Characteristics and distribution of ERP by different field stimulation / 法医学杂志

OBJECTIVE@#To study the variation of latency and amplitude of the event related potential (ERP) and its distribution in human scalp when the normal subjects were stimulated with different visual fields.@*METHODS@#The ERP recorded in scalp with the stimulation of 10 degrees visual field and 60 degrees visual field respectively in 20 healthy volunteers with normal visual function.@*RESULTS@#Two different visual field stimulation may evoke the different exogenous components P1 (70-125 ms), N1 (90-170 ms), P2 (140-220 ms) and endogenous components N2 (190-280 ms) and P3 (290-430 ms). The latencies of all the components evoked by 10 degrees visual field were shorter than that of the 60 degrees visual field while the amplitudes of N1 and N2 were lower and appeared over the extensive encephalic region; and the amplitudes of the P1, P2 and P3 were higher and appeared in occipitotemporal, prefrontal and occipital region, respectively.@*CONCLUSION@#Two different visual field stimulation may evoke all the ERP components with significant differences in the latency, amplitude and distribution. The differences may reflect the different visual information integration and processing in human brain during the different visual field stimulation.

Variación estacional del tricograma en residentes chilenos / Seasonal variation of trichogram in Chilean subjects

Background: Human hair follicle experiments cyclical transformations throughout its life. These are rest (telogen phase), growth (anagen phase) and regression mediated by apoptosis (catagen). During summer the percentage of telogen increases and the percentage of anagen decreases. Aim: To determine the seasonal changes of scalp hair follicle phases among Chilean subjects. Material and methods: Retrospective analysis of 514 differential trichograms of normal scalps from subjects aged 36±14 years, obtained between 1998 and 2008. Results: During summer and winter, the mean percentage of telogen was 20 percent±10 percent and 16 percent±10 percent, respectively (p <0.01). The figures for anagen in the same periods were 80 percent±10 percent and 83 percent±10 percent, respectively. Conclusions: This study confirms the presence of seasonal variations in normal trichogram.

Hair transplantation: standard guidelines of care.

Hair transplantation is a surgical method of hair restoration. PHYSICIAN QUALIFICATION: The physician performing hair transplantation should have completed post graduation training in dermatology; he should have adequate background training in dermatosurgery at a centre that provides education training in cutaneous surgery. In addition, he should obtain specific hair transplantation training or experience at the surgical table(hands on) under the supervision of an appropriately trained and experienced hair transplant surgeon. In addition to the surgical technique, training should include instruction in local anesthesia and emergency resuscitation and care. FACILITY: Hair transplantation can be performed safely in an outpatient day case dermatosurgical facility. The day case theatre should be equipped with facilities for monitoring and handling emergencies. A plan for handling emergencies should be in place and all nursing staff should be familiar with the emergency plan. It is preferable, but not mandatory to have a standby anesthetist. Indication for hair transplantation is pattern hair loss in males and also in females. In female pattern hair loss, investigations to rule out any underlying cause for hair loss such as anemia and thyroid deficiency should be carried out. Hair transplantation can also be performed in selected cases of scarring alopecia, eyebrows and eye lashes, by experienced surgeons. PREOPERATIVE COUNSELING AND INFORMED CONSENT: Detailed consent form listing details about the procedure and possible complications should be signed by the patient. The consent form should specifically state the limitations of the procedure and if more procedures are needed for proper results, it should be clearly mentioned. Patient should be provided with adequate opportunity to seek information through brochures, computer presentations, and personal discussions. Need for concomitant medical therapy should be emphasized. Patients should understand that proper hair growth can be expected after about 9 months after transplantation. Preoperative laboratory studies to be performed include Hb%, blood counts including platelet count, bleeding and clotting time (or prothrombin time and activated partial thromboplastin time), blood chemistry profile including sugar. METHODS: Follicular unit hair transplantation is the gold standard method of hair transplantation; it preserves the natural architecture of the hair units and gives natural results. Mini-micro-grafting is a method hair transplantation involving randomly assorted groups of hairs, with out consideration of their natural configuration of follicular units, under loupe or naked eye examination. Mini-grafts consist of 4-5-6 hairs while micro-grafts consist of 1-3 hairs. Punch gives ugly cosmetically unacceptable results and should no longer be used. PATIENT SELECTION: Hair transplantation can be performed in any person with pattern hair loss, with good donor area, in good general health and reasonable expectations. Caution should be exercised in, very young patients whose early alopecia is still evolving, patients with Norwood grade VI or VII with poor density, patients with unrealistic expectations, and patients with significant systemic health problems. MEDICAL THERAPY: Most patients will need concurrent medical treatment since the process of pattern hair loss is progressive and may affect the remaining hairs. MANPOWER: Hair transplantation is a team effort. Particularly, performing large sessions, needs a well trained team of trained assistants. ANESTHESIA: 2% lignocaine with adrenaline is generally used for anesthesia; tumescent technique is preferred. Bupivacaine has been used by some authors in view of its prolonged duration of action. DONOR DISSECTION: Strip dissection by single blade is recommended for donor area. Steromicroscopic dissection is recommended for dissection of hair units in follicular unit transplantation; mini-micro-grafting does not need microscopic dissection. RECIPIENT INSERTION: Different techniques and different instruments have been used for recipient site creation ;these depend on the choice of the operating surgeon and have been described in the guidelines. Graft preservation is important to ensure survival. DENSITY: Minimum density of 35-45 units per sq cm is recommended. Results depend on donor characteristics, technique used and individual skills of the surgeon.

