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Biomedical subjects

F Camacho

Publications and source records attributed to F Camacho.

At least 73 records · Page 4Linked to original sources
PubMed1997

Molecular Identification and Localization of Filamentous Symbiotic Bacteria Associated with the Hydrothermal Vent Annelid Alvinella pompejana.

Alvinella pompejana is a polychaetous annelid that inhabits high-temperature environments associated with active deep-sea hydrothermal vents along the East Pacific Rise. A unique and diverse epibiotic microflora with a prominent filamentous morphotype is found associated with the worm's dorsal integument. A previous study established the taxonomic positions of two epsilon proteobacterial phylotypes, 13B and 5A, which dominated a clone library of 16S rRNA genes amplified by PCR from the epibiotic microbial community of an A. pompejana specimen. In the present study deoxyoligonucleotide PCR primers specific for phylotypes 13B and 5A were used to demonstrate that these phylotypes are regular features of the bacterial community associated with A. pompejana. Assaying of other surfaces around colonies of A. pompejana revealed that phylotypes 13B and 5A are not restricted to A. pompejana. Phylotype 13B occurs on the exterior surfaces of other invertebrate genera and rock surfaces, and phylotype 5A occurs on a congener, Alvinella caudata. The 13B and 5A phylotypes were identified and localized on A. pompejana by in situ hybridization, demonstrating that these two phylotypes are, in fact, the prominent filamentous bacteria on the dorsal integument of A. pompejana. These findings indicate that the filamentous bacterial symbionts of A. pompejana are epsilon Proteobacteria which do not have an obligate requirement for A. pompejana.

Journal Article↗
PubMed1997

Acne keloidalis nuchae and tufted hair folliculitis.

Acne keloidalis nuchae is a chronic, scarring folliculitis that affects mostly black patients and is located on the back of the neck of young adults. The course is progressive and leads to hypertrophic scarring, chronic abscesses and hair loss. We discuss the relationship between acne keloidalis and tufted hair folliculitis, pointing out the possibility that tufted hair folliculitis is not a specific disease but secondary to other progressive folliculitis like folliculitis decalvans, dissecting cellulitis or acne keloidalis.

Abscess↗
PubMed1997

Pharmacological activity and safety profile of P10358, a novel, orally active acetylcholinesterase inhibitor for Alzheimer's disease.

1-[(3-Fluoro-4-pyridinyl)amino]-3-methyl-1(H)-indol-5-yl methyl carbamate (P10358) is a potent, reversible acetylcholinesterase inhibitor that produces central cholinergic stimulation after oral and parental administration in rats and mice. P10358 is a 2.5 times more potent acetylcholinesterase inhibitor than THA in vitro (IC50 = 0.10 +/- 0.02 microM vs. IC50 = 0.25 +/- 0.03 microM). It also inhibits butyrylcholinesterase activity as potently as THA (IC50 = 0.08 +/- 0.05 microM vs. IC50 = 0.07 +/- 0.01 microM). Ex vivo, P10358 (0.2 - 20 mg/kg, p.o.) produced dose-dependent inhibition of brain acetylcholinesterase activity. At 10 and 20 mg/ kg, it produced profound and long-lasting hypothermia in mice. P10358 enhanced performance in rats in a step-down passive avoidance task (0.62 and 1.25 mg/kg) and in a social recognition paradigm (0.32, 0.64 and 1.25 mg/kg) in mice. It reversed scopolamine-induced deficits in the Morris Water maze in rats (1.25 and 2.5 mg/kg) and a higher dose elevated striatal homovanillic acid levels. These behavioral and biochemical effects are consistent with central cholinergic stimulation. Hemodynamic studies in the rat demonstrated a 16-fold separation between behaviorally active doses (1.25 mg/kg) and those that elevated arterial pressure (20 mg/kg). Lethality in rats occurred at an oral dose of 80 mg/kg, but not at lower doses. Chemically, P10358 is an N-aminoindole and may not have the hepatotoxic liability associated with aminoacridine structure of tacrine. P10358 had weak affinity (>10 microM) at a variety of aminergic and peptidergic receptors and uptake carriers. These properties suggest that P10358 may be a safe and promising symptomatic treatment for Alzheimer's disease.

Acetylcholinesterase↗
PubMed1997

Cryosurgical treatment of professional chronic radiodermatitis.

