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Biomedical subjects

S Rubin

Publications and source records attributed to S Rubin.

At least 55 records · Page 3Linked to original sources
PubMed1996

Evaluating a change in practice: femoral sheath removal by registered nurses.

A descriptive study was conducted to assess whether there was a difference in patient outcomes when femoral venous and arterial sheaths were removed post percutaneous transluminal coronary angioplasty (PTCA) by MDs as compared to RNs. In addition, the impact on nursing practice of nurses assuming this new task was examined. A chart review revealed a greater occurrence of bleeding in patients whose sheaths had been removed by MDs rather than by RNs (chi square; p < 0.01). Patients received analgesics and anxiolytics pre-sheath removal more frequently when nurses removed femoral sheaths (p < 0.01). Forty-two percent of RNs were not satisfied with the change in practice, and 46% were satisfied. Further research is needed to evaluate patient satisfaction with pain and anxiety management at the time of sheath removal.

Angioplasty, Balloon, Coronary↗
PubMed1995

Testicular fate after incarcerated hernia repair and/or orchiopexy performed in patients under 6 months of age.

This study assessed testicular viability after 476 inguinal procedures performed in 338 infants under 6 months of age, between 1974 and 1993. One hundred twenty-one elective hernia repairs (contralateral explorations) were compared with 355 hernia repairs complicated by incarceration and/or orchiopexy. Clinical examination of 323 testes in the early postoperative period showed 20 atrophic testes. Since January 1994, 71 of the 338 patients have had testicular measurements obtained through ultrasonography (US). An additional 13 atrophic testes were found during US examination. Of these, nine were believed to be normal during early postoperative examination. Assuming that US examination will confirm atrophy in the 20 atrophic testes noted early in the postoperative clinical evaluation, and that all other testes not yet scanned are found to be normal, the minimal atrophy rate (MAR) would be 9.3% (33 of 355). Neither operative nor early postoperative testicular assessment correlates with ultimate testicular survival. Testicular pathology may become more evident after puberty, and the real incidence of atrophy may increase.

Atrophy↗
PubMed1995

Randomized trial of interferon maintenance in multiple myeloma: a study of the National Cancer Institute of Canada Clinical Trials Group.

PURPOSE: To determine whether interferon maintenance therapy improves overall survival and response duration in patients with multiple myeloma who have responded to induction therapy with melphalan and prednisone. PATIENTS AND METHODS: In a multicenter trial, patients with symptomatic clinical stage I and stage II and III multiple myeloma were registered at diagnosis and those who responded to melphalan-prednisone (MP) were randomized either to receive interferon (2 mU/m2) subcutaneously three times per week or no maintenance. MP was discontinued in both groups once a stable response plateau of the monoclonal protein was reached. Interferon was continued until relapse, and then was restarted on subsequent response to MP. Interferon toxicity was recorded using a self-report diary. Survival and response duration were calculated using life-table methods, and were adjusted in the analysis for imbalances in baseline prognostic factors. RESULTS: Four hundred two patients were registered and 176 responders were randomized (85 to interferon and 91 to control). At a median follow-up time of 43 months, the median survival duration was 43 months for interferon and 35 months for control (P = .16), but when adjusted for chance imbalances in baseline prognostic factors (mainly performance status), the median survival duration was 44 months and 33 months for interferon and control, respectively (P = .049). Progression-free survival from randomization to first relapse also favored interferon (unadjusted P < .002; adjusted P < .003). Interferon toxicity caused 58% of patients to reduce their dose, of which 84% were able to return to the initial dose; 14% had to discontinue interferon treatment. CONCLUSION: Interferon maintenance therapy improves progression-free and overall survival of patients with multiple myeloma who respond to melphalan and prednisone. Toxicity is substantial and must be weighed by patients against the potential benefits in response duration and survival.

Aged↗
PubMed1995

Lids, lacrimals, and lashes.

The eyelids and lashes serve to protect the globe from foreign bodies and injuries, and the lacrimal system protects the eyes through lubrication of the corneal and conjunctival surfaces. This article discusses trauma, infection, inflammation, anatomic abnormalities, and tumors that may result in serious complications interfering with normal eye function.

