Paradoxical effect of dopamine-agonists on IGF-1 in patients with prolactinoma: the role of weight.

PURPOSE: An increase of IGF-1 has been reported during therapy with dopamine agonists (DA) for prolactinomas; in such cases a correct diagnosis is pivotal to avoid an unnecessary reduction or withdrawal of DA, which are needed to maintain normal prolactin levels. This study was aimed to measure IGF-1 levels, at baseline and during follow-up, in a cohort of patients with prolactinoma, treated with cabergoline, stratified by body mass index. METHODS: We retrospectively enrolled 35 patients (15 F/20 M; age m ± SD, years: 43.4 ± 13.7) with prolactinoma (21 microadenomas and 14 macroadenomas) who were followed-up at the Endocrinology Unit, in Siena, and with available pituitary hormone assessment at baseline and during follow-up (m ± SD, years: 2.74 ± 0.55). RESULTS: IGF-1 increased in the whole cohort, but remaining within normal range, except two patients, in whom acromegaly was ruled out with oral glucose tolerance test. After dividing patients by weight, this trend was confirmed only in subjects with overweight and obesity (OV/OB) (p = 0.04). Interestingly, the reduction of prolactin levels was significantly greater in the OV/OB compared to normal-weight patients (median decrease of 97.5% versus 88.2%, p = 0.04). CONCLUSIONS: Since DA and normalization of prolactin are known to improve insulin sensitivity, we speculated they have favored the increase of IGF-1 in OV/OB. Our results should be confirmed and the hypothesis proven by further studies.

Identification of runs of homozygosity (ROHs) in Curraleiro Pé-Duro and Pantaneiro cattle breeds.

This study aimed to identify and characterize runs of homozygosis (ROHs), genes involved in production characteristics and adaptation to tropical systems and to estimate the inbreeding coefficient of Curraleiro Pé-Duro (CPD) and Pantaneiro (PANT), two brazilian locally adapted cattle breeds. The results demonstrated that 79.25% and 54.29% of ROH segments were bigger than 8 Mb in CPD and PANT, respectively, indicating recent inbred matings in the studied population. Six homozygosis islands were identified simultaneously in both breeds, where 175 QTLs and 1072 genes previously described as associated with production traits are located. The inbreeding coefficient (FROH) estimated based on ROHs (FROH) showed that inbreeding is low (2 to 4%), which is different from expected for small populations such as locally adapted ones.

[What factors contributed to the higher incidence rate of in-hospital falls at the time of Covid 19? A paradigm shift?] / Quali sono I fattori contribuenti la caduta dei pazienti in ospedale al tempo del Covid 19? Un cambio di paradigma?

