Human nucleotide excision repair protein XPA: extended X-ray absorption fine-structure evidence for a metal-binding domain.

The ubiquitous, multi-enzyme, nucleotide excision repair (NER) pathway is responsible for correcting a wide range of chemically and structurally distinct DNA lesions in the eukaryotic genome. Human XPA, a 31 kDa, zinc-associated protein, is thought to play a major NER role in the recognition of damaged DNA and the recruitment of other proteins, including RPA, ERCC1, and TFIIH, to repair the damage. Sequence analyses and genetic evidence suggest that zinc is associated with a C4-type motif, C105-X2-C108-X17-C126-X2-C129, located in the minimal DNA binding region of XPA (M98-F219). The zinc-associated motif is essential for damaged DNA recognition. Extended X-ray absorption fine structure (EXAFS) spectra collected on the zinc associated minimal DNA-binding domain of XPA (ZnXPA-MBD) show directly, for the first time, that the zinc is coordinated to the sulfur atoms of four cysteine residues with an average Zn-S bond length of 2.34+/-0.01 A. XPA-MBD was also expressed in minimal medium supplemented with cobalt nitrate to yield a blue-colored protein that was primarily (>95%) cobalt associated (CoXPA-MBD). EXAFS spectra collected on CoXPA-MBD show that the cobalt is also coordinated to the sulfur atoms of four cysteine residues with an average Co-S bond length of 2.33+/-0.02 A.

Differentiated metabolic stimulation of rat pituitary lobes by peripheral and central endothelin-1.

Intravenous infusion (14 nmol/min) and lateral cerebral ventricular injection (9 pmol) of endothelin-1 increased rates of glucose utilization (quantitative autoradiographic [14C]deoxyglucose method) by 75-219% in pars intermedia and distalis of the rat pituitary gland. In rats given intraventricular endothelin, glucose metabolism was also increased significantly in pars nervosa (+92%). Metabolic activation by central endothelin in pars intermedia and distalis was inhibited by intraventricular pretreatment with the dihydropyridine, nimodipine, indicating that endothelin stimulates energy metabolism and probably hormone secretion in melanotrophs and pars distalis cells via L-type calcium channels.

Neurotoxicity in conscious rats following intraventricular SNAP, a nitric oxide donor.

A solution containing S-nitroso-N-acetylpenicillamine (SNAP), a nitric oxide (NO.-releasing compound, was microinjected in doses of 0.25-2 mumol into a lateral ventricle of conscious rats. SNAP produced dose-dependent convulsions similar to those associated with limbic stimulation, such as tonic extension of the hindlimbs and tail, and dystonia of the forepaws. At 2 mumol, SNAP evoked hyperventilation (arterial hypocapnia), arterial hyperglycemia and caused necrotic lesions of periventricular gray (e.g. lateral septal nucleus) and white matter structures. In the caudate nucleus and lateral septal nucleus ipsilateral to injection, SNAP elicited a bipolar metabolic pattern of low glucose metabolism proximal to the ventricle with higher values occurring more distally. In control studies, we proved that the residue of SNAP decomposition, N-acetylpenicillamine disulfide injected intraventricularly (2 mumol), was without physiological, behavioral, or histological effects. Ventricular pretreatment with methylene blue (2 nmol), a putative inhibitor of guanylate cyclase and superoxide generator, suppressed several of the behavioral manifestations of 1 mumol SNAP, such as the forepaw dystonia, squinting, and facial clonus, but was ineffective on the physiological and histological variables affected by the 2 mumol SNAP dose. Another NO. donor, sodium nitroprusside (2 mumol), produced fewer behavioral and cytotoxic effects over a 55-min observation period, but caused more intense and widely distributed metabolic stimulation, especially in commissural and projection white matter tracts. The results are the basis for a conscious rat model using intraventricular injection of nitrocompounds to examine the physiological, behavioral, metabolic and cytotoxic properties of NO. in the brain.

Cerebral hypermetabolism produced by intraventricular endothelin-1 in rats: inhibition by nimodipine.

