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R S Shapiro

Publications and source records attributed to R S Shapiro.

At least 19 recordsLinked to original sources
PubMed2000

Microbialite morphostratigraphy as a tool for correlating Late Cambrian-Early Ordovician sequences.

Microbialite morphostratigraphy is a new tool for intrabasinal correlation using diverse microbialite structures (morphotypes). The recognition of the succession of morphotypes over constrained temporal intervals and broad areas is a function of the complex interactions that operate to create the structure. Because so many nonlinked variables (e.g., biotic, sedimentological, physicochemical) are involved, similar morphotypes do not reoccur over long temporal intervals. To demonstrate the technique, the upper Cambrian-lowermost Ordovician shelf strata of the Great Basin, United States, were correlated using both morphostratigraphy and standard lithostratigraphy. Six morphozones and one morphosubzone were recognized, as were four main lithologic successions. Because the boundaries between the morphozones and lithologic successions did not coincide, it is inferred that the characteristics of the various microbialite structures are not solely controlled by physical factors. The principles for establishing a morphostratigraphy outlined in this article allow for the potential to correlate along other ancient marine margins in both the same Cambrian and Ordovician interval, as well as any interval in the Phanerozoic in which diverse microbialite structures occur.

Biological Evolution↗
PubMed2000

Prone positioning attenuates and redistributes ventilator-induced lung injury in dogs.

BACKGROUND: We previously demonstrated a markedly dependent distribution of ventilator-induced lung injury in oleic acid-injured supine animals ventilated with large tidal volumes and positive end-expiratory pressure > or =10 cm H2O. Because pleural pressure distributes more uniformly in the prone position, we hypothesized that the extent of injury induced by purely mechanical forces applied to the lungs of normal animals might improve and that the distribution of injury might be altered with prone positioning. OBJECTIVE: To compare the extent and distribution of histologic changes and edema resulting from identical patterns of high end-inspiratory/low end-expiratory airway pressures in both supine and prone normal dogs. DESIGN/SETTING: We ventilated 10 normal dogs (5 prone, 5 supine) for 6 hrs with identical ventilatory patterns (a tidal volume that generated a peak transpulmonary pressure of 35 cm H2O when implemented in the supine position before randomization, positive end-expiratory pressure = 3 cm H2O). Ventilator-induced lung injury was assessed by gravimetric analysis and histologic grading. MEASUREMENTS AND MAIN RESULTS: Wet weight/dry weight ratios (WW/DW) and histologic scores were greater in the supine than the prone group (8.8+/-2.8 vs. 6.1+/-0.7; p = .01 and 1.4+/-0.3 vs. 1+/-0.3; p = .037, respectively). In the supine group, WW/DW and histologic scores were significantly greater in dependent than nondependent regions (9.4+/-1.9 vs. 6.7+/-0.9; p = .01 and 2.0+/-0.4 vs. 0.9+/-0.4; p = .043, respectively). In the prone group, WW/DW also was greater in dependent regions (6.7+/-1.1 vs. 5.8+/-0.5; p = .054), but no significant differences were found in histologic scores between dependent and nondependent regions (p = .42). CONCLUSION: In this model of lung injury induced solely by mechanical forces, the prone position resulted in a less severe and more homogeneous distribution of ventilator-induced lung injury. These results parallel those previously obtained in oleic acid-preinjured animals ventilated with higher positive end-expiratory pressure.

Airway Resistance↗
PubMed2000

Recruitment maneuvers in three experimental models of acute lung injury. Effect on lung volume and gas exchange.

Recruitment maneuvers (RM), consisting of sustained inflations at high airway pressures, have been advocated as an adjunct to mechanical ventilation in acute respiratory distress syndrome (ARDS). We studied the effect of baseline ventilatory strategy and RM on end-expiratory lung volume (EELV) and oxygenation in 18 dogs, using three models of acute lung injury (ALI; n = 6 in each group): saline lavage (LAV), oleic acid injury (OAI), and intratracheal instillation of Escherichia coli (pneumonia; PNM). All three models exhibited similar degrees of lung injury. The PNM model was less responsive to positive end-expiratory pressure (PEEP) than was the LAV or OAI model. Only the LAV model showed an oxygenation response to increasing tidal volume (VT). After RM, there were transient increases in Pa(O(2)) and EELV when ventilating with PEEP = 10 cm H(2)O. At PEEP = 20 cm H(2)O the lungs were probably fully recruited, since the plateau airway pressures were relatively high ( approximately 45 cm H(2)O) and the oxygenation was similar to preinjury values, thus making the system unresponsive to RM. Sustained improvement in oxygenation after RM was seen in the LAV model when ventilating with PEEP = 10 cm H(2)O and VT = 15 ml/kg. Changes in EELV correlated with changes in Pa(O(2)) only in the OAI model with PEEP = 10 cm H(2)O. We conclude that responses to PEEP, VT, and RM differ among these models of ALI. RM may have a role in some patients with ARDS who are ventilated with low PEEP and low VT.

