Using n-alkanes to estimate diet composition of herbivores: a novel mathematical approach.

N-alkanes are long-chain saturated hydrocarbons occurring in plant cuticles that can be used as chemical markers for estimating the diet composition of herbivores. An important constraint of using n-alkanes to estimate diet composition with currently employed mathematical procedures is that the number of markers must be equal or larger than the number of diet components. This is a considerable limitation when dealing with free-ranging herbivores feeding on complex plant communities. We present a novel approach for the estimation of diet composition using n-alkanes which applies equally to cases where the number of markers is lower, equal or greater than the number of plant species in the diet. The model uses linear programming to estimate the minimum and maximum proportions of each plant in the diet, and avoids the need for grouping species in order to reduce the number of estimated dietary components. We illustrate the model with two data sets of n-alkane content of plants and faeces obtained from a sheep grazing experiment conducted in Australia and a red deer study in Portugal. Our results are consistent with previous studies on those data sets and provide additional information on the proportions of individual species in the diet. Results show that sheep included in the diet high proportions of white clover (from 0.25 to 0.37), and relatively high proportions of grasses (e.g. brome from 0.14 to 0.26) but tended to avoid Lotus spp. (always less than 0.04 of the diet). For red deer we found high proportions of legumes (e.g. Trifolium angustifolium and Vicia sativa reaching maximum proportions of 0.42 and 0.30 of the diet, respectively) with grasses being less important and Cistus ladanifer, a browse, also having relevance (from 0.21 to 0.42 of the diet).

Telementoring. A practical option in surgical training.

BACKGROUND: Telemedicine offers significant advantages in bringing consulting support to distant colleagues. There is a shortage of surgeons trained in performing advanced laparoscopic operations. AIM: Our aim was to evaluate the role of telementoring in the training of advanced laparoscopic surgical procedures. METHODS: Student surgeons received a uniform training format to enhance their laparoscopic skills and intracorporeal suturing techniques and specific procedural training in laparoscopic colonic resections and Nissen fundoplication. Subsequently, operating rooms were equipped with three cameras. Telestrator (teleguidance device), instant replay (to critique errors), and CD-ROM programs (to provide information of reference) were used as intraoperative educational assistance tools. In phase I, four colonic resections were performed with the mentor in the operating room (group A) and four colonic resections were performed with the mentor on the hospital grounds, but not in the operating room (group B). The voice and video signals were received at the mentor's location, using coaxial cable. In phase II, two Nissen fundoplications were performed with the mentors in the operating room (group C) and two Nissen fundoplications were performed with the mentors positioned five miles away from the operating room (group D), using currently existing land lines at the T-1 level. RESULTS: There were no differences in the performances of the surgeons and outcome of the operations between groups A & B and C & D. It was possible to tackle the intraoperative problems effectively. CONCLUSIONS: The telementoring concept is potentially a safe and cost-effective option for advanced training in laparoscopic operations. Further investigation is necessary before routine transcontinental patient applications are attempted.

Biliary access procedure in the management of oriental cholangiohepatitis.

The objective was to review the treatment of oriental cholangiohepatitis using a combined approach of surgical access to the biliary tree with a cutaneous choledochoenteric conduit and interventional radiology to remove intrahepatic stones and dilate biliary strictures. Design was a retrospective case series. Oriental cholangiohepatitis is a condition marked by intrahepatic strictures and extensive formation of pigmented stones leading to recurrent biliary sepsis and hepatic abscesses. It is a common condition in southeast Asia and is seen with increasing frequency in Western populations due to Asian immigration. Ten patients were treated at Tripler Army Medical Center from 1986 to 1994. Tripler is a 500 bed tertiary referral center located in Honolulu, Hawaii, and serves the military community in the Pacific basin as well as beneficiaries of the Trust Territories of Micronesia. Patients underwent cholecystectomy and formation of a Roux-en-Y choledochojejunostomy with a lateral limb that was brought out as a cutaneous stoma. After 4 weeks of healing, the intestinal conduit was used by the interventional radiologist to extract retained stones and dilate strictures using a variety of techniques. This was easily performed under light sedation. After completion of therapy, the stoma was closed and buried subcutaneously. This retains the option for accessing the conduit percutaneously or reopening the stoma if necessary for recurrence. Resolution of symptoms and radiologic clearance of intrahepatic stones, biliary strictures, and hepatic abscesses were the main outcome measures. Eight patients underwent the biliary access procedure and had clearance of stones and strictures after one to 10 interventional sessions. There was no major morbidity associated with treatment. No patient required liver resection, and there was resolution of the hepatic abscesses in all cases. The access procedure could not be completed in one patient due to extensive adhesions; this patient was successfully treated by endoscopic retrograde cannulation of the biliary duct. Another patient was treated by the same method on several occasions and never referred to surgery. A combined approach using surgical access to the biliary tree and interventional radiology offers effective treatment of oriental cholangiohepatitis without the need for hepatic resection.