Eye Injuries↗
PubMed1995

The patient as commodity: managed care and the question of ethics.

Managed care has come to the fore in the medical landscape with such rapidity, vigor, and nearly evangelical zeal that startled witnesses to the transformation have reacted with awe and outrage. In this article we will take a sober look at the system that has in some markets all but consumed the fee-for-service relationships that characterized healthcare just five years ago and dominated the last failed debate on healthcare reform. We will look at selected arguments for and against the justice of such a system, raise pertinent ethical concerns about managed care, and suggest some normative guidelines that a society ought to develop as a way of regulating the medical commons. In the emerging debate about ethical conflicts in the rapidly developing market of managed healthcare, it is critical to remember that all care that is given to patients is managed by someone. The need for management is a function of how healthcare delivery is organized--relying on the intervention of a host of strangers, and, to some extent, the cooperation of a large industrialized state. Strangers must agree on the parameters of care that will address any given expressed need. Even the embodied experience of the patient is named, defined, and categorized not by the patient, but by a stranger, who then, by evaluating the patient's pain, treatment, and outcome, becomes part of the management and narrative of the case. Who owns the instruments, regulates the drugs, and pays the fees will be a critical factor in who sets the parameters and limits in healthcare. What makes the reality of management a subject of ethical discourse is the issue of power, the problem of the marketplace relationships that exist simultaneously, and the norms that ought to guide stranger-to-stranger interaction in a just social order.

Beneficence↗
PubMed1994

MR imaging: its role in detecting occult fractures.

Magnetic resonance (MR) studies were performed on 30 consecutive patients who continued to be symptomatic despite negative or inconclusive findings on radiographs and other imaging studies including radionuclide bone scans, computed tomography, and/or polytomography. There were 9 men and 21 women, 20-92 years old (mean age 63 years) whose MR studies were done 3-72 h after frank trauma in 22 cases and in another 8 after 1-4 weeks of increasing pain subsequently attributed to trauma or unaccustomed effort. MR studies were performed using 0.5-T (Phillips) or 1.5-T (Phillips, GE) superconductive magnets. Results indicated that: (1) MR images allowed identification of acute fractures in an emergency room setting, as well as subtle subacute or chronic fractures in the context of strong clinical suspicions despite negative or inconclusive radiographs and other subsequently indecisive imaging studies. (2) MR imaging is the most sensitive way of documenting the earliest changes in traumatized osseous and soft tissue structures simultaneously.

Adult↗
PubMed1994

Gastrointestinal mucormycosis causing an acute abdomen in the immunocompromised pediatric patient--three cases.

Mucormycosis is an infection caused by a ubiquitous fungus in immunocompromised individuals. Typically, it invades blood vessels, producing thrombosis and tissue infarction. This infection spans all pediatric age groups and can lead to hollow viscus perforation and bowel obstruction. A 30-month old male with large cell anaplastic lymphoma had a bowel obstruction. During emergency laparotomy, an ileoileal intussusception was identified, which required resection and anastomosis. In the pathological specimen, fungi of the Mucorales order were found to be associated with tissue necrosis. On the eighth day of life, a premature infant had abdominal distension secondary to bowel perforation. Partial gastric resection and multiple intestinal stomas were performed. Death occurred soon after, secondary to multiorgan failure. The autopsy and surgical specimens showed widespread mucormycosis. An adolescent had meningococcemia-induced septic shock. During recovery, hemorrhagic colitis developed, which led to perforation. The subtotal colectomy specimen showed widespread mucormycosis. The laparotomy findings are typical (black necrotic tissue involving the bowel), and when seen in the immunocompromised patient, should make one suspect gastrointestinal mucormycosis. Aggressive surgical debridement of devitalized tissue augmented by intravenous antifungal medication is the mainstay of treatment.

Abdomen, Acute↗
PubMed1994

Leukocyte involvement in cerebral infarct generation after ischemia and reperfusion.

