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At least 865 records · Page 48Linked to original sources
PubMed2003

Transplants from balding and hairy androgenetic alopecia scalp regrow hair comparably well on immunodeficient mice.

Human hair follicles were grafted onto 2 strains of immunodeficient mice to compare the regeneration potential of vellus (miniaturized, balding) and terminal (hairy, nonbalding) follicles from males and a female exhibiting pattern baldness. Each mouse had transplants of both types of follicles from a single donor for direct comparison. Grafted follicles from 2 male donors resulted in nonsignificant differences in mean length (52 mm vs 54 mm) and mean diameter (99 microm vs 93 microm) at 22 weeks for hairs originating from balding and hairy scalp, respectively, corresponding to 400% versus 62% of the mean pretransplantation diameters. Follicles from the female donor transplanted to several mice also resulted in nonsignificant differences in length (43 mm vs 37 mm) for hairs from balding and hairy scalp, respectively, during a period of 22 weeks. The mean diameter of the originally vellus hairs increased 3-fold, whereas the terminal hairs plateaued at approximately 50% of pretransplantation diameter, resulting in a final balding hair volume double that of the nonbalding hairs. This report shows that miniaturized hair follicles of pattern alopecia can quickly regenerate once removed from the human scalp and can grow as well as or better than terminal follicles from the same individual.

Adult↗
PubMed1980

Etiology of ringworm of the scalp, beard and body in Rome, Italy.

From 1972 to 1977 the authors examined 1,311 patients in Rome affected by ringworm of the scalp, beard and body, comparing their findings with a study made in Milan between 1969 to 1973 and with earlier Italian studies from 1900 to date. It appears that at the beginning of the century scalp ringworm was usually caused by Trichophyton violaceum and T. tonsurans, whereas Microsporum canis was rarely found. Today the Trichophyton species are rarely isolated, whereas Microsporum species, particularly M. canis (88.9% of the cases in Rome, 74.6% in Milan), predominate in the etiology of scalp ringworm. Ringworm of the beard in Rome is mainly caused by T. mentagrophytes (50% of the cases) and T. verrucosum (25%). In Milan the frequency of T. verrucosum is 51.2% and of T. mentagrophytes 38.5%. Ringworm of the body today is mainly due to M. canis (47.8% of the cases in Rome and 65.7% of those in Milan). These ringworms in Rome and Milan are caused mostly by the zoophilic dermatophytes that have supplanted the anthropophilic dermatophytes, which were the main cause of dermatomycoses in the early years of this century. This change, particularly evident after World War II, appears to result from improved socio-economic and hygienic conditions, with resulting decrease of infections through interhuman contacts, and from increased numbers of pet animals and consequent increase of stray cats and dogs, which result in increase of infections of animal origin.

Epidermophyton↗
PubMed1980

Fungal infections of the scalp in Western Australia.

Between 1963 and 1972, 1,212 fungi were isolated from patients with tinea capitis (ringworm of the scalp) in Western Australia. The clinical diagnosis was confirmed by microscopic examination examination and/or culture of hairs, scale or pus. Microsporum canis, a zoophilic fungus, was found to be the most common agent of tinea capitis in Western Australia, causing 1,100 infections and accounting for 90.8% of the total isolates. The highest incidence of M. canis infections occurred in children between the ages of 2 and 8 years. Males accounted for 57.7% of scalp infections, and there were comparatively few cases in either males or females over the age of 10 years. Trichophyton tonsurans was found to be the main cause of endothrix scalp infections in Western Australia.

Adolescent↗
PubMedDate not supplied

Study of aroma scalping through thermosealable polymers used in food packaging by inverse gas chromatography.

Scalping of aroma components in polymers used for food packaging was determined by solubility experiments. Aromas were selected from different families: esters, alcohols, hydrocarbons and ketones. Polymers were a linear low density polyethylene (LLDPE), an ionomer and a new thermosealable polyester (PET). Polymers were selected from thermosealable materials because of their resistance to fats and oils. Sorption isotherms (low sorbate activity range) for every system aroma (vapour)/polymer were determined by inverse gas chromatography. Isotherms were found to be linear. Hence, solubility coefficients (S) as defined by Henry's law were calculated from the isotherm slopes. According to S values, PET appears to be the best choice to minimize aroma scalping by sorption in the packaging inner layer, Ionomers improve the barrier to aroma when compared with LLDPE except for polar sorbates. Sorption of aroma components was shown to be selective, e.g. limonene was preferentially sorbed in LLDPE. The value of S for the limonene/LLDPE system was 2.5 times the value of S for ethyl caproate/LLDPE. This selectivity may lead to an imbalance in the flavour and may be more important than the prevention of overall scalping.