The COVID-19 pandemic has put a strain on all health systems as there has been a growing rapidity in the demand for health care from COVID 19 positive patients in hospitals around the world. With the intensification of the pandemic, determining in real time the consequent needs for health resources (beds, personnel, equipment) has in fact become the fundamental priority for many countries to ensure health services consistent with the health needs expressed by the population. In Italy, the demand has often been satisfied with the conversion of existing beds and the remodeling of the healthcare offer or where the available resources allow it also with the opening of new beds dedicated to pandemic assistance. This work analyzes the falls detected at the time of COVID in patients and hospitalized in direct hospital beds (600 beds) of a Local Health Authority of Lazio (ASL ROMA 2). Although the data on the incidence of falls recorded in the three centers were equal to 2.21 every 1000 days of beds occupied and that the data recorded are lower than those reported in the literature, it is also true that the increase in average hospital stay and the reduction in the rotation rate of beds had an impact on the still low occupancy rates compared to the literature data.The COVID-19 pandemic has put a strain on all health systems as there has been a growing rapidity in the demand for health care from COVID 19 positive patients in hospitals around the world. With the intensification of the pandemic, determining in real time the consequent needs for health resources (beds, personnel, equipment) has in fact become the fundamental priority for many countries to ensure health services consistent with the health needs expressed by the population. In Italy, the demand has often been satisfied with the conversion of existing beds and the remodeling of the healthcare offer or where the available resources allow it also with the opening of new beds dedicated to pandemic assistance. This work analyzes the falls detected at the time of COVID in patients and hospitalized in direct hospital beds (600 beds) of a Local Health Authority of Lazio (ASL ROMA 2). Although the data on the incidence of falls recorded in the three centers were equal to 2.21 every 1000 days of beds occupied and that the data recorded are lower than those reported in the literature, it is also true that the increase in average hospital stay and the reduction in the rotation rate of beds had an impact on the still low occupancy rates compared to the literature data. In fact, the scientific literature shows that in England and Wales, whose national health service is very similar to the Italian one, the falls of patients in hospitals with optimal bed occupancy rates and optimal average hospitalization rates (equal to 4.5 days in general medicine, 3.5 days in general surgery, 3 days in orthopedics) represent the first sentinel event in terms of incidence and frequency, albeit with a very variable damage detection. The average falls is 6.63 falls per 1,000 bed-occupied days, which equates to approximately 1,700 falls per year in an 800-bed hospital with an optimal occupancy rate. Regarding damage, the literature documents that physical injuries and fractures occur in 30-50% of events and fractures occur in 1-3% of cases. The data collected in ASL ROMA 2 have documented that despite the increase in staff dedicated to assistance by 15 - 30%, an increase due to the application of COVID pathways and to the activities of compression of the risk of circulation of the virus among hospitalized patients , the rate of falls has nevertheless increased by 13.5% despite the persistence of standards of quality and safety of patients in care activities, debunking the paradigm that falls can be caused by an undersizing of the care staff and by the possible overcrowding of the emergency departments - urgency.

Inhibition in the somatosensory system: An integrative neuropharmacological and neuroimaging approach.

The presented study investigates the functional role of GABA in somatosensory processing, using a combined neuropharmacological-neuroimaging approach. Three different GABA agonists (GABAA: alprazolam, ethanol; GABAB: baclofen) were investigated in a double blind cross-over design in 16 male participants, accomplishing a tactile perception task. Somatosensory evoked magnetic fields modulated by GABAR-agonists and placebo were recorded using whole-head magnetoencephalography. Peak latencies and amplitudes of primary (SI) and secondary (SII) somatosensory cortex source activities confirmed the previously reported role of GABA as a modulator of somatosensory processing. Significant inhibitory effects on the latency of SII and on the amplitude of SI and SII were found exclusively for alprazolam, a positive allosteric modulator at GABAA receptors. The GABAB agonist baclofen did not have any modulatory effect. Moreover, we investigated whether the observed effects of alprazolam on the level of SII were explainable by the mere propagation of activity from SI to SII modulated by GABAA receptors, independently from any further GABAA-mediated inhibition in SII. By estimating the transfer function between SI and SII activation under placebo conditions, we were able to predict SII activity for the administration of GABA receptors agonists under the assumption that GABA exclusively acts at the level of SI. By comparing measured and predicted data, we propose a model in which the initial activation of SI is modulated through GABAA receptors and subsequently propagated to SII, without any significant further inhibition. In addition, initial GABAA effects in SI appear to be strongly potentiated with time, selectively in SI but not in SII.

Diagnostic accuracy and interobserver agreement of Quasistatic Ultrasound Elastography in the diagnosis of thyroid nodules.

