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Biomedical subjects

R S Cohen

Publications and source records attributed to R S Cohen.

At least 19 recordsLinked to original sources
PubMed1998

Measurement of facial movement with computer software.

OBJECTIVE: To adapt desktop computer software to objectively grade facial movement. DESIGN: The criteria of the facial nerve grading system by House and Brackmann, the current "gold standard," are prone to ambiguous interpretation. Proposed objective grading systems compare the movement of points on each side of the face or use subtraction and thresholding of digitized images of the face to yield images that represent moving areas of the face. The movement of a point on the face and the area of motion determined by digital subtraction were compared during an increasing smile in healthy subjects. The Nottingham system (calculated using measurement of the movement of 4 points on the face) using desktop computer software (Adobe Photoshop 3.0, Adobe Systems Inc, Mountain View, Calif) to measure movement of the points was compared with the system by House and Brackmann. The computer software was used to subtract digitized images and derive a facial movement score, which was compared with the scores of the systems by Nottingham and House and Brackmann. SETTING: Academic otologic practice. STUDY PARTICIPANTS: Nine patients with varying degrees of facial nerve disability and 7 individuals with normal facial nerve function. RESULTS: The movement of the oral commissure compared with the apparent area of movement of the face determined by digital subtraction had high intersubject variability. In patients with facial weakness, the Nottingham score had a correlation coefficient of -0.97 compared with the House and Brackmann grade, and the digital subtraction score had a correlation coefficient of -0.62 (paired Student t test). CONCLUSIONS: The desktop computer software can be used to calculate the Nottingham score. Digital subtraction as a measure of facial function warrants further study.

CD-ROM↗
PubMed1997

Neuropsychiatric manifestations following the use of 3,4-methylenedioxymethamphetamine (MDMA: "Ecstasy").

1. The recurring side-effects associated with MDMA consumption are reviewed. 2. The recreational use of "Ecstasy" has been implicated in the onset of various psychological, neurological, and organic complications. A table has been employed to depict the deleterious reactions that have occurred following MDMA ingestion. 3. An original case report is presented in which an individual developed perpetual neuropsychiatric symptomatology after having consumed MDMA. This case indicates that MDMA may induce long lasting effects, even after one exposure.

Adolescent↗
PubMed1997

Glyceraldehyde-3-phosphate dehydrogenase activity and F-actin associations in synaptosomes and postsynaptic densities of porcine cerebral cortex.

1. Glyceraldehyde-3-phosphate dehydrogenase (G3PD) is a glycolytic enzyme that has also been implicated in a wide variety of functions within neurons. Because of the well-documented role of G3PD as an actin-binding protein, we sought evidence for a G3PD-actin complex in synaptosomes and postsynaptic densities (PSDs). 2. We have shown G3PD association with 0.5-microgram synaptosomal particles by immunofluorescence as similarly demonstrated for actin (Toh et al., Nature 264:648-650, 1976). An immunoblot analysis also showed G3PD and actin to be enriched in synaptosomes. Further analysis of subcellular fractions from synaptosomes showed the PSD but not the synaptosomal plasma membranes to be enriched in G3PD and actin. 3. Highest levels of G3PD catalytic activity were found in synaptosomes and PSDs. Although synaptosomes showed significant activity for phosphoglycerate kinase (PGK), an enzyme in sequence with G3PD for ATP production in the glycolytic pathway, no such activity was detected in the PSD fraction. 4. Our studies indicate that a G3PD-actin complex may exist at the synapse. A physical association of G3PD with endogenous F-actin in synaptosomes and PSDs was demonstrated by combined phalloidin shift velocity sedimentation/immunoblot studies. By this approach, synaptosomal G3PD-actin complexes were also found to be significantly less dense than the PSD G3PD-actin complexes. 5. G3PD and PGK catalytic activity in synaptosomes suggests a role in glycolysis, as well as actin binding, in the presynaptic terminals. On the other hand, the high levels of G3PD activity in PSDs but lack of PGK activity suggests that G3PD is involved in nonglycolytic functions, such as actin binding and actin filament network organization.

Actins↗
PubMed1997

Multicenter controlled clinical trial of high-frequency jet ventilation in preterm infants with uncomplicated respiratory distress syndrome.

