Multiantigen print immunoassay (MAPIA) for the diagnosis of neurocysticercosis: a single-center diagnostic optimization and accuracy study in Lima, Peru

Neurocysticercosis (NCC) is the most common helminthic infection of the human central nervous system. The antibody detection assay of choice is the enzyme-linked immunoelectrotransfer blot assay using lentil-lectin purified parasite antigens (LLGP-EITB, Western blot), an immunoassay with exceptional performance in clinical samples. However, its use is mainly restricted to a few research laboratories because the assay is labor-intensive and requires sophisticated equipment, expertise, and large amounts of parasite material for preparation of reagents. We report a new immunoprint assay (MAPIA) that overcomes most of these barriers. We initially compared the performance of five different antigen combinations in a subset of defined samples in the MAPIA format. After selecting the best-performing assay format (a combination of rGP50 + rT24H + sTs14 antigens), 148 archived serum samples were tested, including 40 from individuals with parenchymal NCC, 40 with subarachnoid NCC, and 68 healthy controls with no evidence of neurologic disease. MAPIA using three antigens (rGP50 + rT24H + sTs14) was highly sensitive and specific for detecting antibodies in NCC. It detected 39 out of 40 (97.5%) parenchymal NCC cases and 40/40 (100%) subarachnoid cases and was negative in 67 out of 68 (98.53%) negative samples. MAPIA using three recombinant and synthetic antigens is a simple and economical tool with a performance equivalent to the LLGP-EITB assay for the detection of specific antibodies to NCC. The MAPIA overcomes existing barriers to adoption of the EITG LLGP and is a candidate for worldwide use.

Neurocysticercosis. A frequent cause of seizures, epilepsy, and other neurological morbidity in most of the world

Neurocysticercosis is endemic in most of the world and in endemic areas it accounts for approximately 30% of cases of epilepsy. Appropriate diagnosis and management of neurocysticercosis requires understanding the diverse presentations of the disease since these will vary in regards to clinical manifestation, sensitivity of diagnostic tests, and most importantly, therapeutic approach. This review attempts to familiarize tropical neurology practitioners with the diverse types of neurocysticercosis and the more appropriate management approaches for each.

Mycobacterium tuberculosis ribosomal protein S1 (RpsA) and variants with truncated C-terminal end show absence of interaction with pyrazinoic acid

Pyrazinamide (PZA) is an antibiotic used in first- and second-line tuberculosis treatment regimens. Approximately 50% of multidrug-resistant tuberculosis and over 90% of extensively drug-resistant tuberculosis strains are also PZA resistant. Despite the key role played by PZA, its mechanisms of action are not yet fully understood. It has been postulated that pyrazinoic acid (POA), the hydrolyzed product of PZA, could inhibit trans-translation by binding to Ribosomal protein S1 (RpsA) and competing with tmRNA, the natural cofactor of RpsA. Subsequent data, however, indicate that these early findings resulted from experimental artifact. Hence, in this study we assess the capacity of POA to compete with tmRNA for RpsA. We evaluated RpsA wild type (WT), RpsA ∆A438, and RpsA ∆A438 variants with truncations towards the carboxy terminal end. Interactions were measured using Nuclear Magnetic Resonance spectroscopy (NMR), Isothermal Titration Calorimetry (ITC), Microscale Thermophoresis (MST), and Electrophoretic Mobility Shift Assay (EMSA). We found no measurable binding between POA and RpsA (WT or variants). This suggests that RpsA may not be involved in the mechanism of action of PZA in Mycobacterium tuberculosis, as previously thought. Interactions observed between tmRNA and RpsA WT, RpsA ∆A438, and each of the truncated variants of RpsA ∆A438, are reported.

Nudt19 is a renal CoA diphosphohydrolase with biochemical and regulatory properties that are distinct from the hepatic Nudt7 isoform