Injection of endothelin-1 (9 pmol) into the lateral cerebral ventricle of rats produced barrel-rotations, convulsions, tonic hindlimb extensions, facial clonus, and kinetic ataxia for up to 45 min. Quantitative metabolic autoradiographs produced from the [14C]deoxyglucose method and analyzed over 60 individual brain structures or subregions revealed intense hypermetabolism in periventricular tissues close to the injection site and in many of their efferent projection sites. Histological examination of these areas proved that this dose of endothelin was without toxic or ischemic effects on neurons or glial cells. Structures metabolically affected ipsilateral to injection were caudate nucleus (+164%), lateral septal nucleus (+270%), and two white matter tracts--corpus callosum (+236%) and hippocampal fimbria (+318%). Distant stimulated structures included cerebellar cortical layers, but not cerebellar nuclei or white matter. Increased rates of glucose metabolism among many other nuclei, particularly distinct subunits of the hippocampal formation and structures in contact with the ventricular system, signify that endothelin induced widespread metabolic stimulation over much of the neuraxis. Furthermore, although the 9 pmol concentration of endothelin produced convulsive movements and diverse metabolic stimulation, it did not evoke detectable electroencephalographic seizure activity assessed by intra- or extracerebral electroencephalography. Both the convulsions and hypermetabolic activation were inhibited by intraventricular pretreatment with the dihydropyridine calcium-channel antagonist, nimodipine. The results identify endothelin-1 as a calcium-mediated 'convulsive' peptide with selective stimulatory effects on cerebral glucose metabolism.

Intraventricular endothelin-1 uncouples the blood flow: metabolism relationship in periventricular structures of the rat brain: involvement of L-type calcium channels.

Endothelin-1 (ET) produces contraction of cerebral resistance vessels in vitro and in situ, but also is neuroactive causing increases in tissue energy metabolism as measured by [14C]deoxyglucose autoradiography in the intact rat brain. ET may, therefore, disengage the normally tight linkage between cerebral blood flow and tissue metabolism. Using anatomically rigorous autoradiographic and imaging techniques to measure focal blood flow in anesthetized, ventilated rats, we found that intraventricular injection of 9 pmol of ET reduced rates of perfusion by an average of 29% (compared to a saline-injected condition) in 6 individual periventricular structures bordering the injected lateral ventricle. A significant vasoconstrictor effect (41% decrease in blood flow) also occurred in the ipsilateral choroid plexus after ET injection, despite its increased rate of glucose metabolism. We employed a hydrogen clearance method to monitor rates of blood flow serially within the periventricular margin of the caudate nucleus after intraventricular injection of the dihydropyridine calcium-channel antagonist, nimodipine (72 nmol), or 9 pmol ET, alone and in sequence. Nimodipine increased caudate blood flow (by 47%) and prevented the vasoconstriction produced by ET. The results indicate that ET causes vasoconstriction in penventricular brain structures and choroid plexus even in the presence of substantial increases in glucose metabolism. The simultaneous stimulation by intraventricular ET of tissue hypermetabolic and vascular constrictor mechanisms, leading to a net reduction of periventricular blood flow, is mediated, at least in part, by dihydropyridine-sensitive calcium L-channels.

Calcium-mediated metabolic stimulation of neuroendocrine structures by intraventricular endothelin-1 in conscious rats.

We examined the hypothesis that the vascular- and brain-derived peptide, endothelin-1 (ET), would affect cerebral neuroendocrine structures when administered via the peripheral circulation or via a lateral cerebral ventricle (i.c.v.). ET was infused intravenously (14 nmol/min) or injected i.c.v. (9 pmol) in conscious rats in which local cerebral glucose metabolism was assessed by the quantitative autoradiographic [14C]deoxyglucose technique. Whereas intravenously infused ET was previously demonstrated to selectively stimulate metabolic activity in the pituitary intermediate and anterior lobes of conscious rats, it was without effect in 20 individual structures or subnuclei involved in neuroendocrine functions, including several circumventricular organs. Intraventricular ET, however, caused hypermetabolic responses in 9 neuroendocrine structures, including the pineal gland, subfornical organ, median eminence, the hypothalamic paraventricular and supraoptic nuclei, and other hypothalamic and preoptic structures. The metabolic stimulation resulting from central ET was abolished or attenuated regionally by i.c.v. pretreatment with the calcium L-channel inhibitor, nimodipine. The findings indicate that i.c.v. ET elicits a calcium-mediated hypermetabolic effect on several neuroendocrine structures in the forebrain involved in the regulation of fluid homeostasis, the cardiovascular system, and body temperature.

Radiographic changes in the first metatarsal head after distal chevron osteotomy combined with lateral release through a plantar approach.

