Benefits and limitations of belatacept in 4 hand-transplanted patients.

Belatacept (cytotoxic T-lymphocyte-associated protein 4 Ig) is an emerging treatment in kidney transplantation. Lack of nephrotoxicity and possibly an inhibitory effect on the development of donor-specific antibodies (DSAs) make it an interesting agent in hand transplantation. To reduce calcineurin inhibitor immunosuppression and preserve kidney function, we have added belatacept to the therapeutic regimen of 4 hand-transplanted patients at month 4 and at 6, 9, and 13 years after hand-forearm transplantation. Patients received 5 mg/kg belatacept every 2 weeks, and the dosing interval was extended to 4 weeks after 5 applications. Belatacept was initially well tolerated in all cases. Two patients were weaned to a low-dose tacrolimus monotherapy together with monthly belatacept applications. One patient is taking belatacept with lowered tacrolimus and sirolimus trough levels. A fourth patient had significant levels of DSAs at time of conversion and progressed to a severe necrotizing rejection early despite an unaltered baseline immunosuppression. Finger skin necrosis and histologic signs of severe chronic allograft vasculopathy eventually led to amputation of the graft. Implementation of belatacept can be beneficial in hand transplantation. However, our findings indicated both potential and caution and reflection of the immunologic state at the time of conversion.

Iatrogenic lesions of peripheral nerves.

Iatrogenic nerve lesions (INLs) are an integral part of peripheral neurology and require dedicated neurologists to manage them. INLs of peripheral nerves are most frequently caused by surgery, immobilization, injections, radiation, or drugs. Early recognition and diagnosis is important not to delay appropriate therapeutic measures and to improve the outcome. Treatment can be causative or symptomatic, conservative, or surgical. Rehabilitative measures play a key role in the conservative treatment, but the point at which an INL requires surgical intervention should not be missed or delayed. This is why INLs require close multiprofessional monitoring and continuous re-evaluation of the therapeutic effect. With increasing number of surgical interventions and increasing number of drugs applied, it is quite likely that the prevalence of INLs will further increase. To provide an optimal management, more studies about the frequency of the various INLs and studies evaluating therapies need to be conducted. Management of INLs can be particularly improved if those confronted with INLs get state-of-the-art education and advanced training about INLs. Management and outcome of INLs can be further improved if the multiprofessional interplay is optimized and adapted to the needs of the patient, the healthcare system, and those responsible for sustaining medical infrastructure.

Development of a novel instrument for assessing intentional non-adherence to official medical recommendations (iNAR-12): a sequential mixed-methods study in Serbia.

OBJECTIVES: We aimed to (1) develop a novel instrument, suitable for the general population, capturing intentional non-adherence (iNAR), consisting of non-adherence to prescribed therapy, self-medication and avoidance of seeking medical treatment; (2) differentiate it from other forms of non-adherence, for example, smoking; and (3) relate iNAR to patient-related factors, such as sociodemographics, health status and endorsement of irrational beliefs (conspiratorial thinking and superstitions) and to healthcare-related beliefs and experiences ((mis)trust and negative experiences with the healthcare system, normalisation of patient passivity). DESIGN: То generate iNAR items, we employed a focus group with medical doctors, supplemented it with a literature search and invited a public health expert to refine it further. We examined the internal structure and predictors of iNAR in an observational study. SETTING: Data were collected online using snowball sampling and social networks. PARTICIPANTS: After excluding those who failed one or more out of three attention checks, the final sample size was n=583 adult Serbian citizens, 74.4% female, mean age 39.01 years (SD=12.10). PRIMARY AND SECONDARY OUTCOME MEASURES: The primary, planned outcome is the iNAR Questionnaire, while smoking was used for comparison purposes. RESULTS: Factor analysis yielded a one-factor solution, and the final 12-item iNAR Questionnaire had satisfactory internal reliability (alpha=0.72). Health condition and healthcare-related variables accounted for 14% of the variance of iNAR behaviours, whereas sociodemographics and irrational beliefs did not additionally contribute. CONCLUSIONS: We constructed a brief yet comprehensive measure of iNAR behaviours and related them to health and sociodemographic variables and irrational beliefs. The findings suggest that public health interventions should attempt to improve patients' experiences with the system and build trust with their healthcare practitioners rather than aim at specific demographic groups or at correcting patients' unfounded beliefs. STUDY REGISTRATION: The design and confirmatory analyses plan were preregistered (https://osf.io/pnugm).

