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Biomedical subjects

D Rosenberg

Publications and source records attributed to D Rosenberg.

At least 19 recordsLinked to original sources
PubMed2003

Memory effects in amorphous solids below 20 mK.

At temperatures below 1 K, the capacitance of a glass sample changes due to the application of a dc field in accordance with Burin's dipole gap theory [J. Low Temp. Phys. 100, 309 (1995)]]. However, we now report that below 20 mK, during the first sweep cycle of the dc electric field, the capacitance is smaller by about 10(-5) compared to any subsequent sweep. Despite this overall shift, the field dependence follows the dipole gap predictions. In a subsequent sweep to higher dc fields the dielectric constant drops by about 10(-5) as soon as the applied field is higher than any field previously applied. A picture involving the dynamics of resonant pairs provides a qualitative description of this behavior.

Journal Article↗
PubMed2003

Dynamics of the destruction and rebuilding of a dipole gap in glasses.

After a strong electric bias field is applied to the polyester glass Mylar at temperatures in the mK range, its dielectric constant increases and then decays logarithmically in time. We observed its dielectric response for several temperatures and different field sweeps. Starting from the dipole gap theory, we developed a model suggesting that the change in dielectric constant after transient application of a bias field is only partly due to relaxational processes. In particular, nonadiabatic driving of tunneling states (TSs) by applied electric fields causes additional dielectric response. Also, we find that for T less, similar 50 mK the relaxation of TSs is caused primarily by mutual interactions.

Journal Article↗
PubMed2002

Role of the PKA-regulated transcription factor CREB in development and tumorigenesis of endocrine tissues.

The cAMP pathway plays a major role in the development of endocrine tissues and various molecular defects of key components of this pathway (G protein, receptors, PKA, etc.) have been observed in endocrine tumors. The ubiquitous transcription factor CREB (cAMP-response element binding protein) binds to the cAMP response element (CRE) and stimulates transcription after phosphorylation on Ser(133) by PKA. The CREB family of transcription factors contains three members: CREB, CREM, and ATF-1. Targeted expression of dominant-negative mutants of CREB in transgenic mice leads to somatotrophs or thyroid hypoplasia. GH-secreting adenomas are benign secreting tumors expressing an activated mutant G alpha s protein (Gsp) in about 40% of cases. In GH-secreting adenomas CREB is always expressed and often highly phosphorylated. The CREM isoform ICER is stimulated by cAMP, and its expression is increased in Gsp-harboring tumors. After transfection in pituitary somatotroph cells, activating mutations of Gs protein (Gsp) and overexpression of wild-type G alpha S stimulate transcription of various CRE-containing promoters via CREB in a Ser(133)-specific-dependent manner. Activation of the cAMP pathway by ACTH is required for adrenal cortex (AdCx) maintenance and steroidogenesis. CREB is expressed in normal AdCx. Alterations of CRE binding proteins with loss of CREB expression and compensatory overexpression of CREMtau is observed in the human adrenocortical cancer cell line H295R. Similar alterations are found at the protein level in human malignant adrenocortical tumors. In conclusion, the CREB family of transcription factors plays an important role in the development, differentiation, and proliferation of endocrine tissues. Various alterations of the CREB family of transcription factors can be observed in endocrine tumors.

Amino Acid Sequence↗
PubMed2001

Effect of liquid bolus consistency and delivery method on aspiration and pharyngeal retention in dysphagia patients.

There is no empirically derived consensus as to what food consistency types and method of food delivery (spoon, cup, straw) should be included in the videofluoroscopic swallowing (VFSS) studies. In the present study, we examine the rates of aspiration and pharyngeal retention in 190 dysphagic patients given thin (apple juice) and thick (apricot nectar) liquids delivered by teaspoon and cup and ultrathick (pudding-like) liquid delivered by teaspoon. Each patient was tested with each of the bolus/delivery method combinations. The fractions of patients exhibiting aspiration for each bolus/method of delivery combination were (1) thick liquids (cup), 13.2%; (2) thick liquids (spoon), 8.9%; (3) thin liquids (cup), 23.7%; (4) thin liquids (spoon), 15.8%, (5) ultrathick liquids (spoon), 5.8%. In each comparison [thick liquid (cup) vs. thick liquid (spoon), thin liquid (cup) vs. thin liquid (spoon), thick liquid (cup) vs. thin liquid (cup), thick liquid (spoon) vs. thin liquid (spoon), and thick liquid (spoon) vs. ultrathick liquid (spoon)], the p value for chi 2 was < 0.001. These results suggest that utilizing thin, thick, and ultrathick liquids and delivery by cup and spoon during a VFSS of a patient with mild or moderate dysphagia can increase the chances of identifying a consistency that the patient can swallow without aspirating and without pharyngeal retention after swallowing.

