Tricofoliculomas múltiples: reporte de un caso / Multiple trichofolliculomas: a case report

Resumen El tricofoliculomaes un tumor benigno infrecuente del folículo piloso, de mayor prevalencia entre la segunda y la sexta década de vida. Suele presentarse como una lesión solitaria en forma de nódulo,pápulas o placas del color de la piel,asintomático, con un poro o cavidad central obstruido con queratina de la que emerge un "penacho de pelos".La localización más frecuente suele ser el rostro, seguido del cuero cabelludo y el cuello.1Las características histopatológicas son diagnósticas. Se reporta el caso clínico de un paciente de 44 años de edad con tricofoliculomas múltiples en rostro.

Abstract Trichofolliculoma is an infrequent benign tumor of the hair follicle, with a higher prevalence between the second and sixth decade of life. It usually presents as a solitary lesion in the form of a nodule, papules or asymptomatic skin-colored plaques with a pore or central cavity obstructed with keratin from which a "tuft of hairs" emerges.The most frequent location is usually the face, followed by the scalp and neck.1 Histopathological characteristics are diagnostic. We report a case of a 44-year-old man with multiple trichofolliculomas on his face.

Spiral drawing performance as an indicator of fine motor function in people with multiple sclerosis.

This study investigated spiral drawing performance as an indicator of fine motor function, as well as to gain insight into adaptive movement strategies used by people with multiple sclerosis (MS). Seven people with MS, nine younger controls (mean age of 20) and eight older controls (mean age of 40) drew spirals on a graphics tablet at a comfortable speed and size. Spirography (i.e., a subjective visual assessment of the static trace) revealed indications of reduced control of the pen for people with MS. Analysis of the movements showed that people with MS tended to draw the spirals slower and with less pen pressure than controls. All groups increased their speed and pressure along with spiral size, but this increase was much steeper for the controls. MS participants drew spirals with more variability around an ideal trajectory, highlighting fine motor control degradation. MS patients tended to use a smaller scaling ratio, resulting in smaller spirals for a given number of revolutions. The younger and older control groups drew the spirals in a similar manner, and age was not a significant factor in any of the analyses. It is argued that the relatively lower pressure used, and slower, smaller movements (particularly during the more difficult outer sections of the spiral) are in part an adaptive strategy used to reduce movement variability. These results demonstrate the utility of the analysis of spiral movements as an objective technique for assessing motor control degradation, which can compliment the subjective rating based on the static pen trace. As such, it can provide further insight into the biomechanical strategies used when performing fine movements.

Movement precues in planning and execution of aiming movements in Parkinson's disease.

Two experiments tested how changing a planned movement affects movement initiation and execution in idiopathic Parkinson's disease (PD) patients. In Experiment 1, PD patients, elderly controls, and young adults performed discrete aiming movements to one of two targets on a digitizer. A precue (80% valid cue and 20% invalid cue of all trials) reflecting the subsequent movement direction was presented prior to the imperative stimulus. All groups produced slower reaction times (RTs) to the invalid precue condition. Only the subgroup of patients with slowest movement time showed a significant prolongation of movement for the invalid condition. This suggests that, in the most impaired patients, modifying a planned action also affects movement execution. In Experiment 2, two-segment aiming movements were used to increase the demand on movement planning. PD patients and elderly controls underwent the two precue conditions (80% valid, 20% invalid). Patients exhibited longer RTs than the controls. RT was similarly increased for the invalid condition in both groups. The patients, however, exhibited longer movement times, lower peak velocities, and higher normalized jerk scores of the first segment in the invalid condition compared to the valid condition. Conversely, the controls showed no difference between the valid and invalid cue conditions. Thus, PD patients demonstrated substantially pronounced movement slowness and variability when required to change a planned action. The results from both experiments suggest that modifying a planned action may continue beyond the initiation phase into the execution phase in PD patients.