OBJECTIVE: To test the hypothesis that high-frequency jet ventilation (HFJV) will reduce the incidence and/or severity of bronchopulmonary dysplasia (BPD) and acute airleak in premature infants who, despite surfactant administration, require mechanical ventilation for respiratory distress syndrome. DESIGN: Multicenter, randomized, controlled clinical trial of HFJV and conventional ventilation (CV). Patients were to remain on assigned therapy for 14 days or until extubation, whichever came first. Crossover from CV to HFJV was allowed if bilateral pulmonary interstitial emphysema or bronchopleural fistula developed. Patients could cross over to the other ventilatory mode if failure criteria were met. The optimal lung volume strategy was mandated for HFJV by protocol to provide alveolar recruitment and optimize lung volume and ventilation/perfusion matching, while minimizing pressure amplitude and O2 requirements. CV management was not controlled by protocol. SETTING: Eight tertiary neonatal intensive care units. PATIENTS: Preterm infants with birth weights between 700 and 1500 g and gestational age <36 weeks who required mechanical ventilation with FIO2 >0.30 at 2 to 12 hours after surfactant administration, received surfactant by 8 hours of age, were <20 hours old, and had been ventilated for <12 hours. Outcome Measures. Primary outcome variables were BPD at 28 days and 36 weeks of postconceptional age. Secondary outcome variables were survival, gas exchange, airway pressures, airleak, intraventricular hemorrhage (IVH), periventricular leukomalacia (PVL), and other nonpulmonary complications. RESULTS: A total of 130 patients were included in the final analysis; 65 were randomized to HFJV and 65 to CV. The groups were of comparable birth weight, gestational age, severity of illness, postnatal age, and other demographics. The incidence of BPD at 36 weeks of postconceptional age was significantly lower in babies randomized to HFJV compared with CV (20.0% vs 40.4%). The need for home oxygen was also significantly lower in infants receiving HFJV compared with CV (5.5% vs 23.1%). Survival, incidence of BPD at 28 days, retinopathy of prematurity, airleak, pulmonary hemorrhage, grade I-II IVH, and other complications were similar. In retrospect, it was noted that the traditional HFJV strategy emphasizing low airway pressures (HF-LO) rather than the prescribed optimal volume strategy (HF-OPT) was used in 29/65 HFJV infants. This presented a unique opportunity to examine the effects of different HFJV strategies on gas exchange, airway pressures, and outcomes. HF-OPT was defined as increase in positive end-expiratory pressure (PEEP) by >/=1 cm H2O from pre-HFJV baseline and/or use of PEEP of >/=7 cm H2O. Severe neuroimaging abnormalities (PVL and/or grade III-IV IVH) were not different between the CV and HFJV infants. However, there was a significantly lower incidence of severe IVH/PVL in HFJV infants treated with HF-OPT compared with CV and HF-LO. Oxygenation was similar between CV and HFJV groups as a whole, but HF-OPT infants had better oxygenation compared with the other two groups. There were no differences in PaCO2 between CV and HFJV, but the PaCO2 was lower for HF-LO compared with the other two groups. The peak inspiratory pressure and DeltaP (peak inspiratory pressure-PEEP) were lower for HFJV infants compared with CV infants. CONCLUSIONS: HFJV reduces the incidence of BPD at 36 weeks and the need for home oxygen in premature infants with uncomplicated RDS, but does not reduce the risk of acute airleak. There is no increase in adverse outcomes compared with CV. HF-OPT improves oxygenation, decreases exposure to hypocarbia, and reduces the risk of grade III-IV IVH and/or PVL.

Bronchopulmonary Dysplasia↗
PubMed1996

NADPH diaphorase activity and nitric oxide synthase immunoreactivity in lordosis-relevant neurons of the ventromedial hypothalamus.