PURPOSE: To assess the best technique and the diagnostic accuracy of Quasistatic Ultrasound Elastography (QUE) in thyroid nodules. Interobserver agreement was also evaluated. MATERIALS AND METHODS: A preliminary study of 50 patients with 54 thyroid nodules was performed with quantitative software in order to define the best cut-off value of different imaging methods. All patients underwent total thyroidectomy and histopathology findings served as the standard of reference. Thereafter, 154 nodules in 137 consecutive patients were prospectively evaluated by three operators. Findings at fine-needle aspiration cytology and histopathology (N = 60) served as the standard of reference. RESULTS: The most accurate technique was the axial peri-intranodular measurement method which achieved an area under the ROC curve of 0.961 (95 %CI 0.848 - 1.00) and had an optimal cut-off value of 3.00. QUE in the differentiation of thyroid nodules showed for operator 1: sensitivity 90 % (95 %CI 73.5 - 97.9 %), specificity 92.7 % (95 %CI 86.7 - 96.6 %), LR+ 12.40 (6.54 - 23.50), LR- 0.11 (0.04 - 0.32) and accuracy 91.4 % (95 %CI 85.4 - 97.3 %); for operator 2: sensitivity 86.7 % (95 %CI 69.3 - 96.2 %), specificity 87.1 % (95 %CI 79.9 - 92.4 %), LR+ 6.72 (4.16 - 10.80), LR- 0.15 (0.06 - 0.38) and accuracy 86.9 % (95 %CI 80.0 - 93.7 %); for operator 3: sensitivity 80 % (95 %CI 61.4 - 92.3 %), specificity 83.9 % (95 %CI 76.2 - 89.9 %), LR+ 4.96 (3.20 - 7.70), LR- 0.24 (0.12 - 0.49) and accuracy 81.9 % (95 %CI 74.0 - 89.9 %). Interobserver agreement values between operator 1 and operator 2 (k = 0.79) (p < 0.05, 95 %CI 0.684 - 0.904), between operator 1 and operator 3 (k = 0.73, 95 %CI: 0.607 - 0.854) and between operator 2 and operator 3 (k = 0.71, 95 %CI: 0.584 - 0.835) were significant. CONCLUSION: QUE provides accurate quantitative evaluation of thyroid nodules with low interobserver variability.

[Tuscan Chronic Care Model: a preliminary analysis]. / Chronic Care Model Toscano: un'analisi preliminare.

OBJECT: the aim of this study is to present a preliminary analysis of efficacy and effectiveness of a model of chronically ill care (Chronic Care Model, CCM). METHODS: the analysis took into account 106 territorial modules, 1016 General Practitioners and 1,228,595 patients. The diagnostic and therapeutic pathways activated (PDTA), involved four chronic conditions, selected according to the prevalence and incidence, in Tuscany Region: Diabetes Mellitus (DM), Heart Failure (SC), Chronic Obstructive Pulmonary Disease (COPD) and stroke. Six epidemiological indicators of process and output were selected, in order to measure the model of care performed, before and after its application: adherence to specific follow-up for each pathology (use of clinical and laboratory indicators), annual average of expenditure per/capita/euro for diagnostic tests, in laboratory and instrumental, average expenditure per/capita/year for specialist visits; hospitalization rate for diseases related to the main pathology, hospitalization rate for long-term complications and rate of access to the emergency department (ED). Data were collected through the database; the differences before and after the intervention and between exposed and unexposed, were analyzed by method "Before-After (Controlled and Uncontrolled) Studies". The impact of the intervention was calculated as DD (difference of the differences). RESULTS: DM management showed an increased adhesion to follow-up (DD: +8.1%), and the use of laboratory diagnostics (DD: +4,9 €/year/pc), less hospitalization for long-term complications and for endocrine related diseases (DD respectively: 5.8/1000 and DD: +1.2/1000), finally a smaller increase of access to PS (DD: -1.6/1000), despite a slight increase of specialistic visits (DD: +0,38 €/year/pc). The management of SC initially showed a rising adherence to follow-up (DD: +2.3%), a decrease of specialist visits (DD:E 1.03 €/year/pc), hospitalization and access to PS for exacerbations (DD: -4.4/1000 and DD: -6.1/100, respectively), compared with a slight increase of diagnostic tests (DD: +2.10 €/year/pc). Stroke showed the following outcomes: increased consumption of instrumental diagnostics and imaging (DD: +1.65 €/year/pc) and growing hospitalizations for related conditions (DD 6.1/1,000). The care of patients with COPD, finally, has produced an increase in overall expenditure on medicines (DD: +39.71/year/pc) associated with the decrease of hospitalization for related conditions (DD: -2.7/1,000). CONCLUSION: the Tuscany CCM has proven a promising model of integrated management and taking care for chronic patients, can have a positive impact on the quality of life and on the total health expenditure. Additional monitoring studies are desirable in perspective of expanding the model on all over the national territory.

