Search for Lorentz invariance and CPT violation with the MINOS far detector.

We searched for a sidereal modulation in the MINOS far detector neutrino rate. Such a signal would be a consequence of Lorentz and CPT violation as described by the standard-model extension framework. It also would be the first detection of a perturbative effect to conventional neutrino mass oscillations. We found no evidence for this sidereal signature, and the upper limits placed on the magnitudes of the Lorentz and CPT violating coefficients describing the theory are an improvement by factors of 20-510 over the current best limits found by using the MINOS near detector.

Search for muon-neutrino to electron-neutrino transitions in MINOS.

This Letter reports on a search for nu(mu) --> nu(e) transitions by the MINOS experiment based on a 3.14x10(20) protons-on-target exposure in the Fermilab NuMI beam. We observe 35 events in the Far Detector with a background of 27+/-5(stat)+/-2(syst) events predicted by the measurements in the Near Detector. If interpreted in terms of nu(mu) --> nu(e) oscillations, this 1.5sigma excess of events is consistent with sin2(2theta(13)) comparable to the CHOOZ limit when |Delta m2|=2.43x10(-3) eV2 and sin2(2theta(23))=1.0 are assumed.

Search for active neutrino disappearance using neutral-current interactions in the MINOS long-baseline experiment.

We report the first detailed comparisons of the rates and spectra of neutral-current neutrino interactions at two widely separated locations. A depletion in the rate at the far site would indicate mixing between nu(mu) and a sterile particle. No anomalous depletion in the reconstructed energy spectrum is observed. Assuming oscillations occur at a single mass-squared splitting, a fit to the neutral- and charged-current energy spectra limits the fraction of nu(mu) oscillating to a sterile neutrino to be below 0.68 at 90% confidence level. A less stringent limit due to a possible contribution to the measured neutral-current event rate at the far site from nu(e) appearance at the current experimental limit is also presented.

Testing Lorentz invariance and CPT conservation with NuMI neutrinos in the MINOS near detector.

A search for a sidereal modulation in the MINOS near detector neutrino data was performed. If present, this signature could be a consequence of Lorentz and CPT violation as predicted by the effective field theory called the standard-model extension. No evidence for a sidereal signal in the data set was found, implying that there is no significant change in neutrino propagation that depends on the direction of the neutrino beam in a sun-centered inertial frame. Upper limits on the magnitudes of the Lorentz and CPT violating terms in the standard-model extension lie between 10(-4) and 10(-2) of the maximum expected, assuming a suppression of these signatures by a factor of 10(-17).

Measurement of neutrino oscillations with the MINOS detectors in the NuMI beam.

This Letter reports new results from the MINOS experiment based on a two-year exposure to muon neutrinos from the Fermilab NuMI beam. Our data are consistent with quantum-mechanical oscillations of neutrino flavor with mass splitting |Deltam2| = (2.43+/-0.13) x 10(-3) eV2 (68% C.L.) and mixing angle sin2(2theta) > 0.90 (90% C.L.). Our data disfavor two alternative explanations for the disappearance of neutrinos in flight: namely, neutrino decays into lighter particles and quantum decoherence of neutrinos, at the 3.7 and 5.7 standard-deviation levels, respectively.

Observation of muon neutrino disappearance with the MINOS detectors in the NuMI neutrino beam.

This Letter reports results from the MINOS experiment based on its initial exposure to neutrinos from the Fermilab NuMI beam. The rates and energy spectra of charged current nu(mu) interactions are compared in two detectors located along the beam axis at distances of 1 and 735 km. With 1.27 x 10(20) 120 GeV protons incident on the NuMI target, 215 events with energies below 30 GeV are observed at the Far Detector, compared to an expectation of 336+/-14 events. The data are consistent with nu(mu) disappearance via oscillations with |Delta(m)2/32|=2.74 +0.44/-0.26 x10(-3)eV(2) and sin(2)(2theta(23))>0.87 (68% C.L.).

Surgical smoke: a review of the literature. Is this just a lot of hot air?

Surgical smoke is omnipresent in the day-to-day life of the surgeon and other medical personnel who work in the operating room. In addition, patients are also exposed, especially and uniquely so in laparoscopic cases where smoke is created and trapped in a closed and absorptive space. Surgical smoke has typically been produced by electrocautery but is now ever more present in a new form with the burgeoning use of the laser and the harmonic scalpel. Several cases of transmission of human papillomavirus (HPV) from patient to treating professional via laser smoke have alerted us to the reality that surgical smoke in certain situations is far form benign. However, surgeons rarely take measures to protect themselves, their co-coworkers and patients from surgical smoke. Should we and, if so, how do we differentiate between different types of smoke and should we move toward increasing our efforts to protect ourselves, our co-workers, and patients from it? This article attempts to sort through the available data and draw some reasonable conclusions regarding surgical smoke. In general, surgical smoke is a biohazard and cannot be ignored. At a minimum, surgical smoke is a toxin similar to cigarette smoke. However, other dangers exist. This is especially true in specific circumstances such as when tissue infected with dangerous viruses is aerosolized by lasers. In addition, smoke generated by the harmonic scalpel, being a relatively cold vapor similar to laser smoke, should be further investigated for its potential ill effects and until then, looked upon with reasonable caution. Although not a high-priority in most surgical cases, surgeons should support efforts to minimize OR personnel, patients, and their own exposure to surgical smoke.

