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C Pena

Publications and source records attributed to C Pena.

18 recordsLinked to original sources
PubMed2001

Restoration of mitochondrial function reverses developmental neuronal death in vitro.

In a previous study characterizing morphological and functional features of cell death in trophically deprived chick ciliary ganglion neurons (Pena and Pilar [2000] J. Comp. Neurol. 424:377-396), we hypothesized that early cell death events might be targets for reversal, allowing for rescue of dying neurons. To test this hypothesis, ciliary ganglion (CG) neurons were cultured with or without trophic support (choroid, iris, and pigment epithelium soluble extract [CIPE]), or without trophic support for 11 or 18 hours and then exposed to trophic support. Prior to and at the onset of cell death commitment (11 hours) CIPE-deprived neurons exhibited increased membrane permeability, blebbing, cytoplasmic vacuolization, swollen mitochondria, low adenosine triphosphate levels, and release of cytochrome c from mitochondria. CIPE readdition at 11 hours reversed these changes. Between 11 and 18 hours, irreversible DNA fragmentation increased in CIPE-deprived neurons. Cyclosporin A and bongkrekic acid (inhibitors of mitochondrial transition permeability pores) prevented membrane permeability increases and delayed the progression to death in trophically deprived neurons by 12 hours; however, by 48 hours all neurons had died. BOC-Asp-CH2F (BAF), a pan-caspase inhibitor, did not prevent early events of cell death including increased membrane permeability and Cyto c release, but it inhibited DNA fragmentation and prolonged neuronal survival to 48 hours. We conclude that mitochondria changes occur early, prior to commitment and that the suppression of these changes can prevent all the downstream events of death, whereas caspase inhibitors have no effect on the early mitochondria/plasma membrane changes. Mitochondria thus play a critical role in the transition from reversible to irreversible commitment to developmental neuronal death. Furthermore, neuronal death is brought about by activation of one of two distinct pathways, one localized in mitochondria and the other dependent on activation of caspases.

Adenosine Triphosphate↗
PubMed2000

Histidine 186 of the nicotinic acetylcholine receptor alpha subunit requires the presence of the 192-193 disulfide bridge to interact with alpha-bungarotoxin.

We have previously shown that two histidine residues of the nicotinic acetylcholine receptor are relevant for alpha-bungarotoxin binding. This paper studies: (1) the interaction between alpha-bungarotoxin and the peptide alpha173-202--synthesized according to the sequence of the Torpedo californica receptor alpha subunit--and between the toxin and the same peptide containing His186 modified with ethoxyformic anhydride or substituted by Ala; (2) the influence of the presence of Cys192-Cys193 disulfide bridge on such interactions. Solid-phase and in-solution competition assays were performed: ethoxyformylation of His186 or its substitution by Ala led to a significant drop in the toxin binding capacity only for peptides containing the bridge. Circular dichroism and fourth derivate spectra of all peptides were also analyzed. Results strongly indicate the involvement of His186 in the toxin binding to those peptides with the bridge--also present in the native receptor molecules--but not to their reduced forms; on the other hand, they give further support to the already established premise that, though the bridge does not participate directly in receptor-toxin binding, its presence is relevant to define the appropriate conformation of the interaction area.

Amino Acid Sequence↗
PubMed1999

Hyperostotic macrodactyly and lipofibromatous hamartoma of the median nerve associated with carpal tunnel syndrome.

A new case with 14-year follow-up of an extremely rare variety of congenital hand macrodactyly is presented. The disease characteristically presents a diffuse proliferation of fibrofatty tissue, but in this special type, osteocartilaginous deposits around the joints can also be found. The case presented included the troublesome feature of a lipofibromatous hamartoma in the median nerve at the wrist and its branches producing carpal tunnel syndrome. The patient obtained benefit from carpal tunnel release and epineurolysis. The hyperostotic development was managed with conservative resection of the periarticular osteochondromas. The literature reviewed suggests that the hyperostotic cases of macrodactyly do not differ from general cases of this congenital condition, except for the osteochondral deposits. These tumours develop during adulthood or after previous trauma, before epiphyseal closure.