The influence of motor system degradation on the control of handwriting movements: a dynamical systems analysis.

The complex dynamics of the human hand/arm system need to be precisely controlled to produce fine movements such as those found in handwriting. This study employs dynamical systems analysis techniques to further understand how this system is controlled when it is functioning well and when it is compromised through motor function degradation (e.g. from tremor). Seven people with and 16 people without multiple sclerosis (MS) participated in this study. Tremor was assessed using spirography with participants being separated into "tremor" (6 people with and 1 person without MS; 2 male, 5 female; age range 40-68) and control (1 person with and 15 people without MS; 5 male, 11 female, age range 18-59) groups. Participants wrote the pseudo-word "lanordam" six times on a digitizer, in a quiet as well as a noisy, mildly stressful environment. Velocity profiles of the pen tip for the best four trials were concatenated and analyzed to determine their dimensionality (a measure of the number of control variables) and Lyapunov exponents (a measure of predictability). Results indicate that the velocity profiles for people with tremor were lower dimensional and had less predictable dynamics than for controls, with no effect of sound condition. Interpreted in the context of related research, it was speculated that the lower dimensionality reflected the loss of control of variables related to the minimization of movement variability, resulting in less predictable movements.

Discrete and dynamic scaling of the size of continuous graphic movements of parkinsonian patients and elderly controls.

OBJECTIVES: To systematically investigate the ability of Parkinson's disease patients to discretely and dynamically scale the size of continuous movements and to assess the impact of movement size on outcome variability. METHODS: Ten patients with Parkinson's disease (mean age 72 years) were compared with 12 healthy elderly controls (mean age 70 years). The subjects wrote with a stylus on a graphics tablet. In experiment 1 they drew circles, matching the size of five target circles ranging in magnitude from a radius of 0.5 cm up to 2.5 cm. In experiment 2 they drew spirals with a radius of at least 2 cm. In both experiments the drawings were initially performed as accurately as possible then as fast and accurately as possible. RESULTS: In both experiments the patients and controls drew at a similar speed. The within trial variability of the pen trajectory was greater for patients than controls, and increased disproportionately with the size of the movement. When the emphasis was on size rather than variability (circles), the patients' drawing movements were the same size as controls. When the emphasis was on accuracy of pen trajectory (that is, minimum variability) rather than size (spirals), the patients' drawing movements were smaller than controls. CONCLUSIONS: The movements made by Parkinson's disease patients are hypometric partly as an adaptive strategy used to reduce movement variability. This strategy is used primarily when the requirement to make accurate movements outweighs the need to make large movements.

Response-time dynamics: evidence for linear and low-dimensional nonlinear structure in human choice sequences.

Response time (RT) is a commonly used measure of cognitive performance, which is usually characterized as stochastic. However, useful information may be hidden in the apparently random fluctuations of RT. Dynamical systems analysis techniques allow an exploration of the alternative hypothesis that RT fluctuations are deterministic, albeit in a complex manner. We applied careful task construction and noise-reduction and surrogate series tests to show that RT series from a forced-pace serial response-time task have low-dimensional chaotic characteristics. In Experiment 1, 80% of subjects' filtered RT series had low dimensionality, sensitive dependence on initial conditions, spectra close to 1/f, and stable attractor geometry across sessions. In Experiment 2, we showed that the size of the inter-stimulus interval (ISI) determined the number of subjects with low-dimensional chaotic series. A small ISI caused 100% of subjects to respond in the chaotic regime, whereas only 25% had a low-dimensional chaotic RT component when the ISI was large. We argue that demanding task requirements cause a reduction in the dimensionality of the dynamics, producing RT fluctuations that may reflect a response strategy for controlling RT.

Detecting nonlinearity in psychological data: techniques and applications.