CoA is the major acyl carrier in mammals and a key cofactor in energy metabolism. Dynamic regulation of CoA in different tissues and organs supports metabolic flexibility. Two mammalian Nudix hydrolases, Nudt19 and Nudt7, degrade CoA in vitro Nudt19 and Nudt7 possess conserved Nudix and CoA signature sequences and specifically hydrolyze the diphosphate bond of free CoA and acyl-CoAs to form 3',5'-ADP and 4'-(acyl)phosphopantetheine. Limited information is available on these enzymes, but the relatively high abundance of Nudt19 and Nudt7 mRNA in the kidney and liver, respectively, suggests that they play specific roles in the regulation of CoA levels in these organs. Here, we analyzed Nudt19-/- mice and found that deletion of Nudt19 elevates kidney CoA levels in mice fed ad libitum, indicating that Nudt19 contributes to the regulation of CoA in vivo Unlike what was observed for the regulation of Nudt7 in the liver, Nudt19 transcript and protein levels in the kidney did not differ between fed and fasted states. Instead, we identified chenodeoxycholic acid as a specific Nudt19 inhibitor that competed with CoA for Nudt19 binding but did not bind to Nudt7. Exchange of the Nudix and CoA signature motifs between the two isoforms dramatically decreased their kcat Furthermore, substitutions of conserved residues within these motifs identified amino acids playing different roles in CoA binding and hydrolysis in Nudt19 and Nudt7. Our results reveal that the kidney and liver each possesses a distinct peroxisomal CoA diphosphohydrolase.

Genetically tunable frustration controls allostery in an intrinsically disordered transcription factor

Intrinsically disordered proteins (IDPs) present a functional paradox because they lack stable tertiary structure, but nonetheless play a central role in signaling, utilizing a process known as allostery. Historically, allostery in structured proteins has been interpreted in terms of propagated structural changes that are induced by effector binding. Thus, it is not clear how IDPs, lacking such well-defined structures, can allosterically affect function. Here, we show a mechanism by which an IDP can allosterically control function by simultaneously tuning transcriptional activation and repression, using a novel strategy that relies on the principle of ‘energetic frustration’. We demonstrate that human glucocorticoid receptor tunes this signaling in vivo by producing translational isoforms differing only in the length of the disordered region, which modulates the degree of frustration. We expect this frustration-based model of allostery will prove to be generally important in explaining signaling in other IDPs.

Proteins carry out most of the key tasks inside cells. To perform these roles, proteins must fold up to form complex three-dimensional structures. Researchers used to think that the useful parts of proteins all had set structures. However, we now know that ‘disordered’ proteins with variable structures are common and disordered parts of proteins can have vital roles.

In a process called allosteric regulation, regulator molecules can increase or decrease the activity of a protein by binding to it. This binding was thought to work by changing the structure of the protein, but it was not clear how this works in disordered proteins. To investigate, Li et al. studied a disordered protein called glucocorticoid receptor, and found that disordered regions can have opposing effects on other regions of the protein. This creates a ‘tug-of-war’ that Li et al. term “energetic frustration”, whereby the activity of the protein results from the combination of the opposing interactions.

Further investigation revealed that the glucorticoid receptor produces different versions of itself that have different degrees of energetic frustration, which alters how effectively the proteins perform their tasks. This means that the protein can regulate its own activity even in the absence of binding to regulator molecules.

The concept of energetic frustration could enhance our understanding of the many different proteins that contain disordered regions. Eventually, this knowledge could be used to develop drugs that alter the activity of these proteins and so could form part of treatments for a wide range of conditions including autoimmune diseases (such as rheumatoid arthritis and lupus), cancers, and organ rejection for transplant patients. The results presented by Li et al. suggest where more research is needed to achieve this goal. For example, we need to understand more about the stability of disordered protein regions, and to identify which surfaces of the proteins interact with each other.

Structural insight into the inactivation of Mycobacterium tuberculosis non-classical transpeptidase LdtMt2 by biapenem and tebipenem

Background

The carbapenem subclass of β-lactams is among the most potent antibiotics available today. Emerging evidence shows that, unlike other subclasses of β-lactams, carbapenems bind to and inhibit non-classical transpeptidases (L,D-transpeptidases) that generate 3 → 3 linkages in bacterial peptidoglycan. The carbapenems biapenem and tebipenem exhibit therapeutically valuable potencies against Mycobacterium tuberculosis (Mtb).

Results

Here, we report the X-ray crystal structures of MtbL,D-transpeptidase-2 (Ldt_Mt2) complexed with biapenem or tebipenem. Despite significant variations in carbapenem sulfur side chains, biapenem and tebipenem ultimately form an identical adduct that docks to the outer cavity of Ldt_Mt2. We propose that this common adduct is an enzyme catalyzed decomposition of the carbapenem adduct by a mechanism similar to S-conjugate elimination by β-lyases.