High resolution 3-T MR imaging in the evaluation of the facial nerve course.

OBJECTIVES: To assess the value of 3-Tesla (3-T) MR imaging (MRI) in the evaluation of the course of the intracranial and extra-cranial tracts of the facial nerve. PATIENTS AND METHODS: 83 patients were studied by MRI in order to detect the course of facial nerve; a total of 166 facial nerves were examined. T2-weighted 3D Fast imaging employing steady-state acquisition (FIESTA) and T1-weighted Fast spoiled gradient recalled echo (fast SPRG) sequences were used. Two radiologists (reader A and B), independently, evaluated the course of the tracts of the facial nerve according to a qualitative scale (excellent, good, fair, poor). The Intraclass Correlation Coefficient (ICC) and Pearson correlation coefficient were used to assess the intra-observer and interobserver variability in the nerve course evaluation. RESULTS: Reader A evaluated 35 facial nerves as excellent, 94 as good, 33 as fair and 4 as poor. Reader B rated 31 facial nerves excellent, 89 good, 43 fair and 3 poor. The intraobserver variability was ICC = 0.919 in reader A and ICC = 0.842 in reader B. The interobserver variability (Pearson correlation coefficient) was 0.713 (p ≤ 0.01). CONCLUSIONS: According to the preliminary results of our study the use of 3-T MRI with FIESTA and fast SPGR sequences may allow the study of the course of the facial nerve and its branches. The knowledge of the course and of the anatomic relationships of these nerve bundles with surrounding structures, as well as of the anatomical variants, provide useful informations for a prompt neurosurgery and maxillofacial surgical planning.

The use of ultrasensitive thyroglobulin assays reduces but does not abolish the need for TSH stimulation in patients with differentiated thyroid carcinoma.

Measurement of serum Tg using ultrasensitive assays is proposed to replace TSH-stimulated Tg measurement in the follow-up of differentiated thyroid cancer (DTC). Aim of our study was to verify this possibility using two ultrasensitive Tg assays. We selected 215 DTC patients with undetectable (<1 ng/ml) basal serum Tg at the time of a recombinant human TSH (rhTSH) stimulation. According to standard criteria, 173 (80.4%) patients were considered free of disease, 17 (7.9%) had documented disease and 25 (11.7%) had no evidence of disease but detectable serum rhTSH-stimulated Tg (biochemical disease). The sera of these patients were re-assayed with two commercial ultrasensitive assays and the results were compared with the clinical data. Basal Access and E-Iason Tg assays were able to distinguish patients with persistent disease or free of disease with a sensitivity of 82.3 and 82.3%, specificity of 85.5 and 86.1%, positive predictive value (PPV) of 35.8 and 36.8%, negative predictive value (NPV) of 98 and 98.6%, respectively. With both assays the addition of neck ultrasound to basal Tg increased the sensitivity and the NPV to 100% and decreased the false negative rate to 0%. In patients with detectable basal Tg without evidence of disease, serum Tg converted from detectable to undetectable in about 80% of the cases during 2-yr follow-up. Our study indicates that the combination of neck ultrasound and basal ultrasensitive Tg allows to identify all patients free of disease and can decrease the need for rhTSH stimulation in nearly 80% of the patients.

Transhydrogenase and the anaerobic mitochondrial metabolism of adult Hymenolepis diminuta.