BACKGROUND: Chronic x-ray dermatitis in professionals is a frequent problem for doctors in our country due to the fact that many of them widely used radiotherapy without any protection 15-20 years ago. Surgery has been the most accepted treatment, though it generally decreases hand function. OBJECTIVE: Up to now, cryosurgery was not usually considered as a possible treatment if the lesions were located on fingers. In this study, the advantages of cryosurgery for the treatment of professional chronic radiodermatitis with incipient pretumoral lesions are emphasized. METHODS: Cryosurgery was performed on six patients affected with chronic professional radiodermatitis that showed keratomas and ulcerations, using both spray (keratomas) and a probe 0.5 cm in diameter (ulcerations, in situ squamous cell carcinoma). Nerve block anesthesia with mepivacaine 1% was used in all cases. Before the treatment, all suspected lesions were biopsied; if invasive squamous cell carcinoma was revealed in the dermatopathological study, the patient was rejected. Variables such as blister and necrosis formation, pain, and achromatic, sensibility, and mobility disorders were studied. The follow-up period was 2 years. RESULTS: Immediate postoperative results showed great pain and blistering in all cases. Residual achromias were observed early postoperatively in all cases, but were repigmented 1 year after therapy in four cases (66%). Sensory alterations (hypo- and hyperthesias) were found in four cases (66%) 1 month after treatment, although this complication was not observed 6 months after treatment. Finger mobility was perfect in all cases 2 months after treatment, and there was no recurrence in any case after 2 years of follow-up. CONCLUSIONS: We believe cryosurgery must be considered as an excellent treatment for professional chronic radiodermatitis with keratomas, ulcerations, and incipient squamous cell carcinomas. Its use may prevent further dramatic surgical treatment, like amputations, allowing the preservation of finger function.

Aged↗
PubMed1996

Alpha 2-adrenoceptor antagonists potentiate acetylcholinesterase inhibitor effects on passive avoidance learning in the rat.

The cholinergic hypothesis of Alzheimer's disease (AD) has strongly influenced research on learning and memory over the last decade. However, there has been limited success treating AD dementia with cholinomimetics. Furthermore, there are indications that other neurotransmitter systems affected by this disease may be involved in cognitive processes. Animal studies have suggested that norepinephrine and acetylcholine may interact in learning and memory. The current experiments investigate this interaction in a step-down passive avoidance paradigm after coadministration of acetylcholinesterase inhibitors and alpha 2-adrenoceptor antagonists. Administration of acetylcholinesterase inhibitors heptylphysostigmine (0.625-5.0 mg/kg, IP), tacrine (2.5-10.0 mg/kg, PO), velnacrine (0.312-2.5 mg/kg, SC), and galanthamine (0.312-2.5 mg/kg IP) each enhanced retention of a passive avoidance response at selected moderate doses administered 30-60 min prior to training. The alpha 2-adrenoceptor antagonists idazoxan (0.312-2.5 mg/kg, IP), yohimbine (0.078-0.312 mg/kg, IP) and P86 7480 (0.156-0.625 mg/kg, IP) alone failed to enhance learning in this paradigm. Coadministration of a subthreshold dose of heptylphysostigmine (0.625 mg/kg, IP) with doses of idazoxan, yohimbine or P86 7480 enhanced passive avoidance learning. This synergistic interaction may represent effects of antagonism of presynaptic alpha 2-adrenoceptor since coadministration of heptylphysostigmine and the selective postsynaptic alpha 2-adrenoceptor antagonist SKF 104856 did not result in enhanced learning. Taken together these data suggest noradrenergic activation through pre-synaptic alpha 2-adrenoceptor blockade may potentiate cholinergic activity in the formation of a long-term memory trace. These observations may have implications for the treatment of AD with cholinergic and adrenergic agents.

Adrenergic alpha-Antagonists↗
PubMed1996

Cellular blue nevus with massive regional lymph node metastases.

BACKGROUND: Small, well-differentiated groups of nevus cells have been found occasionally in the marginal sinuses and parenchyma of regional lymph nodes that drain sites of cellular blue nevi. OBJECTIVE: The histologic, immunohistochemical, and karyometric description of a pigmented cutaneous lesion, with the features of cellular blue nevus and located on the leg of a 14-year-old woman, that was accompanied by synchronic presentation of massive inguinal lymph-node metastases. METHODS: The excised specimens were processed routinely, embedded in paraffin, and sectioned into 4-microm-thick slices. The sections were stained using hematoxylin-eosin and the ABC immunohistochemical method for demonstrating S-100 and HMB-45. Karyometric analysis was performed in a static cytometer using Feulgen-stained sections. RESULTS: The cutaneous lesion had the cytologic and architectural features of cellular blue nevus. The lymph nodes showed massive invasion by pigmented cells and contained extensive necrotic foci. After 3.5 years of clinical follow-up, the patient is free from disease. CONCLUSIONS: The absence of malignant features in the cutaneous lesion and the bland nuclear features of the pigmented cells in the regional lymph node metastases suggest that this case could be interpreted as an unusual form of benign cellular blue nevus with metastases. Nonetheless, other possibilities, such as malignant melanoma mimicking a cellular blue nevus or primary malignant melanoma of the lymph nodes with concomitant cutaneous cellular blue nevus, cannot be definitively excluded. A conservative surgical approach with close follow-up was recommended.