Adipose Tissue↗
PubMed1999

Synovial osteochondromatosis at the elbow producing ulnar and median nerve palsy. Case report and review of the literature.

The authors present the case of a 53-year-old woman suffering from synovial osteochondromatosis of her right elbow responsible for ulnar and median nerve entrapment neuropathy. This condition is characterised by the formation of multiple cartilaginous nodules in the metaplastic synovium of otherwise normal joints, bursae or tendon sheaths. Treatment consisted of partial synovectomy, removal of loose bodies and microscopic nerve release. Synovial osteochondromatosis complicated by nerve compression syndromes has been rarely reported, usually with ulnar tunnel syndrome at the elbow. The literature on this subject is reviewed.

Chondromatosis, Synovial↗
PubMed1998

Clinical evaluation of the Gen-Probe Amplified Direct Test for detection of Mycobacterium tuberculosis complex organisms in cerebrospinal fluid.

Eighty-four cerebrospinal fluid (CSF) samples from different children who presented with signs and symptoms of meningitis were evaluated for the presence of Mycobacterium tuberculosis complex organisms by the Gen-Probe Amplified Mycobacterium tuberculosis Direct Test (MTD; Gen-Probe, San Diego, Calif.). All CSF samples had negative acid-fast smears by the Ziehl-Neelsen staining method. M. tuberculosis was recovered from five samples. M. tuberculosis did not grow from 19 additional samples, but the samples were from patients who fulfilled specific clinical and laboratory criteria for probable tuberculous meningitis (TBM). The remaining samples (n = 60) were from patients with other infections or noninfectious causes of meningitis. The results of the MTD were interpreted as positive or negative on the basis of recommended cutoff values for respiratory specimens. These results were interpreted as true or false positives or true or false negatives on the basis of the results of M. tuberculosis culture or whether the patient fulfilled criteria for probable TBM. The Gen-Probe MTD was 33% sensitive and 100% specific for detecting M. tuberculosis complex organisms in these 84 CSF samples. If the cutoff values for positive results were decreased for the MTD (> or = 11,000 versus > or = 30,000 relative light units), the sensitivity increased to 83% and the specificity remained 100%. These results for the MTD are encouraging considering that TBM is a highly fatal disease and difficult to diagnose by conventional laboratory techniques.

Adolescent↗
PubMed1997

[Diseases of the pericardium in Avenzoar's Kitab al-Taysir (c.1095-1162)].

Avenzoar has been credited as the author of the first description of inflammation of the pericardium in medical historical literature. Our study shows that although Avenzoar authored a study of diseases of the pericardium with emphasis on pathologies, his epistemological framework was similar to that used by Galen and Avicenna, authors who constituted the source of knowledge for Islamic medicine. We show that the approach used by Avenzoar appears to derive from the absence of anatomical and physiological information, and from a detailed description of the indications and treatments, which distinguish his work from earlier writings.

Arab World↗
PubMed1996

Lyme disease surveillance in Maryland, 1992.

The incidence of Lyme disease (LD) reported to the Maryland Department of Health and Mental Hygiene during 1992 was 6.5/100,000 population, ranging from 29.3 cases/100,000 on the Eastern Shore (74.4% of all cases) to no cases in the mountains of western Maryland. Among the 317 reported patients, 44.4% gave a history of tick exposure and 78.9% had positive serologic test results. For the 187 (59.0%) patients meeting the Centers for Disease Control and Prevention (CDC) surveillance case definition, erythema migrans (EM) occurred in 69.5%, with arthritic (26.7%), neurologic (13.4%), and cardiac (2.1%) manifestations being less frequent. Patients not meeting the surveillance case definition were significantly more likely to have influenza-like symptoms, a smaller rash, and arthralgia. Patients meeting the CDC criteria were more likely to have an onset during the major transmission season in the summer (odds ratio (OR): 2.1; confidence interval (CI): 1.2 to 3.6) since this was the time when most (115/130) patients with EM were detected. Positive serologic results were more likely (OR: 2.2; CI: 1.2 to 4.2) in those not meeting the case definition. The treatment given to patients thought to have LD was almost always that recommended in the literature and there was no difference between treatment prescribed for patients meeting and those not meeting the case definition. These data show that physicians in Maryland are treating many patients for LD who are clinically diagnosed as having LD (e.g., febrile patients with flulike symptoms, patients with arthralgias or erythematous rashes < 5 cm in size) and who have positive serologic test results but who do not meet the CDC surveillance case definition. These patients and the large number of unreported patients being seen and treated for LD or tick bites must be added to the overall burden of LD in the state.