Conclusion

The results presented here demonstrate biapenem and tebipenem bind to the outer cavity of Ldt_Mt2, covalently inactivate the enzyme, and subsequently degrade via an S-conjugate elimination mechanism. We discuss structure based drug design based on the findings and propose that the S-conjugate elimination can be leveraged to design novel agents to deliver and locally release antimicrobial factors to act synergistically with the carbapenem carrier.

Electronic supplementary material

The online version of this article (doi:10.1186/s12858-017-0082-4) contains supplementary material, which is available to authorized users.

Chromosome Instability Associates with Radiation and Doxorubicin Resistance in Triple Negative Breast Cancer Cell Lines

BackgroundTriple negative (TN) breast cancers often have a worse prognosis, despite receiving appropriate chemotherapy and radiation treatment. Thus, one of the most pressing issues in breast cancer research is investigating the molecular basis for the inherent resistance of TN cells to standard of care treatment. Chromosome instability strongly associates with chemo-resistance and poor prognosis in breast cancer. We hypothesized that genetic heterogeneity imparted by chromosome instability provides the basis for chemotherapy and radiotherapy resistance in TN cells.MethodsFour TN cell lines (HS578, HCC1806, MB231, MB468) and a benign breast tissue line (MCF10) were treated with radiation or doxorubicin. The effects of the treatments were evaluated by the colony forming unit (CFU), MTT survival, Ki-67 immuno-histochemistry (IHC), caspase-3 IHC, micronuclei, and γ-H2AX assays.ResultsRadiation and Chemotherapy Dose Responses: Table I reveals the data from the CFU and MTT assays after treatment with radiation at 0, 1, 2, 4, 6, 8 Gy or doxorubicin at 0.5, 1, 2 μg/ml, respectively. The analyses revealed a range of sensitivities to radiation and doxorubicin, where HS578 was more sensitive to both treatments.Table I. Relative radio- and chemo-resistance of TN cell linesCell TypeTD 50 (Gy)IC50 (μg/ml)HS5781.60.31HCC18061.80.86MB4681.90.95MB2311.91.05MCF101.80.32 Apoptosis and Proliferation: Because the basis for chemo-and radio-resistance of TN cells may be uncontrolled proliferation frequencies and/or decreased apoptosis, proliferation assays (assessed by Ki-67 IHC), as well as apoptotic indexes (i.e. cleaved caspase 3) were performed. The Ki-67 assay showed that 2 Gy reduced proliferation by 13% in the HS578 line, but by only 2% with the MB231cells.After receiving 2 Gy, there was a wide range of apoptotic activity among the TN cell lines. The largest percentage of apoptosis occurred with the MB468 cells at 19% vs the lowest apoptotic activity seen with the HCC1806 line, 7%. Importantly, apoptotic activity was ≤ 7% when these cell lines were treated with 1 μg/ml of doxorubicin.Chromosome instability: The micronuclei and the γ-H2AX assays showed that 3 of the 4 TN cell lines harbored active genomic instability in the absence of doxorubicin or irradiation. The unstable TN cell lines had 15-30% γ-H2AX activity and 20-40% micronuclei formation, whereas the MCF10 and HCC1806 cells had approximately 11% γ-H2AX activity and 10% micronuclei present. To assess the molecular markers contributing to chromosome instability, we performed a real time PCR screen, as well as Western blot analyses of the cyclins, cyclin-dependent inhibitors and other signaling molecules that may contribute to chromosome instability. All cell lines that had high frequencies of chromosome instability had increased levels of cyclin D1, whereas a subset also de-regulated cyclin A.ConclusionOur results show that radio- and chemo- resistance in TN breast cancer cells closely associates with a de-regulated cell cycle and active chromosome instability. We conclude that the molecular basis for chromosome instability, chemotherapy and radiation resistance may be secondary to the unregulated expression of cyclins D1 and A.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 1143.

Failure of one-day praziquantel treatment in patients with multiple neurocysticercosis lesions

A recently described one-day regimen of praziquantel (PZQ) therapy for neurocysticercosis (NCC), three doses of 25 mg/k given at 2 h intervals, was applied in eight patients with viable NCC cysts without any evidence of inflammation. Resolution of lesions in computed tomography (CT) was observed in all five patients with a single cyst, whereas all cysts survived in three patients with multiple brain parasites. One-day praziquantel is a good regimen for patients with a single viable brain cysticercus but is poorly effective for multiple cysts.