Adolescent↗
PubMed1996

Pharmacological evaluation of novel Alzheimer's disease therapeutics: acetylcholinesterase inhibitors related to galanthamine.

Acetylcholinesterase (AChE) inhibitors from several chemical classes have been tested for the symptomatic treatment of Alzheimer's disease; however, the therapeutic success of these compounds has been limited. Recently, another AChE inhibitor, galanthamine hydrobromide (GAL), has shown increased clinical efficacy and safety. Using biochemical, behavioral and pharmacokinetic analyses, this report compares GAL with two of its analogs, 6-O-acetyl-6-O-demethylgalanthamine hydrochloride (P11012) and 6-O-demethyl-6-O[(adamantan-1-yl)-carbonyl]galanthamine hydrochloride (P11149), for their therapeutic potential. P11012 and P11149 were found to be potent, competitive and selective inhibitors of AChE, demonstrating central cholinergic activity, behavioral efficacy and safety. P11012 and P11149, though pharmacokinetic analyses, were shown to act as pro-drugs, yielding significant levels of 6-O-demethylgalanthamine. In vitro, 6-O-demethylgalanthamine was 10- to 20-fold more potent than GAL as an inhibitor of AChE, and it demonstrated greater selectivity for inhibition of AChE vs. butyrylcholinesterase. Like GAL, both P11012 and P11149 showed central cholinergic activity biochemically, by significantly inhibiting rat brain AChE; physiologically, by causing hypothermia; and behaviorally, by attenuating scopolamine-induced deficits in passive avoidance. In addition, GAL, P11012 and P11149 enhanced step-down passive avoidance, another measure of behavioral efficacy. By comparing efficacious doses with primary overt effects, P11012 and P11149 had better oral therapeutic indices than GAL. Oral pharmacokinetic analyses of GAL, P11012 and P11149 revealed differences. Although P11012 and P11149 exhibited similar area under the curve values, 191149 had slower, lower and more sustained concentration maximum levels. P11012 and GAL rapidly reached their concentration maximums, but GAL, in brain had the highest area under the curve and concentration maximum. Because of its composite profile, including duration of action, oral therapeutic index and pharmacokinetics, P11149 is considered the better therapeutic candidate for the treatment of Alzheimer's disease.

Alzheimer Disease↗
PubMed1996

Two cases of contact dermatitis caused by calcipotriol cream.

Two patients with psoriasis were treated with calcipotriol cream, and both developed contact dermatitis. Patch test results were positive to calcipotriol and negative to the ingredients of the vehicle in both cases. The first case may be explained by a compound allergy or by a false-negative reaction to calcipotriol due to the very low concentration used for patch tests. The second patient was clearly positive to calcipotriol despite low concentration. This is the first case reported thus far with sensitivity to calcipotriol at a concentration < 2 mc/mL, as recommended in other studies.

Administration, Topical↗
PubMed1995

Cholinergic modulation of a decrement in social investigation following repeated contacts between mice.

Social recognition has been inferred from a decline in olfactory investigation of conspecific intruders during repeated or protracted confrontation with a resident rat. A stimulus-response relationship defined by lack of response remains somewhat ambiguous. Since it is likely that behavior continues to be emitted by the resident animal, how behavior reorganizes as the resident becomes familiar with an intruder represents an important issue in the characterization of recognition. We examined the decline in olfactory investigation of ovariectomized females by adult male mice. The duration and frequency of olfactory investigation was measured during four 1 minute confrontations with 10-min intertrial intervals (Training trials). If the same female was presented in each trial, investigation declined to less than 50% of initial levels. Aggressive behavior gradually increased with repeated trials. No decline in investigation or increased aggression was measured when females were changed in each trial. Administration of doses of scopolamine (0.16-1.0 mg/kg, IP) blocked decrements in olfactory investigation in repeated confrontations and significantly reduced aggression. Co-administration of heptylphysostigmine (0.32-5.0 mg/kg, IP) reversed scopolamine's effects on olfactory investigation but not aggression. Acetylcholinesterase inhibitors heptylphysostigmine, galanthamine (0.63-2.5 mg/kg, IP) and tacrine (0.63-10.0 mg/kg, IP) all enhanced the rate of decrement of olfactory investigation when administered alone, but had differential effects on aggression. The decline in investigation corresponds to criteria for habituation. Increased responsivity expressed as aggression indicates recognition may also be characterized as a change in behavioral strategy dependent on the sexual and social status of the stimulus animal. Pharmacological data support a role for acetylcholine release in the development of social recognition as an olfactory memory, or through modulation of olfactory perception.

