Patellar tendinopathy: an overview of prevalence, risk factors, screening, diagnosis, treatment and prevention

Patellar tendinopathy (PT), or jumper's knee, is an overuse injury that occurs in professional, as well as recreational, athletes. This condition is a noncontact injury, typically characterized by gradually increasing pain in the patellar tendon. It is prevalent in participants of several sports, but it occurs mostly in jumping sports. The diagnosis of PT is primarily clinical; however, imaging techniques can be useful as well. Risk factors differ between sexes, playing conditions, the kind of sport, playing level and personal characteristics. Screening is an essential tool to assess PT. This condition affects athletic performance and often persists for years. The use of preventative methods is imperative because of the persistence of this condition, especially in elite athletes who sometimes end their career after long and failed treatments. There are a wide variety of treatment and rehabilitation options available, the majority of which are non-operative, such as eccentric exercises, cryotherapy, platelet-rich plasma (PRP) injections, and anti-inflammatory strategies. If conservative treatment fails, surgery is the next most preferable step. Even though there are many surgical treatment methods, there is no clear evidence on what is the most effective approach to address PT. Taking this into consideration, as well as the extent of this clinical entity, novel therapeutic techniques, as well as screening and prevention methods, are expected to emerge in the near future.

Garbage in, toxic data out: a proposal for ethical artificial intelligence sustainability impact statements

Data and autonomous systems are taking over our lives, from healthcare to smart homes very few aspects of our day to day are not permeated by them. The technological advances enabled by these technologies are limitless. However, with advantages so too come challenges. As these technologies encompass more and more aspects of our lives, we are forgetting the ethical, legal, safety and moral concerns that arise as an outcome of integrating our lives with technology. In this work, we study the lifecycle of artificial intelligence from data gathering to deployment, providing a structured analytical assessment of the potential ethical, safety and legal concerns. The paper then presents the foundations for the first ethical artificial intelligence sustainability statement to guide future development of AI in a safe and sustainable manner.

Let Me Take Over: Variable Autonomy for Meaningful Human Control

As Artificial Intelligence (AI) continues to expand its reach, the demand for human control and the development of AI systems that adhere to our legal, ethical, and social values also grows. Many (international and national) institutions have taken steps in this direction and published guidelines for the development and deployment of responsible AI systems. These guidelines, however, rely heavily on high-level statements that provide no clear criteria for system assessment, making the effective control over systems a challenge. "Human oversight" is one of the requirements being put forward as a means to support human autonomy and agency. In this paper, we argue that human presence alone does not meet this requirement and that such a misconception may limit the use of automation where it can otherwise provide so much benefit across industries. We therefore propose the development of systems with variable autonomy-dynamically adjustable levels of autonomy-as a means of ensuring meaningful human control over an artefact by satisfying all three core values commonly advocated in ethical guidelines: accountability, responsibility, and transparency.

IEEE P7001: A Proposed Standard on Transparency

This paper describes IEEE P7001, a new draft standard on transparency of autonomous systems. In the paper, we outline the development and structure of the draft standard. We present the rationale for transparency as a measurable, testable property. We outline five stakeholder groups: users, the general public and bystanders, safety certification agencies, incident/accident investigators and lawyers/expert witnesses, and explain the thinking behind the normative definitions of "levels" of transparency for each stakeholder group in P7001. The paper illustrates the application of P7001 through worked examples of both specification and assessment of fictional autonomous systems.

A socio-technical framework for digital contact tracing

In their efforts to tackle the COVID-19 crisis, decision makers are considering the development and use of smartphone applications for contact tracing. Even though these applications differ in technology and methods, there is an increasing concern about their implications for privacy and human rights. Here we propose a framework to evaluate their suitability in terms of impact on the users, employed technology and governance methods. We illustrate its usage with three applications, and with the European Data Protection Board (EDPB) guidelines, highlighting their limitations.

