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Biomedical subjects

M Sher

Publications and source records attributed to M Sher.

At least 19 recordsLinked to original sources

Large electric dipole moments of heavy leptons.

In many models of CP violation, the electric dipole moment (EDM) of a heavy charged or neutral lepton could be very large. In models in which the EDMs scale as the cube of the mass, as well as in vectorlike models, a 100 GeV heavy lepton can have an EDM as large as 0.01e fermi. This could dominate the electromagnetic properties of heavy leptons. The angular distribution and production cross section of charged and neutral heavy leptons with large EDMs is calculated and discussed. The interesting possibility that a heavy neutrino with a large EDM could leave an ionization track in a drift chamber is investigated.

Journal Article↗

The nonoperative management of fistula-in-ano.

BACKGROUND/PURPOSE: Fistulotomy is the accepted treatment for infants with perianal fistula. Although recurrence rates range from 0% to 68%. Based on the experience of a senior colleague who noted that babies suffering from perianal fistula follow a self-limited course the authors decided to determine if this observation was accurate. METHODS: A conservative approach to perianal abscess and fistula was used prospectively in 18 male infants. Abscesses were to be drained only if the baby was very uncomfortable or febrile. Once a fistula developed the authors continued observation until the fistula healed. Data are expressed as mean +/- SD. Mean follow-up period was 37 months. RESULTS: Mean age at onset of symptoms was 4 +/- 3 months. Fistulas developed in 14 patients (77%). All fistulas healed without operation. Four patients had abscesses drained for discomfort (n = 3) or fever (n = 1). No patient required antibiotics. Mean duration of symptoms was 6 +/- 4 months. Four patients in whom fistulas did not form healed after incision (n = 3) or spontaneous drainage (n = 1). All patients currently are asymptomatic. CONCLUSIONS: In healthy neonates, perianal abscess and fistula are self-limited conditions rarely requiring surgical drainage and not requiring antibiotics. The conservative management of perianal abscess and fistula in healthy infants appears to be safe and effective.

Abscess↗

Shade selection. Communicating with the laboratory technician.

Shade selection for anterior crowns has always set up a communications problem between the dentist and laboratory technician. Over the years, many different techniques have been formulated to help overcome the problem. These techniques include picture taking, drawing diagrams and using multiple porcelain shade guides. However, they have not completely erased the difficulty of communicating the choice of the proper shade of an anterior crown. This was especially true in the 1990's when all-ceramic crowns were introduced. Popular techniques dentists use for communicating shade selections will be reviewed, along with guidelines for making the proper selection. Many dentists are familiar only with the techniques they were taught in dental school and/or residency program and are unaware of the superior methods that can be used. This type of review can be extremely helpful to restorative dentists.

Ceramics↗

What's behind your smile?

Dentistry in the 1990s has seen an evolution in new cosmetic materials and techniques. In order to appreciate and use these methods and materials properly, it is important to have an understanding of cosmetic dentistry and its origins. This article gives a brief history of esthetic dentistry and guidelines for cosmetic dentists of the future.

Esthetics, Dental↗

Laparoscopic colorectal surgery. Do we get faster?

BACKGROUND: A variety of parameters can affect the outcome of laparoscopic colorectal surgery. All consecutive laparoscopic colorectal procedures (LCP) were analyzed in an attempt to define an operative time curve for different categories of procedures. Additionally, impacts of case number and procedure type on length of procedure were assessed. METHODS: Our computerized data system was reviewed for all patients who underwent LCP in a 4-year period. Parameters reviewed included age, sex, surgical indications, procedures performed, length of procedure, intraoperative and postoperative complications, incidence and causes for conversion, duration of postoperative ileus, and hospital stay. RESULTS: Between August 1991 and December 1995, 175 patients with a mean age of 48.4 (range 15-88) years underwent LCP. Patients were divided chronologically into five consecutive groups. Procedures were classified as either basic or complex. Complex procedures were those in which there was either a fixed tumor, an abscess or fistula, or extensive intraabdominal adhesions from prior surgery. Complex procedures performed each year ranged from 37% to 66%. As well, the percentage of patients with adhesions increased from 17% in 1991 to 29% in 1995. Despite increased difficulty, the intraoperative complication rate fell significantly from 29% in 1991 to 8% in 1995 (p < 0.005). Additionally, the operative length decreased from a mean of 201 min in 1991 to a mean of 141 min in 1995 (p < 0.05). CONCLUSION: The rapid improvement in these parameters may reflect both ascents in the learning curve and change in type of procedure. Adhesions, due to prior surgery or inflammation making dissection tedious, is the most important technical factor which effects operation time (p < 0.001). However, despite increased complexity, operating time decreased, reflecting improved skills. Thus, the experienced laparoscopic surgeon can increase the spectrum of applications with expectations of shorter operations and lower complication rates.