Neuronal changes induced by chronic toluene exposure in the cat

Chronic toluene inhalation provokes significant deleterious neurological effects in young glue sniffers and exposed workers. We have developed a chronic toluene inhalation model in the cat to address this issue. Neuronal changes using Loyez and acid fuchsinegallocianine stainings were studied at prefrontal cortex, cerebellun and hippocampus. All this structures showed varying degrees of neuronal degeneration to necrosis. Even if injury signs were widespread, the neuronal layers weren't equally affected and there were clear differences in injury severity. In the prefrontal cortex, injured neurons were observed in layers II, III and V/VI extending over several gyri. Lesions were time related, as was more clearly observed in Purkinje cells. In dorsal hippocampus alterations were particulary severe in CA1 and CA3. In ventral hippocampus damaged neurons were scarce and located mainly in CA2. The possible relation of this findings with behavioral changes observed during chronic toluene inhalation are noted.

Glutamate, GABA, calbindin-D28k and parvalbumin immunoreactivity in the pulvinar-lateralis posterior complex of the cat: relation to the projection to the Clare-Bishop area

Neurons of the pulvinar-lateralis posterior complex (Pul-LP) containing glutamate (Glu) and GABA, as presumed neurotransmitters, and calbindin- D28k (calbindin) and parvalbumin (PV), as Ca-binding proteins, were identified in the cat by using immunohistochemical methods. In vibratome sections, neurons immunoreactive (IR) to each of the four antibodies were observed throughout the Pul-LP. In semithin sections, GABA-IR neurons were also PV-IR but not calbindin-IR and some of them also co-localized Glu. The Glu-IR neurons which were negative for GABA co-localized calbindin but not PV. The neurons of the Pul-LP projecting to the Clare-Bishop area (CB) in the suprasylvian gyrus were identified with a retrogradely transported tracer and the sections were then immunostained for Glu, GABA, calbindin and PV. Only Glu- and calbindin-IR neurons were retrogradely labeled. These results show that, if calbindin and PV have a Ca-binding role, the presumably excitatory Glu-IR neurons projecting to the CB are use calbindin whereas the presumably inhibitory GABA-IR neurons are intrinsic and use PV. This relationship implies that these proteins probably have other roles specifically related to the kind of agonist to be released at the neuron.

Successful treatment of Trypanosoma cruzi encephalitis in a patient with hemophilia and AIDS

Although the frequency of infection with the human immunodeficiency virus (HIV) is increasing dramatically in areas where Trypanosoma cruzi is endemic, trypanosomiasis has been rarely reported in persons with HIV infection or AIDS. Persons with hemophilia who receive multiple blood product transfusions from blood banks with little or no screening for infectious agents are at particularly high risk for infections with both HIV and T. cruzi. We describe the case of a person with hemophilia who was infected by blood transfusion with HIV and T. cruzi and in whom a multifocal, necrotic trypanosomal encephalitis was demonstrated by brain biopsy and electron microscopy. Treatment with benznidazole followed by that with itraconazole and fluconazole was associated with significant clinical and radiographic improvement.

Antinociceptive effects of Ca2+ channel blockers

The antinociceptive action of four Ca2+ channel blockers, nifedipine, nimodipine, verapamil and diltiazem, was evaluated and compared to that of morphine using three algesiometric tests in mice and rats, namely, formalin, writhing and modified hot-plate test. Dose-response curves for all the drugs tested were similar and a significant dose-dependent antinociceptive action was evident in the formalin and writhing tests. However, in the hot-plate test, only nimodipine exhibited a significant analgesic effect, confirming the misleading results previously reported for this test. The findings suggest a pharmacological role of Ca2+ channel blockers in the modulation of antinociception under acute conditions. The analgesic action of Ca2+ channel blockers could be mediated by an increase in the nociceptive threshold resulting from interference with Ca2+ influx at opioid receptors, because Ca2+ influx is critical for the release of neurotransmitters and other substances implicated in nociception and inflammation. It is suggested that if a substance has a Ca2+ channel blocking effect, it should probably have some antinociceptive properties.

[Chagas disease with the acquired immunodeficiency syndrome. Clinical cases]

We report 2 patients with AIDS who developed Chagas infection, one with encephalitis, the other with acute myocarditis. The implications of immune depression for the manifestations and course of Chagas disease are discussed. Chagas disease should be considered in patients with AIDS who live in endemic zones and who develop cerebral or cardiac manifestations.