Animals↗
PubMed1999

Lemierre syndrome in an immunocompromised patient.

Lemierre syndrome or septic thrombophlebitis of the internal jugular vein is a potentially life-threatening complication. This condition may result from oropharyngeal infection, central venous catheterization, and intravenous drug abuse. Immunocompromised patients and individuals with systemic disease are at higher risk of developing the syndrome. We present here a case of septic jugular vein thrombosis in an adolescent with systemic lupus erythematosus. The etiological factors, pathogenesis, and diagnostic and therapeutic measures are discussed.

Adolescent↗
PubMed1999

In re Edna MF: case law confusion in surrogate decision making.

I review the recent case of Edna Folz, a 73 year-old woman who was suffering through the end stages of very advanced Alzheimer's dementia when her case was adjudicated by the Wisconsin Supreme Court. I consider this case as an example of how courts are increasingly misinterpreting the ethical and legal decision-making-standards known as "substituted judgment" and "best interests" and thereby threatening individuals' treatment decision-making rights as developed by other courts over the past two decades and creating serious roadblocks to health-care providers' ability to render appropriate patient care. The Wisconsin Supreme Court held that Edna's legal guardian could not authorize withdrawal of Edna's treatment, ruling that as a matter of law, if an incompetent person is not in a persistent vegetative state, it is not in his or her best interests for life-sustaining treatment to be withdrawn unless (s)he has executed an advance directive or other statement clearly indicating his or her desires.

Aged↗
PubMed1999

B cell lymphoproliferative disorders following hematopoietic stem cell transplantation: risk factors, treatment and outcome.

Twenty-six cases of B cell lymphoproliferative disorder (BLPD) were identified among 2395 patients following hematopoietic stem cell transplants (HSCT) for which an overall incidence of BLPD was 1.2%. The true incidence was probably higher, since 9/26 of the diagnoses were made at autopsy. No BLPD was observed following autologous HSCT, so risk factor analyses were confined to the 1542 allogeneic HSCT. Factors assessed were HLA-mismatching (> or = 1 antigen), T cell depletion (TCD), presence of acute GvHD (grades II-IV), donor type (related vs unrelated), age of recipient and donor, and underlying disease. Factors found to be statistically significant included patients transplanted for immune deficiency and CML, donor age > or = 18 years, TCD, and HLA-mismatching, with recipients of combined TCD and HLA-mismatched grafts having the highest incidence. Factors found to be statistically significant in a multiple regression analysis were TCD, donor age and immune deficiency, although 7/8 of the patients with immunodeficiencies and BLPD received a TCD graft from a haploidentical parent. The overall mortality was 92% (24/26). One patient had a spontaneous remission, but subsequently died >1 year later of chronic GVHD. Thirteen patients received therapy for BLPD. Three patients received lymphocyte infusions without response. The only patients with responses and longterm survival received alpha interferon (alphaIFN). Of seven patients treated with alphaIFN there were four responses (one partial and three complete). These data demonstrate that alphaIFN can be an effective agent against BLPD following HSCT, if a timely diagnosis is made.

Acyclovir↗
PubMed1999

Small cis-acting sequences that specify secondary structures in a chloroplast mRNA are essential for RNA stability and translation.

Nucleus-encoded proteins interact with cis-acting elements in chloroplast transcripts to promote RNA stability and translation. We have analyzed the structure and function of three such elements within the Chlamydomonas petD 5' untranslated region; petD encodes subunit IV of the cytochrome b(6)/f complex. These elements were delineated by linker-scanning mutagenesis, and RNA secondary structures were investigated by mapping nuclease-sensitive sites in vitro and by in vivo dimethyl sulfate RNA modification. Element I spans a maximum of 8 nucleotides (nt) at the 5' end of the mRNA; it is essential for RNA stability and plays a role in translation. This element appears to form a small stem-loop that may interact with a previously described nucleus-encoded factor to block 5'-->3' exoribonucleolytic degradation. Elements II and III, located in the center and near the 3' end of the 5' untranslated region, respectively, are essential for translation, but mutations in these elements do not affect mRNA stability. Element II is a maximum of 16 nt in length, does not form an obvious secondary structure, and appears to bind proteins that protect it from dimethyl sulfate modification. Element III spans a maximum of 14 nt and appears to form a stem-loop in vivo, based on dimethyl sulfate modification and the sequences of intragenic suppressors of element III mutations. Furthermore, mutations in element II result in changes in the RNA structure near element III, consistent with a long-range interaction that may promote translation.