Base-of-tongue cancer: survival, function, and quality of life after external-beam irradiation and brachytherapy.

OBJECTIVE: Base-of-tongue cancer has traditionally been treated by surgical resection followed by radiation therapy. Primary radiation therapy with brachytherapy has recently been proposed as an alternative. In a prior analysis, we found that patients with advanced tongue-base cancer treated by total glossectomy and postoperative radiation therapy can be cured while potentially maintaining good quality of life. Therefore, we designed the current study to assess survival, function, and quality of life in our patients with tongue-base cancer who were treated with primary radiation therapy and brachytherapy with neck dissection as indicated. STUDY DESIGN: Consecutive case series. METHODS: Twenty patients were treated between 1993 and 1997 using the approach just named. The T stages were T1 (3), T2 (10), T3 (6), and T4 (1). The N stages were N0 (3), N1 (3), N2 (11), and N3 (3). At the time of brachytherapy catheter placement, neck dissections were performed in all 14 patients with N2 or N3 disease. Surviving patients completed a functional status survey and quality of life questionnaire. RESULTS: The 3- and 5-year Kaplan-Meier corrected actuarial survival rates were 57% and 38%, respectively. Eight patients remained alive at the time of this writing and completed the functional status survey and quality of life assessment. Function and quality of life were well maintained in patients treated with external-beam irradiation followed by brachytherapy and neck dissection. However, none of our patients with T3 disease had long-term survival. CONCLUSION: Although we do not endorse external-beam irradiation and brachytherapy for advanced tongue-base cancers, this treatment should be strongly considered for patients with T1 or T2 tumors in whom preservation of function and quality of life is a priority.

Clinical oncology clerkship for third-year medical students.

BACKGROUND: A two-week elective clerkship in clinical oncology is offered to third-year medical students. METHODS: Two students at a time participated in the rotation and spent time with attendings in a one-to-one setting in outpatient clinics in the cancer specialties. The students also attended multidisciplinary tumor boards. Grand rounds, peer review conferences, and problem-case conferences were attended by the students as well. The students met with an attending for one-hour, twice-per-week to discuss pertinent oncologic cases and problems. The exposure to clinical oncology for two weeks is intended to educate the students relative to the presentation, evaluation, treatment, prognosis, and follow-up for a variety of cancers. RESULTS: The rotation has been highly successful as measured by its popularity and by consistently high course evaluations from the medical students. CONCLUSION: The overall quality of the learning experience for the rotation has been rated by the students as the highest among all courses in their four-year curriculum.

Intestinal obstruction from midgut volvulus after laparoscopic cholecystectomy. A report of an unusual complication.

Congenital midgut malrotation, a rare anatomic anomaly that can lead to duodenal or small bowel obstruction, rarely is recognized beyond the first year of life. We report a case of unrecognized congenital midgut malrotation that resulted in midgut volvulus, causing intestinal obstruction and requiring emergent reoperation after laparoscopic cholecystectomy. This unusual complication, first reported in 1994, involved a 56-year-old man and resulted in cecal infarction recognized and treated on the second postoperative day. This second case describes a less acute postoperative course, with multiple bouts of partial bowel obstruction leading to two readmissions and finally resulting in a reexploration and definitive treatment on the 19th postoperative day.

Decreased cerebrospinal fluid absorption during abdominal insufflation.