Cholinergic receptors in the human vas deferens

This study represents the first investigation demonstrating the contractile response to exogenous acetylcholine (ACh) in the isolated human vas deferens. Pharmacological characterization of cholinergic receptors was achieved using selective antagonists to define receptor subtypes. In the HVD the effect of exogenous ACh is revealed as a dose-dependent sudden increase in the basal tension of the vasa. The ACh receptors of the HVD were competitively antagonized by atropine (ATR) with a high pA2 value (8.78). The main finding of this study is the presence of cholinergic receptors of the pharmacologically defined M1-ACh subtype in the isolated HVD, according to the pA2 values obtained with pirenzepine (PRZ) 7.39, AF-DX 116 (AF) 5.92 and 4-DAMP 5.65, M1-ACh, M2-ACh and M3-ACh selective antagonists, respectively. Prazosin (PZ), a selective alpha 1-adrenergic antagonist, displayed a similar competitive antagonism for the contractile response evoked both by ACh (pA2 = 8.69) and NE (pA2 = 8.58) in the HVD. The antagonism exerted by PZ on the ACh-induced contractile response of the HVD, suggests that ACh probably acts at a presynaptic level stimulating the release of NE from an adrenergic neuron. According to these findings, the receptor involved in this action, located in the proximity of the nerve terminals, seems to be of the M1-ACh subtype.

[A form for soliciting the measurement of drug plasma level and its use in a university hospital]

The correct clinical use of drug plasma levels is frequently jeopardized by neglecting to consider pharmacokinetic parameters at the time of sample drawing. A form to be filled at this time revealed that inadequate information concerning the drug was present in 28% and sampling time in 50% of cases. Accordingly, a new form is proposed to help avoid this information inadequacies and thus lead to better clinical use of drug plasma levels.

The effects of lesioning both the superior colliculus and the substantia nigra of cats on turning behavior

In twenty two adult cats, distributed in four groups, stainless steel electrodes were implanted in the superior colliculus and the substantia nigra of both sides in order: 1) to find the current intensity threshold values necessary to evoke turning behavior, and record their variations after lesion of the cited structures; 2) to study the effects of lesioning two of these structures, specifically related to the direction of turning behavior, and 3) to assess the time-course of recovery from postural asymmetry after damaging two structures involved in rotation behavior, located either in the same or in the opposite side, as well as the importance of performing these lesions simultaneously or at different periods. Three main results were observed: 1) a large proportion of lesioned cats showed an increase in threshold values necessary to evoke rotation of the implanted structures located either in the same or in the opposite side; 2) the lesions induced in a significant number of cats a transient postural asymmetry. After lesioning the superior colliculus, the direction of turning was towards the damaged hemisphere. Apomorphine injected fourteen days later demonstrated the existence of an occult asymmetry, and the direction of turning was maintained. In the substantia nigra lesioned animals, the direction of turning, was towards the non-lesioned side. Apomorphine reversed the direction of turning; 3) the cats showed a remarkable capacity to recover from the postural asymmetry produced by the lesion. This experimental series further support the hypothesis of a close functional relationship between structures of both cerebral hemispheres related to turning behavior.

Analgesia produced by intrathecal administration of the kappa opioid agonist, U-50,488H, on formalin-evoked cutaneous pain in the rat

The antinociceptive activity of the selective kappa opioid agonist U-50,488H, given intrathecally (i.t.) against chemically induced cutaneous pain in rats, was assessed from cumulative dose-response experiments and the formalin test. Three successive i.t. doses of 5, 10 and 35 nmol of U-50,488H produced a gradual reduction of pain scores which was statistically significant at all observation periods. This effect was antagonized significantly by 3 mg/kg i.p. of the opiate antagonists, naloxone and WIN 44,441-3. The analgesia profile showed a clear dose-response relationship. A dose producing 50% 'maximum possible analgesia' of 6.20 nmol (95% confidence interval: 3.05-12.59 nmol) was calculated. The results indicated that cutaneous pain of a chemical/inflammatory nature is highly sensitive to activation of kappa receptors of the spinal cord dorsal horn.