Evaluación fetal intraparto: análisis crítico de la evidencia / Fetal intrapartum surveillance: critical appraisal of evidence

La evaluación de la condición fetal intraparto constituye uno de los principales desafíos de la obstetricia. En un intento por mejorar la discreta capacidad diagnóstica del registro electrónico intraparto de la frecuencia cardiaca fetal, se han ideado y desarrollado métodos complementarios de vigilancia fetal intraparto. El objetivo del presente artículo es realizar un análisis crítico de estos métodos complementarios de vigilancia fetal intraparto, respecto de su rendimiento diagnóstico y de su utilidad clínica, para concluir si se justifica la incorporación de alguno(s) de ellos como estándar de la práctica clínica habitual.

Excess of counterclockwise scalp hair-whorl rotation in homosexual men.

While most men prefer women as their sexual partners, some are bisexual and others are homosexuals. It has been debated for a long time whether a person's sexual preference is innate, learned, or due to a combination of both causes. It was recently discovered that the human right-versus-left-hand use preference and the direction of scalp hair-whorl rotation develop from a common genetic mechanism. Such a mechanism controls functional specialization of brain hemispheres. Whether the same mechanism specifying mental makeup influences sexual preference was determined here by comparing hair-whorl rotation in groups enriched with homosexual men with that in males at large. Only a minority of 8.2% (n = 207) unselected 'control' group of males had counterclockwise rotation. In contrast, all three samples enriched with homosexual men exhibited highly significant (P < 0.0001), 3.6-fold excess (29.8%, n = 272) counterclockwise rotation. These results suggest that sexual preference may be influenced in a significant proportion of homosexual men by a biological/genetic factor that also controls direction of hair-whorl rotation.

Observaçöes relacionadas à utilizaçäo de montagens entre a face posterior do pescoço e o couro cabeludo no potencial evocado por estimulaçäo do nervo mediano / Related observations for the use of mounting between neck posterior and scalp in evoked potentials by median nerve stimulation

Foram realizados potenciais evocados por estimulaçäo do nervo mediano no punho, em grupo de voluntários normais. Foram avaliados os componentes que ocorreram entre 12 e 22 ms. Os registros foram feitos com referências cefálicas e näo cefálicas. Foi evidenciada maior contribuiçäo do complexo P13-14 na amplitude do componente N13 registrado entre C6 e Fz. Näo foram detectadas diferenças significativas na amplitude e latência dos componentes N18 e P22 quando avaliados nas montagens FZ-näo cefálico e C6-FZ. Säo discutidas as implicaçöes desses achados para a interpretaçäo clínica dessas respostas

O tricograma: Parte II. Resultados e interpretaçäo / The trichogram: Part II. Results and interpretation

O tricograma é um exame que avalia o ciclo de crescimento do cabelo. Desta forma pode ser usado para o diagnóstico, evoluçäo e prognóstico de um processo patológico, bem como parâmetro para avaliar o uso de drogas em tricologia e cancerologia