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Biomedical subjects

D Rosen

Publications and source records attributed to D Rosen.

At least 19 recordsLinked to original sources
PubMed1999

DOAS measurements of tropospheric bromine oxide in mid-latitudes

Episodes of elevated bromine oxide (BrO) concentration are known to occur at high latitudes in the Arctic boundary layer and to lead to catalytic destruction of ozone at those latitudes; these events have not been observed at lower latitudes. With the use of differential optical absorption spectroscopy (DOAS), locally high BrO concentrations were observed at mid-latitudes at the Dead Sea, Israel, during spring 1997. Mixing ratios peaked daily at around 80 parts per trillion around noon and were correlated with low boundary-layer ozone mixing ratios.

Journal Article↗
PubMed1999

Clinical and radiographic features of eosinophilic granuloma in the jaws: review of 41 lesions treated by surgery and low-dose radiotherapy.

Eosinophilic granuloma within the jaws may radiographically mimic other benign odontogenic cysts and tumors, and different protocols have been suggested in the literature for treating eosinophilic granuloma of the jaws. Forty-one lesions of eosinophilic granuloma, diagnosed in 25 patients, were reviewed retrospectively, and data were collected regarding age, gender, ethnic origin, location, symptoms, clinical appearance, radiographic features, treatment, and recurrence. The lesions were found in youngsters (18.1 +/- 4.7 years of age), mostly in the posterior parts of the mandible, and the most common presenting symptom was pain (92%), often accompanied by swelling. Approximately one half of the lesions were radiographically well defined without ossification. All patients were treated by enucleation (with or without peripheral ostectomy) and radiotherapy; 7.3% lesions recurred during follow-up (9.3 +/- 4.6 years). In addition, the different treatments suggested in the literature for eosinophilic granuloma of the jaws were reviewed.

Adolescent↗
PubMed1998

The regulation of CD95 ligand expression and function in CTL.

Previous studies with CTL lines and CTL hybridomas have suggested that functional CD95 (APO-1/Fas)-ligand (CD95L) expression on effector CTLs is a consequence of specific CTL-target recognition and TCR triggering of newly transcribed CD95L. Such a control on the expression of CD95L could provide a double safeguard for killing only cognate target cells. Here the regulation of CD95L expression and function was tested in in vivo primed, alloreactive peritoneal exudate CTL (PEL) from perforin-deficient (P0) mice. CD95L-based, PEL-mediated cytotoxicity was blocked by brefeldin A, an inhibitor of intracellular protein transport, but not by the protein synthesis inhibitor emetine, the immunosuppressive drug cyclosporin A, or the DNA transcription inhibitor actinomycin D. CD95L mRNA transcripts in freshly isolated PEL were shown by RT-PCR; CD95L surface expression was evident by staining with Fas-Fc as well as CD95L Abs. Undiminished CD95L expression and cytocidal activity were found in PEL incubated for 48 h in culture, without adding Ag, mitogen, or cytokines. PEL expressed functional CD95L, yet exhibited target cell-specific killing, except when encountering high CD95-expressing cells. The results indicate that PEL use CD95L probably expressed in the Golgi and/or on the cell surface and do not require newly transcribed CD95L upon target cell conjugation. Hence the TCR-triggered recruitment of preformed CD95L, rather than its biosynthesis, controls CD95L-based specific lysis induced by CTL.

Animals↗
PubMed1998

Distribution of parthenogenesis-inducing symbionts in ovaries and eggs of Aphytis (Hymentoptera: Aphelinidae).

In parasitic Hymenoptera, severe sex ratio distortions are sometimes associated with the presence of symbiotic microorganisms. Symbiont-induced uniparental reproduction is found in several species of the genus Aphytis and is suspected in others. These intracellular bacteria (called Wolbachia) reside within the egg cytoplasm. In order to follow their vertical transmission, the distribution pattern of the symbionts in ovaries and eggs of two uniparental lines (A. lingnanensis and A. yanonensis) was studied by electron, confocal, and two-photon microscopy. The results obtained suggest that Wolbachia move from nurse cells to developing oocytes. In freshly laid eggs, the symbionts are concentrated in the posterior pole, away from the micropyle, and in later stages of embryogenesis they are found surrounding nuclei throughout the embryo.