Nationwide Survey in Greece about Knowledge, Risk Perceptions, and Preventive Behaviors for COVID-19 during the General Lockdown in April 2020

Background: The aim of this study was to investigate the knowledge, attitudes, and practices of the Greek general population toward coronavirus disease 2019 (COVID-19) during the lockdown period in April 2020, to examine factors associated with misperceptions and to determine behavioral patterns that may require interventions. Methods: A cross-sectional study of the general Greek population (N = 1858) was conducted. A geographically stratified cluster sampling was implemented. A questionnaire was composed consisting of 35 questions. Data collection took place from 15 April to 2 May 2020. A random-digit dialing survey was conducted by 29 interviewers. Results: The majority of respondents (62.7%) answered ≥12/17 questions correctly. Participants aged 18–44 years, male gender, specific occupations (freelancer, unemployed, housewife, retiree) and those who sought information about COVID-19 from less than two sources received lower aggregated scores on knowledge questions. Regarding attitudes toward future vaccination, 18.9% declared that were against it, while 81.1% that they may consider or will be vaccinated. About 40% were not using a face mask and only 42% washed their hands appropriately. Conclusion: Adjusting information campaigns targeting especially people below 45 years of age can help to sensitize them and realise their role to control the spread. Further targeted surveys are needed to adjust/design prevention campaigns.

Approach to High Volume Enrollment in Clinical Research: Experiences from an All of Us Research Program Site

Clinical trials and cohort studies are required to meet target recruitment of study participants within stipulated timelines, especially when the priority is to include populations traditionally unrepresented in biomedical research. By the third quarter of 2019, the University of Arizona‐Banner Health Provider Organization (UA‐Banner HPO) has enrolled > 30,000 core participants into the All of Us Research Program (AoURP), the research cohort of the Precision Medicine Initiative. The majority of enrolled participants meet the criteria for individuals under‐represented in biomedical research. The enrollment goals were calculated based on a target of 20,000 as set by the National Institutes of Health and our health provider organization achieved enrollment numbers between 17% and 86% above the targeted daily enrollment. We evaluated enrollment methods and challenges to enrollments encountered by the UA‐Banner Health Provider Organization into the AoURP. Challenges to enrollment centered around the need for high‐touch engagement methods, time investment necessary for stakeholder inclusion, and the use of purely digital enrollment methods especially in populations under‐represented in biomedical research. These challenges occurred at the level of the individual, provider, institutions, and community, and cumulatively impacted participant enrollment. Successful strategies for engagement and enrollment leveraged provider partners as advocates for the program. For high‐volume enrollment in clinical research, it is important to engage leaders in the healthcare setting, patient providers, and tailor engagement and enrollment to potential participant needs. We emphasize the need for precision engagement and enrollment methods tailored to individual needs.

Hospitals with more-active participation in conducting standardized in-situ mock codes have improved survival after in-hospital cardiopulmonary arrest

AIM

The American Heart Association (AHA) and the Institute of Medicine have published a national "call-to-action" to improve survival from in-hospital cardiopulmonary arrest (IHCA). Our aim was to determine if more-active hospital participation in standardized in-situ mock code (ISMC) training is associated with increased IHCA survival.

METHODS

We performed an ecological study across a multi-state healthcare system comprising 26 hospitals. Hospital-level ISMC performance was measured during 2016-2017 and IHCA hospital discharge survival rates in 2017. We performed univariate and multivariate analysis of the hospital-level association between more-active ISCM participation and IHCA survival, with adjustment for hospital expected mortality as determined by a commercial severity scoring system. Other potential confounders were analyzed using univariate statistics.

