Utilization of submandibular ultrasound in assessing upper airway changes following the administration of propofol

Background and Aims

Our study aimed to use submandibular ultrasound to measure upper airway parameters before and after induction dose of propofol in order to further understand upper airway changes that occur during induction of anesthesia. Measuring the changes that occur in airway anatomy due to the hypotonic effects of induction agents will allow for a deeper understanding of airway management.

Material and Methods

We enrolled 39 patients between November 2021 and January 2022. Submandibular ultrasound was used to measure tongue thickness, geniohyoid muscle thickness, the distance between the lingual arteries (DLA), lateral pharyngeal wall thickness, and hyomental distance before and after administration of induction doses of the commonly used, sedative-hypnotic agent, propofol.

Results

The mean DLA increased significantly after propofol administration, from 3.62 ± 0.63 cm to 3.79 ± 0.56 cm (P < 0.001). The mean tongue thickness was 4.89 ± 0.51 cm and decreased significantly to a mean of 4.62 ± 0.50 cm after propofol administration (P < 0.001). The change in DLA measurements after propofol administration decreased significantly as STOP-BANG score increased (r = -0.344, P = 0.037). However, DLA measurements when patients were awake increased significantly with an increase in the STOP-BANG score (r = 0.351, P = 0.031).

Conclusion

These findings suggest that propofol widens and flattens the tongue, which are changes that may contribute to difficult airway management. Given the quick and non-invasive nature of ultrasound, further studies should evaluate the role of submandibular ultrasound for understanding the upper airway and airway management in various populations.

Health care utilization and costs of systemic lupus erythematosus in the United States: A systematic review

OBJECTIVES

To evaluate health care utilization and costs for patients with systemic lupus erythematosus (SLE) by disease severity.

METHODS

We searched PubMed and Embase from January 2000 to June 2020 for observational studies examining health care utilization and costs associated with SLE among adults in the United States. Two independent reviewers reviewed the selected full-text articles to determine the final set of included studies. Costs were converted to 2020 US $.

RESULTS

We screened 9224 articles, of which 51 were included. Mean emergency department visits were 0.3-3.5 per year, and mean hospitalizations were 0.1-2.4 per year (mean length of stay 0.4-13.0 days). Patients averaged 10-26 physician visits/year. Mean annual direct total costs were $17,258-$63,022 per patient and were greater for patients with moderate or severe disease ($19,099-$82,391) compared with mild disease ($12,242-$29,233). Mean annual direct costs were larger from commercial claims ($24,585-$63,022) than public payers (Medicare and Medicaid: $18,302-$27,142).

CONCLUSIONS

SLE remains a significant driver of health care utilization and costs. Patients with moderate to severe SLE use more health care services and incur greater direct and indirect costs than those with mild disease.

Role of Submandibular Ultrasound in Airway Management of a Patient With Angioedema

Angioedema is one of several life-threatening clinical scenarios that lacks clarity on when a patient requires intubation. We present a case of angiotensin-converting enzyme-inhibitor-induced angioedema with peri-oral swelling and normal airway measurements on ultrasound, who was intubated with an abundance of caution and extubated successfully. Current tests for intubation and extubation, such as traditional bedside assessments and the cuff leak test, vary in reliability for angioedema and similar urgent situations. Submandibular ultrasound is a quick, low-cost, non-invasive method for determining quantitative criteria for and assessing when intubation and extubation is indicated, which may lead to improved quality of care and patient safety.

Healthcare Utilization and Costs of Systemic Lupus Erythematosus by Disease Severity in the United States

OBJECTIVE

To quantify healthcare utilization and costs by disease severity for patients with systemic lupus erythematosus (SLE) in the United States.

METHODS

We conducted descriptive analyses of Humedica electronic health record (EHR) data from 2011 to 2015 (utilization analysis) and integrated Optum administrative claims/Humedica EHR data from 2012 to 2015 (cost analysis) for patients with SLE. All-cause utilization outcomes examined were hospitalizations, outpatient visits, emergency department (ED) visits, and prescription drug use. Analyses of costs stratified by disease severity were limited to patients enrolled in an Optum-participating health insurance plan for ≥ 1 year after the earliest observed SLE diagnosis date. Costs were converted to 2016 US dollars (US$).