Eye movement-related neurons in the red nucleus

Extracellular unit activity of the parvocellular red nucleus (RN) and spontaneous horizontal eye movements were recorded in adult, nitrous oxide-anesthetized and C1 transected cats. It was found that 7.5% of the neurons of each RN were related to spontaneous horizontal saccadic eye movements. Three types of neurons were observed: (1) bidirectional neurons which increased their frequency of discharge in relation to any horizontal eye movement; (2) unidirectional neurons which altered their frequency of discharge in relation to a horizontal eye movement of a precise direction; and (3) neurons which increased their frequency of discharge in relation to the rapid phase of an horizontal nystagmus. These 3 types of neurons modified their frequency of discharge before the initiation of the eye movement. One pair of oculomotor neurons recorded simultaneously in both RN showed a significant correlation coefficient. These results suggest that the RN may contribute to the preparation or execution of horizontal eye movements.

[Antitubercular agents: pharmacogenetic factors in the development of adverse effects]

We studied the distribution of the acetylator phenotype in 47 patients aged 15 to 77 years receiving isonyazid as antituberculous therapy. 62% were fast and 32% slow acetylators. Ethnical, socio-economic and biologic factors were not related to acetylator type. The incidence of liver alterations, mainly elevated transaminase levels, was higher than reported in the literature and was not shown to be influenced by acetylator type. Adverse reactions to isonyacid were not related to drug serum levels.

Comparison of the analgesic and anti-inflammatory effects of diclofenac potassium versus piroxicam versus placebo in ankle sprain patients

In a double-blind between-patient study the efficacy of diclofenac potassium, a non-steroidal anti-inflammatory drug, was assessed in 93 patients with mild to severe sprained ankles; patients with more severe sports injuries were excluded. Patients were randomly allocated to receive 50 mg diclofenac potassium three times daily, 20 mg/day piroxicam or placebo for 7 days. Diclofenac potassium was more effective than piroxicam or placebo in reducing pain at rest and on walking, but did not significantly reduce the degree of swelling when measured volumetrically by water displacement. No serious side-effects were reported. It is concluded that diclofenac potassium is useful in the treatment of moderately inflammatory processes with the advantage that it had a rapid onset of action with good overall tolerability.

Evidence that the action of clonixin is non-dependent of ACh release

1. The present study was designed to verify the ACh-mediated role in the action of ClX using cardiovascular and non-cardiovascular tissues taken from rats. 2. In the vasa deferentia preparations the muscular twitch induced by TNS was not changed by atropine, however in the presence of this drug, ClX induced a significant reduction of the height of the TNS-evoked twitch. 3. In the cardiorespiratory experiments, the administration of ClX produced a dose-dependent decrease in MAP, HR and RF. These effects were not changed by bilateral vagotomy and cervical sympathectomy. 4. The results obtained with atropine and with bilateral vagotomy and sympathectomy, attempt to delineate the possibility of a direct action of ClX. 5. All the evidence taken together does not support the hypothesis that ClX may be acting through an indirect action by releasing ACh.

[Genetic polymorphism of isoniazid acetylation in Chilean patients with tuberculosis]

We studied genetic polymorphism of isoniazid acetylation in 47 tuberculous patients treated with 4 drugs between Aug 1987 and Dec 1988. Inactivation of isoniazid was estimated from urine samples after administration of the drug (10 mg/kg). There were 18 slow and 29 fast acetylators. The frequency of the slow mutant gene was estimated at 0.612, which is intermediate between values found in american natives (0.46) and western europeans (0.73). No associations of the presence of slow gene with sex, ABO group, ancestors, socioeconomic level, undernutrition, alcoholism or tobacco consumption were found.

[Genetic factors as determinants of drug response]

Pharmacogenetics deals with the influence of genetic factors upon the response to drugs. Therapeutic and side effects are affected by pharmacokinetic and pharmacodynamic changes. Classic examples are presented, in particular those concerning mechanisms of oxidation, acetylation and hydrolysis. The impact of this discipline on therapeutics is discussed.

[The use of opiates in hospital practice]

We analyzed the type and dosage of opiates used for pain in a large general hospital from April to September 1985. Information was obtained from the computerized data base in 234 patients with a mean age of 49 years. Most patients came from the surgical service. The route of administration was intramuscular in 64% and not specified in 10% of patients. The most common drug was meperidine, the dose being 65 +/- 26 mg intramuscular and 39 +/- 26 intravenously. Methadone and morphine were used with less frequency. Good analgesic effect was recorded in 42 of 71 (59%) of patients, but the effect was not written down in the majority of subjects (70%). Other analgesics were associated in 73% of cases, most commonly a pyrazolone derivative. Nausea or vomiting was observed in only 12 patients; there were no instances of respiratory depression. We conclude that the dose of opiate used was frequently low and the associated drugs were not the best to obtain increased analgesic effect. Better recording of clinical effect of analgesics is needed in medical practice.