The distribution of the enzymes NADPH diaphorase and nitric oxide synthase in the ventromedial nucleus of the hypothalamus of cycling and ovariectomized/estrogen-treated and control female rats was demonstrated using histochemical and immunocytochemical methods. Serial section analysis of vibratome sections through the entire ventromedial nucleus showed that NADPH diaphorase cellular staining was localized primarily in the ventrolateral subdivision. NADPH diaphorase staining was visible in both neuronal perikarya and processes. Light microscopic immunocytochemistry using affinity-purified polyclonal antibodies to brain nitric oxide synthase revealed a similar pattern of labelling within the ventromedial nucleus and within neurons of the ventrolateral subdivision of the ventromedial nucleus. Control experiments involved omitting the primary antibodies; no labelling was visible under these conditions. Some, but not all, neurons in the ventrolateral subdivision of the ventromedial nucleus contained both NADPH diaphorase and brain nitric oxide synthase as demonstrated by co-localization of these two enzymes in individual cells of this area. That NADPH diaphorase and brain nitric oxide synthase were found in estrogen-binding cells was shown by co-localization of NADPH diaphorase and estrogen receptor and brain nitric oxide synthase and estrogen receptor at the light and ultrastructural levels, respectively. Our studies suggest that brain nitric oxide synthase is present and may be subject to estrogenic influences in lordosis-relevant neurons in the ventrolateral subdivision of the ventromedial nucleus. The hypothalamus is a primary subcortical regulatory center controlling sympathetic function. Therefore, not only is nitric oxide likely to be important for reproductive behavior, but also for the regulation of responses to emotional stress and other autonomic functions.

Animals↗
PubMed1996

Comparative analysis of the kinetics and dynamics of K10, bicoid, and oskar mRNA localization in the Drosophila oocyte.

The localization of mRNAs to discrete cytoplasmic sites is important for the function of many, and perhaps all, cells. Many mRNAs are thought to be localized in a directed fashion along microtubule tracts. This appears to be the case for several mRNAs that are synthesized in Drosophila nurse cells and then transported into, and localized within, the oocyte. In this report, we compare the transport/localization kinetics and dynamics of three such mRNAs, K10, bicoid, and oskar. We generated flies carrying heat shock-K10, -bicoid, or -oskar fusion genes, which allowed us to carry out the molecular genetics equivalent of a pulse chase experiment. Our analyses indicate that K10, bicoid, and oskar mRNA transport and localization are a continuous process involving multiple movements of the same mRNA molecules. The transport and early localization dynamics of the three mRNAs are indistinguishable from each other and, in order, include accumulation in the apical regions of nurse cells, transport to the posterior pole of the oocyte, and movement to the oocyte's anterior cortex at stage 8. We also show that the rate of transport is the same in each case, approximately 1.1 microns/min. Only after stage 8 are RNA-specific movements seen. The similarities in the transport/ early localization kinetics and dynamics of K10, bicoid, and oskar mRNAs suggest that such events are mediated by a common set of factors. We also observe that all three mRNAs localize to the apical regions of somatic follicle cells when expressed in such cells, suggesting that the transport/early localization factors are widespread and involved in the localization of mRNAs in many tissues.

Animals↗
PubMed1995

gamma-Aminobutyric acid and somatostatin immunoreactivity in the visual cortex of normal and dark-reared rats.

Our previous single unit and ultrastructural studies of visual cortex of dark-reared rats revealed an impairment of intracortical inhibitory mechanisms [2,3,5]. Neurochemical changes in inhibitory neurotransmitter and/or neuropeptides, such as gamma-aminobutyric acid (GABA) and somatostatin (SS), respectively, may contribute to the observed alterations. The present study was designed to measure GABA and SS alterations in the visual cortex of the same dark-reared preparation, as possible neurochemical correlates of the changes seen both physiologically and anatomically in previous companion studies. In the present investigation the mean densities of GABA- and SS-immunoreactive neurons in area 17 of dark-reared rats were determined and compared to the density of those of rats reared in normal lighting conditions. Dark-rearing resulted in a significant decrease in the density of GABA-immunoreactive neurons in all cell layers of area 17 of the rat visual cortex; not limited to the thalamorecipient layer(s). There was also a higher mean density of total cortical cells in dark-reared animals. No differences, however, were seen in the density of SS-immunoreactive neurons. The alterations of GABA-immunoreactive neurons in all cortical layers agree with the altered synaptic ultrastructure and physiological responses seen in all cortical layers as reported in our previous companion studies. Taken together, these studies further support the notion of a deficit in intracortical inhibitory mechanisms in the visual cortex of dark-reared adult rats.

Animals↗
PubMed1995

Subjective reports on the effects of the MDMA ('ecstasy') experience in humans.

1. The objective of this paper was to provide an understanding of methylenedioxymethamphetamine (MDMA) use. This investigation provides the subjective effects that were reported by MDMA users. 2. There were a total of (500) humans who participated in this study. 3. Using a survey device, data from users were collected. Symptomatology associated with both the consumption of MDMA and its residual effects are documented. 4. Tables have been constructed to present prevalent psychological and physical side-effects associated with MDMA intake. 5. The results suggest that MDMA has significant implications with various psychological disorders and physical manifestations.