RESULTS

Hospitals with more-active ISMC participation conducted a median of 17.6 ISMCs/100 beds/year (vs 3.2/100 beds/year in less-active hospitals, p = 0.001) in 2016-2017. 220,379 patients were admitted and 3289 experienced IHCA in study hospitals in 2017, with an overall survival rate of 37.4%. Hospitals with more-active ISMC participation had a mean IHCA survival rate of 42.8% vs. 31.8% in hospitals with less-active ISMC participation (p < 0.0001), and a significantly reduced odds ratio (OR) of 0.62 for IHCA mortality (95% CI: 0.54-0.72; p < 0.0001) which was unchanged after adjustment for hospital-level expected mortality (adjusted OR: 0.62; 95% CI: 0.54-0.71; p < 0.001).

CONCLUSIONS

Hospitals in our healthcare system with more-active ISMC participation have higher IHCA survival. Prospective trials are needed to establish the efficacy of standardized ISMC training programs in improving patient survival after cardiac arrest.

Performance indices selection for assessing anaerobic power during a 30 second vertical jump test

AIM

The aim of the present study was to assess the validity of jump height (h), absolute (VPOWERABS) and relative to body mass (VPOWERREL) performance indices when elicited of a modified 30 s Bosco vertical jump test (VJT) based on the absolute (WPOWERABS) and relative (WPOWERREL) power values of a 30 s Wingate test (WAnT).

METHODS

Nineteen physical education students with mean ± SD age 21 ± 3 y, body mass 73.8 ± 7 kg and height 1.8 ± 0.06 m performed a 30 s VJT on a force plate and a 30 s WAnT on a Monark cycle ergometer. Performance data were expressed in W and W.kg-1 of body mass for WPOWERABS and WPOWERREL; in cm, W and W.kg-1 for h, VPOWERABS and VPOWERREL, respectively. The performance indices' values were expressed as means and SDs of the 30 s duration of both tests, as well as in 4 time intervals of 7.5 s (0-7.5 s, 7.5-15 s, 15-22.5 s, and 22.5-30 s).

RESULTS

WPOWERABS and h were significantly (P<0.05) correlated in the 4 time intervals (0-7.5 s: r=0.51; 7.5-15 s: r=0.36; 15-22.5 s: r=0.39) and in the overall duration of the test (0-30 s: r=0.38). Significant correlation was also revealed between VPOWERABS and WPOWERABS, but only for the interval 0-7.5 s (r=0.48).

CONCLUSION

A 30 s VJT is valid against a 30 s WAnT only when h is used as performance indices. The selection of the appropriate unit of measurement is important for assessing effort distribution in maximum effort tests of short duration.

Field data analysis and application of a complex water column biogeochemical model in different areas of a semi-enclosed basin: towards the development of an ecosystem management tool

The Pagasitikos gulf ecosystem is studied through the analysis of experimental field data acquired during several monitoring projects and the application of a complex biogeochemical model. The gulf was separated into three different parts (internal, top central-external, bottom central-external) according to the patterns exhibited by the key ecosystem indicators. Unlike other semi-enclosed gulfs Pagasitikos can be characterised as meso-oligotrophic undergoing periods of P or N limitation. Although the signal of nutrient inputs is not very clear in the field data, their importance is assessed through simulation. Increased phosphate concentrations either due to mixing or due to anthropogenic activities can result in phytoplanktonic blooms with significant contribution by diatoms. The effect of hydrodynamic patterns on primary production has been demonstrated through ecosystem modeling indicating that due to long stratification periods, all nutrients released through the benthic regeneration are trapped in the deeper layers, developing a microbial food web. However when the thermocline erodes nutrients find their way up in the upper layers of the euphotic zone and the system turns into more classical type with primary producers growing significantly faster.

Hyponatremic hypertensive syndrome (HHS) in an 18-month old-child presenting as malignant hypertension: a case report

Background

The combination of hyponatremia and renovascular hypertension is called hyponatremic hypertensive syndrome (HHS). Malignant hypertension as a presentation has been reported in adults with HHS but is rare in children.