The adult cestode, Hymenolepis diminuta, is essentially anaerobic energetically. Carbohydrate dissimilation results in acetate, lactate and succinate accumulation with succinate being the major end product. Succinate accumulation results from the anaerobic, mitochondrial, 'malic' enzyme-dependent utilization of malate coupled to ATP generation via the electron transport-linked fumarate reductase. A lesser peroxide-forming oxidase is apparent, however, fumarate reduction to succinate predominates even in air. The H. diminuta matrix-localized 'malic' enzyme is NADP-specific whereas the inner membrane (IM)-associated electron transport system prefers NADH. This dilemma is circumvented by the mitochondrial, IM-associated NADPH-->NAD+ transhydrogenase in catalyzing hydride ion transfer from NADPH to NAD+ on the IM matrix surface. Hydride transfer is reversible and phospholipid-dependent. NADP+ reduction occurs as a non energy-linked and energy-linked reaction with the latter requiring electron transport NADH utilization or ATP hydrolysis. With NAD+ reduction, the cestode transhydrogenase also engages in concomitant proton translocation from the mitochondrial matrix to the intermembrane space and supports net ATP generation. Thus, the cestode NADPH-->NAD+ system can serve not only as a metabolic connector, but an additional anaerobic phosphorylation site. Although its function(s) is unknown, a separate IM-associated NADH--> NAD+ transhydrogenation, catalyzed by the lipoamide and NADH dehydrogenases, is noted.

Limited value of repeat recombinant human thyrotropin (rhTSH)-stimulated thyroglobulin testing in differentiated thyroid carcinoma patients with previous negative rhTSH-stimulated thyroglobulin and undetectable basal serum thyroglobulin levels.

CONTEXT: One year after initial treatment, low-risk differentiated thyroid cancer (DTC) patients undergo recombinant human (rh)TSH-stimulated serum thyroglobulin (Tg) (rhTSH-Tg) and neck ultrasound (US). OBJECTIVE: The need for more rhTSH-Tg in these patients is controversial. We evaluated the utility of a second rhTSH-Tg in DTC patients 2-3 yr after their first evaluation. RESULTS: At the first rhTSH-Tg, basal and stimulated serum Tg was undetectable in 68 of 85 patients. Neck US was unremarkable in all but one, who had evidence of lymph node disease. Seventeen of 85 patients had undetectable serum Tg that became positive after rhTSH, with negative imaging in 10 and evidence of disease in seven. Patients with no evidence of disease were reevaluated 2-3 yr later (second rhTSH-Tg). In patients in which the first stimulated Tg was undetectable, all had undetectable basal serum Tg, which remained undetectable after rhTSH in 66 of 67 patients (98.5%) and became detectable in one (1.5%) (positive neck US). In the 10 patients with detectable stimulated Tg in the first test, basal serum Tg and US were negative at the second test, but rhTSH-Tg became detectable in six. Compared with the first rhTSH-Tg, the second stimulated Tg in these six patients decreased in one, increased in three, and stabilized in two patients. CONCLUSIONS: The second rhTSH-Tg was informative in patients who had first stimulated Tg detectable but not in those who had undetectable Tg at the first test, in which the only patient with recurrence was diagnosed by neck US. Thus, rhTSH-Tg should be repeated only in patients who have had a positive first rhTSH-Tg and negative imaging.

Physical, chemical and microbiological characterization of the intertidal sediments of Pereque Beach, Guarujá (SP), Brazil.

Physical and chemical characteristics of intertidal sediments and their relationships with bacteria and cyanobacteria were analyzed at four stations at Pereque Beach. Granulometric analysis showed that Pereque beach has sediment that is classified as sand. The lowest value of the sediment C/N rates (6.08), mainly due to a higher concentration of organic nitrogen, was found at the northern part of Pereque Beach, where organic matter of marine source was more prominent. In this area, density (9.6x10(6)cells cm(-3)), biomass (1992.04ngC cm(-3)) and activity of bacteria were higher than at the southern end. In contrast, cyanobacteria density varied from 2.0 to 4.0x10(5)cells cm(-3), with biomass and total chlorophyll a of the sediment being higher at the southern part, where there are water input from Pereque River and higher organic matter of continental origin. The variability in the microbial population is discussed in the light of the sediment granulometry, organic matter quality, fresh water inflow and pollution.