Modern graphical and computational techniques for detecting nonlinearity in psychological data sets are presented. These procedures allow researchers to determine the information complexity of temporal data, using physiological and psychological measurements, and to provide evidence for chaos in time series contaminated by measurement noise. Problems with noise reduction and appropriate experimental control, using surrogate time series, are discussed, and applications of the technology are illustrated, using response time, handwriting, and typing data sets. In an experimental application of appropriate nonlinear analysis procedures, the results of a time series prediction experiment confirm that some subjects are sensitive to chaos. In contrast to previous attempts demonstrating sensitivity to chaos, the experiment reported here employs surrogate series to control for linear stochastic aspects of the stimulus sequences, such as autocorrelation. Recommendations for the selection of appropriate software for performing nonlinear analyses are presented, including a comprehensive list of World-Wide Web sites offering such software.

Immunogenicity of peptides derived from a fibronectin-binding protein of S. aureus expressed on two different plant viruses.

The D2 peptide derived from an S. aureus fibronectin-binding protein (FnBP) was expressed on the surface of the icosahedral cowpea mosaic virus (amino acids 1-30 of D2) or on the rod-shaped potato virus X (amino acids 1-38 of D2), termed CPMV-MAST1 and PVX-MAST8, respectively. Mice and rats were immunized subcutaneously with CPMV-MAST1 and mice with PVX-MAST8 in adjuvant and high titres of FnBP-specific antibody were obtained. The mouse IgG was predominantly of the IgG2a and IgG2b isotypes, which strongly bound complement component C1q, suggesting a TH1-bias in the peptide-specific responses. Sera from mice and rats immunized with CPMV-MAST1 and from mice immunized with PVX-MAST8 were shown to completely inhibit the binding of fibronectin to immobilised recombinant FnBP and rat sera against CPMV-MAST1 were able to block adherence of S. aureus to fibronectin. These studies demonstrate that the D2 peptide is highly immunogenic when expressed on 2 different plant viruses and highlight the potential of plant virus-based vaccines to protect against S. aureus infections.

Binding characteristics of anti-atrazine monoclonal antibodies and their fragments synthesised in bacteria and plants.

Single-chain antibody fragments (scAb), specific for the herbicide atrazine, have been expressed in the bacterium Escherichia coli and in transgenic tobacco plants. The scAb could be purified as a monomer (monovalent) via a hexa-histidine tail or as a dimer (divalent) by antibody affinity chromatography. In competition ELISA, the bacterial scAb showed the same specificity for atrazine and related triazine herbicides as the parental mAb cell line, but both plant and bacterial monomeric scAbs showed increased sensitivity to free atrazine. Surface plasmon resonance (BIAcore 2000) analysis confirmed that purified scAb, derived from plant or bacteria, retained similar association rates as the mAb. However, the monomeric plant and bacterial scAbs showed a lower affinity for immobilised antigen, than the equivalent dimeric scAbs or mAb. This decrease in affinity was due to a 10 fold slower dissociation rate and is likely due to loss of the avidity contribution of dimeric molecules.

Expression and characterisation of single-chain antibody fragments produced in transgenic plants against the organic herbicides atrazine and paraquat.

Single-chain antibody fragments (scAbs), which have a human C-kappa constant domain and a hexa-histidine tail attached to the carboxy terminus of the single-chain Fv (ScFv) fragments to facilitate purification, have been raised against the herbicides paraquat and atrazine and expressed in transgenic Nicotiana tabacum cv. Samsun NN. Prior to purification, the anti-atrazine scAb is expressed as up to 0.014% of soluble leaf protein and has a binding profile in ELISA, against an atrazine-bovine serum albumin (BSA) conjugate, similar to that of the scAb produced in Escherichia coli. Competition ELISA has shown that the plant-derived scAb also recognises free atrazine. Following antibody affinity purification to isolate dimers, the affinity for immobilised antigen approaches that of the parental monoclonal antibody. This was confirmed by surface plasmon resonance analysis. The purified scAb also recognises related triazine herbicides. When isolated from cell-suspension cultures, the anti-paraquat scAb binds to a paraquat conjugate in a concentration-dependent manner, with a profile similar to the parental monoclonal antibody. This is the first demonstration that functional scAbs against organic pollutants can be produced in transgenic plants and that the scAbs may be appropriate for the development of immunoassay-based detection systems.