Case presentation

An eighteen month-old male presented with drowsiness, sudden onset status epilepticus and blood pressure of 210/160. The electrolytes on admission revealed sodium of 120 mEq/L and potassium of 2.1 mEq/L. The peripheral renin activity (PRA) was 172 ng/ml/min (normal 3–11 ng/ml/min) and serum aldosterone level was 91 ng/dl (normal 4 to 16 ng/dl). Patient underwent angioplasty with no success, followed by surgical correction. Two years since the diagnosis, the blood pressure is controlled with labetolol and amlodipine (at less than sixth of the pre-operative dosages). The PRA is 2.4 ng/ml/min and aldosterone 15.5 ng/dl. The child not only had three renal arteries on left but all of them were stenosed which to best of our knowledge has not been described.

Conclusion

As uncommon as HHS with malignant hypertension may be in adults it is under-reported in children and purpose of the case report is to raise its awareness.

Wireless and Web-based medical monitoring in the home

A remote medical monitoring system is described, which continuously monitors patients' state of health. The system uses the services provided by intranets and the Internet to allow remote supervision of patients, who may be domiciled in their own home. A hardware/software prototype system has been constructed to demonstrate the use of non-invasive and minimally intrusive sensors attached to patients. Continuous real-time data is acquired, stored and processed. A wireless system or wires connect these monitor devices to the World Wide Web and, on request, information is delivered to authorized medical staff via a web browser or Wireless Application Protocol-enabled mobile telephones. Medical staff may examine real-time data or graphical information and make comparisons with historical data. Parameters may be set to select and control the data acquisition devices. The potential exists for augmentation of patient health by development of novel sensors and low-power electronic circuitry, and this research continues.

Assessing marine ecosystem response to nutrient inputs

The response of the Pagasitikos Gulf to enrichment caused by run-off fertilizers and the development and evolution of harmful algal blooms is investigated through ecosystem modelling. A standard generic complex model has been developed to describe the ecosystem processes of Pagasitikos and has been validated with in situ data. Additionally external nutrient fluxes have been assimilated and incorporated into the ecosystem dynamics. The investigation of spatial effects due to nutrient enrichment is investigated along a North-South transect. When externally forced the model successfully assimilates the external river inputs producing nutrient and chlorophyll-a concentrations, which are in good agreement with the in situ data. The nutrient inputs result in a more stable ecosystem at the north part of the Gulf and in the development of eutrophic conditions. The changes in the ecosystem functioning with emphasis on the nutrient cycling, the increase of primary production, and the modes of operation are investigated and discussed.

Ragweed sensitization alters pulmonary vascular responses to bronchoprovocation in beagle dogs

In ragweed (RW)-sensitized beagle dogs, we tested the hypothesis that reactivity of the pulmonary vasculature was enhanced with aerosolized histamine (Hist) and RW. Seven dogs were neonatally sensitized with repeated intraperitoneal RW injections, and 12 dogs were controls (Con). The dogs were anesthetized with intravenous chloralose, mechanically ventilated, and instrumented with femoral arterial and pulmonary artery catheters. Specific lung compliance (CLsp), specific lung conductance (Gsp), systemic vascular resistance index, and pulmonary vascular resistance index (PVRI) were measured before and after bronchoprovocation with Hist and RW. After Hist inhalation (5 breaths of 30 mg/ml), both Con and RW dogs had significant (P < 0.05) decreases in CLsp (-51 +/- 4 and -53 +/- 5%, respectively) and Gsp (-65 +/- 5 and -69 +/- 3%, respectively), but only RW-sensitized dogs had a significant increase in PVRI (38 +/- 10%). After RW inhalation (60 breaths of 0.8 mg/ml), only RW-sensitized dogs had significant increases (62 +/- 20%) in PVRI and decreases in Gsp (-77 +/- 4%) and CLsp (-65 +/- 7%). We conclude that, compared with Con, RW-sensitized beagle dogs have increased pulmonary vasoconstrictive responses with Hist or RW inhalation.