Catalysis of NADH-->NADP+ transhydrogenation by adult Hymenolepis diminuta mitochondria.

Hymenolepis diminuta mitochondria catalyze nonenergy-linked and energy-linked NADH-->NADP(+) transhydrogenations, with the latter driven by electron-transport dependent NADH oxidation (electron transport-driven, ETD) or ATP hydrolysis (ATP-driven, ATPD). Using submitochondrial particles, NADH-->NADP(+) transhydrogenations were characterized further. ETD and ATPD reactions were enhanced by bovine serum albumin (BSA) and were inhibited by N,N'-dicyclohexylcarbodiimide (DCCD), carbonyl cyanide 3-chlorophenylhydrazone (CCCP), carbonyl cyanide 4-(trifluoromethoxy) phenylhydrazone (FCCP), and niclosamide. The nonenergy-linked reaction was unaffected by these additives. Except for DCCD inhibition of the ATPD reaction, BSA mitigated inhibitor effects on energy-linked activities. BSA enhanced NADH oxidase (but not ATPase) activity. Although DCCD inhibited NADH oxidase and ATPase, BSA only lessened oxidase inhibition. With protonophores, an increase in NADH oxidase (but not ATPase) activity was suggested. Oxidase inhibition by rotenone was unaffected by BSA. The ATP-hydrolyzed/NADPH-formed for the ATPD reaction was almost unity. A model for H. diminuta energy-linked transhydrogenation is presented.

Effects of training and motivation on auditory P300 brain-computer interface performance.

OBJECTIVES: Brain-computer interface (BCI) technology aims at helping end-users with severe motor paralysis to communicate with their environment without using the natural output pathways of the brain. For end-users in complete paralysis, loss of gaze control may necessitate non-visual BCI systems. The present study investigated the effect of training on performance with an auditory P300 multi-class speller paradigm. For half of the participants, spatial cues were added to the auditory stimuli to see whether performance can be further optimized. The influence of motivation, mood and workload on performance and P300 component was also examined. METHODS: In five sessions, 16 healthy participants were instructed to spell several words by attending to animal sounds representing the rows and columns of a 5 × 5 letter matrix. RESULTS: 81% of the participants achieved an average online accuracy of ⩾ 70%. From the first to the fifth session information transfer rates increased from 3.72 bits/min to 5.63 bits/min. Motivation significantly influenced P300 amplitude and online ITR. No significant facilitative effect of spatial cues on performance was observed. CONCLUSIONS: Training improves performance in an auditory BCI paradigm. Motivation influences performance and P300 amplitude. SIGNIFICANCE: The described auditory BCI system may help end-users to communicate independently of gaze control with their environment.

Positron emission tomography neuroreceptor imaging as a tool in drug discovery, research and development.

Improved communication and cooperation between research-driven drug companies and academic positron emission tomography (PET) centers, coupled with improvements in PET camera resolution, the availability of small animal PET cameras and a growing list of neuroreceptor-specific PET tracers, have all contributed to a substantial increase in the use and value of PET as a tool in central nervous system drug discovery and development.

Autologous blood preparations rich in platelets, fibrin and growth factors.