Animals↗
PubMed1998

Life-threatening complications and irreversible damage following maxillofacial trauma.

Trauma remains one of the principal causes of mortality in the western world, especially among young adults. The most serious immediate life-threatening complication following maxillofacial trauma is airway obstruction. The onset can be sudden, as with foreign body aspiration, or following soft-tissue damage that can lead at a later stage to airway-compromising oedema. The medical literature regarding facial trauma appears to support the hypothesis that maxillofacial trauma alone is rarely life threatening, or will not lead to life-threatening conditions unless associated with airway compromise. There are some causes of life-threatening complications following trauma to the maxillofacial region such as massive bleeding or undiagnosed cervical spine injury. However, there are some situations that may cause irreversible damage unless immediate operation is undertaken. The almost complete lack of reports dealing with death or irreversible damage in trauma involving the maxillofacial region prompted us to review and analyse the importance of immediate intervention following trauma to the maxillofacial region, in order to treat life-threatening complications and prevent irreversible damage.

Adolescent↗
PubMed1998

Differential sensory-motor effects of pentobarbital in intact rats genetically selected for high vs. low neuropathic pain-related behaviour.

Denervation of the hindpaw in rodents triggers autotomy, a behaviour of licking, scratching and self-mutilation of the denervated paw. This behaviour has been used as a model of paraesthesia, dysaesthesia and neuropathic pain. HA and LA rats are lines that have been genetically selected for high or low levels of autotomy, respectively. Compared to intact LA rats, HA rats are more sensitive to convulsions induced by pentylenetetrazol (PTZ), a blocker of the chloride channel associated with the GABA(A) receptor. Here we tested whether an acute administration of a sedative but not anaesthetic dose of pentobarbital (PB) would differentiate between these rat lines, in a number of sensory and motor tests performed in intact rats. This drug was tested since in contrast to PTZ, PB enhances central nervous system (CNS) inhibition by increasing chloride flux through the same channel. We found that PB was significantly more ataxic, antinociceptive, and reduced touch sensitivity in LA rats, compared to HA rats. These results suggest that HA and LA rats genetically differ in the levels of central inhibitions mediated by the GABA system presumably at the chloride channel. This difference may be associated with the dichotomous expression of neuropathic pain in these rat lines.

Animals↗
PubMed1998

Phylogenetic analysis of parthenogenesis-inducing Wolbachia in the genus Aphytis (Hymenoptera: Aphelinidae).

Parthenogenesis-inducing intracellular bacteria of the genus Wolbachia are found in a variety of parasitoid wasp genera. The presence of Wolbachia in the uniparental Aphytis species A. lingnanensis Compere, A. diaspidis (Howard), A. chilensis Howard, and A. chrysomphali (Mercet) was tested using primers specific for the ftsZ gene. The symbiont was detected in all of these species. Wolbachia ftsZ genes that were sequenced from the four hosts show a high degree of similarity. Both the PCR with specific primers for group 'A' and phylogenetic analysis place these Wolbachia in group 'A'. The fact that the tested Aphytis species belong to different phylogenetic groups and harbour what seem to be almost identical Wolbachia, lends credence to the horizontal transmission hypothesis.

Animals↗
PubMed1998

Parvovirus B19-induced anemia as the presenting manifestation of X-linked hyper-IgM syndrome.