RESULTS

Healthcare utilization was evaluated in 17,257 patients with SLE. Averaged over the 2011-2015 study period, 13.7% of patients had ≥ 1 hospitalization per year, 25.7% had ≥ 1 ED visit, and 94.4% had ≥ 1 outpatient visit. Utilization patterns were generally similar across each year studied. Annually, 88.0% of patients had ≥ 1 prescription, including 1.3% who used biologics. Biologic treatment doubled between 2011 (0.7%) and 2015 (1.4%). Cost analyses included 397 patients. From 2012 to 2015, patients with severe SLE had mean annual costs of $52,951, compared with $28,936 and $21,052 for patients with moderate and mild SLE, respectively. Patients with severe SLE had increased costs in all service categories: inpatient, ED, clinic/office visits, and pharmacy.

CONCLUSION

Patients from the US with SLE, especially individuals with moderate or severe disease, utilize significant healthcare resources and incur high medical costs.

Association between organ damage and mortality in systemic lupus erythematosus: a systematic review and meta-analysis

OBJECTIVE

At least half of patients with systemic lupus erythematosus (SLE) develop organ damage as a consequence of autoimmune disease or long-term therapeutic steroid use. This study synthesised evidence on the association between organ damage and mortality in patients with SLE.

DESIGN

Systematic review and meta-analysis.

METHODS

Electronic searches were performed in PubMed, Embase, Cochrane Library and Latin American and Caribbean Health Sciences Literature for observational (cohort, case-control and cross-sectional) studies published between January 2000 and February 2017. Included studies reported HRs or ORs on the association between organ damage (measured by the Systemic Lupus International Collaborating Clinics/American College of Rheumatology Damage Index (SDI) score) and mortality. Study quality was assessed using the modified Newcastle-Ottawa assessment. Pooled HRs were obtained using the DerSimonian and Laird random-effects model. Heterogeneity was assessed using the Cochrane Q (Q) and I² statistics.

RESULTS

The search yielded 10 420 articles, from which 21 longitudinal studies were selected. Most studies (85%) were of high quality. For 10 studies evaluating organ damage (SDI) as a continuous variable and reporting HR as a measure of association, a 1-unit increase in SDI was associated with increased mortality; pooled HR was 1.34 (95% CI: 1.24 to 1.44, p<0.001; Q p=0.027, I²=52.1%). Exclusion of one potential outlying study reduced heterogeneity with minimal impact on pooled HR (1.33 (95% CI: 1.25 to 1.42), p<0.001, Q p=0.087, I²=42.0%). The 11 remaining studies, although they could not be aggregated because of their varying patient populations and analyses, consistently demonstrated that greater SDI was associated with increased mortality.

CONCLUSIONS

Organ damage in SLE is consistently associated with increased mortality across studies from various countries. Modifying the disease course with effective therapies and steroid-sparing regimens may reduce organ damage, improve outcomes and decrease mortality for patients with SLE.

Coverage of Nonpharmacologic Treatments for Low Back Pain Among US Public and Private Insurers

Importance

Despite epidemic rates of addiction and death from prescription opioids in the United States, suggesting the importance of providing alternatives to opioids in the treatment of pain, little is known regarding how payers' coverage policies may facilitate or impede access to such treatments.

Objective

To examine coverage policies for 5 nonpharmacologic approaches commonly used to treat acute or chronic low back pain among commercial and Medicare Advantage insurance plans, plus an additional 6 treatments among Medicaid plans.

Design, Setting, and Participants

Cross-sectional study of 15 commercial, 15 Medicaid, and 15 Medicare Advantage health plans for the 2017 calendar year in 16 states representing more than half of the US population. Interviews were conducted with 43 senior medical and pharmacy health plan executives from representative plans.

Main Outcomes and Measures

Medical necessity and coverage status for the treatments examined, as well as the use of utilization management tools and cost-sharing magnitude and structure.

