult inpatients and outpatients with cancer who could understand and complete the self-report measures used in the study. The same instruments also were administered to 290 community-dwelling adults to obtain a comparison sample. Research staff completed a form that indicated the primary site and stage of the cancer, rated the Eastern Cooperative Oncology Group performance status of the patient, described the characteristics of the pain, and described the current pain treatment being provided to the patients.

RESULTS

The BFI was shown to be an internally stable (reliable) measure that tapped a single dimension, best interpreted as severity of fatigue. It correlated highly with similar fatigue measures. Greater than 98% of patients were able to complete it. A range of scores defining severe fatigue was identified.

CONCLUSIONS

The BFI is a reliable instrument that allows for the rapid assessment of fatigue level in cancer patients and identifies those patients with severe fatigue.

Flexible sigmoidoscopy: screening for colorectal cancer

Flexible sigmoidoscopy is an important screening procedure because of its ability to detect early changes in the distal colon. The 60-cm flexible sigmoidoscope provides excellent visualization with minimal discomfort to patients. Successful sigmoidoscopy requires adequate patient preparation, proper equipment and an experienced examiner who can recognize both normal and abnormal findings. Complications arising from sigmoidoscopy are rare, but patients may experience some cramping, gas or watery stools. Screening and primary preventive measures, including regular exercise and increased dietary fiber intake, can lower the morbidity and mortality associated with colorectal cancer.

Ethnic differences in the neuroleptic treatment of schizophrenia

Ethnic differences in psychopharmacological treatment have received much attention in the last two decades. Most of the research efforts conducted so far in the field of ethnopsychopharmacology have focused on comparative responses to neuroleptics and lithium between white and Asian-American patients, and on comparative responses to tricyclic antidepressants among white, African-American and Hispanic patients. In this article we focus on the response to neuroleptic treatment among white, African-American and Hispanic patients suffering from schizophrenia. Our findings suggest that Hispanic patients need lower doses of neuroleptics than white or African-American patients to attain a similar response in the treatment of schizophrenia. Additionally, our study suggests that, if weight is taken to consideration, African-American patients need the same dose of neuroleptics as do white patients in order to attain a similar response in the treatment of schizophrenia. Further studies are suggested to confirm our findings.

Medications to treat alcoholism

Advances in neurobiology support the development of medications to treat alcoholism by modifying the activity of specific chemical messengers (i.e., neurotransmitters) in the brain. Among the most promising new medications is acamprosate, which appears to decrease the intensity of craving after a person has stopped drinking. Naltrexone (ReVia) has been shown to decrease alcohol consumption, although its practical effectiveness may be compromised by poor patient compliance and other factors. Ondansetron shows promise for decreasing drinking and increasing abstinence rates among early onset alcoholics, who respond poorly to psychosocial treatment alone. Researchers are investigating whether the use of specific medications in combination can further enhance their effectiveness. Additional research is needed to determine how medications interact with different psychosocial factors and treatments.

Contemporary spinal CT applications

Despite the widespread availability of MR imaging, CT remains a vital modality for the evaluation of disorders of the spine, offering superior assessment of bone abnormalities, as well as calcification. Advances in technology have enhanced the capabilities of CT, providing exciting new options for data rendering and display. Depending on the clinical indication, either CT or MR may be the modality of choice in the evaluation of spinal disease.

Achieving JCAHO accreditation in a university student health center

Of the approximately 1,500 colleges and universities in the United States, only approximately 100 university student health centers are accredited by either of the two major ambulatory healthcare accreditation agencies. The accreditation process can be daunting. We found few examples in the accreditation literature that assisted us in our endeavor. This article is designed as a primer to assist college health center administrators in achieving accreditation by the Joint Commission on Accreditation of Healthcare Organizations.

Inhibiting geranylgeranylation blocks growth and promotes apoptosis in pulmonary vascular smooth muscle cells

The activity of small GTP-binding proteins is regulated by a critical step in posttranslational processing, namely, the addition of isoprenoid lipids farnesyl and geranylgeranyl, mediated by the enzymes farnesyltransferase (FTase) and geranylgeranyltransferase I (GGTase I), respectively. We have developed compounds that inhibit these enzymes specifically and in this study sought to determine their effects on smooth muscle cells (SMC) from the pulmonary microvasculature. We found that the GGTase I inhibitor GGTI-298 suppressed protein geranylgeranylation and blocked serum-dependent growth as measured by thymidine uptake and cell counts. In the absence of serum, however, GGTI-298 induced apoptosis in these cells as measured by both DNA staining and flow cytometry. The FTase inhibitor FTI-277 selectively inhibited protein farnesylation but had a minor effect on growth and no effect on apoptosis. To further investigate the role of geranylgeranylated proteins in apoptosis, we added the cholesterol synthesis inhibitor lovastatin, which inhibits the biosynthesis of farnesyl and geranylgeranyl pyrophosphates. This also induced apoptosis, but when geranylgeraniol was added to replenish cellular pools of geranylgeranyl pyrophosphate, apoptosis was reduced to baseline. In contrast, farnesol achieved only partial rescue of the cells. These results imply that geranylgeranylated proteins are required for growth and protect SMC against apoptosis. GGTase I inhibitors may be useful in preventing hyperplastic remodeling and may have the potential to induce the apoptotic regression of established vascular lesions.

Reconstructing a sense of self in patients with chronic mental illness

TOPIC

The loss and reconstruction of self in patients with a chronic mental illness.

PURPOSE

To describe the loss of self and its reconstruction.

SOURCES

The authors' own clinical work and review of the literature.

CONCLUSIONS

Nurses can help patients who have undergone a loss of self to discover a more active sense of self, take stock of the self, put the self into action, and use the enhanced self as a refuge. This process involves the fostering of hope.