Tracking variations in daily questionable health behaviors and their psychological roots: a preregistered experience sampling study.

People resort to various questionable health practices to preserve or regain health - they intentionally do not adhere to medical recommendations (e.g. self-medicate or modify the prescribed therapies; iNAR), or use traditional/complementary/alternative (TCAM) medicine. As retrospective reports overestimate adherence and suffer from recall and desirability bias, we tracked the variations in daily questionable health behaviors and compared them to their retrospectively reported lifetime use. We also preregistered and explored their relations to a wide set of psychological predictors - distal (personality traits and basic thinking dispositions) and proximal (different unfounded beliefs and biases grouped under the term irrational mindset). A community sample (N = 224) tracked daily engagement in iNAR and TCAM use for 14 days, resulting in 3136 data points. We observed a high rate of questionable health practices over the 14 days; daily engagement rates roughly corresponded to lifetime ones. Both iNAR and TCAM were weakly, but robustly positively related. Independent of the assessment method, an irrational mindset was the most important predictor of TCAM use. For iNAR, however, psychological predictors emerged as relevant only when assessed retrospectively. Our study offers insight into questionable health behaviors from both a within and between-person perspective and highlights the importance of their psychological roots.

Reconstruction of the hand in Apert syndrome: two case reports and a literature review of updated strategies for diagnosis and management.

BACKGROUND: Apert syndrome is a set of complex malformations of the first brachial arch, with manifestations on the skull, face, hands and feet. At the level of the hand, the following signs are always present: complex syndactyly of the second, third and fourth digits with distal bone fusion; simple syndactyly of the fifth digit; foreshortened thumb with radial clinodactily; and symphalangism excluding the fifth digit. METHODS: The digital separation of an Apert hand should begin at 9 months of age and should be completed by 2 to 4 years of age. Our simplified approach consists of early bilateral surgery on border digits followed by unilateral separation of middle syndactily combined with thumb and digit osteotomies and bone grafting as required. RESULTS: Between 1995 and 2010 seven patients with Apert syndrome underwent reconstructive surgery of the complex hand syndactyly. The main target in our surgical strategy involved early bilateral separation of border digits, which started between 1 and 2 years of age. The unilateral middle syndactyly mass division with osteotomy of the thumb and other digits and bone grafting (as required) was carried out in later surgeries, which are usually completed by 4 years of age. The evaluation of the results was performed based on the functional results of the hand, morbidity, flap necrosis, skin graft lysis, postoperative range of motion in the small joints, gross grasp, pincer grasp, scar appearance, contractures of digits, and aesthetic outcome. CONCLUSION: As intended, this study proves the need for a complex surgical approach as early as possible with low revision rate, and acceptable functional and aesthetic outcome.

The Innsbruck hand transplant program: update at 8 years after the first transplant.

We herein provide an update on two bilateral hand and one bilateral forearm transplants with emphasis on immunosuppression (IS), function, morphology, and graft vascular changes at 8 years and 2 years after bilateral hand and 5 years after bilateral forearm transplantation. Between March 2000 and May 2006, three patients underwent bilateral hand or forearm transplantation at our institution. Following induction therapy with antithymocyte globulin (ATG) (n = 2) or alemtuzumab (n = 1), tacrolimus, prednisolone +/- mycophenolate mofetil (MMF) were given for maintenance IS. Later, tacrolimus (n = 1) or MMF (n = 1) was replaced by sirolimus/everolimus for long-term IS. Clinical follow-ups with evaluation of hand function, skin biopsies, X-ray, ultrasound, angiography, computed tomography angiography, electrophysiological studies, and somatosensory evoked potentials were performed at regular intervals. Three, six, and three rejection episodes were successfully treated with bolused steroids, anti-CD25 or anti-CD52 antibodies. Subsequently, skin histology remained normal without any evidence of chronic rejection. Hand function continuously improved during the first 3 years and since then remained stable with minor improvements. Investigation of hand arteries revealed no signs of occlusion or stenosis. Motor and intrinsic hand muscle function continues to improve in all patients. Protective sensation was observed in all patients; however, discriminative sensation was only accomplished after hand but not forearm transplantation. No life-threatening adverse events occurred. Despite immunologic challenging postoperative courses, patients are now free of rejection with moderate levels of IS and good functional results. No signs indicating chronic rejection have been encountered.