Administration, Oral↗
PubMed2001

[Pigmented villonodular synovitis. Diffuse and localized forms in children].

UNLABELLED: Pigmented villonodular synovitis (PVS) is characterized by a locally aggressive synovial proliferation that engenders progressive destruction of cartilage and bone. Two cases, a diffuse and a localized form, are reported. CASE REPORT: 1) A 9.9-year-old boy followed up for a popliteal cyst presented with chronic arthritis of the left knee. Aspiration yielded a bloody synovial fluid. MRI showed a heterogeneous synovial process with decreased signal in both T1- and T2-weighted images. The diagnosis of PVS was made on histology of an excisional biopsy. A complete open synovectomy was then performed. 2) A 13.8-year-old boy had a palpable mass on the internal side of the right patellofemoral joint. MRI showed a heterogenous mass with areas of hypointensity on all spin echo sequences corresponding to hemosiderin deposits suggestive of PVS. Surgical excision of a reddish-brown circumscribed lesion was performed. Diagnosis of PVS was made at surgery and confirmed by histologic examination. CONCLUSION: PVS diagnosis is frequently delayed due to nonspecific symptoms. Bloody fluid aspiration and MRI are valuable tools for early diagnosis. Treatment is surgical: extensive synovectomy for the diffuse form, excision of the lesion for the localized form.

Adolescent↗
PubMed2001

Short-term efficiency and safety of gene delivery into canine kidneys.

BACKGROUND: Gene delivery of biologically active molecules to the kidney may have potential therapeutic applications in renal and cardiovascular diseases. Recombinant adenovirus is one of the most efficient vectors for in vivo gene delivery. However, in vivo toxicity at the site of administration has to be evaluated for the successful use of adenovirus-mediated gene transfer. The aim of this study was to document precisely the short-term safety of different routes of intra-renal adenoviral administration and to compare their transduction efficiency. METHODS: Dog puppies were injected with an adenoviral vector expressing the beta-galactosidase reporter gene in both kidneys via three different routes, i.e. intra-renal-ureteral route (IU) and intra-renal-arterial route with (IAC) or without (IA) clamping of the renal vein. Toxicity of viral administration was assayed on day 4 at both physiological and histological levels. Renal samples were monitored for the presence of nuclear beta-galactosidase-expressing cells. RESULTS: All renal physiological parameters (glomerular filtration rate, effective renal plasma flow, and electrolyte excretion fractions) remained stable whatever the route of viral administration. No histological lesion was detected in any of the haematoxylin-eosin-stained kidney sections, and there was no evidence of ischaemia-reperfusion injury in the kidneys subjected to venous clamping. Efficient transgene expression was obtained in dog kidneys following IAC and IU injection of adenoviral vectors. Gene transfer via the IAC route induced gene expression predominantly in the cortical interstitial cells. Retrograde IU adenoviral injection resulted in reduced transduction efficiency compared with the IAC route, with transgene expression occurring mainly in the distal tubular and pyelic epithelial cells. CONCLUSIONS: The two major findings of this study were (i) the absence of acute histological and functional renal alteration following intra-arterial and intra-ureteral injections of adenoviral vectors in both kidneys of healthy dogs, and (ii) the efficiency of transgene expression with specific cellular targeting according to the route of administration.

Adenoviridae↗
PubMed2001

Nocturnal enuresis in pediatric sickle cell disease.

To assess the prevalence of nocturnal enuresis in children and adolescents with sickle cell disease (SCD) and associated factors, structured telephone interviews were conducted with primary caregivers of 217 children and adolescents with SCD aged 5 years or older. Prevalence, perceived causes, interventions undertaken, and emotional impact were assessed. Nocturnal enuresis was significantly higher for males (28.2% of males) than for females (11% of females), p = .002, and compared with cited population prevalence rates, nocturnal enuresis was significantly higher for children with SCD, p < .01. SCD was the most common reason given by primary caregivers for enuresis. Primary caregivers used a wide range of interventions for nocturnal enuresis, but few used empirically supported treatments for enuresis or spoke with their health care team about the enuresis. These data suggest that systematic assessment and intervention for nocturnal enuresis must be implemented in the follow-up care of children and adolescents with SCD.

Adolescent↗