Results

Commercial and Medicare insurers consistently regarded physical and occupational therapy as medically necessary, but policies varied for other therapies examined. Payers most commonly covered physical therapy (98% [44 of 45 plans]), occupational therapy (96% [43 of 45 plans]), and chiropractic care (89% [40 of 45 plans]), while transcutaneous electrical nerve stimulation (67% [10 of 15 plans]) and steroid injections (60% [9 of 15 plans]) were the most commonly covered among the therapies examined for Medicaid plans only. Despite evidence in the literature to support use of acupuncture and psychological interventions, these therapies were either not covered by plans examined (67% of all plans [30 of 45] did not cover acupuncture) or lacked information about coverage (80% of Medicaid plans [12 of 15] lacked information about coverage of psychological interventions). Utilization management tools, such as prior authorization, were common, but criteria varied greatly with respect to which conditions and what quantity and duration of services were covered. Interviewees represented 6 Medicaid managed care organizations, 2 Medicare Advantage or Part D plans, 9 commercial plans, and 3 trade organizations (eg, Blue Cross Blue Shield Association). Interviews with plan executives indicated a low level of integration between the coverage decision-making processes for pharmacologic and nonpharmacologic therapies for chronic pain.

Conclusions and Relevance

Wide variation in coverage of nonpharmacologic treatments for low back pain may be driven by the absence of best practices, the administrative complexities of developing and revising coverage policies, and payers' economic incentives. Such variation suggests an important opportunity to improve the accessibility of services, reduce opioid use, and ultimately improve the quality of care for individuals with chronic, noncancer pain while alleviating the burden of opioid addiction and overdose.

Prescription Drug Coverage for Treatment of Low Back Pain Among US Medicaid, Medicare Advantage, and Commercial Insurers

IMPORTANCE

Despite unprecedented injuries and deaths from prescription opioids, little is known regarding medication coverage policies for the treatment of chronic noncancer pain among US insurers.

OBJECTIVE

To assess medication coverage policies for 62 products used to treat low back pain.

DESIGN, SETTING, AND PARTICIPANTS

A cross-sectional study of health plan documents from 15 Medicaid, 15 Medicare Advantage, and 20 commercial health plans in 2017 from 16 US states representing more than half the US population and 20 interviews with more than 43 senior medical and pharmacy health plan executives from representative plans. Data analysis was conducted from April 2017 to January 2018.

MAIN OUTCOMES AND MEASURES

Formulary coverage, utilization management, and patient out-of-pocket costs.

RESULTS

Of the 62 products examined, 30 were prescription opioids and 32 were nonopioid analgesics, including 10 nonsteroidal anti-inflammatory drugs, 10 antidepressants, 6 muscle relaxants, 4 anticonvulsants, and 2 topical analgesics. Medicaid plans covered a median of 19 opioids examined (interquartile range [IQR], 12-27; median, 63%; IQR, 40%-90%) and a median of 22 nonopioids examined (IQR, 21-27; median, 69%; IQR, 66%-83%). Medicare Advantage plans covered similar proportions (median [IQR], opioids: 17 [15-22]; 57% [50%-73%]; nonopioids: 22 [22-26]; 69% [69%-81%]), while commercial plans covered more opioids (median [IQR], 23 [21-25]; 77% [70%-84%]) and nonopioids (median [IQR], 26 [24-27]; 81% [74%-85%]). Utilization management strategies were common for opioids in Medicaid plans (median [IQR], 15 [11-20] opioids; 91% [74%-97%]), Medicare Advantage plans (median [IQR], 15 [9-18] opioids; 100% [100%-100%]), and commercial plans (median [IQR], 16 [11-20] opioids; 74% [53%-94%]), generally relying on 30-day quantity limits rather than prior authorization. Step therapy was especially uncommon. Many of the nonopioids examined also were subject to utilization management, especially quantity limits (24%-32% of products across payers) and prior authorization (median [IQR], commercial plans: 2 [0-3] nonopioids; 9% [0%-11%]; Medicare Advantage plans: 4 [3-5] nonopioids; 19% [10%-23%]; Medicaid plans: 6 [1-13] nonopioids; 38% [2%-52%]). Among commercial plans, the median plan placed 18 opioids (74%) and 20 nonopioids (81%) in tier 1, which was associated with a median out-of-pocket cost of $10 (IQR, $9-$10) per 30-day supply. Key informant interviews revealed an emphasis on increasing opioid utilization management and identifying high-risk prescribers and patients, rather than promoting comprehensive strategies to improve treatment of chronic pain or better integrating pharmacologic and nonpharmacologic alternatives to opioids.

CONCLUSIONS AND RELEVANCE

Given the effect of coverage policies on drug utilization and health outcomes, these findings provide an important opportunity to evaluate how formulary placement, utilization management, copayments, and integration of nonpharmacologic treatments can be optimized to improve pain care while reducing opioid-related injuries and deaths.