Evidence of a central component in the analgesic effect of indoprofene

1. The central nervous system effects of the analgesic antiinflammatory drug, indoprofene were studied. 2. CNS effects were found using EEG in rats and cats. 3. Evoked cortical potentials were studied in cats, and evoked activity in ventroposterolateral thalamic nucleus and laminae V of spinal cord were studied in rats. 4. Indoprofene induced a modification of all the parameters studied. 5. Evoked activity of thalamic nuclei and laminae V were significantly depressed. 6. Central effects were not antagonized by naloxone. 7. It is postulated that indoprofene has a central component in its effect, which would contribute to its strong and rapid analgesic effect.

New differences between the Wistar rat and Octodon degus, a putative laboratory animal resistant to morphine

1. The effects of CNS depressants (methadone and alcohol) and natural neurotransmitters (NA and ACh) are studied in O. degus. 2. O. degus shows resistance to methadone in the formalin algesiometric test and EEG. 3. Ethanol elimination profile suggest the presence of an atypical alcohol dehydrogenase in O. degus 4. O. degus is extremely resistant to the pressor effects of noradrenaline 5. the isolated atrium of this rodent is 40 times more sensitive to the negative chronotropic effect of methadone, than the rat atrium. 6. These effects could be explained in terms of an important catecholamine and endorphin co-secretion from adrenal glands in O. degus.

Further studies on the understanding of Octodon degus natural resistance to morphine: a comparative study with the Wistar rat

1. Octodon degus shows higher levels of tolerance to morphine when compared with the Wistar rat. 2. In the formalin algesiometric test, this caviomorph is more resistant to pain (P less than 0.01) and to the analgesic effect of morphine (P less than 0.001). 3. CD50 and LD50 were significantly higher in Octodon degus as compared with Wistar rat. 4. Morphine caused in rat severe hypotension, while doses eight times higher in O. degus had a transient effect. 5. 3H-naloxone binding in adrenal glands of O. degus is higher than in other tissue samples assayed from the same animal or rats.

Experimental cardio-depressant effects of clonixin

1. The cardiovascular effects of CLX were studied. 2. CLX induced hypotension, bradycardia, negative chronotropism and negative inotropism. 3. Electrophysiological studies showed a decrease of sinus venosus discharge frequency. The action potential configuration was changed: the overshoot amplitude and (dV/dt)max were reduced and duration increased. 4. CLX at higher concentrations displaced the maximum diastolic potential and phase 4 slow diastolic depolarization was lengthened. 5. The above findings could be explained by a depressant action of CLX on the electrical activity of the pacemaker cells, possibly by a modification of the slow calcium currents.

Output pathway for turning behavior from the neostriatum and substantia nigra in cats

The goal of the present work was to study the output pathway of the information for turning behavior originating in the striatum and coursing through the substantia nigra pars reticulata (SNR). In 45 adult cats distributed in 3 groups, Ni-Cr electrodes were implanted in the caudate nucleus and substantia nigra pars reticulata and depending on the animal group in the superior colliculus (SC), nucleus ventralis lateralis/nucleus ventralis medialis (VL/VM) complex or nucleus tegmenti pedunculopontinus (TPP) of one cerebral hemisphere. The threshold current required to evoke turning behavior was determined in each animal for each implantation site. An electrolytic lesion of the superior colliculus, the VL/VM complex or the nucleus tegmenti pedunculopontinus was carried out in each group of cats. The effects of the lesions on behavior and on the electrical threshold currents were determined and compared with the prelesion values. Finally the extent of the lesions and electrode positions were analyzed. The results show that the substantia nigra pars reticulata is the structure with the lowest thresholds for turning and that the superior colliculus appears to be more relevant for carrying the information for turning than either the VL/VM complex or the nucleus tegmenti pedunculopontinus.

Extracellular unit responses in the pulvinar-lateral posterior complex of the cat through electrical stimulation of substantia nigra reticulata and lateralis

Extracellular single-unit responses of neurons in the ipsilateral pulvinar-lateral posterior complex were recorded in 10 encéphale isolé cats with stimulating electrodes implanted in the substantia nigra pars reticulata and pars lateralis. Fifteen percent of 101 pulvinar-lateral posterior complex thalamic neurons increased their spike discharges when the substantia nigra was stimulated and none decreased its activity. The excitatory effect of this stimulation is discussed in relation to the eventual excitatory or inhibitory character of the efferent projection from the substantia nigra pars reticulata and lateralis to the pulvinar-lateral posterior complex.

