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Biomedical subjects

S Margulies

Publications and source records attributed to S Margulies.

13 recordsLinked to original sources
PubMed2000

The postconcussion syndrome after mild head trauma: is brain damage overdiagnosed? Part 1.

UNLABELLED: Many investigators attribute the postconcussion syndrome following mild closed head injury to permanent brain damage. The evidence supporting this conclusion is reviewed, including the force necessary to cause permanent brain damage; the basis for determining whether the patient was exposed to sufficient force in the accident to permanently damage the brain; the basis for determining whether the patient actually has permanent brain damage (not just brain dysfunction) traceable to the accident; and whether the location and severity of brain damage is sufficient to account for the postconcussion syndrome. CONCLUSION: the evidence for permanent traumatic brain damage as the cause of the postconcussion syndrome following mild closed head injury is weak.

Brain Damage, Chronic↗
PubMed1999

Lamellarity of cationic liposomes and mode of preparation of lipoplexes affect transfection efficiency.

Transfection of NIH-3T3 cells by a human growth hormone expression vector complexed with liposomes composed of N-(1-(2, 3-dioleoyloxy)propyl)-N,N,N-trimethylammonium chloride (DOTAP) with or without helper lipids was studied. The transfection efficiency was dependent on the lamellarity of the liposomes used to prepare the lipoplexes. Multilamellar vesicles (MLV) were more effective than large unilamellar vesicles (LUV) of approximately 100 nm, irrespective of lipid composition. The optimal DNA/DOTAP mole ratio for transfection was </=0.5, at which only 10-30% of DOTAP in the lipoplex is neutralized. Prolonged incubation time of lipoplexes before addition to cells slightly decreased the level of transfection. A major influence on the lipofection level was found when the mode of lipoplex preparation was varied. Mixing plasmid DNA and DOTAP/DOPE (1:1) LUV in two steps instead of one step resulted in a higher lipofection when at the first step the DNA/DOTAP mole ratio was 0.5 than when it was 2.0. Only static light-scattering measurement, which is related to particle size and particle size instability, revealed differences between the lipoplexes as a function of lamellarity of the vesicles (MLV or LUV), mixing order, and number of mixing steps. Other physical properties of these lipoplexes were dependent only on the DNA/DOTAP mole ratio, i.e. the extent of DOTAP neutralization (as monitored by ionization of the fluorophore 4-heptadecyl-7-hydroxycoumarin) and the extent of defects in lipid organization (as monitored by level of exposure of the fluorophore 1-(4-trimethylammoniumphenyl)-6-phenyl-1,3, 5-hexatriene to water). The secondary and tertiary structure of DNA in lipoplexes was evaluated by circular dichroism spectroscopy. The results of this study point out that the structure of lipoplexes should be physicochemically characterized at two different levels: the macro level, which relates to size and size instability, and the micro level, which relates to the properties described above which are involved in the intimate interaction between the plasmid DNA and the lipids. At the micro level, all parameters are reversible, history-independent and are determined by DNA/DOTAP mole ratio. On the other hand, the macro level (which is the most important for transfection efficiency) is history-dependent and not reversible.

3T3 Cells↗
PubMed1999

Rectus sheath hematoma.

We describe 3 patients with rectus sheath hematoma presenting to the emergency department. Prompt consideration of this uncommon cause of abdominal pain may prevent more expensive and invasive diagnostic tests and, in some cases, unnecessary hospitalization and laparotomy.

Abdomen, Acute↗
PubMed1995

Crush injuries to the head in children.

Although the majority of head injuries in children and adults involve dynamic loading conditions, some patients suffer static loading. Static loading occurs when forces are applied slowly to the head, and it produces a much different pattern of injuries. Crush injuries are usually described in the context of industrial accidents, but in our experience, these injuries are not rare in children. We report a series of seven crush injuries in young children admitted during a period of 29 months and describe our experience in the evaluation and treatment of this complex entity. Patient ages ranged from 15 months to 6 years. In four cases, the child's head was run over by a motor vehicle backing up in a driveway or parking lot. In the three other patients, the static loading occurred when the child climbed or pulled on a heavy object, which then fell over with the child and landed on the child's head. One child with cervicomedullary disruption died shortly after his arrival at the hospital. The others showed varying degrees of soft tissue injury to the face and scalp, with Glasgow Coma Scale scores ranging from 7 to 15. Computed tomograms and magnetic resonance images showed multiple and often extensive comminuted calvarial fractures, as well as subarachnoid and parenchymal hemorrhages. All patients had basilar cranial fractures. There was one cervical spine injury but no major vascular injuries. One child had pituitary transection, four had cranial nerve palsies, and another developed a delayed cerebrospinal fluid rhinorrhea 18 months after injury. All children made good cognitive recoveries, with some having relatively mild fixed focal deficits.(ABSTRACT TRUNCATED AT 250 WORDS)

Biomechanical Phenomena↗
PubMed1994

Emotional disclosure through writing or speaking modulates latent Epstein-Barr virus antibody titers.

Healthy Epstein-Barr virus (EBV) seropositive undergraduates (N = 57) completed a personality inventory, provided blood samples, and were randomly assigned to write or talk about stressful events, or to write about trivial events, during three weekly 20-min sessions, after which they provided a final blood sample. Individuals assigned to the verbal/stressful condition had significantly lower EBV antibody titers (suggesting better cellular immune control over the latent virus) after the intervention than those in the written/stressful group, who had significantly lower values than those in the written/trivial control group. Subjects assigned to the written/stressful condition expressed more negative emotional words than the verbal/stressful and control groups and more positive emotional words than the verbal/stressful group at each time point. The verbal/stressful group expressed more negative emotional words compared with the control group at baseline. Content analysis indicated that the verbal/stressful group achieved the greatest improvements in cognitive change, self-esteem, and adaptive coping strategies.

Adaptation, Psychological↗