Adolescent↗
PubMed1995

The role of fs(1)K10 in the localization of the mRNA of the TGF alpha homolog gurken within the Drosophila oocyte.

A critical step in Drosophila dorsoventral patterning is the movement of gurken mRNA from the anterior cortex of the oocyte to the oocyte's anterodorsal corner at stage 8 of oogenesis. Such movement is dependent on fs(1)K10. It has been proposed that fs(1)K10 mediates gurken mRNA movement by down-regulating gurken mRNA levels, thus ensuring that gurken mRNA does not saturate its receptors located in the oocyte's anterodorsal corner. In contradiction to this model, we show here--both genetically and immunocytochemically--that GRK protein levels are lower in the anterodorsal region of fs(1)K10 mutant oocytes than in the anterodorsal region of fs(1)K10+ oocytes. From this and other data, we propose a more direct role for fs(1)K10 in the gurken mRNA localization process.

Animals↗
PubMed1995

A small predicted stem-loop structure mediates oocyte localization of Drosophila K10 mRNA.

The establishment of dorsoventral polarity in the Drosophila oocyte and future embryo is dependent on the efficient transport of K10 mRNA from nurse cells into the oocyte. To investigate the cis-requirements of K10 mRNA transport, we used a transgenic fly assay to analyze the expression patterns of a series of K10 deletion variants. Such studies identify a 44 nucleotide sequence within the K10 3' untranslated region that is required and sufficient for K10 mRNA transport and subsequent localization to the oocyte's anterior cortex. An inspection of the 44 nucleotide transport/localization sequence (TLS) reveals a strong potential for the formation of a stem-loop secondary structure. Nucleotide substitutions that interfere with the predicted base-pairing of the TLS block mRNA transport and anterior localization. Conversely, mutations that alter the base composition of the TLS while maintaining predicted base-pairing do not block mRNA transport or anterior localization. We conclude that K10 mRNA transport and anterior localization is mediated by a 44 nucleotide stem-loop structure. A similar putative stem-loop structure is found in the 3' untranslated region of the Drosophila orb mRNA, suggesting that the same factors mediate the transport and anterior localization of both K10 and orb mRNAs. Apart from orb, the K10 TLS is not found in any other localized mRNA, raising the possibility that the transport and localization of other mRNAs, e.g., bicoid, oskar and gurken, are mediated by novel sets of cis- and trans-acting factors. Moreover, we find that the K10 TLS overrides the activity of oskar cis-regulatory elements that mediate the late stage movement of the mRNA to the posterior pole. We propose the existence of a family of cis-regulatory elements that mediate mRNA transport into the oocyte, only some of which are compatible with the elements that mediate late stage movements.

Animals↗
PubMed1995

Gratuitous mRNA localization in the Drosophila oocyte.

Many of the genes that control pattern formation in Drosophila encode mRNAs that are localized to discrete regions of the oocyte during oogenesis. While such localization is generally assumed to be important for the pattern-forming activities of these genes, this has been rigorously demonstrated in only a few cases. Here we address the role of mRNA localization for the dorsoventral patterning gene K10. K10 mRNA is localized to the oocyte's anterior cortex following its transport into the cell during early stages of oogenesis. We show that mutations in cappuccino and spire, which permit K10 mRNA transport, but prevent subsequent anterior localization, do not disrupt the synthesis or localization of K10 protein. We also show that modified K10 transgenes that produce transcripts which are uniformly distributed throughout the oocyte, or which are mislocalized to the oocyte's posterior pole, produce localized and functional K10 protein. We conclude that the anterior localization of K10 mRNA is not important for K10 protein targeting or gene function. We propose that the anterior localization of K10, and probably other mRNAs, is a by-product of mRNA transport and does not necessarily reflect a requirement for localization per se.

Animals↗
PubMed1994

P element transformation vectors for studying Drosophila melanogaster oogenesis and early embryogenesis.