Absorption↗
PubMed1996

The effects of scalp expansion on the cranial bone: a clinical, histological, and instrumental study.

The effects of chronic compression of the cranial bone due to progressive expansion of the scalp have been investigated. Ten patients were studied, 6 adults and 4 children, who were treated for congenital (microtia) or acquired (burns or traumatic) deformities by chronic expansion over a 2-month period. All underwent computed tomography scans of the expansion site prior to introduction of the expansion device, immediately before removal, and at 9 months after the operation. A case of postburn alopecia was lost to the study, because the patient, who had ultimated scalp expansion, did not return for flap advancement. Instead, she came back 3 months later, without the expander, which had been removed at another institution following an automobile accident. In this case, because of slower healing, we performed computed tomography scans 18 months postoperation. During the second procedure (expander removal and flap transposition), bone samples for histological examination were collected directly underneath and along the perimeter of the expanders. Macroscopically, the bone appeared thinned and had a reduced convexity. This reaction, although temporary, appeared more intense in the children and in the posttraumatic cases. Histological examination showed osteoclastic activation, bony hypotrophy, and reaction (deposition of osteoid matrix) under the device, with consequent bone resorption and remodeling. A marked hyperplasia with a hyperostotic reaction was observed around the expanders. At 9 months postoperation, in most cases, a complete normalization was confirmed by computed tomography scans. Expansion of target (fontanellar and sagittal) areas of the skull in children, as well as previous trauma to both scalp and skull should be taken into consideration as a risk factor. Further investigations are suggested.

Adolescent↗
PubMed1992

Effects of age, gender, and stimulus side on the scalp topography of somatosensory evoked potentials following posterior tibial nerve stimulation.

This is the first thorough study to evaluate the effects of age, gender, and stimulus side on the scalp topographies of somatosensory evoked potentials (SEPs) following stimulation of the posterior tibial nerve by using computerized bit-mapped color images and the significance probability mapping method. Seventy-four normal subjects whose ages ranged from 7 to 88 years were studied. Topographic mappings of most components in aged subjects were significantly different from those in young subjects, mainly because of higher amplitudes of the components in the aged group. However, scalp distribution of each component did not show a large difference among different age groups. There was a tendency that amplitudes in women were larger than those in men, and the gender differences of some components were significantly larger for some age groups. Stimulus side and handedness caused no significant difference in amplitudes and topographies of the components. These results were very similar to our previous results of the scalp topographies of SEPs following median nerve stimulation.

Adolescent↗
PubMed1994

Use of scalp-sphenoidal EEG for seizure localization in temporal lobe epilepsy.

We determined the accuracy and sensitivity of scalp-sphenoidal EEG for seizure focus localization in 50 patients who became seizure-free or had rare seizures following temporal lobectomy. EEG localization was based on concordant interpretations of scalp-sphenoidal ictal EEG by three independent interpreters. All patients became seizure-free or had rare seizures following temporal lobectomy. Localization from EEG disagreed with the side of surgery in only 1 (2%) of 50 patients. We identified 3 distinct patient groups with a low, moderate, and high likelihood of having a focal ictal EEG pattern during a seizure. These groups comprised 31% (low likelihood), 44% (moderate likelihood), and 25% (high likelihood) of patients. A model based on these results suggests that with multiple ictal EEG recordings, accurate localization from scalp-sphenoidal EEG is possible in approximately up to 65-70% of patients with temporal lobe epilepsy.

Brain↗
PubMed1995

Middle-latency somatosensory evoked potentials after stimulation of the radial and median nerves: component structure and scalp topography.