Production and purification of active snowdrop lectin in Escherichia coli.

Recombinant snowdrop lectin was produced in Escherichia coli from a cDNA clone encoding mature Galanthus nivalis agglutinin. After induction with isopropylthio-beta-D-galactoside, inclusion bodies from E. coli were solubilised and the G. nivalis agglutinin purified by metal-affinity chromatography using a carboxy-terminal hexahistidine tag. The protein was refolded on the metal-affinity column prior to elution. After purification, the recombinant G. nivalis agglutinin agglutinated rabbit erythrocytes to a dilution similar to that determined for 'native' lectin purified from snowdrop, and showed similar specific binding to mannose. The toxicity of the recombinant G. nivalis agglutinin towards rice brown planthopper (Nilaparvata lugens) was shown to be similar to that of 'native' G. nivalis agglutinin when incorporated into an artificial diet. The recombinant G. nivalis agglutinin is thus functionally similar to 'native' snowdrop lectin.

Methods: pain.

Pain is one of the most common reasons for patient attendance at A&E departments ( 1 ), and its management should be a high priority in patient care. In order to do this, an assessment of pain is vital in determining the patient's progress, the impact and efficacy of treatment, and in some cases, as a diagnostic tool ( 2 ).

The influence of proanthocyanidin-rich bean hulls and level of dietary protein on energy metabolizability and nutrient digestibility by adult cockerels.

Cotyledons and hulls were prepared from twelve varieties of field beans (Vicia faba L.). Adult cockerels were tube-fed either beans, cotyledons or hull diets containing high or low levels of protein. Metabolizable energy coefficients and starch digestibility coefficients were determined for beans, cotyledons and hull diets. Lipid digestibility coefficients from hull diets were also determined. When cotyledons were fed there were no significant differences in the way in which adult cockerels metabolized energy or digested starch from the proanthocyanidin-free and proanthocyanidin-rich varieties (0.780, 0.908, 0.775 and 0.918 respectively). When beans were fed, however, both energy metabolizability and starch digestibility decreased due to the presence of hulls, with proanthocyanidin-rich hulls decreasing values the most to 0.660 and 0.819 respectively, and proanthocyanidin-free hulls decreasing values to a lesser extent to 0.709 and 0.886 respectively. Diets composed of proanthocyanidin-rich hulls depressed metabolizable energy and maize starch digestibility. Their effect on maize starch digestibility, however, was considerably less than that on bean starch. Lipid digestibility was enhanced by proanthocyanidins but only when the protein content of the diet was high. There was a significant correlation (P < 0.05) between the vanillin and anthocyanidin formation methods for the estimation of proanthocyanidins (r 0.779). There was also a highly significant regression of bean starch digestibility v. proanthocyanidin content of coloured-flowered bean hulls (P < 0.001). The regression of maize starch digestibility v. hull proanthocyanidins was also significant at P < 0.005.

Development of Limit Dextrinase in Germinated Barley (Hordeum vulgare L.) (Evidence of Proteolytic Activation).