Aggression↗
PubMed1995

Antipsychotic agents antagonize non-competitive N-methyl-D-aspartate antagonist-induced behaviors.

Antipsychotic agents were tested for their ability to antagonize both dopaminergic-induced and non-competitive N-methyl-D-aspartate (NMDA) antagonist-induced behaviors. All of the agents dose-dependently antagonized the apomorphine-induced climbing mouse assay (CMA) and dizocilpine (MK-801)-induced locomotion and falling assay (MK-801-LF) with a CMA/MK-801-LF ratio of less than or equal to 1.6. However, clozapine and its structural analog olanzapine more potently antagonized MK-801-LF (1.1 and 0.05 mg/kg) than the CMA (12.3 and 0.45 mg/kg) and as a result had a CMA/MK-801-LF ratio of 11.2 and 9, respectively. Furthermore, phencyclidine (PCP) (2 mg/kg) can selectively induce social withdrawal in naive rats that were housed in pairs (familiar) for 10 days prior to testing without affecting motor activity. SCH 23390, raclopride, haloperidol, chlorpromazine and risperidone failed to reverse the social withdrawal induced by PCP up to doses which produced significant motor impairment. However, clozapine (2.5 and 5.0 mg/kg) and olanzapine (0.25 and 0.5 mg/kg) significantly reversed this social withdrawal in rats. Therefore, the non-competitive NMDA antagonists PCP and MK-801 can induce behaviors in Rodents which are selectively antagonized by clozapine and olanzapine. Furthermore, assessment of the effects of antipsychotic agents in the CMA, MK-801-LF and PCP-induced social withdrawal assays may provide a preclinical approach to identify novel agents for negative symptoms and treatment resistant schizophrenia.

Amphetamine↗
PubMed1995

Darier's disease associated with basal cell carcinomas.

BACKGROUND: Only three patients have been reported with basal cell carcinomas in skin involved with Darier's disease. OBJECTIVE: We report the fourth case and discuss the possible pathogenetic relationship between both diseases. RESULTS: In our case, oral retinoids made evident other basal cell carcinomas hidden in keratotic papules of the Darier's disease. CONCLUSION: Early excision of the tumor could be obtained.

Administration, Oral↗
PubMed1995

Congenital triangular alopecia (Brauer nevus).

Congenital triangular alopecia is manifested at 3 to 5 years of age by unilateral or, less frequently, bilateral patches of alopecia in the frontotemporal region. At this age the differential diagnosis is important, particularly as regards alopecia areata. Only about 47 cases have been reported, probably because the lesion is benign and nonprogressive. In 6200 patients seen in index visits, we found 7 with triangular alopecia, a frequency of 0.11%. We believe that males do not require treatment because of the later development of androgenic alopecia, but in women, surgical treatment is successful.

Adolescent↗
PubMed1995

Phylogenetic characterization of the epibiotic bacteria associated with the hydrothermal vent polychaete Alvinella pompejana.

Alvinella pompejana is a polychaetous annelid that inhabits active deep-sea hydrothermal vent sites along the East Pacific Rise, where it colonizes the walls of actively venting high-temperature chimneys. An abundant, morphologically diverse epibiotic microflora is associated with the worm's dorsal integument, with a highly integrated filamentous morphotype clearly dominating the microbial biomass. It has been suggested that this bacterial population participates in either the nutrition of the worm or in detoxification of the worm's immediate environment. The primary goal of this study was to phylogenetically characterize selected epibionts through the analysis of 16S rRNA gene sequences. Nucleic acids were extracted from bacteria collected from the dorsal surface of A. pompejana. 16S rRNA genes were amplified with universal bacterial primers by the PCR. These genes were subsequently cloned, and the resulting clone library was screened by restriction fragment length polymorphism analysis to identify distinct clone types. The restriction fragment length polymorphism analysis identified 32 different clone families in the library. Four of these families were clearly dominant, representing more than 65% of the library. Representatives from the four most abundant clone families were chosen for complete 16S rRNA gene sequencing and phylogenetic analysis. These gene sequences were analyzed by a variety of phylogenetic inference methods and found to be related to the newly established epsilon subdivision of the division Proteobacteria. Secondary structural model comparisons and comparisons of established signature base positions in the 16S rRNA confirmed the placement of the Alvinella clones in the epsilon subdivision of the Proteobacteria.

Animals↗