White blood cell involvement in the generation of cerebral infarcts was evaluated following ischemia and reperfusion injury in the rat. Control and leukopenic rats (induced by vinblastine, WBC counts < 1500/mm3) were compared in a global forebrain ischemic model after 1 h of ischemia and 1 h 15 min of reperfusion. Cerebral infarcts were defined on coronal brain sections using Triphenyl tetrazolium chloride (TTC) staining. Electroencephalographic activity (EEG) and somatosensory evoked potentials (SSEP) were also compared. Results indicate that the area infarcted in leukopenic rats was significantly less than infarcts generated in corresponding controls (21 +/- 16% vs. 70 +/- 16%). In addition, EEG was preserved in all leukopenic animals when compared to controls, both during ischemia and after reperfusion. The cortical peak component of the SSEP was also better preserved in the leukopenic animals both during ischemia and at 60 min of reperfusion. These results indicate white blood cell participation in the generation of cerebral damage in a model of global forebrain ischemia and reperfusion as indicated by TTC staining of cerebral infarcts.

Animals↗
PubMed1994

Photoregulation of alpha-chymotrypsin activity in organic media: effects of bioimprinting.

alpha-Chymotrypsin exhibits photoswitchable activities in an organic solvent after covalent modification of the protein backbone with thiophenefulgide active ester (2). The thiophenefulgide-modified alpha-chymotrypsin exhibits reversible photoisomerizable properties between states (3)-E and (3)-C. The modified alpha-chymotrypsin, where nine lysine residues are substituted by thiophenefulgide units, retains 60% of the activity of the native enzyme. The activities of thiophenefulgide-modified alpha-chymotrypsin toward esterification of N-acetyl-L-phenylalanine (4) by ethanol in cyclohexane are controlled by the configuration of the attached photoisomerizable component and by prior bioimprinting of the protein backbone with the reaction substrate (4). The esterification of (4) in cyclohexane using bioimprinted (3)-C is two-fold faster than in the presence of (3)-E. In the presence of a nonbioimprinted enzyme, esterification of (4) by (3)-C is five-fold faster than with (3)-E. The activity of bioimprinted (3)-E toward esterification of (4) is 4.5-fold higher than that of nonbioimprinted (3)-E. Switchable cyclic esterification of (4) is accomplished by sequential photoisomerization of the thiophenefulgide-modified alpha-chymotrypsin between states (3)-C and (3)-E.

Chymotrypsin↗
PubMed1994

Distribution of nitric oxide synthase activity in arterioles and venules of rat and human intestine.

NO is produced within peripheral blood vessels through the action of the differentially distributed constitutive and inducible NO synthase isoforms in the vessel wall. As in other sites in the periphery, NO exerts local vasodilatory actions in the gastrointestinal microvasculature and is proposed to play a role in enteric vasomotor regulation. Using NO synthase histochemistry and endothelial cell immunohistochemistry, we provide the first anatomic evidence of NO synthesis in both endothelial and smooth muscle cells of submucosal blood vessels in the rat and human intestine. The findings of this study indicate that 1) as in the periphery, both the endothelial and vascular smooth muscle cells of the microvessels irrigating the rat and human intestinal wall possess NO synthesis potential, 2) NO synthase activity is predominantly localized to discrete subcellular patches, and 3) the source of NO within the vascular wall, either intimal or medial, should be a consideration in future studies in terms of the relative contribution of these sources of vasomotor tone in the rat and human gut wall.

Amino Acid Oxidoreductases↗
PubMed1994

Intraperitoneal Taxol (paclitaxel) in the management of ovarian cancer.

In an effort to examine the safety and pharmacology of the intraperitoneal (i.p.) delivery of paclitaxel, 25 patients (24 with ovarian cancer) were treated in a phase I dose escalation trial. The drug was administered in normal saline every 3 to 4 weeks, starting at a dose of 25 mg/m2. The dose-limiting toxicity at doses at or above 175 mg/m2 was abdominal pain. A 3-log pharmacokinetic advantage for peritoneal cavity exposure to paclitaxel, compared with the systemic compartment, was observed. High levels of drug persisted within the cavity for longer than 48 hours following a single treatment. In addition, significant paclitaxel concentrations were found in the systemic compartment after i.p. treatment, despite the pharmacokinetic advantage demonstrated for cavity exposure. Several patients exhibited clinical and laboratory evidence of an antitumor response. On the basis of these data, further exploration of a potential role for i.p. paclitaxel in the management of ovarian cancer appears justified.