Physician attitudes and experiences with Maryland's prescription drug monitoring program (PDMP)

AIMS

Physicians' use of prescription drug monitoring programs (PDMPs) varies by state. Among Maryland physicians, we sought to (1) estimate the PDMP impact on changes in opioid prescribing, (2) approximate the scope of PDMP utility and (3) determine the barriers to PDMP use after its 2013 implementation.

DESIGN

Cross-sectional postal survey linking responses to state records of PDMP registration and use, randomly sampling physicians within specialty and registration strata.

SETTING

Maryland, USA.

PARTICIPANTS

A total of 1000 surveyed primary care, pain and emergency medicine physicians stratified into three subpopulations: PDMP non-registrants, PDMP registrants who were non-users and PDMP users; 405 respondents (44%) of 916 eligible physicians were analysed.

MEASUREMENTS

Primary outcome measure was PDMP use. Key predictors were clinic characteristics, including type of practice and number of patients prescribed opioids.

FINDINGS

No response-wave bias was identified. Seventy per cent of physicians believed PDMP access decreased their amount and increased their comfort level in prescribing opioids. Three-fourths (74%) of PDMP users reported the data very useful for informing opioid prescribing, although one-fifth (20%) reported difficulty accessing the data. Commonly reported barriers to PDMP use were lack of knowledge regarding its existence and registration process. In multivariable analysis after adjusting for key clinic characteristics, practicing at a managed care organization was associated with lower PDMP use [incidence rate ratio (IRR) = 0.19, 95% confidence interval (CI) = 0.05-0.73]. Conversely, physicians who prescribed opioids for more than 50 patients accessed the PDMP three times as often as those prescribing opioids for fewer than 10 patients monthly (IRR = 3.00, 95 % CI = 1.07-8.43).

CONCLUSIONS

In this survey of Maryland, USA physicians, most participants reported that prescription drug monitoring programs (PDMPs) improved their opioid prescribing by decreasing prescription amounts and increasing comfort with prescribing opioids. Common barriers to PDMP use included not knowing about the program, registration difficulties and data access difficulties.

Estrogen-modulated estrogen receptor x Pit-1 protein complex formation and prolactin gene activation require novel protein synthesis

Both estrogen receptor (ER) and Pit-1 proteins are essential for the estrogen-activated expression of the rat prolactin gene. Our results show that ER.Pit-1 protein complex formation is reduced by estrogen in GH3 and PR1 rat pituitary tumor cells. In the latter, this decrease was blocked by cycloheximide, a protein synthesis inhibitor. On the other hand, the direct addition of estrogen to PR1 cell lysates had no effect on the formation of ER.Pit-1 complexes. Estrogen-activated prolactin gene expression was also inhibited by cycloheximide, suggesting that some form of protein synthesis is involved in ER.Pit-1 complex formation and subsequent prolactin gene activation. In support of this notion, we showed that estrogen-induced regulation of ER.Pit-1 complex formation could be transferred from cell lysates prepared from estrogen-treated PR1 cells to control cell lysates. This is not true for GH3 cells; instead, direct administration of estrogen to GH3 cell lysates readily abolished ER.Pit-1 protein complex formation in a dose-dependent manner, and such estrogen-induced regulation was blocked by the antiestrogen ICI 182,780. These findings thus indicate that 1) interaction between ER and Pit-1 proteins is estrogen-regulated in ways specific to different cell types, and 2) auxiliary protein factor synthesis may be involved in this process.

Interaction between estrogen receptor and Pit-1 protein is influenced by estrogen in pituitary cells

The estrogen responsiveness of the rat prolactin gene expression requires the presence of both the estrogen receptor (ER) and the tissue-specific transcription factor, Pit-1 protein. We performed protein interaction assays using anti-rat Pit-1 antiserum (a-rPit-1) to investigate the physical interactions which occur between ER and Pit-1 proteins following estrogen treatment. After fusing maltose binding protein (MBP) and Pit-1 protein, we used the resulting MBP Pit-1 fusion protein to prepare a-rPit-1. Our results show that the estrogen receptor readily co-precipitated with the Pit-1 protein drawn from the lysates of two prolactin-expressing pituitary cell lines GH3 and PR1. The rate of precipitation appears to be both estrogen- and time-dependent. Cellular levels of estrogen receptors and Pit-1 proteins did not show significant changes during the time of estrogen treatment. We therefore suggest that an estrogen-dependent physical interaction between ER and Pit-1 protein exists in vivo, and that this interaction may play an important role in the regulation of prolactin gene expression.