[Histological study of different organs in clinically healthy Amazon parrots]

Histologic examination of organs of clinically healthy amazons was carried out. Only variations from the chicken are presented, among others: Occurrence of a complex of vessels and many Herbst' corpuscles in the nasal cavity; evidence of a thick muscular layer as well as many Herbst' corpuscles and nerve fibers as the cover of the syrinx; demonstration of muscular trabeculae in the parabronchia; detection of an artery accompanying the testes with muscular layers reaching into the adventitia and many nerve fibers; very small numbers of active lymph follicles within the white pulp of the spleen.

Therapeutic interchange of ampicillin-sulbactam for cefoxitin

A therapeutic interchange program based on microbial patterns within an institution is described. A change in anaerobic susceptibility patterns, increased prevalence of enterococcal infections, and cost factors provided the rationale for the therapeutic interchange of ampicillin-sulbactam for cefoxitin. Ampicillin-sulbactam was recommended for prophylaxis in intraabdominal or gynecological surgery as well as for treatment for gynecological infections. Cefoxitin was restricted to penicillin-allergic patients and women who were pregnant or breast-feeding. The transition from cefoxitin to ampicillin-sulbactam proceeded smoothly as a result of preliminary education of pharmacists and physicians. Pharmacists participated in continuing-education programs and received concise guidelines for the interchange and follow-up instructions; physicians learned of the program from the drug newsletter published by the pharmacy department. Three months after the program began, only one physician was resistant to the interchange. After the program began, 11 antimicrobials, including cefoxitin, were used less frequently and ampicillin-sulbactam use increased. No adverse clinical consequences from the interchange were detected. A therapeutic interchange program based on institution-specific microbial patterns and educational efforts by the pharmacy department produced a change in physician prescribing.

Effects of discontinuous drug administration on the development of dopamine receptor supersensitivity during chronic trifluoperazine or cis-flupenthixol administration to rats

Rats received continuous or discontinuous administration of trifluoperazine or cis-flupenthixol in drinking water for up to 12 months. Continuous and discontinuous trifluoperazine administration had no consistent effect on apomorphine-induced stereotyped behaviour and there was no difference between drug treatments. Continuous and discontinuous cis-flupenthixol administration enhanced apomorphine-induced stereotypy, but there was no difference in the effect of the two drug treatments. Both continuous and discontinuous administration of trifluoperazine increased the number of specific striatal 3H-spiperone binding sites (Bmax). Over the period of treatment there was no difference in the effects of the different treatments. Continuous or discontinuous cis-flupenthixol intake did not increase Bmax after 6 or 12 months intake. Continuous or discontinuous neuroleptic treatment produced no difference in functional striatal dopamine receptor activity as judged by apomorphine-induced stereotyped behaviour. Ligand binding studies also suggest that the overall change in striatal receptor function is not affected by the use of a discontinuous drug regime.

Alterations in different populations of striatal dopamine receptors produced by 18 months continuous administration of cis- or trans-flupenthixol to rats

Administration of cis-flupenthixol (0.8-1.2 mg/kg per day) for 18 months enhanced stereotyped behaviour induced by apomorphine, bromocriptine and lergotrile, but not that induced by amphetamine or lisuride. Catalepsy induced by acute administration of haloperidol, trifluoperazine or cis-flupenthixol was reduced by continuous chronic intake of cis-flupenthixol. The number (Bmax) and dissociation constant (KD) of specific [3H]spiperone binding sites on striatal membranes was increased by chronic administration of cis-flupenthixol, but not trans-flupenthixol. In contrast, the Bmax and KD for specific binding of [3H]N,n-propylnorapomorphine were decreased by administration of cis-flupenthixol compared to the effect of the trans-isomer. Specific binding of [3H]piflutixol was unaffected by chronic administration of cis- or trans-flupenthixol, but chronic administration of cis-flupenthixol enhanced stimulation by dopamine of the activity of striatal adenylate cyclase. As a result of chronic continuous administration of cis-flupenthixol dopamine receptors in the striatum appeared to be supersensitive to most dopamine agonists but sub-sensitive to dopamine antagonists. This was reflected by increased numbers of D-2 antagonist receptor sites of decreased affinity, but by a decreased number of agonist sites of higher affinity. The D-1 recognition sites appeared to be unaltered, but activity of adenylate cyclase stimulated by dopamine was enhanced, suggesting post-junctional changes. The D-2 receptors appear to be primarily concerned with altered function of dopamine receptors.