Parvovirus B19 (B19) can cause chronic anemia due to persistent infection in immunocompromised hosts who cannot produce neutralizing antibody necessary for clearing B19. Three patients with X-linked hyper-IgM syndrome (XHIM), who were all asymptomatic until they developed B19-induced chronic anemia at the ages of 8, 14, and 17 years, respectively, were found to have mutations of the CD40L gene, including a missense mutation (T254M), a nonsense mutation resulting in a new initiation codon and loss of the intracellular domain (R11X), and a splice site mutation (nt 309+2t-->a). Antibody responses to the T cell-dependent antigen, bacteriophage phiX174, were impaired, but neutralizing antibody titers were higher than in XHIM patients with classic phenotype. All 3 patients responded to intravenous immune globulin (IVIG) treatment. Certain mutations of the CD40L gene result in a mild XHIM phenotype that may become apparent following B19 infection in patients not on IVIG therapy and therefore not protected from B19 infection.

Adolescent↗
PubMed1997

[Distraction osteogenesis for hypoplastic facial bones].

Distraction osteogenesis is a well-known method for bone lengthening which stretches callus to generate new bone in the distracted area. The method was developed by Ilizarov for the lengthening of long enchondral bones. In recent years the method has also been applied to the facial bones and to the jaw.

Adolescent↗
PubMed1997

Structure and expression of the human FHIT gene in normal and tumor cells.

The FHIT gene, encoded by 10 exons in a 1.1-kb transcript, encompasses approximately 1 Mb of genomic DNA, which includes the hereditary RCC t(3;8) translocation break at 3p14.2, the FRA3B common fragile region, and homozygous deletions in various cancer-derived cell lines. Because some of these genetic landmarks (e.g., the t(3;8) break between untranslated FHIT exons 3 and 4, a major fragile region that includes a viral integration site between exons 4 and 5, and cancer cell homozygous deletions in intron 5) do not necessarily affect coding exons and yet apparently affect expression of the gene product, we examined the FHIT locus and its expression in detail in more than 10 tumor-derived cell lines to clarify mechanisms underlying aberrant expression. We observed some cell lines with apparently continuous large homozygous deletions, which included one or more coding exons; cell lines with discontinuous deletions, some of which included or excluded coding exons; and cell lines that exhibited heterozygous and/or homozygous deletions, by Southern blot analysis for the presence of specific exons. Most of the cell lines that exhibited genomic alterations showed alteration of FHIT transcripts and absence or diminution of Fhit protein.

Acid Anhydride Hydrolases↗
PubMed1997

Expression of the RET/PTC fusion gene as a marker for papillary carcinoma in Hashimoto's thyroiditis.

Hashimoto's thyroiditis is an inflammatory disease of the thyroid gland with autoimmune etiology. Patients afflicted with Hashimoto's have a higher risk of thyroid malignancies such as papillary thyroid carcinoma. In the present study, we investigated the frequency of papillary thyroid carcinoma specific genes in patients diagnosed with Hashimoto's disease. The newly identified oncogenes RET/PTC1 and RET/PTC3 provide useful and specific markers of the early stages of papillary carcinoma as they are highly specific for malignant cells. Using a sensitive and specific reverse transcriptase-polymerase chain reaction (RT-PCR) assay, we found messenger RNA (mRNA) expression for the RET/PTC1 and RET/PTC3 oncogenes in 95% of the Hashimoto's patients studied. All Hashimoto's patients presenting without histopathologic evidence of papillary thyroid cancer showed molecular genetic evidence of cancer. These data suggest that multiple, independent occult tumors exist in these patients at high frequency.

Adult↗
PubMed1997

Identifying areas with vitamin A deficiency: the validity of a semiquantitative food frequency method.