How to build a specialty MSO

The specialty-based management services organization (MSO), with its focus on management support, contracting, information systems and related benefits, is intended to help preserve specialist physician access to patients. It does this by enabling the MSO's physicians to clearly differentiate themselves from other specialist providers. To be successful, however, an MSO must be built on a shared vision of its goals. Considerations of structural, operational, ownership, antitrust and governance concerns should all follow from that ground. All parties should recognize that MSOs are best in the long-term; they are not short-term solutions.

Spatial coding of odorant features in the glomerular layer of the rat olfactory bulb

In order to determine whether molecular features of odorants are represented spatially in the glomerular layer of the olfactory bulb, we used metabolic mapping of [14C] 2-deoxyglucose uptake in rats exposed to equal vapor concentrations of odorants differing systematically in chemical structure. The odorants were ethyl acetate, ethyl butyrate, isoamyl acetate, and isoamyl butyrate. Statistical analysis of anatomically standardized arrays of uptake revealed that each ester produced a characteristic spatial pattern of activity in the glomerular layer. The patterns were similar in different rats exposed to the same odorant, and their complexity increased with increasing odorant carbon number. This finding suggests that the presence of more potentially recognized molecular features is associated with a greater number of activated receptors. Individual regions of the glomerular layer responded specifically to isoamyl esters, and other regions preferred ethyl esters. Regions of similar specificity occurred in lateral and medial aspects of the bulb, the medial representation being more caudal and ventral than the lateral one. This pattern correlates with projections of olfactory sensory neurons expressing the same putative olfactory receptor gene. The patterns overlapped greatly in the posterolateral and posteromedial glomerular layer, a finding one should predict, given the large overlap in chemical structure across the aliphatic esters. Thus, molecular features appear to be encoded spatially in the glomerular layer, and the identity of the odorant may be determined by a subsequent decoding of the combination of molecular features represented in the glomerular layer.

How to save distressed IDS-physician marriages: a case study

A hospital-driven IDS that encounters serious problems resulting from ownership of a physician practice should address those problems by focusing on three core areas: vision and leadership, effectiveness of operations, and physician compensation arrangements. If changes in these areas do not lead to improvements, the IDS may need to consider organizational restructuring. In one case study, a hospital-driven IDS faced the problem of owning a poorly performing MSO with a captive physician group. The IDS's governing board determined that the organization lacked effective communication with the physicians and that realization of the organization's vision would require greater physician involvement in organizational decision making. The organization is expected to undergo some corporate reorganization in which physicians will acquire an equity interest in the enterprise.

Effects of acute and chronic doses of naltrexone on ethanol self-administration in rhesus monkeys

The effects of acute and chronic administration of intramuscular naltrexone (0.1, 0.3, 1.0, and 3.0 mg/kg) on oral ethanol (8%) self-administration were examined. Naltrexone (1.0 mg/kg) effects on the self-administration of ethanol concentrations ranging from 0.5 to 8% (w/v) were also investigated. Rhesus monkeys with substantial histories of drug and ethanol drinking served as subjects. During daily 3-hr sessions, monkeys were presented with ethanol solutions, concurrently available with water, under fixed-ratio reinforcement schedules. Naltrexone decreased the consumption of ethanol (g/kg). Biphasic temporal effects were observed within sessions. Naltrexone dose-dependently decreased the number of ethanol deliveries by a maximum of 56% (n = 18; 3 monkeys x 6 sessions) during the first hour of the session. During the second and third hours, however, ethanol intake recovered such that maximum decreases over the 3-hr session were approximately 27% (n = 18), and the mean decrease was 16% (n = 18). Often marked tolerance was observed, such that the effects of acute naltrexone administration were greater than effects after chronic administration. The self-administration of low ethanol concentrations (< or =2% w/v) was increased in several monkeys, by up to 340%, after naltrexone pretreatment. In summary, the effects of naltrexone on ethanol self-administration, in drug- and alcohol-experienced rhesus monkeys, are not characterized by unitary decreases in measures of ethanol self-administration. Rather, differential naltrexone effects were a function of experimental parameters, including the dose and number of naltrexone injections, the ethanol concentration, and the time point of measurement.

New Stark regulations: Key issues for health care decision-makers

On Jan. 9, 1998, The Health Care Financing Administration (HCFA) issued long-awaited Proposed Regulations for what has become known as Stark II. The regulations are subject to a comment period and later refinement. However, they lay out HCFA's basic understanding of what kinds of practices constitute an illegal kickback. In general terms, the law prohibits physicians from referring Medicare or Medicaid patients to entities with which they (or an immediate family member) have a "financial relationship" for the delivery of a specific list of designated health services. There are, however, exceptions also included in the new proposal. Group practices will want to pay special attention to HCFA's new definition of group practice.

The familial aggregation of adolescent suicide attempts

The objective of this study was to determine whether the familial aggregation of suicidal behaviour is explained by the familial aggregation of personality disorder and aggression. The relatives of 62 clinically referred adolescent suicide attempters were compared with 70 never-suicidal psychiatric controls. The first-degree relatives of the suicide attempters had a higher rate of suicide attempts/completion than those of the psychiatric controls. This rate remained significantly higher after controlling for Axis I and II differences in the probands and the relatives, but familial personality disorder was significantly associated with suicidal risk in probands. Among the adolescent attempters, high scores on a measure of assaultiveness were associated with significantly higher familial rates of suicide attempts/completion. Our results support the hypothesis that suicidal behaviour may be transmitted as a trait independent of Axis I and II psychopathology but that, in addition, personality disorder has a role in the transmission of suicidal behaviour. An interrelationship between proband assaultiveness and the familial aggregation of suicidality was noted.