Algal Proteins↗
PubMed1998

Torsion of the fallopian tube: progression of sonographic features.

Isolated torsion of the fallopian tube is a rare gynecologic condition that is difficult to diagnose preoperatively. We present the sonographic and CT findings over a 48-hour period in a case of isolated torsion of the fallopian tube. The radiologic features of isolated torsion have been described previously; however, to our knowledge, the progressive findings have not been previously reported.

Adult↗
PubMed1998

Tissue harmonic imaging sonography: evaluation of image quality compared with conventional sonography.

OBJECTIVE: The purpose of this study was to determine if tissue harmonic imaging (THI) sonography produced higher quality images than did conventional sonography. SUBJECTS AND METHODS: A prospective study was performed on 89 patients to compare the image quality of THI sonography with that of conventional sonography. Each examination was performed using THI sonography (transmitted frequency, 2.0 MHz; received frequency, 4.0 MHz) and conventional sonography at 2.5 and 4.0 MHz. The pancreatic area was studied in 60 patients, and other anatomic areas were studied in 68 patients. The images were then graded for penetration, detail, and total image quality. Graders were unaware of the sonographic technique. RESULTS: Of the 60 pancreatic examinations, THI sonography was the best technique for penetration in 45, detail in 54, and total image quality in 50. For the pancreas, THI sonography was significantly better than 2.5-MHz conventional sonography for penetration (p = .0002), detail (p < .0001), and total image quality (p < .0001). THI sonography was significantly better than 4.0-MHz conventional sonography for penetration (p < .0001), detail (p < .0001), and total image quality (p < .0001). Of the 68 examinations of other anatomic areas, THI sonography was the best technique for penetration in 42, detail in 57, and total image quality in 58. For other anatomic areas, THI sonography was significantly better than 2.5-MHz conventional sonography for penetration (p = .05), detail (p < .0001), and total image quality (p < .0001). THI sonography was significantly better than 4.0-MHz conventional sonography for penetration (p < .0001), detail (p < .0001), and total image quality (p < .0001). CONCLUSION: The THI technique improved sonographic image quality.

Aged↗
PubMed1998

The role of tacrolimus in adult kidney transplantation: a review.

The use of tacrolimus (FK506) in adult kidney-transplant recipients has been the subject of a number of single- and multi-center studies. This review article focuses on those studies in which tacrolimus was used either as rescue therapy in patients who developed refractory rejection on cyclosporine (CyA)-based regimens or as primary immunosuppression in adult renal-allograft recipients. Twenty-five prospective and retrospective studies conducted in the US, Japan and Europe, including single- and multi-center experiences, were identified in the medical literature. Of these studies, most show a 74-98% initial success rate for tacrolimus rescue therapy. Comparative studies reviewed herein demonstrate comparable patient- and graft-survival rates between tacrolimus- and CyA-treated patients. Many studies have shown that rejection episodes occur with similar or lower frequency among patients treated with tacrolimus than among those given CyA as primary immunosuppression. The major toxicities associated with tacrolimus are nephrotoxicity, neurotoxicity and diabetogenicity. Results from several studies have also demonstrated an association between these tacrolimus side effects and high whole-blood trough levels of tacrolimus. In many cases, a reduction in dosage can reverse these adverse effects. In summary, based on both single- and multi-center data, tacrolimus has been demonstrated to be efficacious when used for either primary immunosuppression or as rescue therapy for refractory acute rejection in adult renal-allograft recipients.

Adult↗
PubMed1997

Successful correction of hemophagocytic lymphohistiocytosis with related or unrelated bone marrow transplantation.

Hemophagocytic lymphohistiocytosis (HLH) is a life-threatening disorder of immune regulation leading to widespread lymphocytic and hemophagocytic infiltration of vital organs. Apparent cure has only been achieved with allogeneic bone marrow transplantation (BMT). This report describes 20 consecutive patients, who underwent either matched sibling donor (n = 4) or unrelated donor (URD; n = 16) BMT. Age at the time of BMT was 0.4 to 5.3 years (median, 0.8 years). Central nervous system disease was present at diagnosis in 13 patients. At BMT, 14 patients were in a clinical remission, whereas 6 patients had active HLH. All patients were engrafted after cytoreduction with busulfan, cyclophosphamide, and etoposide. The probability of grade II-III acute graft-versus-host disease (GVHD) for all patients was 57% (95% confidence limit [CL], 0.28, 0.86), and 73% (95% CL, 0.44, 1.0) in URD patients. The overall probability of survival at 3 years was 45% (95% CL, 0.23, 0.67) and 44% (95% CL, 0.19, 0.68) when URD BMT was evaluated separately. Favorable BMT outcome was associated with clinical remission status at the time of BMT. The preparative regimen was well tolerated, and in the 9 surviving patients it provided durable engraftment and was effective at eradicating the underlying disease.