Adolescent↗
PubMed1992

Superior mesenteric artery embolism: treatment with intraarterial urokinase.

Four patients with a superior mesenteric artery (SMA) embolism were successfully treated with intraarterial urokinase. Angiography showed partial SMA occlusion by intraluminal thrombus in two cases and almost total occlusion in two cases. Laparotomy was performed in the latter two cases, one of which required resection of infarcted bowel. Several additional reports of partially occluding SMA emboli treated successfully with streptokinase were found in the literature. The use of intraarterial thrombolytic drugs is an important addition to the treatment of mesenteric embolism that, in some cases, can eliminate or simplify surgical management.

Aged↗
PubMed1990

Hemodialysis and the elderly patient: potential advantages as to quality of life, urea generation, serum creatinine, and less interdialytic weight gain.

A total of 204 patients treated by maintenance hemodialysis or continuous ambulatory peritoneal dialysis (CAPD) were studied to ascertain how advancing age influences adaptation to uremia therapy. No difference in Karnofsky score was noted among patients over 70 years of age and two groups of patients, 16 to 59, and 60 to 69 years of age, respectively. In a subset of 33 hemodialysis patients studied midweek, it was noted that increasing age is associated with a lower serum creatinine concentration, lower interdialytic weight gain, and a lower urea generation rate. These three findings contribute to a relative ease in treating older uremia patients with hemodialysis or CAPD, as they tend to be stable and compliant relative to younger patients.

Adolescent↗
PubMed1989

Histochemical study, morphometric analysis and systematic distribution of fiber types in the rectus femoris muscle of the albino rats.

The histochemical and morphometric characteristics as well as the systematic distribution of fiber types in the muscle rectus femoris (RF) of adult male rats were studied from ATPase (pre-incubated at pH 9'4, 4'6 and 4'2) and NADH stained sections. The muscle fiber types were classified as I type, IIA type and IIB-type. In 20 RF muscles 90-95% of total fibers were sampled and the mean diameter, length and irregularity-degree analysed. The data were grouped in four quadrants and the percent of fiber types was determined. The type IIB fibers predominate in all quadrants. The largest fibers were the IIB type and the smallest ones the type I, for all the quadrants. Our findings support a functional compartmentalization as proposed by many authors.

Animals↗
PubMed1984

Comparative study of the cytoprotective effects of anticholinergic agents on the gastric mucosal lesions produced by intragastric administration of 0.6 M HCl in rats.

CFY strain rats (both sexes, 180-210 g) were fasted for 24 hr. Several anticholinergic agents atropine, oxyphencyclimine, propantheline, trantheline, hexocyclium) were administered (i.p.) in equimolar doses (28.78 nM X kg-1), and to compared to the cyto-protective effect of atropine sulfate (0.01 mg X kg-1). Their effects were studied in (1) one hour pylorus-ligated rats, being given when the surgical procedure had just finished: volume and acid output were measured; (2) the gastric mucosal lesions induced by 0.6 M HCl. Drugs were applied 30 min before the administration of HCl (1 ml, i.g.). Rats were killed 1 hr later and the number and severity of lesions were calculated. We found that (1) atropine, oxyphencyclimine, and propantheline did not significantly decrease acid secretion, while trantheline and hexocyclium inhibited acid output; (2) all drugs provided significant protection against the gastric damage induced by HCl; (3) no significant difference was found in the extent of protection produced by the different drugs in the HCl-model. We conclude that atropine, oxyphencyclimine, and propantheline are gastric cytoprotective agents.

Animals↗