Alterations in cerebral dopamine function caused by administration of cis- or trans-flupenthixol for up to 18 months

Rats received either cis-flupenthixol (0.8-1.2 mg/kg per day) or trans-flupenthixol (0.9-1.2 mg/kg per day) continuously in drinking water for periods up to 18 months. cis-Flupenthixol, but not trans-flupenthixol, initially inhibited apomorphine-induced stereotyped behaviour but by 6 months and thereafter the stereotyped response was enhanced compared to age-matched control animals. Striatal and mesolimbic homovanillic acid and 3,4-dihydroxyphenylacetic acid concentrations were elevated for up to 3 months after starting cis-, but not trans-flupenthixol intake, but thereafter levels generally fell below those for age-matched control animals. Dopamine concentrations were not altered by cis- or trans-flupenthixol administration. The number of striatal [3H]spiperone binding sites (Bmax) was decreased by 40% after 1 months' administration of cis-flupenthixol but this gradually reversed, such that by 18 months a 40% increase in Bmax was apparent. Administration of trans-flupenthixol decreased Bmax up to 3 months but thereafter values were not different from those found in age-matched control animals. The dissociation constant (KD) for [3H]spiperone binding in striatum was not altered by 6 months cis-flupenthixol intake, but then increased as drug administration continued. trans-Flupenthixol administration did not alter striatal KD values. Bmax for [3H]spiperone binding to mesolimbic preparations was not altered by up to 12 months cis-flupenthixol intake, but was decreased after 18 months drug administration. cis-Flupenthixol administration had no effect on mesolimbic KD values. Administration of trans-flupenthixol for up to 18 months did not alter mesolimbic Bmax or KD values for [3H]spiperone binding.(ABSTRACT TRUNCATED AT 250 WORDS)

Persistent increase in striatal dopamine stimulated adenylate cyclase activity persists for more than 6 months but disappears after 1 year following withdrawal from 18 months cis-flupenthixol intake

Administration of cis-flupenthixol to rats for 18 months enhanced apomorphine-induced stereotyped behaviour, increased the number of specific [3H]spiperone binding sites in striatum and potentiated striatal dopamine stimulated cyclic AMP formation, but did not alter specific [3H]piflutixol binding. Following withdrawal of cis-flupenthixol intake, apomorphine-induced stereotypy returned to control values after 1 month and Bmax for [3H]spiperone binding returned to normal after 3 months. In contrast, the increased dopamine stimulated adenylate cyclase activity remained elevated 6 months after drug removal, but was normal 1 year after drug withdrawal.

Repeated administration of sulpiride for three weeks produces behavioural and biochemical evidence for cerebral dopamine receptor supersensitivity

Administration of sulpiride (2 X 100 mg/kg i.p.) or haloperidol (5 mg/kg i.p.) to rats for 3 weeks with subsequent withdrawal for 3 or 4 days induced cerebral dopamine receptor supersensitivity. Apomorphine-induced stereotyped behaviour after drug withdrawal was enhanced by pretreatment with either haloperidol or sulpiride both of which increased the number of specific striatal binding sites (Bmax) for [3H]spiperone, [3H]N,n-propylnorapomorphine and [3H]sulpiride. Neither drug altered the dissociation constant (KD) for the ligand binding assays. Striatal dopamine sensitive adenylate cyclase activity was unaltered by such a pretreatment with either haloperidol or sulpiride. The data show that sulpiride, like haloperidol, is capable of inducing behavioural and biochemical supersensitivity of cerebral dopamine receptors.