Colon↗

The laryngeal mask airway: a new technique for fiberoptic guided vocal cord biopsy.

STUDY OBJECTIVE: To describe a new technique for vocal cord biopsy involving placement of a laryngeal mask airway (LMA) during general anesthesia and fiberoptic guided biopsy. To report our early experience with this technique. DESIGN: Descriptive study. SETTING: Teaching hospital. PATIENTS: 10 patients undergoing vocal cord biopsy for minor laryngeal pathology and with no evidence of infraglottic airway obstruction. INTERVENTIONS: Patients were premedicated 1 hour preoperatively with pethidine 1 mg/kg and atropine 0.01 mg/kg. Following preoxygenation, anesthesia was induced with propofol 2.5 mg/kg and fentanyl 1 mg/kg. Once airway control was established with a facemask, vecuronium 0.1 mg was given and anesthesia established with oxygen (O2) and nitrous oxide mixture and isoflurane 1% to 2%. Gentle direct laryngoscopy was then performed to inspect the pharyngeal structures and the LMA was then inserted in the standard manner by highly experienced LMA users. A fiberoptic scope was passed via a self-sealing mount down the shaft of the LMA to the level of the vocal cords. The vocal cords were then sprayed with local anesthetic and the biopsy taken. MEASUREMENTS AND MAIN RESULTS: The age and weight range were 29 to 57 years and 65 to 85 kg, respectively. All patients were smokers or recent ex-smokers. LMA insertion was readily achieved in all patients, and an excellent view of the vocal cords was obtained. There were no problems with ventilation or obtaining tissue samples, and O2 saturation remained greater than 95% throughout the perioperative period. Tissue samples were adequate in all patients. Hypertension and other adverse cardiac events did not occur during the procedure, which lasted 10 to 20 minutes. There were no problems during emergence from anesthesia, and all patients were discharged home on the same day. CONCLUSIONS: The technique has potential advantages over suspension microlaryngoscopy in that it is relatively noninvasive, it allows good airway control with adequate views of the vocal cords, and it facilitates a smooth recovery.

Adult↗

Anaesthesia for laser pharyngoplasty--a comparison of the tracheal tube with the reinforced laryngeal mask airway.

A common cause of snoring is palatal flutter which occurs when turbulent air flow causes the flexible soft palate to flutter. Surgical correction involves either removal of the soft palate or a reduction in its flexibility. Laser pharyngoplasty is a new surgical procedure designed to stiffen the soft palate. It presents a unique combination of problems for the anaesthetist. In this paper we describe the evolution of the anaesthetic technique for laser pharyngoplasty and analyse the results of the first 165 cases. Points of particular interest include the use of the reinforced laryngeal mask airway compared with the tracheal tube and late onset pain.

Adult↗

Epidermolysis bullosa. A case report.

Epidermolysis bullosa is a group of rare genetic-related skin disorders. It is characterized by bullae and vesicles on the skin and mucosa, that result from friction, trauma, or heat. This article reports a case of Epidermolysis bullosa. With proper diagnosis, the dentist can treat a patient with this type of disorder without causing bullae as a result of treatment.

Dental Care for Persons with Disabilities↗