OBJECTIVES: The prevalence of vitamin A deficiency has traditionally been assessed through xerophthalmia or biochemical surveys. The cost and complexity of implementing these methods limits the ability of nonresearch organizations to identify vitamin A deficiency. This study examined the validity of a simple, inexpensive food frequency method to identify areas with a high prevalence of vitamin A deficiency. METHODS: The validity of the method was tested in 15 communities, 5 each from the Philippines, Guatemala, and Tanzania. Serum retinol concentrations of less than 20 micrograms/dL defined vitamin A deficiency. RESULTS: Weighted measures of vitamin A intake six or fewer times per week and unweighted measures of consumption of animal sources of vitamin A four or fewer times per week correctly classified seven of eight communities as having a high prevalence of vitamin A deficiency (i.e., 15% or more preschool-aged children in the community had the deficiency) (sensitivity = 87.5%) and four of seven communities as having a low prevalence (specificity = 57.1%). CONCLUSIONS: This method correctly classified the vitamin A deficiency status of 73.3% of the communities but demonstrated a high false-positive rate (42.9%).

Child, Preschool↗
PubMed1996

Streptokinase for acute ischemic stroke with relationship to time of administration: Australian Streptokinase (ASK) Trial Study Group.

OBJECTIVES: To determine whether the administration of 1.5 million units of streptokinase intravenously within 4 hours of the onset of acute ischemic stroke would reduce morbidity and mortality at 3 months and whether outcomes may be better for those receiving therapy within 3 hours of stroke onset compared with those receiving it after 3 hours. DESIGN: Randomized, double-blind, placebo-controlled trial with 3-month follow-up. PARTICIPANTS: A total of 340 patients, aged 18 to 85 years, with moderate to severe strokes were randomized from 40 centers throughout Australia from June 1992 to November 1994. INTERVENTION: Administration of 1.5 million units of streptokinase or placebo intravenously in 100 mL of normal saline over 1 hour. MAIN OUTCOME MEASURE: Combined death and disability score (Barthel index <60) 3 months after the stroke. RESULTS: Using an intention-to-treat analysis with a combined death and disability score at 3 months after stroke as the primary end point, we found a nonsignificant overall trend toward unfavorable outcomes for streptokinase vs placebo (relative risk [RR] of unfavorable outcome, 1.08; 95% confidence interval [CI], 0.74-1.58) and an excess of hematomas (13.2%[12.6% symptomatic] in the treated group, 3% [2.4% symptomatic] for placebo [P<.01]). However, poor outcomes were confined to patients receiving therapy more than 3 hours after stroke onset (RR of unfavorable outcome, 1.22; 95% CI, 0.80-1.86). In contrast, among the 70 patients who were entered into the trial within 3 hours of stroke onset, there was a trend toward improved outcomes for those who received streptokinase (RR of unfavorable outcome, 0.66; 95% CI, 0.28-1.58), and this outcome pattern was significantly better than for those receiving therapy after 3 hours (P=.04). Streptokinase administration resulted in excess deaths in the group treated after 3 hours (RR, 1.98; 95% CI, 1.18-3.35), but not among those treated within 3 hours (RR, 1.11; 95% CI, 0.38-3.21). CONCLUSION: The administration of streptokinase within 4 hours of acute ischemic stroke increased morbidity and mortality at 3 months. While treatment within 3 hours of stroke was safer and associated with significantly better outcomes than later treatment, it showed no significant benefit over placebo. The timing of thrombolytic therapy for acute stroke is critical.

Acute Disease↗
PubMed1996

The effect of thigh-length support stockings on the hemodynamic response to ambulation in pregnancy.

OBJECTIVE: Our purpose was to determine the effect of thigh-length support stockings on hemodynamic response when pregnant subjects change from the sitting to the lateral recumbent position and then after standing with ambulation. STUDY DESIGN: Eighteen subjects in the late second and early third trimester of pregnancy acted as their own controls. The cardiovascular status of the subjects was assessed by a noninvasive technique--thoracic electrical bioimpedance before and after wearing support stockings for 1 week. Urine catecholamines were measured in 13 patients before and after wearing support stocking to assess the release of catecholamines. Samples were collected after the subjects had been in the lateral recumbent position 40 minutes and again 40 minutes later after standing with ambulation. RESULTS: Heart rate and mean arterial blood pressure decreased significantly when subjects changed from the sitting to the lateral recumbent position and then increased with ambulation. Wearing compression stockings significantly increased mean arterial pressure and afterload in all three positions. Position change from lateral recumbent to standing and ambulation marginally increased urinary dopamine levels (p = 0.097) and significantly increased norepinephrine levels (p = 0.006). CONCLUSIONS: There are significant hemodynamic changes in pregnant subjects when they change from the sitting position to the lateral recumbent position and then change to standing with ambulation. Support stocking have a significant mechanical effect: they significantly increase afterload and systemic vascular resistance by preventing pooling of blood in the lower extremities. There may also be a biochemical effect that results in less catecholamine release. These results suggest that compression stockings could play an important role in supporting the circulation during ambulation.