[Quality in coloproctology training : How is coloproctology training qualitatively integrated into the national training catalogue?] / Qualität in der koloproktologischen Ausbildung : Wie lässt sich koloproktologische Ausbildung in den nationalen Ausbildungskatalogen qualitativ integrieren?

The incorporation of coloproctology as a part of the surgical training and further education of assistant and specialist physicians shows great differences between Germany, Austria and Switzerland. In this article the international and national possibilities before and after specialist medical training are described in detail. In Austria, an optional coloproctology module can already be chosen in the third year of surgical training. Coloproctology is a compulsory component during the complete surgical training in Germany but a lower number of operations are required. In the basic module in Switzerland coloproctology is compulsory but contained in the operation catalogue to a lesser extent, although it has to be explicitly chosen in the further specialist training. The mandatory training in coloproctology in Germany enables all surgical assistants to undergo training, even if it is less intensive. As a result of partially compulsory and partially optional modules in Switzerland, a lower proportion of trainees receive specific training but it is more detailed. The number of trainees who are trained in coloproctology is even smaller in Austria due to the coloproctological training being optional. In the German-speaking regions a variety of specialized courses and further education are available for assistants and surgeons to further deepen their knowledge, no matter which form of training they had. At the international level the European Board of Surgical Qualification (EBSQ) for coloproctology has been available since 1998 and for many European specialists is the only possibility for formal specialization. The quality of a coloproctology training and further education curriculum may vary with national and international factors; however, it is a parameter for high standards in coloproctology in routine daily work, for the numbers of young coloproctology surgeons and is associated with a sufficient research performance in this discipline.

[A critical analysis of perception of plastic surgery in Germany]. / Kritische Perzeptionsanalyse der plastischen Chirurgie in Deutschland.

BACKGROUND AND OBJECTIVES: Plastic surgery includes a broad range of activities; however, there are no studies available in Germany which evaluated the specific role plastic surgeons play in providing patient care. The aim of the project was thus to analyze the public and professional perception of plastic surgery in Germany and to what degree the range of activities is appropriately represented. MATERIAL AND METHODS: An anonymous survey inquiring about demographic data and specific knowledge regarding plastic surgery procedures was conducted in various regions in German. Furthermore, factors that potentially influence the state of knowledge and personal perception were collated. The questionnaire was distributed among healthcare professionals and patients in plastic surgery. The statistical evaluation was performed using SPSS software. RESULTS: A total of 2100 people participated in the nationwide survey. While classical aesthetic operations were mostly assigned to plastic surgery, there was no uniformity as to whether other indications, such as reconstructive interventions and hand surgery were assigned to this specialty or not. In this context various factors could be elucidated, such as the place of residence, education and age of the survey participants and the respective knowledge, which influence the perception. CONCLUSION: Plastic surgery in Germany classically consists of the four pillars of general reconstruction, hand surgery, burn management and aesthetic procedures; however, the results of this survey revealed that plastic surgery in Germany is predominantly understood as burn management and aesthetic surgery. As a multidisciplinary specialty, plastic surgery could apparently benefit from a more positive lobby and from a better portrayal of its scope in the media and general public.

Impact of intraoperative use of vasopressors in lower extremity reconstruction: Single centre analysis of 437 free gracilis muscle and fasciocutaneous anterolateral thigh flaps.

BACKGROUND: While complication rates in free tissue transfers have continuously decreased over time due to improved techniques, the intraoperative use of vasopressors and their negative effects on flap microcirculation and patency of the anastomoses remains controversial. To further elucidate this matter, this retrospective study examines the effect of intraoperative vasopressors on free gracilis muscle and free fasciocutaneous anterolateral thigh (ALT) flaps for lower extremity reconstruction. METHODS: A total of 425 patients underwent 437 free flaps for lower limb reconstruction. The series was divided into two groups: use of intraoperative vasopressors (V, n = 318) or no use (NV, n = 119). The data were retrospectively screened for patients' demographics, perioperative details, and surgical complications. RESULTS: The two groups were comparable regarding patient comorbidities. Independently of flap type, there were no significant difference between the groups regarding major complications, i.e. total flap loss (V: 5.35% versus NV: 5.04%, p = 0.899) or revision rate (V: 18.87% versus NV: 12.61%; p = 0.122), or minor complications, i.e. partial flap loss (V: 6.29% versus NV: 5.88%, p = 0.875). CONCLUSION: This study confirms that the usage of intraoperative vasopressors has no influence on free flap survival rate in lower extremity reconstruction. It seems to be no difference between free muscle or fasciocutaneous flaps.