Adrenal Cortex Hormones↗
PubMed1997

Influence of prone position on the extent and distribution of lung injury in a high tidal volume oleic acid model of acute respiratory distress syndrome.

OBJECTIVE: To evaluate the influence of body position on the extent and distribution of experimental lung damage in an oleic acid canine model of acute respiratory distress syndrome, using mechanical ventilation with high tidal volumes and positive end-expiratory pressure (PEEP). DESIGN: Prospective, randomized study. SETTING: Experimental animal laboratory. SUBJECTS: Twelve anesthetized and paralyzed dogs. INTERVENTIONS: Ninety minutes after lung injury was induced by injection of oleic acid, 12 animals were randomized to be ventilated for 4 hrs, in either the supine (supine group, n = 6) or prone (prone group, n = 6) positions, using the same ventilatory pattern (F10(2) 0.6, PEEP > or = 10 cm H2O, and a tidal volume that generated a peak transpulmonary pressure of 35 cm H2O when implemented in the supine position). Regardless of randomization to position, the tidal volumes, F10(2), and PEEP were kept constant and the pulmonary artery occlusion pressure was maintained between 4 and 6 mm Hg for the duration of the study. MEASUREMENTS AND MAIN RESULTS: At the end of the protocol, the lungs were excised for gravimetric determination (wet/dry weight ratio) and histologic examination (histologic score). Changes over time in the static pressure-volume curve of the lungs (obtained in the supine position) were also used as end-point variables. At baseline, hemodynamic and respiratory variables did not differ between groups. Just before randomization to position (90 mins after oleic acid injection), both groups presented similar lung static pressure-volume curves. Pulmonary artery occlusion pressure (4.3 +/- 1.9 vs. 4.8 +/- 1.3 mm Hg [supine vs. prone group]), cardiac output (4.1 +/- 0.4 vs. 5.2 +/- 1.3 L/min [supine vs. prone group]), and venous admixture (36.7 +/- 20.7% vs. 28.3 +/- 19.4% [supine vs. prone group]) were also not significantly (p > .05) different when measured in the supine position. At the end of the experiment, lung gravimetric data in the two experimental groups were not statistically different, suggesting a similar extent of edema. Histologic abnormalities, however, were less in the prone group than in the supine group (p < .01), due primarily to marked differences in extent and severity in the dependent regions of the lungs. Static lung compliance improved over time in the prone group (34 +/- 9 to 46 +/- 19 mL/cm H2O)(p = .02), but not in the supine group (34 +/- 6 to 36 +/- 6 mL/cm H2O). CONCLUSIONS: After oleic acid-induced lung injury, animals ventilated with high tidal volume and PEEP undergo less extensive histologic change in the prone position than in the supine position. The prone position alters the distribution of histologic abnormalities.

Animals↗
PubMed1997

Ablative adenoidectomy: a new technique using simultaneous liquefaction/aspiration.

OBJECTIVE: This study was performed to critically evaluate a new cautery technique for adenoidectomy that combines indirect visualization with complete hemostasis, ultimately permitting the surgeon to tailor the procedure to the patient's specific needs. DESIGN: This prospective study of 138 consecutive adenoidectomy patients of the senior author was carried out at the Montreal Children's Hospital over 17 months. Concurrent adenoidectomy patients of another senior otolaryngologist in our institution as well as cases of the senior author using the conventional cold curettage technique served as controls. METHOD: Data were collected preoperatively with respect to indication for surgery and radiologic findings. Operative findings including duration of surgery, concurrent procedures, position of adenoid hypertrophy, and blood loss were also recorded. Postoperative complications such as hemorrhage, infection, dehydration, as well as the incidence of velopharyngeal insufficiency and nasopharyngeal stenosis were also recorded up to 1 year from the date of surgery. The operative technique involves indirect visualization of the nasopharynx with a laryngeal mirror combined with cautery-liquefaction and suction ablation of the adenoid tissue. RESULTS: Our results demonstrate a significant reduction in blood loss as well as a reduction in operative time. There was a low incidence of postoperative infection, no patients required a return to the operating room for hemostasis, and there were no cases of recurrent adenoid hypertrophy. There was no detectable difference in the incidence of postoperative complications. CONCLUSION: We conclude that this technique is safe and time-efficient, with the advantages of excellent visualization and essentially no operative blood loss.

Adenoidectomy↗