A multiaxial constitutive law for mammalian left ventricular myocardium in steady-state barium contracture or tetanus

The constitutive law of the material comprising any structure is essential for mechanical analysis since this law enables calculation of the stresses from the deformations and vice versa. To date, there is no constitutive law for actively contracting myocardial tissue. Using 2,3-butanedione monoxime to protect the myocardium from mechanical trauma, we subjected thin midwall slices of rabbit myocardium to multiaxial stretching first in the passive state and then during steady-state barium contracture or during tetani in ryanodine-loaded tissue. Assuming transverse isotropy in both the passive and active conditions, we used our previously described methods (Humphrey et al., 1990a) to obtain both passive and active constitutive laws. The major results of this study are: (1) This is the first multiaxial constitutive law for actively contracting mammalian myocardium. (2) The functional forms of the constitutive law for barium contracture and ryanodine-induced tetani are the same but differ from those in the passive state. Hence, one cannot simply substitute differing values for the coefficients of the passive law to describe the active tissue properties. (3) There are significant stresses developed in the cross-fiber direction (more than 40 percent of those in the fiber direction) that cannot be attributed to either deformation effects or nonparallel muscle fibers. These results provide the foundation for future mechanical analyses of the heart.

Nutrition and the immune system of the gut

Studies suggest that the development and expression of the regional immune system in the gastrointestinal (GI) tract is relatively independent of systemic immunity. This is reflected in significant differences in functional response of T cells and B cells and affects cytokine patterns and activation pathways when regional immunity is compared to systemic immunity. Nutrients have fundamental and regulatory influences on the immune response of the GI tract and, therefore, on host defense. In addition to the effect of nutrition during development, the local impact of different dietary and antigenic elements on the regional immune system contributes to potential diversion of the two systems throughout life. The route of exposure during antigenic contact is known to affect host immune response, whether it be a normal process, happening in the context of normal environmental encounter with nonpathogenic microbes or planned immunization, or occurring as a result of resolution of a potentially pathologic process i.e., an infectious encounter. Interactions at the local level profoundly influence systemic immune response, in part because of intrinsic differences in these systems, and also because of different requirements for optimal function. Although inflammatory processes are central to host defense in the periphery, the protective blocking action of the secretory immunoglobulin A immune response is crucial to local host defense, and, therefore, to the integrity of GI tract immune function. For these reasons, interaction with normal bacteria of the GI tract may be seen as the model of how the system has evolved and provide clues to the restoration of balance in the immunocompromised host. Reduction of normal commensal bacteria in the context of infection or after antibiotic treatment may interfere with nutrient availability and impair beneficial stimulation of GI immune response. This impairment may be associated with continued colonization with opportunistic microbes and inflammatory immune response that could lead to malabsorption and malnutrition. Study of the impact of nutrient imbalance on the function of the GI tract has profound implications for clinical medicine and may in the future lead to the rational design of preventive approaches to support immune response and host defense.

Myoepithelial hamartoma of the duodenal wall

A rare case of myoepithelial hamartoma of the duodenal wall is presented, and previous case reports found in the literature are reviewed. Myoepithelial hamartomas are thought to arise from displaced pancreatic anlage present along the gastrointestinal tract during embryogenesis, which can differentiate into various pancreatic elements; the most highly differentiated form is heterotopic pancreas. An alternative theory is pancreatic metaplasia of endodermal tissues. We describe a 41-year-old man who presented with abdominal pain and vomiting. CT scanning revealed a mass at the head of the pancreas. A pancreaticoduodenectomy was performed for presumed cystadenoma. Histology of the mass revealed a disorderly arrangement of smooth muscle, dilated and nondilated ducts, pancreatic acinar tissue and mucus glands. The relationship of myoepithelial hamartomas involving the small bowel to similar lesions in the stomach, bile ducts and gallbladder is discussed.