Effect of zileuton on osteoporotic bone and its healing, expression of bone, and brain genes in rats.

Estrogen deficiency and aging are associated with osteoporosis, impaired bone healing, and lower cognitive performance. Close functional and physical connections occur between bone and the central nervous system. An anti-inflammatory drug, zileuton (which is an inhibitor of arachidonate 5-lipoxygenase), is known to have a positive effect on bone tissue repair and brain ischemia. We studied the effect of zileuton on osteopenic bone and its healing and on the genes considered to be crucial for the cross talks between bone and brain. Three-month-old Sprague-Dawley rats were ovariectomized or left untreated. After 8 wk, bilateral metaphyseal tibia osteotomy with plate osteosynthesis was performed in all rats. Ovariectomized rats were fed with food containing zileuton (1, 10, or 100 mg/kg body wt) for 5 wk. In tibiae, bone volume, callus and cortical volume, and gene expression of osteocalcin and alkaline phosphatase were enhanced by zileuton (10 or 100 mg); biomechanical properties and bone density were not changed. In femur, zileuton enlarged cortical volume distal and trabecular volume proximal, decreasing their density. The expression level of brain Sema3a, known to regulate bone mass positively, was downregulated after ovariectomy. In contrast, bone Sema4d, a negative regulator of bone mass, was upregulated in the tibia callus after ovariectomy, whereas zileuton treatment (10 or 100 mg) resulted in reverse effects. Here, we describe for the first time the expression of Rbbp4 mRNA and its increase in tibia after ovariectomy. Zileuton caused downregulation of Rbbp4 in the hippocampus and had an effect on bone healing, changed the expression of genes involved in cross talk between bones and brain, and may be a potent drug for further examination in estrogen deficiency-related dysfunction(s). NEW & NOTEWORTHY Zileuton, a 5-lipoxygenase inhibitor, increased bone volume, callus and cortical volume in osteotomized tibia, and trabecular and cortical volume in femur. Although the expression of Sema3a (positively regulating bone mass) in brain was downregulated and Sema4d (negatively regulating bone mass) was upregulated in tibia callus after ovariectomy, zileuton could counteract these effects. Rbbp4 (involved in age-related memory loss) was increased in tibia callus after ovariectomy.

Beard reconstruction: A surgical algorithm.

BACKGROUND AND AIM: Facial defects with loss of hair-bearing regions can be caused by trauma, infection, tumor excision, or burn injury. The presented analysis evaluates a series of different surgical approaches with a focus on male beard reconstruction, emphasizing the role of tissue expansion of regional and free flaps. METHODS: Locoregional and free flap reconstructions were performed in 11 male patients with 14 facial defects affecting the hair-bearing bucco-mandibular or perioral region. In order to minimize donor-site morbidity and obtain large amounts of thin, pliable, hair-bearing tissue, pre-expansion was performed in five of 14 patients. Eight of 14 patients were treated with locoregional flap reconstructions and six with free flap reconstructions. Algorithms regarding pre- and intraoperative decision making are discussed and long-term (mean follow-up 1.5 years) results analyzed. RESULTS: Major complications, including tissue expander infection with the need for removal or exchange, partial or full flap loss, occurred in 0% (0/8) of patients with locoregional flaps and in 17% (1/6) of patients undergoing free flap reconstructions. Secondary refinement surgery was performed in 25% (2/8) of locoregional flaps and in 67% (4/6) of free flaps. CONCLUSION: Both locoregional and distant tissue transfers play a role in beard reconstruction, while pre-expansion remains an invaluable tool. Paying attention to the presented principles and considering the significance of aesthetic facial subunits, range of motion, aesthetics, and patient satisfaction were improved long term in all our patients while minimizing donor-site morbidity.

Air kerma rate constants for gamma emitters used most often in practice.