Somatosensory evoked potentials (SEPs) after radial nerve stimulation are studied less frequently than those after median nerve stimulation. Therefore, little is known about their component structure and scalp topography. We investigated radial nerve SEPs after electrical stimulation at the left wrist. For comparison, the median nerve was also stimulated at the wrist. SEPs were recorded with 15 scalp electrodes (bandpass 0.5-200 Hz) in 27 healthy subjects. The waveform of the radial nerve SEP at a contralateral parietal lead was comparable to that of the median nerve SEP, consisting of P14, N20, P30, and N60. In spite of comparable stimulus intensities, SEP amplitudes were smaller after radial than after median nerve stimulation. Significant latency differences were found only for N20 (earlier for median nerve) and P30 (earlier for radial nerve). The duration of the primary complex N20-P30 thus was significantly shorter for the radial nerve. Whereas N20 and P30 were present with either earlobe or frontal reference, N60 had a prerolandic maximum and was best recorded with a bipolar transverse derivation. In addition, another middle-latency negativity (N110) was found near the secondary somatosensory cortex, which had previously been described only for radial nerve stimulation. In standard SEP derivations, the N110 is riding on the ascending limb of the vertex negativity. It could best be recorded in low temporal leads versus a midline reference. The scalp topographies of P30, N60, and N110 were similar for radial and median nerve stimulation.

Adult↗
PubMed1997

Frontopolar ictal epileptiform discharges on scalp electroencephalogram in temporal lobe epilepsy.

We report 3 patients with medically intractable complex partial seizures (CPS) arising from the temporal lobe judged by surgical outcome, in whom scalp electroencephalogram (EEG) showed ictal epileptiform discharges at the frontopolar region. In all patients, results of cranial magnetic resonance imaging (MRI), positron emission tomography (PET), and ictal single photon emission computed tomography (SPECT) were consistent with those of temporal lobe epilepsy (TLE). The epileptogenic area was defined in the temporal lobe by chronic subdural recording in 2 patients. After surgical treatment (amygdalohippocampectomy, anterior temporal lobectomy, and temporal lesionectomy, respectively), all 3 patients became seizure-free and the interictal frontopolar epileptiform discharges on scalp EEG disappeared. Patients with TLE may show ictal scalp EEG with frontopolar onset. This is most likely explained by direction of dipolar orientation of epileptiform discharges in 1 of our patients; rapid spread of ictal activity to the frontopolar area can also be considered in the 2.

Adult↗
PubMed2000

Scalp marking for a craniotomy using a laser pointer during preoperative computed tomographic imaging: technical note.

OBJECTIVE: The preoperative localization of superficial intracranial lesions is often necessary for accurate burr hole placement or craniotomy siting. It is not always easy, however, to localize the lesions over the scalp working only from computed tomographic images. We developed a simple method for such localization using a laser pointer during the preoperative computed tomographic examination. METHODS: The angle of incidence, extending from a point on the scalp to the center of the computed tomographic image, is measured by the software included with the scanner. In the gantry, at the same angle as on the image, a laser is beamed from a handmade projector onto the patient's scalp toward the center of the gantry. The point illuminated on the patient's head corresponds to that on the image. The device and the method are described in detail herein. RESULTS: We applied this technique to mark the area for the craniotomy before surgery in five patients with superficial brain tumors. At the time of surgery, it was confirmed that the tumors were circumscribed precisely. CONCLUSION: The technique is easy to perform and useful in the preoperative planning for a craniotomy. In addition, the device is easily constructed and inexpensive.

Brain Neoplasms↗
PubMed1998

Reconstruction of upper cranial and cranial base defects utilizing the scalping flap.

Reconstruction of midfacial defects by means of a scalping flap has been widely practiced and described in the literature. The advantages of the flap are familiar to surgeons who perform extirpations and reconstruction of the head and neck and include contiguous availability, simplicity of application, and a robust and redundant blood supply. Despite these merits, the flap has not been widely used for reconstructions of large anterior cranial defects or defects of the cranial base. A retrospective review of 11 patients who underwent reconstructions between 1990 and 1995 was performed. In each case, a reconstruction of a large anterior cranial or cranial base defect was carried out. The resulting soft-tissue defect was restored via the scalping flap. In six cases, this was carried out in a single procedure. In five cases, flap division and insetting were carried out in a subsequent procedure, following a 1- to 2-week delay. In all cases, the extirpation and reconstruction were well tolerated, and the average time of hospitalization was 5.9 days and ranged from 3 to 11 days. No major surgical complications occurred. One of 11 patients had a minor complication not requiring surgical intervention. There was one recurrence of a cranial base tumor approximately 2 years following the initial resection and reconstruction. In all cases, the final aesthetic and functional results were acceptable to excellent. Follow-up ranged from 11 months to 5 years. In conclusion, the scalping flap can be effectively utilized for soft-tissue coverage in the reconstruction of anterior cranial and cranial base defects. Use of this simple and versatile flap in craniofacial reconstruction is well tolerated and is associated with a low morbidity, a good aesthetic result, and a short hospital stay.