Loss of striatal DA innervation increases striatal trophic activity directed at DA neurons in culture

Male rats received intraventricular infusions of the dopamine (DA) neurotoxin 6-hydroxydopamine (6-OHDA; 0, 75, 150, and 250 micrograms) in order to determine if DA neuron loss was associated with an increase in striatal trophic activity. After 4 weeks, the animals were sacrificed and perfused with normal saline, and the brains were removed, immediately frozen, and processed. Intraventricular infusions of 6-OHDA were associated with a dose-dependent reduction in striatal DA content and tyrosine hydroxylase-immunoreactive (THir) cell counts in the substantia nigra while striatal DA activity ([HVA]/[DA]) was increased. Extracts of the striatum from these animals increased the survival of E15 primary, dissociated rostral mesencphalic cultures growing at low cell density. This growth effect was positively correlated with the dose of 6-OHDA infused. THir cell counts present in high-cell-density mesencephalic cultures following 72 h of extract incubation were similarly correlated to 6-OHDA dose but inversely correlated with striatal DA content and THir cell counts in the substantia nigra. Trophic activity in the cerebellar extracts from these animals was significantly lower than that present in striatal extracts and was not influenced by 6-OHDA lesions. These data suggest that loss of DA innervation in the striatum is associated with an increase in striatal trophic activity directed at DA neurons. A compensatory response to the loss of DA neurons involving increased striatal trophic activity may result in increased DA terminal sprouting of remaining viable DA neurons that, in turn would serve to help reinstate normal DA tone.

Morphometry of pig coronary venous system

This is a third part of tripartite morphometric data of the pig coronary blood vessels, giving a complete quantitative description of the arterial tree [Kassab et al., Am. J. Physiol. 265 (Heart Circ. Physiol. 34): H350-H365, 1993], capillary network [Kassab and Fung, Am. J. Physiol. 267 (Heart Circ. Physiol. 36): H319-H325, 1994], and venous tree (this article). Together they provide the quantitative anatomic foundation for coronary hemodynamics. The coronary venules have a unique morphology. Unlike coronary arterioles, which have cylindrical cross sections and a fairly constant diameter in each segment, the venules have approximately elliptical cross sections, are usually wavy in the longitudinal direction, and often converge like fingers to a hand. Measurements were made with the silicone elastomer casting method on five pig hearts. Data on smaller vessels were obtained from histological specimens by optical sectioning. Data on larger vessels were obtained from vascular casts. Arcading veins and anastomoses on the epicardial surface have a unique topology. Data on the number of vessels in each order, the major and minor axes, length, connectivity matrix, and the fractions of the vessels of a given order connected in series in all orders of vessels of the sinusal and thebesian veins are presented. It is shown that of the blood in the coronary blood vessels of a pig heart 27.4% is in the arteries (> 200 microns), 37.1% is in veins (> 200 microns), and 35.5% is in microcirculation (< 200 microns), of which 89.4% is in the capillaries.

Consequences of pruning in morphometry of coronary vasculature

There is a paucity of data on the branching pattern and dimensions of the blood vessels in various organs. The reason for the paucity is undoubtedly the tremendous effort needed to obtain the morphometric data. For those organs whose morphometric data have been determined, pruning was introduced: cutting off branches at successive generations, measuring what remained, using the statistical data to estimate what were cut off, and adding the estimated data to the measured data to obtain the final results. Evaluation of the effects of pruning was not possible, however, because a full set of precise data did not exist. Now a complete set of morphometric data on the coronary arteries is presented by Kassab et al. (8). Hence we are in a position to evaluate pruning versus accuracy. Among several pruning protocols tried we found a simple, easy-to-follow scheme that seemed to be reasonable. It reduced the labor by 79% when it was applied to the left anterior descending (LAD) artery of the pig, and it caused the following percentage errors based on comparison with the unpruned data. The largest error incurred in the mean diameters of all orders of tree is 7.6%. The corresponding maximum errors in the length and number of elements in all orders are -9.8% and 30.0%, respectively. The estimated error of the total equivalent Poiseuille's resistance for the LAD artery computed from pruned data was 25.2% when compared with that computed from unpruned data.

Cerebrospinal fluid from patients with Parkinson's disease alters the survival of dopamine neurons in mesencephalic culture

We have previously demonstrated that extracts of striatal tissue from patients with Parkinson's disease (PD) increase the survival of dopamine neurons in mesencephalic cultures relative to striatal extracts from control patients. In the present study, ventricular cerebrospinal fluid (vCSF) from patients with PD, Alzheimer's disease (AD), and age-matched controls was similarly assessed. vCSF samples were separated into > 10-kDa and < 10-kDa fractions. Cultures incubated with the > 10-kDa fractions from PD and AD patients contained 73 and 13%, respectively, more tyrosine hydroxylase immunoreactive neurons than cultures incubated with vCSF from age-matched controls. This trophic activity was positively correlated with the trophic activity present in striatal extracts from the same patients. The < 10-kDa vCSF fractions from all patient groups inhibited culture growth. These data suggest that the trophic environment in the striatum is altered in PD and can be successfully monitored in CSF.