It is often required to estimate the dose rate at a distance from radionuclides that are sources of X rays and gamma rays. Such calculations may be required for planning radiation protection measures in the vicinity of radioactive sources or patients containing radionuclides, calibrations of radiation instruments or for estimating the absorbed dose rate to patients receiving brachytherapy. The factor relating activity and air kerma rate is called air kerma rate constant--gamma(delta). In this paper, the results of recalculation of this quantity for unfiltered point sources of radionuclides in practice used most often are given. The calculations included corrections for internal conversion of X rays and gamma rays and detailed accounting of the generation of the K and L series X rays from internal conversion and electron capture. Particular air kerma rate constants were calculated for each discrete line in the photon spectrum of radionuclide with a yield per decay event >0.01% and the energy >20 keV. Since the energy structure of the photon spectra and accessible discrete numerical values of the mass energy-transfer coefficient for air are not the same, the cubic spline interpolation was used to obtained the coefficient, where the photon spectrum data are available. In the calculation, the latest gamma ray spectral data for all radionuclides and latest data for the mass energy-transfer coefficient for air are used. Air kerma rate constants for the following 35 radionuclides are calculated: 11C, 13N, 15O, 18F, 24Na, 42K, 43K, 51Cr, 52Fe, 59Fe, 57Co, 58Co, 60Co, 67Ga, 68Ga, 75Se, 99Mo, 99mTc, 111In, 113mIn, 123I, 125I, 131I, 127Xe, 133Xe, 137Cs, 152Eu, 154Eu, 170Tm, 182Ta, 192Ir, 197Hg, 198Au, 201Tl and 241Am.

[Free and pedicled muscle transfer as a therapy option in urological surgery]. / Der freie und gestielte Muskeltransfer als Therapieoption in der urologischen Chirurgie.

Various demands of reconstruction define restoration technique. The basic principle involves optimal anatomical and functional reconstruction with concurrent minimal donor-site morbidity. Dependent on the aetiology of the defect, there are various reconstructive possibilities available for obtaining an optimal result. An immediate single stage reconstruction, with the best possible result for the individual patient as the primary consideration, can be carried out by interdisciplinary teams. In this overview, the most common indications and principles of flap choice are presented in relation to the reconstructive requirements necessary for early rehabilitation of the patient or the earlier start of necessary adjuvant therapy.

Mechanism of bone loss after liver transplantation: A histomorphometric analysis.

Organ transplantation is associated with increased bone loss and high fracture risk, but the pathophysiological mechanisms responsible have not been established. We have performed a histomorphometric analysis of bone remodeling before and 3 months after liver transplantation in 21 patients (14 male, 7 female) aged 38-68 years with chronic liver disease. Eight-micrometer undecalcified sections of trans-iliac biopsies were assessed using image analysis. Preoperatively, bone turnover was low with a tendency toward reduced wall width and erosion depth. The bone formation rate increased from 0.021 +/- 0.016 (mean +/- SD) to 0.067 +/- 0.055 microm2/microm/day after transplantation (p < 0.0002) and activation frequency from 0.24 +/- 0.21/year-1 to 0.81 +/- 0. 67/year-1 (p < 0.0001). No significant change was observed in wall width, but there was a trend toward an increase in indices of resorption cavity size. There was a small increase in osteoid seam width postoperatively (p< 0.02) and decrease in mineralization lag time (p < 0.001). No significant changes in indices of cancellous bone structure were observed in the postoperative biopsies. These results demonstrate a highly significant and quantitatively large increase in bone turnover in the first 3 months after liver transplantation. Although no significant disruption of cancellous bone structure was demonstrated during the time course of the study, the observed changes in bone remodeling predispose to trabecular penetration and may thus result in long-term adverse effects on bone strength.

A double-hand transplant can be worth the effort!

BACKGROUND: Composite-tissue transplantation offers a new therapeutic option for patients with loss of a hand. Little is known, however, about the long-term outcome after such a transplant with regard to graft function and immunosuppression and its side effects. We here report on our experience with a double-hand transplant performed more than 18 months ago. METHODS: Both distal forearms and hands of an age-, gender-, and size-matched cadaveric donor were transplanted to a 47-year-old policeman 6 years after loss of both hands. He received antithymocyte globulin as induction therapy and tacrolimus, mycophenolate mofetil, and prednisone as maintenance immunosuppression. Ganciclovir and co-trimoxazole were given prophylactically for cytomegalovirus and Pneumocystis carinii infection. A special rehabilitation program based mainly on cognitive therapy was designed and continued for 1 year. RESULTS: Apart from a small area of skin that became necrotic early and some arteriovenous fistulas in the left forearm, which required ligation 6 months after transplantation, there were no surgical complications. One acute rejection episode occurred on day 55 and resolved completely after high-dose steroids and topical tacrolimus. Despite ganciclovir prophylaxis, virus replication was observed. The patient became negative for cytomegalovirus only after additional treatment with foscarnet (Foscavir) and cidofovir. At the end of 18 months, graft function with regard to motility is overall 60% of normal and enables the patient to pursue activities he could not with his myoelectric prostheses. CONCLUSIONS: Excellent long-term results can be achieved with double-hand transplantation. Prerequisites are an appropriate surgical technique, careful immunosuppression, and an extensive rehabilitation program.