BACKGROUND: Intracranial pressure (ICP) is known to rise during induced CO(2) pneumoperitoneum. This rise correlates with an increase in inferior vena caval pressure; therefore, it is probably associated with increased pressure in the lumbar venous plexus. Branches of this plexus communicate with arachnoid villi in the lumbar cistern and the dural sleeves of spinal nerve roots-areas where cerebrospinal fluid (CSF) absorption to normally takes place. The increased venous pressure in this area may impede CSF absorption. Because CSF is produced at a constant rate, decreased absorption will increase ICP. We hypothesized that increased ICP occurring during abdominal insufflation is due, at least in part, to decreased absorption of CSF. The purpose of this study is to show that CSF absorption is inhibited during abdominal insufflation. METHODS: After appropriate approval was obtained, 16 domestic swine were anesthetized and injected into the CSF with 100 microcuries (microCu) of I(131) radioactive iodinated human serum albumin (RISA) in 2 ml of normal saline. Eight subjects underwent CO(2) abdominal insufflation to 15 mmHg and were maintained for 4 h. A control group did not undergo insufflation. Blood levels of RISA were measured over a 4-h period to determine the rate of CSF absorption. RESULTS: Blood levels of RISA increased at a slower rate in the subjects undergoing abdominal insufflation than in the control group. The mean change over 2 h in the insufflated group was 15% compared to 34% in the control group (p = 0.02). This difference indicates decreased absorption of CSF in the insufflated group. CONCLUSIONS: These results demonstrate decreased absorption of CSF during abdominal insufflation and support the hypothesis that the increase in ICP pressure occurring during abdominal insufflation is caused, at least in part, by decreased absorption of CSF in the region of the lumbar cistern and the dural sleeves of spinal nerve roots.

Intraabdominal adhesion formation after preperitoneal dissection in the murine model.

BACKGROUND: The laparoscopic approach to hernia repair has been advocated by many as a potentially superior method of herniorraphy. Several techniques have been described, each with its own proposed advantages. These techniques involve different anatomic approaches, the most recent of which is the totally extraperitoneal approach (TEPA). One presumed advantage of the extraperitoneal approach is the avoidance of adhesion formation because the peritoneum is not entered and mesh is not placed in direct contact with intra-abdominal structures. We hypothesize, however, that when the peritoneum is dissected from the abdominal wall, it is partially devascularized, leading to scar formation and potential adhesion formation. This would suggest that the TEPA method of herniorraphy may not completely avoid the risks of intra-abdominal adhesion formation. METHODS: After appropriate approval was obtained, 88 male Sprague-Dawley rats were divided into two equal groups. One group underwent laparotomy followed by careful blunt dissection of the peritoneum from the left abdominal wall. The control group underwent laparotomy without manipulation of the peritoneum. All animals were re-explored 14 days later, and the abdominal cavity was examined for adhesions. The type and location of any adhesion was recorded. RESULTS: Adhesion formation occurred in 10 of 44 (23%) subjects in the peritoneal dissection group, compared with 3 of 44 (7%) in the nondissection group (p < 0.05). CONCLUSIONS: Dissection of the peritoneum from the overlying abdominal wall in the murine model leads to intra-abdominal adhesion formation. This suggests that peritoneal dissection in the TEPA method of herniorraphy may lead to intra-abdominal adhesion formation.

Perianal manifestations of human immunodeficiency virus infection: experience with 260 patients.

PURPOSE: Individuals infected with the human immunodeficiency virus often have disorders affecting the anorectum. These disorders may be complex and difficult to treat. We reported our early experience with 40 human immunodeficiency virus-positive patients with perianal disorders in 1990. We now present our series of 260 consecutive human immunodeficiency virus-positive patients with perianal disorders who underwent evaluation between 1989 and 1996 to examine the distribution of disorders, their treatments, and outcomes. METHOD: Patients were identified at initial presentation and followed prospectively. RESULTS: Two-hundred forty-nine (96 percent) of 260 patients were male, with an average age of 34.9 (range, 19-58) years. Average duration of human immunodeficiency virus positivity was 5 years, 5 months, with a maximum of 11 years, 5 months. Median CD4 count was 175 (range, 2-1,100) cells/mm3. Only 89 (34 percent) patients satisfied the criteria of the Centers for Disease Control and Prevention's for acquired immunodeficiency syndrome at presentation. The most frequent major presenting symptoms were anorectal pain (55 percent), a mass (19 percent), and blood in the stool (16 percent). Risk factors included homosexuality (75 percent) and a prior history of sexually transmitted disease (45 percent). Forty different perianal disorders were identified, which were categorized as benign noninfectious (18), infectious (14), neoplastic (6), and septic (2). The most common disorders were condyloma (42 percent), fistula (34 percent), fissure (32 percent), and abscess (25 percent). Neoplasms were present in 19 patients (7 percent). One hundred seventy-one patients (66 percent) had more than one disorder, with an average of 2.9 disorders among these patients. Four hundred eighty-five procedures were performed on 178 patients (2.7/patient), with no mortalities and a 2 percent complication rate. Thirty-one patients (12 percent) died during the course of follow-up, but anorectal disease was the cause of death in only two patients. CONCLUSIONS: Perianal manifestations of human immunodeficiency virus infection are common, often multiple, and varied. Patients with perianal disorders seek treatment throughout the course of the human immunodeficiency virus infection, and a perianal condition may be this disease's initial manifestation. Although recurrence is common and healing delayed, improved overall management of human immunodeficiency virus infection and a healthier human immunodeficiency virus-positive patient population have improved the outcome of surgical intervention in human immunodeficiency virus-infected patients with perianal disorders.