Dexamethasone↗
PubMed1993

Online repositioning during treatment of the prostate: a study of potential limits and gains.

PURPOSE: With on-line portal imaging devices and image registration tools, the verification of radiation field position prior to each treatment becomes technically feasible. In this paper, we analyze the impact of pre-treatment verification and field position adjustment on target coverage and normal tissue sparing. METHODS AND MATERIALS: Port films were compared with corresponding simulation films to determine the magnitude of setup variations in patients treated for prostate cancer. From these data, an analytic function was determined between geometric coverage of the target and field margin size. A paradigm for on-line patient repositioning was employed to generate a new relationship between margin and target coverage. Margins were selected for the situations of normal treatment and on-line repositioning to ensure target coverage. Dose-volume histograms were generated for a typical prostate treatment using these margins. RESULTS: On-line repositioning, when setup errors exceed 1 cm, results in a 6 mm reduction in margin, suggesting that 10% of the volume of bladder and rectum may be spared of high dose. CONCLUSION: The use of on-line imaging and image registration to guide adjustment of patient setup may lead to a reduction in the volume of normal tissues irradiated, and possibly improve the probability of complication-free survival in future treatments.

Computer Simulation↗
PubMed1993

Effect of subcutaneous recombinant human erythropoietin in cancer patients receiving radiotherapy: preliminary results of a randomized, open-labeled, phase II trial.

PURPOSE: To determine the efficacy and safety of subcutaneous administration of recombinant human erythropoietin (r-HuEPO) at a dose of 200 units/kg/day to cancer patients undergoing radiotherapy. METHODS AND MATERIALS: This is a randomized, open-labeled, Phase II study. Only patients receiving radiotherapy +/- chemotherapy are included. Eligibility is restricted to patients with lung cancer, carcinoma of the uterine cervix, prostatic adenocarcinoma, or adenocarcinoma of the breast. Patients in the control and treatment arms receive radiotherapy with similar policies, and their doses of radiotherapy and treatment volumes are determined by the site and stage of the disease. Patients in the "treatment arm" receive 200 units/kg/day of r-HuEPO, subcutaneously, five times a week with iron (Fe SO4, 325 mg. p.o., t.i.d.) supplements. Complete blood counts are obtained weekly. Quality of life is assessed weekly by the patients themselves by a few simple entries on an analog scale. RESULTS: Twenty-six patients have been entered in the study so far. Twelve patients were placed in the control arm and 14 in the treatment arm. Pre-randomization demographic and laboratory mean values in both arms were comparable, with none of 16 parameters compared reaching statistical significance. Our results can be summarized as follows: (a) Mean hemoglobin, hematocrit, and red blood cell values increased gradually in the treatment arm patients. Week-by-week comparison showed that mean values for these three parameters were significantly higher in the treatment arm than in the control arm. For example, the p values for the differences in hemoglobin mean values for weeks 1-6 were 0.015, 0.002, 0.003, 0.0002, 0.0006, and 0.007, respectively. Similar trends were observed for red blood cells and the hematocrit values. (b) No significant toxicity has been encountered. (c) No significant differences in the mean values of white blood cells and platelet counts were seen between the two arms. The values of these two parameters declined over the course of radiotherapy. (d) The mean weekly increase in hemoglobin levels in the treatment arm was 0.43 gm/dl. CONCLUSION: (a) The safety and efficacy of r-HuEPO, with 200 units/kg/day of subcutaneous administration, have been confirmed in our study group. (b) However, the rate of increase in hemoglobin levels is not very rapid with the doses used. (c) Dose escalation studies are needed for determination of the feasibility of improving hemoglobin levels by about 1 gm/dl/week. (d) The question whether improvement in hemoglobin with r-HuEPO therapy can improve outcome by improving tumor oxygenation needs to be studied in carcinoma of the uterine cervix and squamous cell carcinoma of the head and neck.

Adenocarcinoma↗