Study of the morphological, electrophysiological and behavioral effects of unilateral kainic acid injection into the cat's substantia nigra

Morphological, electrophysiological and behavioral studies were carried out in cats after unilateral kainic acid injection in the substantia nigra. A forced contralateral head turning and compulsive circling was observed after surgery. Fifteen days after, when asymmetry disappeared, apomorphine induced an ipsilateral head and body turning, that was blocked by haloperidol. The percentage of turning, after electrical stimulation in the superior colliculus or pulvinar-lateralis posterior complex, was affected by substantia nigra lesion. This work demonstrates that the nigro-pulvinar-lateral posterior and the nigrotectal projection modulate the capability of electrical stimulation of the target structures to elicit turning, and after unilateral substantia nigra lesion, two opposite directions of asymmetry appear, which are time-dependent and modulated by different neurotransmitters.

Evidence for a nigro-pulvinar-lateralis posterior complex projection in the cat using horseradish peroxidase neuronal retrograde technique

The possible existence of a direct projection from the substantia nigra to the pulvinar-lateral posterior complex (Pul-LP) was investigated in the cat by using the horseradish peroxidase technique. In particular horseradish peroxidase was injected in the Pul-LP of 8 animals, either unilaterally or bilaterally. Tissue sections obtained from the cat's brain 24-48 hrs. after injection were prepared according to Mesulam's method as slightly modified by the authors. Retrogradelly labelled neurons were observed in substantia nigra pars lateralis and reliculata ipsilaterally to the injected pulvinar-lateral posterior complex. A small number of labelled cells were also found in the contralateral substantia nigra. These findings demonstrate the existence of a close connection between two system which are involved in turning behavior: the nigrostriatal and the pulvinar-lateral posterior complex-superior colliculus.

Electrophysiological projections of pulvinar-lateralis posterior complex (P-LP) upon superior colliculus units in the cat

The effect of Pulvinar-Lateral Posterior (P-LP) electrical stimulation on superior colliculus unitary responses and eye movements is analyzed in 17 encéphale isolé cats. Twelve of them were curarized. Out of a total of 190 recorded units, 117 were localized in the superior colliculus and 73 units in the Mesencephalic Reticular Formation (MRF) below the superior colliculus. Thirty eight per cent (n = 45) of the collicular units modified their discharge frequency when the ipsilateral P-LP was electrically stimulated. The current intensity thresholds of transynaptic activation had a range between 0.5 and 2.0 mA. Most of the orthodromic responses were produced by ipsilateral P-LP stimulation and were localized in the intermediate and deep layers of the superior colliculus. Three types of responses were obtained: short latency responses between 2 and 10 ms (57%); intermediate latency responses between 15 and 40 ms (29%), and long latency responses between 50 and 200 ms (14%). Thirty one per cent (n = 18) of the units recorded in the MRF responded to P-LP stimulation with 10 ms pulse-trains duration. In the MRF 3 types of responses were observed: 1) a decrease or blockade in the resting discharge during 20 to 100 ms after stimulation (20%); simple responses with a latency between 25 and 150 ms (40%), and complex responses with an early response and a latency between 15-40 ms, and a late response with a latency between 150 and 200 ms (40%).(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of cortical ablations on the turning response evoked by stimulation of the pulvinar-lateralis posterior nucleus complex in the cat

The role played by the cerebral cortex on turning responses elicited by electrical stimulation of P-LP was studied in 9 chronic cats. In three animals the sensorimotor cortex was bilaterally ablated and the threshold values for inducing a turning response were determined. None of the cats showed abnormal threshold values. In six cats the cerebral cortical area known to have reciprocal anatomical connections with P-LP was unilaterally removed. Seven days after surgery, 50% of the electrodes gave no responses; 25% evoked responses with high thresholds and 25% with normal thresholds. One month after surgery the percentages were: 14, 18 and 68 respectively. Histological findings show important fiber and neuronal degeneration in P-LP. It is postulated that this area of the cerebral cortex plays, a facilitatory role on the P-LP ability to induce turning response and that the recovery of this ability can be explained by the development of P-LP denervation supersensitivity.