The purpose of this study was to evaluate the development of clinically significant avascular necrosis of the head of the first metatarsal after: (1) distal metatarsal osteotomy of the chevron configuration beginning apically at the center of the metatarsal head and extending into the head metatarsal neck junction and (2) release of the adductor hallucis muscle, the lateral capsulosesamoid ligament, and the lateral head of the flexor hallucis brevis via fibular sesamoidectomy in the majority of procedures (71/77). Although there were initial radiographic findings suspicious of avascular necrosis, subchondral lucencies (28 feet), mottling (40 feet), and focal lucencies (29 feet) in 76% of the feet, at final follow-up (12-43 months, average 25 months) this figure had fallen to 25%. The range of motion of the first metatarsophalangeal joint and articular symptoms were important in this study because of the assumption that these two parameters of evaluation would correspond to the severity of radiographic evidence of avascular necrosis. Only those patients (8 feet) with persistent mottling at final follow-up had a statistically significant decrease in the average range of motion (P = .013), with 51 degrees total arc of motion compared with 64 degrees total arc of motion for the remainder. There were no patients with persistent radiographic changes suggesting avascular necrosis who complained of pain.(ABSTRACT TRUNCATED AT 250 WORDS)

Sensitivity of urinary antigen test in relation to clinical severity in a large outbreak of Legionella pneumonia in Spain.

Presented here are the results of Legionella urinary antigen testing correlated with patient characteristics and severity of pneumonia (Fine score) in 295 patients diagnosed with Legionella pneumonia in connection with a large outbreak in Murcia, Spain. Overall, the sensitivity of the urinary antigen test was 47.7% (141/295). A statistically significant association was found between the clinical severity of pneumonia and test sensitivity; 85.7% for patients with severe pneumonia versus 37.9% for patients with mild pneumonia (risk ratio, 2.3). Variables significantly associated with test positivity in multivariate analysis were as follows: pre-existing pulmonary disease, body temperature >40 degrees C, leukocytosis and multilobar infiltrates. Patients with mild pneumonia may go undiagnosed if the urinary antigen test is used alone.

Long-term study to assess the efficacy of tamsulosin in the control of symptoms and complications developed in patients with symptomatic benign prostatic hyperplasia (OMNICONTROL study): first-year follow-up report.

OBJECTIVE: To evaluate: i. long-term efficacy of tamsulosin in the control of lower urinary tract symptoms (LUTS) suggestive of benign prostatic obstruction (BPO) using the I-PSS questionnaire, ii. the frequency of complications related to the disease, and iii. short and long-term tolerability of tamsulosin. METHODS: A total of 2.921 patients with LUTS suggestive of BPO for more than 6 months and total IPSS > 7 treated with tamsulosin (Omnic) in real life practice conditions in Spain entered an observational prospective multicentre clinical study. Efficacy was primarily assessed by changes from baseline to endpoint in I-PSS symptoms score (total, irritative and obstructive), and secondarily by the appearance of disease complications, and urinary flow measurements. Safety was assessed recording every suspected adverse reaction, blood pressure changes and laboratory data on months 6 and 12. Evolution in time of free flow and sonographical evaluation of the prostate were also obtained in 663 (22.7%) and 1346 (46.1%) cases, respectively, and the use of previous and concomitant medication was also analysed. RESULTS: After 6 and 12 months total I-PSS, irritative, and obstructive symptoms were significantly reduced with the use of tamsulosin 0,4 mg once daily. At 1 year follow-up total I-PSS score, irritative symptoms, and obstructive symptoms were reduced in 8.2, 3.5 and 4.8 points 146%, 45% and 48% improvement), respectively (p < 0.0001). The proportion of patients seriously symptomatic (total I-PSS score 20-35) was reduced from 34.8% at the start of the study to 8% at 6 months and 2.9% at 12 months. Mean QoL also significantly improved after 6 and 12 months of treatment. Average score QoL index was reduced from 4.1 to 1.86 after 12 months (2.24 points, 55% improvement) (p < 0.0001). Qmax also significantly improved after 6 and 12 months of treatment (p < 0.0001). The good tolerability profile of tamsulosin has been confirmed after 6 and 12 months of treatment. CONCLUSIONS: Therapeutic intervention with tamsulosin 0,4 mg once daily is effective in all parameters analysed (I-PSS questionnaire and flow study), very well tolerated and safe in the short-term (6 and 12 months) in patients with LUTS suggestive of BPO. Long-term data specifically regarding the decrease in prostate volume and the evolution of the BPH condition will be welcome.

Metabolic and neuroanatomical correlates of barrel-rolling and oculoclonic convulsions induced by intraventricular endothelin-1: a novel peptidergic signaling mechanism in visuovestibular and oculomotor regulation?