High-fidelity in vitro recombination using a proofreading polymerase.

We describe a convenient PCR-based protocol for in vitro recombination of homologous genes, thereby minimizing the rate of associated point mutations. High-fidelity recombination conditions were obtained using Vent DNA polymerase, which, in contrast to Taq DNA polymerase, shows significant proofreading activity and ranges among the slowest thermostable DNA polymerases, allowing tight control of the polymerase-catalyzed DNA extension. To determine the mutagenesis rate and to analyze the efficiency of recombination, 89 clones from a standard experiment were randomly selected for further analysis. Sequence comparison revealed that 21% (19/89) of the clones result from different recombination events in the marker-containing region (260 bp). The overall mutation rate is only 0.02%, which is the lowest rate thus far reported for in vitro recombination experiments.

Alpha-bungarotoxin binding sites on sensory neurones and their axonal transport in sensory afferents.

The autoradiographic localization of [125I]alpha-bungarotoxin binding sites on primary sensory fibres was investigated. Nicotinic alpha-bungarotoxin binding sites were localized to a small sub-population of large dorsal root ganglion cells in the rat, monkey, cat and human dorsal root ganglia. Ligation of the sciatic nerve or dorsal root in the rat resulted in an anterograde accumulation of binding sites proximal to the dorsal root ganglion, and a small retrograde accumulation. Unilateral dorsal root section in the rat produced a loss of toxin binding sites mainly within lamina III of the dorsal horn. These results suggest that nicotinic alpha-bungarotoxin binding sites manufactured in large dorsal root ganglion cell bodies are transported both centrally to the spinal cord and also peripherally.

Effect of dorsal rhizotomy on the autoradiographic distribution of opiate and neurotensin receptors and neurotensin-like immunoreactivity within the rat spinal cord.

The distributions of neurotensin and opiate receptors within the dorsal horn of the rat spinal cord were studied with quantitative autoradiographic techniques and compared with the immunohistochemical localizations of neurotensin and methionine-enkephalin-like immunoreactivity in this region. High densities of both neurotensin and opiate receptors were found within the superficial layers of the spinal cord, paralleling the distribution of neurotensin and enkephalin-containing interneurons and nerve terminals. Dorsal root section produced a 40% loss of opiate receptors throughout layers I and II of the spinal cord whilst no change in neurotensin receptor density or distribution was found. At the electron microscopic level the presence of neurotensin-like immunoreactivity within vesicle-containing profiles in the dorsal horn was demonstrated; however, no interaction of these terminals with primary afferent boutons was seen.

Localization of opiate and histamine H1-receptors in the primate sensory ganglia and spinal cord.

The autoradiographic localizations of opiate and histamine H1-receptors were studied quantitatively and compared following dorsal root section in the primate spinal cord. High densities of opiate and H1-receptors were found in the superficial layers of the dorsal horn. Dorsal root section produced a 40-50% loss of both receptors types throughout layers I and II with no loss in deeper layers of the dorsal horn. "Bursts' of opiate and H1-receptor labelling was observed over a population of small diameter cells (35-45 micron or micrometer) in the primate dorsal root ganglion. These cells represented approximately 8% of the total cells present. Serial consecutive sections demonstrated a population of cells bearing both opiate and histamine H1-receptors.

The distribution of multiple opiate receptors in bovine brain.

The distribution of mu and delta opiate receptors in bovine brain has been investigated using the selective radioligands [3H]morphine and D-[3H]Ala2, D-Leu5-enkephalin. Their distributions were found to vary independently through different brain areas with up to a 10-fold difference between the ratio of mu to delta binding sites for the substantia nigra and the dentate gyrus of the hippocampus.