Adult↗
PubMed2006

Epileptic seizure predictability from scalp EEG incorporating constrained blind source separation.

Most of the methods for prediction of epilepsy recently reported in the literature are based on the evaluation of chaotic behavior of intracranial electroencephalographic (EEG) recordings. These recordings require intensive surgical operations to implant the electrodes within the brain which are hazardous to the patient. Here, we have developed a novel approach to quantify the dynamical changes of the brain using the scalp EEG. The scalp signals are preprocessed by means of an effective block-based blind source separation (BSS) technique to separate the underlying sources within the brain. The algorithm significantly removes the effect of eye blinking artifacts. An overlap window procedure has been incorporated in order to mitigate the inherent permutation problem of BSS and maintain the continuity of the estimated sources. Chaotic behavior of the underlying sources has then been evaluated by measuring the largest Lyapunov exponent. For our experiments, we provided twenty sets of simultaneous intracranial and scalp EEG recordings from twenty patients. The above recordings have been compared. Similar results were obtained when the intracranial electrodes recorded the electrical activity of the epileptic focus. Our preliminary results show a great improvement when the epileptic focus is not captured by the intracranial electrodes.

Algorithms↗
PubMed2004

Unilateral hippocampal sclerosis with contralateral temporal scalp ictal onset.

PURPOSE: To investigate the clinical characteristics and surgical outcomes in patients with unilateral hippocampal sclerosis whose scalp ictal EEG recordings localize to the opposite temporal lobe. METHODS: We retrospectively reviewed the data of all adult patients who had undergone depth electrode implantation for suspected temporal lobe epilepsy (TLE) at UCLA (1993-2000) or the Montreal Neurological Institute (1991-1998) to identify patients who had (a) unilateral hippocampal atrophy, and (b) surface ictal recordings in which the majority of seizures appeared to initiate in the opposite temporal lobe, with few or none that were concordant with the hippocampal atrophy. RESULTS: Of 109 patients with suspected TLE who underwent depth electrode study at the two centers, five patients met the aforementioned criteria. Four of these five had very severe hippocampal atrophy, whereas the fifth had mild atrophy but extensive signal change on magnetic resonance imaging (MRI). Depth electrode recordings in four of the five patients yielded clear ictal onset in the mesial temporal lobe ipsilateral to the imaging abnormality (contralateral to apparent scalp ictal onset). One patient had an unusual bitemporal onset pattern, which was nonetheless suggestive of onset in the sclerotic hippocampus. No patient had intracranial ictal onset contralateral to the imaging abnormality. All patients underwent resection of the structurally abnormal temporal lobe. After follow-up of > or = 2 years, four (80%) of five patients were seizure free, while the fifth showed lesser improvement (class III). CONCLUSIONS: Some patients with severe hippocampal sclerosis (sometimes called a "burned-out hippocampus") have atypical spread of ictal discharges, resulting in apparent gross discordance between imaging and scalp ictal recordings. These patients nonetheless have excellent surgical outcomes on the whole. Whether such patients may forego intracranial recordings requires further study.

Adult↗
PubMed1990

Anesthetic induction with thiopental: its effect on scalp topography of median nerve somatosensory evoked potentials.

The effects on median nerve somatosensory evoked potentials (SEPs) of analgesic doses of fentanyl, meperidine or morphine and of sodium thiopental (STP) anesthesia (4 mg/kg) were tested in 36 surgical patients. We also explored changes in SEP components as a function of their scalp location. Before and after medication, responses were recorded from the scalp overlying the parietal cortex (ipsi- and contralateral to the stimulated arm) and the precentral (contralateral) cortex. None of the three opiates affected SEP latencies or amplitudes. The barbiturate increased the amplitudes of subcortical and early cortical components (N18, N20, P22, P25), whose latencies, however, were not significantly modified. The effect of STP on later SEP cortical components depended on their scalp topography: parietal N33 and P45 underwent significant changes in both latency and amplitude, whereas precentral N30 showed a significant amplitude increase only. Thiopental anesthesia produces clearer short-latency SEP recordings, from both parietal (components N20-P25) and precentral (P22, N30) areas.