The neuroactive peptide endothelin-1 has receptors distributed abundantly among subdivisions and nuclei of the visuovestibular and oculomotor systems. In previous work, we and others described the convulsive manifestations resulting from central injection of this neuropeptide, including nystagmus, oculoclonus, exophthalmos, tonic hindlimb extension, and a generalized repetitive motor disturbance called barrel-rolling. We applied the quantitative, autoradiographic [14C]deoxyglucose method to examine the hypothesis that visuovestibular and oculomotor structures would become metabolically stimulated when endothelin was introduced into the brain via the ventricular system in conscious rats. Since previous work had demonstrated that hypermetabolic responses to endothelin in other neural systems were inhibited by an antagonist of neuronal calcium L-type channels, nimodipine, we further tested whether the increased function of vestibulooculomotor nuclei whose metabolic activity was sensitive to endothelin could be altered following nimodipine pretreatment via the ventricle. A single unilateral injection of endothelin (9 pmol in 3 microliters saline) into a lateral ventricle provoked significantly increased rates of glucose metabolism in 22 of 39 individual anatomical structures of the visuovestibular and oculomotor systems. Among those affected were the superficial stratum of the caudal superior colliculus (+25%), the optic tract bilaterally (+35 to 43%), the oculomotor cranial nerve nuclei (III, IV, VI; range of +21 to 47%), and the medial terminal nucleus of the accessory optic tract which harbors dense fields of endothelin binding sites (bilateral increase of +70 to 96%). Several other nuclei involved in the proprioceptive and visuovestibular disturbance caused by endothelin displayed increased metabolic activity, including the cuneate, gracile, sensory trigeminal, and prepositus hypoglossal nuclei, the vestibular subnuclear system, and the cerebellar flocculus. Identification of hypermetabolic responsivity to endothelin in these structures provides further information on the anatomical substrates mediating the behavioral phenomenology of endothelin-induced motor convulsions which involve the paroxysmal participation of the extraocular muscles and motor control systems producing barrel-rolling convulsions. Nimodipine pretreatment inhibited both the convulsive activity and the cerebral hypermetabolic responses to intraventricular endothelin. The results indicate that the neural systems sensitive to intraventricular endothelin become functionally active via a calcium-mediated process that may involve the neuropeptide as an intrinsic signaling molecule.

Muscle fibre size and type distribution in thoracic and lumbar regions of erector spinae in healthy subjects without low back pain: normal values and sex differences.

This study sought to investigate the normal muscle fibre size and type distribution of the human erector spinae, both in thoracic and lumbar regions, in a group of 31 young healthy male (n = 17) and female (n = 14) volunteers. Two percutaneous muscle biopsy samples were obtained under local anaesthesia, from the belly of the left erector spinae, at the levels of the 10th thoracic and 3rd lumbar vertebrae. Samples were prepared for routine histochemistry for the identification of fibre types. Fibre size (cross-sectional area (CSA) and narrow diameter (ND)) was quantified using computerised image analysis. The mean CSA/ND for each fibre type was greater in the thoracic than the lumbar region, but there was no difference between the 2 regions either for percentage type I (i.e. percentage distribution by number), percentage type I area (i.e. relative area of the muscle occupied by type I fibres) or the ratio describing the size of the type I fibre relative to that of the type II. Men had larger fibres than women, for each fibre type and at both sampling sites. In the men, each fibre type was of a similar mean size, whereas in the women the type I fibres were considerably larger than both the type IIA and type IIB fibres, with no difference between the latter two. In both regions of the erector spinae there was no difference between men and women for the proportion (%) of a given fibre type, but the percentage type I fibre area was significantly higher in the women. The erector spinae display muscle fibre characteristics which are clearly very different from those of other skeletal muscles, and which, with their predominance of relatively large type I (slow twitch) fibres, befit their function as postural muscles. Differences between thoracic and lumbar fascicles of the muscle, and between the muscles of men and women, may reflect adaptive responses to differences in function. In assessing the degree of any pathological change in the muscle of patients with low back pain, it seems clear that (1) sex cannot be disregarded and (2) 'atrophied' (using the criteria from other muscles) type II fibres are not necessarily abnormal for the erector spinae, particularly in women.

Potent metabolic stimulation of septal gray and cerebral white matter in vivo by intraventricular endothelin and nitric oxide.

