Failure of elimination of paternal mitochondrial DNA in abnormal embryos

Paternal mitochondrial DNA is normally eliminated from mammalian embryos. We have shown the presence of paternal mtDNA at the blastocyst stage in some abnormal human embryos.     

Postinflammatory Hyperpigmentation

Postinflammatory hyperpigmentation (PIH) is a reactive hypermelanosis and sequela of a variety of inflammatory skin conditions. PIH can have a negative impact on a patient's quality of life, particularly for darker-skinned patients. Studies show that dyschromias, including PIH, are one of the most common presenting complaints of darker-skinned racial ethnic groups when visiting a dermatologist. This is likely due to an increased production or deposition of melanin into the epidermis or dermis by labile melanocytes. A variety of endogenous or exogenous inflammatory conditions can culminate in PIH and typically most epidermal lesions will appear tan, brown, or dark brown while dermal hypermelanosis has a blue-gray discoloration. Depigmenting agents target different steps in the production of melanin, most commonly inhibiting tyrosinase. These agents include hydroquinone, azelaic acid, kojic acid, arbutin, and certain licorice (glycyrrhiza) extracts. Other agents include retinoids, mequinol, ascorbic acid (vitamin C), niacinamide, N-acetyl glucosamine, and soy, and these products depigment by different mechanisms. Certain procedures can also be effective in the treatment of PIH including chemical peeling and laser therapy. It is important to note that these same therapeutic modalities may also play a role in causing PIH. Lastly, those lesions that are not amenable to medical or surgical therapy may experience some improvement with cosmetic camouflage.     

Visual spatial localization conflict: an fMRI study.

fMRI and ERP studies have shown that tasks comprising conflicting stimulus-response associations activate a variety of cortical regions. It remains unclear whether any of these areas are activated by all conflict tasks, or whether conflict resolution is a common property of a number of distinct anatomical regions. Several regions in frontal and parietal cortex are activated by both exogenous (position) and endogenous (arrow direction) localization cues. The present event-related fMRI study used a version of the Simon task with independent positional and directional cues. The results indicated that spatial localization conflict activated pre-motor and superior parietal regions in the right hemisphere known to be involved in spatial localization, but anterior cingulate activation did not reach threshold. This suggests that conflict within a single functional modality may be processed in the region embodying that modality, and anterior cingulate may be called on only to resolve conflict between modalities.     

Early endocrine events in induced pregnancies

Progesterone (P) and human chorionic gonadotropin (beta-hCG) levels were measured randomly or serially in 141 single clinical intrauterine pregnancies resulting from treatment of infertility. Seventy (group I) were conceived during spontaneous cycles, 36 (group II) with clomiphene citrate, and 35 (group III) with menotropins (hMG). Each group was subdivided into subgroup A (normal pregnancies) and B (pregnancies ending in abortion). Thirteen percent of patients in group I aborted, 19% in group II, and 31% in group III (P less than .05). The overall mean (+/- SD) P level in group IA was 25.8 +/- 10.3 ng/mL and in group IB, 16.6 +/- 9.9 ng/mL (significantly lower, P less than .001); in group IIA the mean P level was 37.8 +/- 21.9 ng/mL and in group IIB, 22.9 +/- 17.9 ng/mL, again significantly lower (P less than .01). In subgroups IB and IIB, 11 of 16 patients showed early abnormal beta-hCG patterns; these findings suggest defective embryonic development and/or deficient corpus luteum function as the cause of abortion. There was no significant difference between mean P in group IIIA (71.1 +/- 43.7 ng/mL) and IIIB (75.7 +/- 55.9 ng/mL). In group IIIB, the mean "peak" P level of 101.1 +/- 73.6 ng/mL was followed by a mean "nadir" of 35.4 +/- 24.8 ng/mL at 6-9 weeks. In group IIIB, 7 of 11 patients showed normal beta-hCG patterns. Three patients with precipitous P decline aborted karyotypically normal fetuses in spite of normally rising beta-hCG levels and the presence of fetal cardiac activity.(ABSTRACT TRUNCATED AT 250 WORDS)     

Near-infrared spectroscopy as an alternative to the Wada test for language mapping in children, adults and special populations.

The intracarotid amobarbital test (IAT) is the most widely used procedure for pre-surgical evaluation of language lateralization in epileptic patients. However, apart from being invasive, this technique is not applicable in young children or patients who present mental retardation and/or language deficits. Functional magnetic resonance imaging (fMRI) is increasingly employed as a non-invasive alternative. Again, this method is more difficult to use with young children, especially hyperactive ones, since they have to remain motionless during data acquisition. The aim of this study was to determine whether near-infrared spectroscopy (NIRS) can be used as an alternative technique to investigate language lateralization in children and special populations. Unlike Wada test, NIRS is non-invasive, and it is more tolerant to movement artefacts than fMRI. In the present study, NIRS data were acquired in four epileptic children, a 12-year-old boy with pervasive developmental disorder and a 3-year-old, healthy child, as well as three healthy and two epileptic adults, while they performed a verbal fluency task and a control task. When applicable, the results were compared to the subjects' fMRI and/or IAT findings. Clear laterality of speech was obtained in all participants, including the two non-epileptic children, and NIRS results matched fMRI and IAT findings. These results, if replicable in larger samples, are encouraging and suggest that NIRS has the potential to become a viable, non-invasive alternative to IAT and fMRI in the determination of speech lateralization in children and clinical populations that cannot be submitted to more invasive techniques.     

The event-related optical signal to electrical stimulation of the median nerve

The event-related optical signal (EROS) uses near-infrared light to study changes in neuronal optical properties in response to stimuli and endogenous events. EROS responses to electrical stimulation of the median nerve at 1, 5, and 8 Hz were collected from 80 channels in 7 subjects. Optical recording channels were spatially aligned by co-registering the digitized fiber locations with structural magnetic resonance images (MRI) for each subject separately. The co-registered data sets were then transformed into Talairach space to permit alignment across subjects. After alignment, data from channels underlying pixels of a surface projection were combined to produce maps of Z statistics. Waveforms associated with voxels within an a priori region of interest (ROI) over the hand area of primary somatosensory (SI) cortex were compared across the three stimulus frequencies. Reliable early increases in light propagation time (i.e., increased phase delay) were found in SI as early as 16-32 ms of poststimulus for all three frequency conditions, and both an increase in phase delay and a decrease in signal intensity were observed over SI at longer latencies. A split-half analysis of the 8 Hz condition demonstrated the replicability of the response. This represents the first direct comparison of intensity and delay measures of these components of the somatosensory response; further, it shows that these early cortical components are replicable across subjects and correspond well to individual subjects' anatomical landmarks for SI.     

Optimum filtering for EROS measurements

The event-related optical signal (EROS) is a relatively new technology that provides noninvasive data about the time course of neural activity in circumscribed cortical areas. However, much still remains to be learned about the physiology and physics underlying the observed signals. We examined the instrumental and physiological noise observed in the intensity modulation and phase-delay measurements produced by a frequency domain oxymeter in response to steady-state auditory stimuli. We present here data on the effects of different filters on the between-subjects response consistency for amplitude and phase measurements. The results of these analyses may help explain some apparently discrepant results previously reported from different laboratories (Steinbrink et al., 2000), and illustrate differences between data from different types of measurements.