Kainic acid lesions of striatum and decortication reduce specific [3H]sulpiride binding in rats, so D-2 receptors exist post-synaptically on corticostriate afferents and striatal neurons

Unilateral kainic acid lesions of rat striatum reduced specific striatal [3H]spiperone and [3H]sulpiride binding sites (Bmax) by 52 and 67% respectively compared with the intact side. The dissociation constant (KD) for [3H]spiperone binding was unchanged but that for [3H]sulpiride binding was reduced. Specific striatal [3H]spiperone and [3H]sulpiride binding was reduced by 22 and 37% respectively in unilateral decorticate animals, but there was no change in KD. Unilateral 6-hydroxydopamine lesions of the medial forebrain bundle caused no change in striatal [3H]spiperone binding sites or KD value, but produced a 27% increase in [3H]sulpiride binding sites with no change in KD. These data support the hypothesis of D-2 receptors located on cortico-striate glutamate fibres, but also indicate the presence of both D-1 and D-2 receptors on the cell bodies of striatal neurons.

Subchronic treatment with the tricyclic antidepressant DMI increases isolation-induced fighting in rats

Male rats treated with desmethylimipramine (DMI) (20 mg/kg for 7 days) were more likely than controls to attack an intruder rat placed in their home cage; they were also more likely to submit when attacked by the intruder. These behavioural changes were not seen at lower doses of DMI. Similar results were obtained in experiments in which is drugged animal and a control were placed together in a "neutral" cage; in this paradigm it was also found that lower doses of DMI were effective, provided that either the period of drug treatment was increased, or a delay of 3-4 days after withdrawal of DMI preceded behavioural testing. A dose dependent resistance to handling developed during drug treatment; drugged animals also showed weight loss and decreased open-field activity. In previous studies, acute treatment with tricyclic antidepressants has not been found to increase fighting; the present results underline the importance of chronic drug studies.

Cerebral dopamine function in rats following withdrawal from one year of continuous neuroleptic administration

Continuous administration of trifluoperazine (2.5--3.5 mg/kg/day) or thioridazine (30--40 mg/kg/day) to rats for 12 months enhanced the stereotyped response to apomorphine (0.5 mg/kg s.c.), increased dopamine 1--150 muM) stimulation of striatal adenylate cyclase, increased KD and Bmax for dopamine (10(-4) M) specific 3H-spiperone striatal binding and produced spontaneous mouthing movements. On drug withdrawal, spontaneous locomotor activity was enhanced after 2 weeks and the enhanced stereotyped response was maintained for up to 1 month. Spontaneous mouthing had disappeared 2 weeks after drug withdrawal. The increase in Bmax for 3H-spiperone binding was maintained for up to 3 months after drug removal, but KD reverted to control levels by 2 weeks. In contrast, the dopamine stimulation of striatal adenylate cyclase remained enhanced for the 6 month withdrawal period. Administration of trifluoperazine (0.7--0.9 mg/kg/day) or thioridazine (6--8 mg/kg/day) for 12 months produced a less marked effect than administration of the higher dose. No enhancement of effect was observed on drug withdrawal and the initial changes disappeared rapidly on removal of drug. Supersensitivity of striatal dopamine mechanisms produced by continuous long-term neuroleptic administration differs from that produced by shorter treatment periods since no enhancement of effect occurs on drug withdrawal. The behavioural and biochemical components of the supersensitivity show variable time courses and in particular the enhanced stimulation of striatal adenylate cyclase persists for at least 6 months. Such effects may be of relevance to tardive dyskinesias in man.