Endothelin-1 (ET) and sodium nitroprusside (SNP, which liberates nitric oxide, NO) were given alone or together into a lateral cerebral ventricle (icv) of anesthetized rats to assess their potential interaction on cerebral rates of glucose metabolism (autoradiographic [14C]deoxyglucose technique). ET (9 pmol) produced hypermetabolic effects ipsilaterally in the septal nuclei and periventricular white matter. NO lesioned the septum, which displayed neuronal damage and diminished metabolic activity, and evoked potent increases in glucose metabolism bilaterally in commissural and projection white matter tracts. Together, ET and NO had synergistic hypermetabolic effects in the hippocampal fimbria, but were antagonistic on the metabolic rate of the lateral septal nucleus and choroid plexus. The results reveal an extraordinary sensitivity in the metabolic rate of septal gray matter to ET and of white matter fibers to NO in vivo. Icv administration offers a useful approach for examination of the metabolic and toxicological properties of the novel neurotransmitter substances ET and NO on septal neurons, myelinated fibers, and choroidal epithelia.

Brucellosis in patients infected with the human immunodeficiency virus.

Brucellosis has been described rarely in patients infected with HIV, despite the fact that eradication of intracellular brucellae is largely dependent on cell-mediated immunity. The characteristics of all patients with HIV infection and brucellosis seen in seven Spanish hospitals are reported. Since the beginning of the AIDS epidemic, 12 HIV-infected patients were diagnosed with brucellosis (8 with cultures positive for Brucella spp., 4 with high anti-Brucella antibody titers). Most patients were male and intravenous drug users. Eleven patients had no symptoms of HIV infection when first diagnosed with brucellosis and had relatively preserved cellular immunity (median CD4 + cell count 588, range 136-1006). There was a clear epidemiologic antecedent for acquisition of brucellosis in 11 patients. Clinical symptoms included fever, arthromyalgia, and sweating in all patients; four patients presented with focal disease. All patients had high agglutinin titers, and eight of nine had cultures positive for Brucella. Therapy with doxycycline and streptomycin was curative in all cases. Two patients experienced a recurrence of symptoms after initial treatment, although no microbiological relapses were documented after a median follow-up period of 18 months. HIV infection does not seem to increase the incidence of brucellosis. Since most cases occur in asymptomatic patients with relatively preserved immunity, the epidemiology, clinical presentation, diagnosis, response to therapy, and outcome are similar to those observed in non-HIV infected patients.

[Right endocarditis caused by Staphylococcus aureus in parenteral drug addicts: evaluation of a combined therapeutic scheme for 2 weeks versus conventional treatment]. / Endocarditis derecha por Staphylococcus aureus en adictos a drogas por vía parenteral: valoración de un régimen terapéutico combinado de 2 semanas frente al tratamiento convencional.

BACKGROUND: Intravenous drug addicts (IVDA) are a group of patients in whom it is difficult to complete standard treatment of infectious endocarditis due to frequent antisocial behavior and in whom, once clinical improvement is achieved, voluntary discharge is frequently requested. This is why the evaluation of new treatment schedules tending to decrease the length of the same is of great interest. This non randomized study has the aim of knowing the efficacy of a short treatment with cloxacillin or vancomycin associated to gentamicin in right-sided endocarditis by methicillin-sensitive Staphylococcus aureus, comparing this with the standard schedule of 28 days. METHODS: This series was made up of IVDA patients diagnosed of right endocarditis by S. aureus. Inclusion criteria were the presence of intravenous drug addiction, isolation of methicillin-sensitive S. aureus in 2 or more blood cultures and achievement of the diagnostic criteria of right-sided endocarditis. Two schedules were used: a) standard: cloxacillin or vancomycin for 4 weeks, associating aminoglucoside in the first 3-5 days; b) short; cloxacillin or vancomycin associated to gentamicin for 2 weeks with no ulterior treatment. The study was not randomized and the treatment of 2 weeks was compared with historic controls treated for 4 weeks. The criteria evaluated were those of clinical cure, relapse, appearance of complications during treatment and mortality. RESULTS: Both the standard treatment and the combination of cloxacillin or vancomycin with gentamicin for 2 weeks cured 100% of the episodes of right endocarditis by S. aureus. There were no relapses and mortality was nul. Neither were there any differences between the two groups with regard to appearance of complications. CONCLUSIONS: In intravenous drug addict patients with right-sided endocarditis by methicillin S. aureus, the association of cloxacillin and gentamicin for 2 weeks is an effective alternative to long (4 week) treatments with only one antibiotic. The low number of cases treated with vancomycin does not allow conclusions to be drawn on its efficacy.