Barley (Hordeum vulgare L.) that had been malted for 5 d developed only a small amount of bound (inactive) limit dextrinase, and very little free (active) enzyme was detected. Continuation of malting for up to 10 d only slightly increased the amount of both bound and free forms. Grain grown under conditions of ample moisture (wet grown) for 5 d produced a much higher amount of bound enzyme but a similarly low amount of free enzyme compared to malting conditions. After 10 d of growth there was a decrease in the amount of bound enzyme and a large increase in the amount of free enzyme, such that almost all of the enzyme was present in the free form. A more detailed study of limit dextrinase development in wet-grown grains revealed that a bound form was rapidly produced soon after germination. Five to 6 d after germination the amount of bound enzyme decreased rapidly and a very low amount was found in grains 9 d after germination. Meanwhile, a free form appeared slightly later and its initial rate of development was slow. At about 5 d after germination, precisely when the bound enzyme began to decrease, the free form increased rapidly, so that by 9 d after germination nearly all the enzyme was in the free form. The release of bound limit dextrinase in vitro occurred by proteolytic modification through the action of cysteine proteinases that were kept active or activated by the presence of reduced thiols in the extraction medium. The presence of cysteine proteinases was confirmed by inhibition studies using the inhibitors iodoacetamide, N-ethylmaleimide, antipain, and leupeptin. In addition, most of the bound form of limit dextrinase was soluble in 0.2 M sodium acetate buffer (pH 5.0) following extraction at 30[deg]C for 16 h and centrifugation at 3000g.

Extreme resistance to potato virus X infection in plants expressing a modified component of the putative viral replicase.

Three types of mutation were introduced into the sequence encoding the GDD motif of the putative replicase component of potato virus X (PVX). All three mutations rendered the viral genome completely noninfectious when inoculated into Nicotiana clevelandii or into protoplasts of Nicotiana tabacum (cv. Samsun NN). In order to test whether these negative mutations could inactivate the viral genome in trans, the mutant genes were expressed in transformed N.tabacum (cv. Samsun NN) under control of the 35S RNA promoter of cauliflower mosaic virus and the transformed lines were inoculated with PVX. In 10 lines tested in which the GDD motif was expressed as GAD or GED there was no effect on susceptibility to PVX. In two of four lines transformed to express the ADD form of the conserved motif, the F1 and F2 progeny plants were highly resistant to infection by PVX, although only to strains closely related to the source of the transgene. The resistance was associated with suppression of PVX accumulation in the inoculated and systemic leaves and in protoplasts of the transformed plants, although some low level viral RNA production was observed in the inoculated but not the systemic leaves when the inoculum was as high as 100 or 250 micrograms/ml PVX RNA. These results suggest for a plant virus, as reported previously for Q beta phage, that virus resistance may be engineered by expression of dominant negative mutant forms of viral genes in transformed cells.

The effect of proanthocyanidin-rich hulls and proanthocyanidin extracts from bean (Vicia faba L.) hulls on nutrient digestibility and digestive enzyme activities in young chicks.

Proanthocyanidins were prepared from three bean (Vicia faba L.) varieties by extracting hulls in aqueous acetone. The amounts of freeze-dried extracts recovered were 74, 89 and 97 g/kg hull for the varieties Brunette, Statissa and Minica respectively. Chicks (3 weeks old) were fed on a maize-soya-bean control diet or the same control diet substituted with either 30 g proanthocyanidin extracts/kg or 300 g proanthocyanidin-rich hulls/kg. Chicks were tube-fed diets twice daily for 4 d. Nutrient digestibilities were calculated from amounts present in diets and freeze-dried excreta with the aid of titanium dioxide as a marker. Enzyme activities were measured in digesta removed from the jejunum. Extracts of proanthocyanidins depressed the digestibility of protein by 34%, starch by 3% and had no effect on the digestibility of lipid. Proanthocyanidin-rich hulls depressed the digestibility of protein by 62%, starch by 6% and lipid by 4%. Digestive enzyme activities were depressed to the same extent by extracts and hulls, trypsin (EC 3.4.21.4) by 55 and 62%, alpha-amylase (EC 3.2.1.1) by 75 and 78% and lipase (EC 3.1.1.3) by 31 and 32% for proanthocyanidin-extract and proanthocyanidin-rich-hull diets respectively. The susceptibility of substrates as well as enzymes to the effects of proanthocyanidins is discussed.