We have constructed six new P-element-based Drosophila melanogaster transformation vectors that specifically allow for the high-level accumulation of any RNA of interest in the developing egg and pre-blastoderm embryo. Such specificity results, in part, from the inclusion in the vectors of an enhancer active exclusively in nurse cells, the principal providers of RNA to the egg and early embryo. The nurse cell enhancer was derived from the hsp26 heat-shock (HS) gene, but its activity was neither dependent on nor sensitive to HS. In addition to the nurse cell enhancer, two of the vectors contain sequences from the K10 gene that promote the early transfer of RNAs from nurse cells into the oocyte; RNAs that contain the K10 sequence are transferred into the oocyte during the early to middle stages of oogenesis (i.e., during stages 2-9), while RNAs that lack such sequences are stored in nurse cells until stage 11. All of the vectors contain a tsp and a multiple cloning site (MCS) immediately downstream from the hsp26 nurse cell enhancer. In three of the vectors, the MCS is preceded by an ATG start codon. A wild-type copy of the white gene is included in all of the vectors as a selectable marker for transformation. The specificity of the vectors was demonstrated by the analysis of the expression patterns of lacZ derivatives.

Amino Acid Sequence↗
PubMed1994

Fecal Clostridium difficile carriage among medical housestaff.

Housestaff, physician assistants, and hospitalized patients at a teaching hospital were tested for fecal carriage of Clostridium difficile. The test results showed that fecal carriage of C. difficile may not be important in the epidemiology of hospital-acquired diarrhea.

Carrier State↗
PubMed1993

Aneurysmal bone cyst of the upper maxilla.

Aneurysmal bone cyst is a nosologic entity of low frequency that appears with greater incidence in large bones. Its presence in the upper maxilla is very rare, even more so in a thirteen year old boy. The author presents the case of an aneurysmal bone cyst of the upper maxilla, together with its investigations and the surgical treatment practiced in 1987. A comment is added on the surgical technique he might adapt nowadays for approaching this type of tumors.

Adolescent↗
PubMed1992

Trisomy 22 with congenital diaphragmatic hernia and absence of corpus callosum in a liveborn premature infant.

We report on a liveborn premature male with trisomy 22 who had multiple congenital anomalies, including congenital diaphragmatic hernia and absence of corpus callosum. He died of pulmonary hypoplasia associated with diaphragmatic hernia within 12 hours of age. Chromosome analysis by multiple banding techniques based on lymphocyte culture confirmed that he had trisomy 22. This may be the first report of congenital diaphragmatic hernia and isolated absence of corpus callosum associated with trisomy 22.

Abnormalities, Multiple↗
PubMed1992

The effects of dark-rearing on the electrophysiology of the rat visual cortex.

Our previous two studies have shown that dark-rearing affects the morphology and chemistry of adult rat primary visual cortex (area 17). In this study we demonstrate correlated physiological alterations with single unit recordings in the same preparation. Rats were raised from birth in either 14 h light/10 h dark (Lt/Dk) or in total darkness (Dk). At the age of 3 months, single units were recorded in area 17 of both groups. The cortical cells of Dk animals showed significantly more spontaneous activity during ambient lighting. The mean rate of randomly appearing spontaneous activity was greatly increased in Dk animals. Moreover, many cells in Dk animals also exhibited a particular type of spontaneous activity which occurred as 'bursts' of spikes, i.e. quantified groupings of fast firing spikes, separated by randomly appearing spontaneous activity. The mean number of bursts per min seen in Dk animals was also significantly more than any such activity seen in Lt/Dk animals. Visual stimuli consisted of white or dark bars moving with different orientations and directions at slow and fast speeds, and full field flashes. In response to moving stimuli, notably fewer cells were orientation- or direction tuned in dark-reared animals, and when they did respond to moving bar stimuli, the responses were of relatively longer duration. The pathologically high spontaneous activity rate, as well as lack of tuning and relatively prolonged duration of responses to moving stimuli indicate that intracortical inhibitory mechanisms are seriously compromised in both the unstimulated and stimulated states and is in agreement with our previous findings (Bakkum, B.W., Port, J.D., Cohen, R.S. and Benevento, L.A., Soc. Neursci. Abst., 15 (1989) 797) of a decreased number of synapses and GABA-containing cells in the visual cortex of the same preparation. Other evidence suggests that there may be a decrease in stimulus-bound excitatory drive. Significantly fewer cells in Dk animals were excited by all visual stimuli, and responses elicited by flashes had relatively longer 'on' latencies, relatively shorter durations, and were generally weaker. This may correlate with our finding of a significantly smaller number of perforated postsynaptic densities in the cortex of the same preparation (Bakkum, B.W., Benevento, L.A. and Cohen, R.S., J. Neurosci. Res., 23 (1991) 65-80).

Action Potentials↗