Levodopa reduces the growth promoting effects of striatal extracts on rostral mesencephalic tegmentum cultures

Rats with unilateral 6-hydroxydopamine lesions (6-OHDA) of the mesencephalon and vehicle controls (SHAM) were chronically treated with carbidopa (CD) or CD plus levodopa (CD/LD) for 18 days. Seventy-two hours following the last treatment, ipsilateral striata, contralateral striata, and cerebellums from each treatment group were homogenized separately and the supernatant extracts were incubated with rostral mesencephalic tegmentum cultures. As indices of growth-promoting activity (GPA), number of viable neurons and their process lengths were measured 40 h later. In all cultures exposed to striatal extracts, the 6-OHDA lesion was associated with greater GPA than the SHAM extracts. CD/LD consumption reduced this GPA in a dose-dependent fashion in both the lesioned and the SHAM animals. These data suggest that denervation of the striatum enhances the production of a striatally derived neurotrophic factor, the production of which is sensitive to levodopa. Chronic levodopa treatment in Parkinson's disease may therefore contribute to disease progression by reducing the compensating effects of this neurotrophic factor on remaining mesencephalic neurons.

Clozapine fails to prevent the development of haloperidol-induced behavioral hypersensitivity in a cotreatment paradigm

We have previously established that chronic cotreatments involving antimuscarinic agents and haloperidol attenuate the development of behavioral hypersensitivity without affecting dopamine receptor proliferation. The antipsychotic agent clozapine also has significant antimuscarinic activity and was coadministered with haloperidol in rats for 2 months to determine if it would similarly attenuate the development of hypersensitivity. Clozapine or chlorpromazine cotreatment, unlike thioridazine cotreatment, did not attenuate the development of haloperidol-induced behavioral hypersensitivity. Clozapine or thioridazine cotreatment also failed to prevent the development of haloperidol-induced D2 receptor proliferation, whereas chlorpromazine cotreatment enhanced D2 receptor proliferation relative to haloperidol-treated animals. Alterations in dopamine biochemistry in the striatum or nucleus accumbens could not explain this dissociation between behavioral hypersensitivity and dopamine receptor proliferation. It is therefore hypothesized that dopamine receptor proliferation is permissive for behavioral hypersensitivity and that factors in addition to alterations in dopamine function contribute to the expression of dopamine hypersensitivity states.

Dopaminergic alterations in cotreatments attenuating haloperidol-induced hypersensitivity

Chronic treatment of the laboratory rat with haloperidol results in an increased stereotypic behavioral response to subsequent dopamine agonist challenge. This behavioral hypersensitivity (BH) is thought to reflect an increase in DA receptor number following chronic pharmacologic denervation. Using a cotreatment strategy, we demonstrate here that a variety of agents can attenuate or prevent the development of BH when administered chronically with haloperidol. Cotreatment with lithium and amantadine prevented the changes in DA biochemistry as well as the proliferation of DA receptors normally associated with chronic haloperidol treatment. Cotreatment with thioridazine or scopolamine did alter the changes in DA biochemistry normally associated with haloperidol treatment, but failed to attenuate the DA receptor proliferation. Taken together, these data suggest that mechanisms in addition to DA biochemical and receptor changes participate in the development and subsequent expression of BH. DA receptor proliferation must, therefore, be considered permissive to the development of BH.

Effects of alcohol on the despair response to peer separation in rhesus monkeys

In humans, alcoholism and depression are often interrelated. This study examines the effects of alcohol on peer separation-induced despair in rhesus monkeys, a proposed nonhuman primate model of depression. Alcohol, at three different dose levels, or placebo was administered to rhesus monkeys undergoing repeated peer separation. Low-dose alcohol (1 g/kg/day) decreased separation-induced despair, whereas high-dose alcohol (3 g/kg/day) exacerbated the despair response as compared to placebo. This biphasic effect of alcohol on the despair response may be analogous to similar effects of alcohol on depression in humans.