Adult↗
PubMed1997

Scalp-recorded, ictal focal DC shift in a patient with tonic seizure.

PURPOSE: We recorded focal ictal DC shifts from scalp electrodes in a 9-year-old boy with intractable, clinically generalized tonic seizures. The patient had a high intensity signal abnormality of the left temporal cortex with thickening of the gyri on T2-weighted MRI. METHODS: Scalp digital EEGs were recorded using electrodes made of silver/silver chloride. The low frequency filter (LFF) was set at 0.016 Hz. Recorded seizures were subsequently analyzed with LFF settings of 1.0, 0.016 and 0.03 Hz. RESULTS: All recorded seizures initially showed diffuse, low voltage, high frequency activity (electrodecremental pattern) followed 10-20 s later by quasirhythmic activity over the left frontotemporal region. In two seizures, LFF of 0.016-0.03 Hz revealed a slow negative shift over the left frontotemporal area simultaneously with onset of the bilateral electrodecremental pattern. However, in the other seizures, this initial slow negative shift was obscured by artifacts. Subsequent electrocorticography (ECoG) delineated frequent epileptiform discharges in the left temporal as well as frontal cortex. CONCLUSIONS: Scalp-recorded ictal DC shifts may help identify focal epileptogenic brain area in patients with clinically generalized seizures although the technique is vulnerable to artifact.

Child↗
PubMed1986

On the spinal pathways mediating scalp-SEPs to upper and lower limb nerve stimulation: case report and discussion.

Scalp-SEPs to peroneal nerve stimulation were abnormal in a patient with an intradural meningeoma which was compressing the antero-lateral quadrant of the 1st and, partly, the 2nd cervical myelomers. In contrast, spine and scalp-SEPs were symmetrically normal during the sural, median and ulnar nerve stimulation of either side. On surgery, it was observed that the tumor had left the dorsal columns (DCs) almost unaffected. It is argued, in agreement with the bulk of experimental evidence, that in humans the scalp-SEPs to lower mixed nerve stimulation are also mediated, at the rostral cord level, by fast-propagating tracts ascending outside the DCs.

Adult↗
PubMed1982

Distribution of auditory brainstem potentials over the scalp and nasopharynx in humans.

Auditory brainstem potentials were recorded from various scalp and nasopharyngeal sites referenced both to a noncephalic site and to certain scalp locations in normal humans. The distribution of amplitudes and latencies of the components were defined. There were significant amplitude, polarity, and latency asymmetries over the scalp in both referential and differential recordings. The data indicated that several of the ABR components have generator sources that are lateralized and move through the brainstem in particular orientations.

Adult↗
PubMed2005

Unusual explosive growth of a squamous cell carcinoma of the scalp after electrical burn injury and subsequent coverage by sequential free flap vascular connection--a case report.

BACKGROUND: Squamous cell carcinomos may arise from chronic ulcerating wounds in scars, most commonly postburn scars. Tumour growth usually takes place over months to years. Localization on the scalp is a relatively rare condition. CASE PRESENTATION: This report presents the case of a 63-year-old man with chronic ulceration of a postburn scar of the scalp due to an electrical burn 58 years ago. Sudden tumour growth started within weeks and on presentation already had extended through the skull into frontal cortex. After radical tumour resection, defect was covered with a free radial forearm flap. Local recurrence occurred 6 weeks later. Subsequent wide excision including discard of the flap and preservation of the radial vessels was followed by transfer of a free latissimus dorsi muscle flap, using the radial vessels of the first flap as recipient vessels. The patient received radiotherapy post-operatively. There were no problems with flap survivals or wound healing. Due to rapidly growing recurrence the patient died 2 months later. CONCLUSION: Explosive SCC tumour growth might occur in post-burn scars after more than 50 years. As a treatment option the use of sequential free flap connections might serve in repeated extensive tumour resections, especially in the scalp region, where suitable donor vessels are often located in distance to the defect.

Burns, Electric↗