The effect of concentration of tannin-rich bean hulls (Vicia faba L.) on activities of lipase (EC 3.1.1.3) and alpha-amylase (EC 3.2.1.1) in digesta and pancreas and on the digestion of lipid and starch by young chicks.

The effect of different concentrations of tannin-rich field-bean (Vicia faba L.) hulls at 0, 20, 50, 150 and 300 g/kg dietary inclusion on the activities of lipase (EC 3.1.1.3) and alpha-amylase (EC 3.2.1.1) in digesta and pancreas and on the digestion of lipid and starch was studied in 2-3-week-old male broiler chicks. Low dietary concentrations of tannins (20 and 50 g hulls/kg) enhanced the activity of lipase in digesta from both the jejunum and ileum, the 20 g hulls/kg effecting the greatest enhancement, but no stimulatory effect on the activity of digesta alpha-amylase was observed. High dietary concentrations of tannins (150 and 300 g hulls/kg) inhibited both lipase and alpha-amylase activities in digesta from both the jejunum and ileum, the 30 g hulls/kg causing the most inhibition. Tannins did not increase the activities of lipase or alpha-amylase in pancreatic homogenates, but at high concentrations (150 and 300 g hulls/kg) they lowered slightly the pancreatic activity of alpha-amylase. Nutrient digestion was less influenced by the concentration of tannins than digesta enzyme activities.

The inhibitory effects of hull polysaccharides and tannins of field beans (Vicia faba L.) on the digestion of amino acids, starch and lipid and on digestive enzyme activities in young chicks.

The effects of polysaccharides and tannins present in the hulls of field beans (Vicia faba L.) on the digestion of amino acids, starch and lipid were studied in poultry. A control diet without hulls and the same diet substituted with 400 g hulls/kg diet from three different varieties of beans were fed to 3-week-old chicks for 4 d. Digestibility coefficients for amino acids, starch and lipid were calculated from measurements made of these nutrients in the diets and the freeze-dried excreta with the aid of titanium dioxide as a marker. Activities of trypsin (EC 3.4.21.4), alpha-amylase (EC 3.2.1.1), and lipase (EC 3.1.1.3) in digesta removed from the upper jejunum, sucrase (EC 3.2.1.48) in the gut mucosa from the upper jejunum, and alpha-amylase and lipase in the pancreas were measured. The hulls were analysed for their polysaccharide and tannin contents. Results showed that the hulls were mostly carbohydrate in composition, with cellulose the predominant polysaccharide. Tannins present in the hulls of two coloured-flowering varieties (Brunette and Minica) were of the condensed type. The diet with tannin-free hulls (white-flowering variety Medes) lowered slightly the digestion of amino acids, starch and lipid compared with the control diet. This effect was believed to be due to inhibition of digestive enzymes, possibly through their adsorption onto the hulls. Diets with tannin-rich hulls (varieties Brunette and Minica) caused a large reduction in the digestion of amino acids, starch and lipid compared with the control diet mainly due to inactivation of digestive enzymes by the formation of tannin-enzyme complexes in the digestive tract. Enzyme activities could be partially restored by the addition of polyvinylpyrrolidone to the digesta. Tannins inactivated trypsin the most, alpha-amylase to a lesser extent and lipase the least and as a consequence lowered the digestion of amino acids the most, starch to a lesser extent and lipid the least. Tannins did not induce an increased pancreatic production of digestive enzymes, nor did they affect activity of jejunum mucosal sucrase. Condensed tannins from Brunette and Minica hulls were partially extractable in methanol alone, but required acidic methanol for fuller extraction. The vanillin:anthocyanidin ratio suggested that tannins were polymerized to the same degree in the Brunette and Minica varieties, both in the methanol and acidic methanol extracts. Hulls from the variety Minica contained a greater amount of methanol-extractable tannins, the quantity of remaining tannins that required acidic methanol for extraction being the same for both varieties.