OBJECTIVES: Bone regeneration is often needed prior to dental implant treatment due to the lack of adequate quantity and quality after infectious diseases. The greatest regenerative power was obtained with autologous tissue, primarily the bone alive, taken from the same site or adjacent sites, up to the use centrifugation of blood with the selection of the parts with the greatest potential regenerative. In fact, various techniques and technologies were chronologically successive to cope with an ever better preparation of these concentrates of blood. Our aim is to review these advances and discuss the ways in which platelet concentrates may provide such unexpected beneficial therapeutic effects. METHODS: The research has been carried out in the MEDLINE and Cochrane Central Register of Controlled Trials database by choosing keywords as "platelet rich plasma", "platelet rich fibrin", "platelet growth factors", and "bone regeneration" and "dentistry". RESULTS: Autologous platelet rich plasma is a safe and low cost procedure to deliver growth factors for bone and soft tissue healing. CONCLUSION: The great heterogeneity of clinical outcomes can be explained by the different PRP products with qualitative and quantitative difference among substance.

The bisphosphonate, alendronate, prevents bone loss in ovariectomized baboons.

We examined the effect of the amino bisphosphonate alendronate, administered IV every 2 weeks at 0.05 and 0.25 mg/kg for 1 year, on bone loss and parameters related to bone metabolism in ovariectomized baboons. Relative to non-OVX animals, the OVX baboons experienced increased bone turnover, reflected in biochemical and histomorphometric measurements, and bone loss assessed by dual-beam absorptiometry in the lumbar spine, which was similar to changes observed in ovariectomized women. Alendronate treatment maintained all parameters of bone turnover at control (nonovariectomized) levels and prevented the bone loss in a dose-dependent manner. We concluded that ovariectomized baboons offer a suitable model for the bone changes observed in ovariectomized women and that these changes can be prevented by sustained administration of an appropriate dose of this aminobisphosphonate.

Rhodoquinone requirement of the Hymenolepis diminuta mitochondrial electron transport system.

The occurrence of rhodoquinone as a mitochondrial membrane component was demonstrated in adult Hymenolepis diminuta. Chromatographic separation of pentane extracts, from lyophilized mitochondrial membranes, coupled with spectral analyses of separated material demonstrated the presence of rhodoquinone. The presence of ubiquinone was not apparent. Rhodoquinone content of membranes was about 1.2 micrograms (mg protein)-1. The rhodoquinone requirement of the H. diminuta electron transport system was demonstrated both in terms of the less active NADH oxidase and the physiologically required, NADH-dependent fumarate reductase employing lyophilized mitochondrial membranes as the source of activities. Pentane extraction of membranes virtually abolished the oxidase and fumarate reductase systems. Supplementation of pentane-treated membranes with H. diminuta rhodoquinone restored oxidase and fumarate reductase activities to levels simulating those of lyophilized membranes. Ubiquinone did not substitute for rhodoquinone. The rhodoquinone-reconstituted membranes displayed rotenone sensitivity. These findings represent the first direct demonstration of the rhodoquinone requirement of helminth electron transport-coupled oxidase and fumarate reductase.

Intramitochondrial localization of fumarate reductase, NADPH----NAD transhydrogenase, 'malic' enzyme and fumarase in adult Hymenolepis diminuta.

The intramitochondrial localization of the fumarate reductase, NADPH----NAD transhydrogenase, 'malic' enzyme and fumarase was determined in adult Hymenolepis diminuta. The distribution of marker enzymes for the inner membrane, matrix, intermembrane space and outer membrane of H. diminuta mitochondria simulated that of the corresponding ascarid and mammalian organelles. The electron transport-coupled fumarate reductase and the NADPH----NAD transhydrogenase were components of the inner membrane whereas the 'malic' enzyme and fumarase were in the matrix soluble compartment. Assessments of NADH utilization, malate-dependent NADP reduction and NADPH----NAD transhydrogenation by presumedly intact and disrupted mitochondria supported the localization data. The findings presented indicate that in H. diminuta mitochondria (a) NADPH and fumarate are accumulated within the matrix compartment; (b) transhydrogenation between NADPH and NAD is an event associated with the matrix side of the inner membrane; and (c) electron transport-dependent NADH oxidation and fumarate reduction occur at sites on the matrix side of the inner membrane.