Adult↗
PubMed1996

Endoscopic sinus surgery in the developmentally delayed child.

Functional endoscopic sinus surgery (FESS) has gained widespread support as the treatment of choice for chronic sinusitis in children. Seven developmentally delayed children were evaluated for chronic sinusitis with symptoms of cough, chronic rhinorrhea, and head banging because of pain. All seven were nonresponsive to repeated courses of oral and sometimes intravenous antibiotics; computed tomography scans on all revealed sinus disease. FESS was performed on all of them. Three children had marked respiratory difficulty at the end of the procedure, with two requiring reintubation. Two children were not able to take oral feedings postoperatively. Because of the complicated postoperative course, a second-look procedure was performed in only two children. We believe that FESS for developmentally delayed children should be tailored accordingly and that a second-look procedure should not be a routine.

Adolescent↗
PubMed1996

Keloid excision and recurrence prophylaxis via intradermal interferon-gamma injections: a pilot study.

Keloids are an abnormal response to wound healing distinguished by an overproduction of collagen. Thickened bundles of collagen in the reticular dermis oriented haphazardly in relation to the overlying epithelium are found in keloids, in contrast to thinner collagen fibers in a more orderly arrangement that are found in normal scars. Previous clinical trials of intralesional interferon-gamma (IFN-G) injections by Larrabee et al. and Granstein et al. showed a decrease in lesion size. These findings led to a conclusion that IFN-G would be a useful adjunct to surgical excision of keloids to aid in preventing recurrence. We performed a double-blind, placebo-controlled trial in patients with two or more keloids treated with excision and subsequent local injections of IFN-G or placebo.

Adolescent↗
PubMed1995

Lytic reaction of in vivo primed peritoneal exudate CTL. Induction of high-conductance single channels in the target cell membrane.

CTL, primary effectors in immune responses, deliver a "lethal hit" signal to target cells, causing their destruction. The precise membrane events associated with the lethal hit remain elusive. We investigated the signal(s) mediating destruction of tumor target cells (EL4) by perforin-deficient peritoneal exudate CTL (PEL). We utilized patch clamp techniques to record electrophysiological events associated with the cytolytic interaction of PEL and EL4 in isolated conjugates. PEL-EL4 interaction resulted in induction in EL4 cells, of single channels (followed by EL4 destruction), with a mean conductance of 437 pS and a reversal potential of -1.0 mV, suggestive of nonselective pathways. Similar channels were induced in EL4 cells conjugated with perforin-rich PEL blasts (PEB), by perforin, postnuclear extract from PEL (pnPEL) and from other cytotoxic lymphocytes, but not from noncytolytic lymphocytes. As similar channels were induced by pnPEL in EL4 membrane patches, we propose that these channels result from a direct effect of PEL-derived channel-forming substance(s) on the target cell's membrane. Importantly, postnuclear extracts from perforin-devoid cytotoxic PEL-hybridomas induced similar channels, suggesting the presence of a nonperforin, channel-forming activity in PEL and PEL-hybridomas. Based on the present study, we conclude that the delivery of the lethal hit by cytolytic PEL and PEL-hybridoma is associated with induction in the target cell of high-conductance channels, which most likely mediate its destruction. We propose that these channels are related to the Fas pathway of lymphocytotoxicity.

Animals↗