Preferential use of the ipsilateral pedicle in TRAM flap breast reconstruction.

Breast reconstruction utilizing the ipsilateral transverse rectus abdominis musculocutaneous (TRAM) flap provides superior results when compared with contralaterally based reconstructions by preserving the medial inframammary fold and eliminating the perixiphoid bulge. Additionally, a longer pedicle can be obtained using the ipsilateral TRAM, thereby allowing greater mobility and flexibility during flap transposition. These findings are based on a retrospective review of 50 consecutive ipsilateral TRAM flap reconstructions in 38 patients. The mean patient age was 45.4 years and mean follow-up was 8.6 months. Thirty-two flaps were performed as immediate reconstructions and 18 flaps were delayed. No patient suffered total flap loss, whereas partial flap loss was observed in three flaps. One patient required suture removal to alleviate venous congestion of the flap. No patient developed a postoperative hernia, but 1 patient required removal of a polytetrafluoroethylene onlay patch following graft exposure. This technique achieves aesthetically pleasing results with acceptable morbidity, allows greater flap mobility without disruption of the medial inframammary fold or creation of a perixiphoid bulge, and is our method of choice for TRAM flap breast reconstruction.

Safety of radiating jejunal interposition grafts in head and neck cancer.

The safety of high-dose postoperative radiation therapy to a jejunal graft has not been established in the literature. The purpose of the present study is to review the effect of postoperative radiation on swallow function in patients who have received a jejunal interposition graft as part of their reconstruction after cancer resection. Charts of patients undergoing hypopharyngeal resections for cancers with placement of jejunal interposition grafts who received postoperative radiation therapy were reviewed. Swallow function was determined from records of patients' subjective characterization of their swallow function, records of weights at each visit, use of gastrostomy tube, need for jejunal dilatation and review of barium swallows. Seventeen patients were identified who had undergone resection of cancers with jejunal interpositions and postoperative radiation therapy. Four patients never regained adequate swallow function postoperatively to allow G-tube removal. The remaining thirteen patients had their G-tubes removed, generally several months after resection, and were able to obtain adequate nutrition orally to maintain or increase their weights. The present series suggests that a segment of jejunum transferred into the neck after laryngopharyngoesophagectomy can be irradiated to high dose with generally acceptable morbidity.

Clinical course of malignancies in renal transplant recipients.

BACKGROUND: The incidence of cancers after renal transplantation is significantly higher than in populations that have not undergone transplantation. The authors report a group of renal transplant patients from the University of Cincinnati who had cancer develop; the focus is on the patients' clinical course. METHODS: Since 1968, 876 renal transplantations have been performed for a variety of causes of end stage renal disease. Charts of transplant patients who had neoplasms were reviewed. RESULTS: Forty-four patients had epithelial skin cancers, and 36 had nonskin cancers or melanoma. No correlations could be established between disease course and type of immunosuppressive agent, type of disease for which transplantation was required, or type of renal allograft donor. The skin cancers demonstrated a propensity for multifocality: 22 of the 44 patients had multiple separate lesions develop. Of the patients with cancer not of the skin, six were treated surgically for carcinoma in situ, and none have experienced disease recurrence. Of 11 patients treated for early invasive disease, 6 are disease-free, 3 died of intercurrent disease, and 2 died of progressive disease 11 and 13 months, respectively, after disease diagnosis. Nineteen patients had advanced disease, and only 1 is alive and disease-free. Sixteen died of progressive disease at a median of 1 month from the time of diagnosis, and 2 died of intercurrent disease within 1 week of diagnosis. CONCLUSIONS: The natural history of cancers developing in renal transplant patients often is more aggressive than would be expected in patients who have not undergone transplants. The immunosuppression induced to allow viability of the renal allograft may allow tumor cells to thrive.

Embryonal sarcoma of the liver in an adult treated with preoperative chemotherapy, radiation therapy, and hepatic lobectomy.

A rare case of embryonal sarcoma of the liver in a 28-year-old man is reported. The patient was treated preoperatively with a combination of chemotherapy and radiation therapy. Complete surgical resection, 4.5 months after diagnosis, consisted of a left hepatic lobectomy. No viable tumor was found in the operative specimen. The patient was disease-free 20 months postoperatively.

Acoustic detection of cosmic-ray air showers.

The signal strength, bandwidth, and detection range of acoustic pulses generated by cosmic-ray air showers striking a water surface are calculated. These signals are strong enough to be audible to a submerged swimmer. The phenomena may be useful for studying very-high-energy cosmic rays and may help answer the important question of whether the origin of cosmic rays is extragalactic or galactic.