Changes in rat striatal dopamine turnover and receptor activity during one years neuroleptic administration

Administration of trifluoperazine (2.5--3.5 mg/kg/day p.o.) or thioridazine (30--40 mg/kg/day) for up to 1 year initially increased homovanillic acid and 3,4-dihydroxyphenylacetic acid concentrations in striatum. However, by 1 month and thereafter metabolite levels returned almost to control values. Dopamine concentrations were elevated after 3 months administration of both drugs and also after 12 months administration of trifluoperazine. Trifluoperazine administration for 1 month produced a marked increase in the dissociation constant (KD) for striatal 3H-spiperone binding but a reduction in receptor numbers. Thereafter receptor numbers increased at 6 and 12 months in both trifluoperazine and thioridazine treated animals compared to control values. The KD for both drug treated groups returned to normal at 6 months; however, by 12 months drug treated animals again demonstrated high KD values. Dopamine stimulation of striatal adenylate cyclase was inhibited after administration of trifluoperazine or thioridazine for 1 week or 1 month. However, by 6 and 12 months this effect was replaced by an enhanced stimulation. Administration of lower doses of trifluoperazine (0.7--0.9 mg/kg/day p.o.) or thioridazine (6--9 mg/kg/day p.o.) for up to 1 year produced similar although generally less marked changes in these biochemical indices of dopamine function. This study provides evidence of biochemical changes which parallel the behavioural findings of enhanced dopamine receptor activity that occur during continuous long-term neuroleptic administration to rodents.

Stereoselective actions of substituted benzamide drugs on cerebral dopamine mechanisms

Apomorphine-induced locomotor activity in reserpine-pretreated mice was antagonized by pretreatment with (-)-sulpiride and (-)-sultopride. The (+)-enantiomers were inactive. Apomorphine- and amphetamine-induced stereotyped behaviour in rats were antagonized by (-)-sultopride but not by the (+)-enantiomer. Neither enantiomer of sulpiride prevented the onset of the stereotyped response. Both (-)-sulpiride and (-)-sultopride induced increases in striatal and mesolimbic HVA and DOPAC concentrations; (+)-sultopride elevated striatal and mesolimbic DOPAC concentrations but not HVA, while (+)-sulpiride had no effect on HVA or DOPAC in either area. Dopamine concentrations were reduced by the enantiomers of sultopride but not by sulpiride. Low concentrations (10−9 −10−66 M) of the (-)-enantiomers of both drugs displaced [3 H]spiperone from its specific binding site in rat striatal preparations, but the (+)-enantiomers were 40 and 100 times less active. However, neither enantiomer of either drug anatagonized the dopamine-induced stimulation of adenylate cyclase in rat striatal preparations. The data suggest that the central pharmacological activity of sulpiride and sultopride resides in the (-)-enantiomers and that this activity occurs at cerebral dopamine receptors not dependent on adenylate cyclase for functional activity.

A comparison of striatal and mesolimbic dopamine function in the rat during 6-month trifluoperazine administration

Previous work has shown that 6---12 months continuous trifluoperazine (TFP) administration to rats causes striatal dopamine receptor supersensitivity. We have now replicated our original findings in the striatum and report concurrent changes in mesolimbic dopamine function during chronic TFP (2.8---4.0 mg/kg/day) administration for 6 months. Initial inhibition of apomorphine-induced stereotyped behaviour, which lasted for 2 weeks after the beginning of drug administration, was replaced by an exaggerated response to apomorphine (0.5 mg/kg SC) after 6 months drug intake. Striatal dopamine sensitive adenylate cyclase activity was inhibited at 1 and 3 months, but y 6 months was enhanced compared to control values. Mesolimbic adenylate cyclase activity was inhibited after 2 weeks and thereafter returned to control levels. Dopamine-identified 3H-spiperone binding sites (Bmax) in the striatum were increased by 2 weeks, reduced at 1 month and increased again at 6 months. In mesolimbic areas Bmax was increased at 2 weeks and 1 month but thereafter returned to control levels. The dissociation constant (kD) of specific 3H-spiperone binding was increased in the striatum and mesolimbic areas at 1 month and 2 weeks respectively. The results show differential changes in dopamine function in striatal and mesolimbic brain areas during 6 months continuous TFP administration to rats.