The impossible airway: a plan.

A patient presented with near complete airway obstruction due to a massive tumor. Nonsurgical methods failed to secure the airway, and surgical approaches were considered unlikely to succeed in a timely fashion. Cardiopulmonary bypass via femoral-femoral cannulation with the use of local anesthesia and a portable unit, followed by IV anesthesia, allowed the surgeons to perform a controlled tracheotomy.

Tuberculous peritonitis--do not miss it.

UNLABELLED: Incidence of tuberculosis is sharply rising in the United States, and tuberculous peritonitis is often diagnosed late in the course of the disease, resulting in undue patient morbidity and mortality. PURPOSE: Purpose of this study was to better identify which clinical, laboratory, radiologic, and invasive procedures were most useful in diagnosing tuberculous peritonitis. METHODS: All cases of tuberculous peritonitis diagnosed between 1982 and 1994 were reviewed retrospectively to discern which laboratory, radiographic, and procedural tests were helpful in diagnosing the condition. RESULTS: Twenty-eight cases of tuberculous peritonitis were diagnosed during the studied period. Two patients were not diagnosed until autopsy. Patients from all socioeconomic classes and multiple races ranged in age from 3 to 69 (mean, 29.5) years. Most patients presented with a chronic wasting illness, mild abdominal pain, and fever. Purified protein derivative was only positive in 5 of 16 patients. Chest radiographs were suggestive of pulmonary tuberculosis (TB) in five patients. Ultrasound examination of the abdomen was helpful in five patients, and computed tomographic scan was suspicious in 16 of 17 patients. Sputum for acid fast bacillus (AFB) smear was positive in 3 of 14 patients, and paracentesis for AFB smear was positive in 1 of 8 patients. Routine blood work was not helpful. Laparoscopy was diagnostic in five of seven patients. Laparotomy and tissue biopsy of characteristic tissue for AFB smear and culture was diagnostic in 20 of 20 patients. Once diagnosed, all patients responded rapidly to empiric antituberculous medical therapy, except one patient with miliary TB who died shortly after diagnosis. A trend in earlier diagnosis was noted in recent years and is felt to be the result of an elevated index of suspicion. CONCLUSIONS: TB peritonitis may be fatal but is medically cured if diagnosed in a timely fashion. It is essential that the clinician suspect the disease in appropriate patients. Tests frequently associated with TB such as chest radiograph and purified protein derivative are not sensitive in detection of TB peritonitis. Computed tomographic scan is the most useful radiographic study. Mini laparotomy with tissue biopsy for smear and culture is the most sensitive and specific diagnostic procedure.

Tincture of benzoin: clinical and microbiological implications of reusable containers.

At our institution, tincture of benzoin solution is commonly used as a topical adhesive agent. As a cost-saving practice, multiple-dose bottles are routinely used in the operating rooms and the clinic on multiple patients. Although clinically pathogenic organisms are known to be capable of survival in both benzoin and its isopropyl alcohol solvent, no prior controlled studies have investigated the potential for tincture of benzoin solution to support the growth of specific pathogens under clinically relevant conditions. In this study, multiple aerobic, anaerobic, and spore-forming bacteria were exposed to tincture of benzoin solution, as well as Candida albicans and Mycobacterium fortuitum. Bacillus cereus was the only index organism demonstrating a clear ability to survive a 15 minute incubation in tincture of benzoin, although 24 hours of exposure to tincture of benzoin resulted in no subsequent viable cultures of this organism after 72 hours of incubation. Thus although certain bacilli might, under ideal circumstances, remain viable and infectious within multiple-dose bottles of tincture of benzoin, the risk of causing iatrogenic infection appears to be rather minimal. Still, the use of multiple-dose dispensers of topical agents, particularly in surgical patients, should be carefully scrutinized for their clinical risk-to-economic benefit ratio.

Pilonidal sinus disease. The conservative approach.

OBJECTIVE: To examine the role of conservative, nonexcisional methods in the treatment of pilonidal sinus disease. DESIGN: Pilot nonrandomized cohort study and follow-up retrospective study. SETTING AND PATIENTS: In the pilot study, all patients treated for pilonidal sinus disease consecutively over 3 years at an Army community hospital, and in the follow-up study within a closed federal population, all patients admitted with a diagnosis of pilonidal sinus disease over 17 years to an Army medical center. INTERVENTIONS: Conservative, nonexcisional therapy (meticulous hair control by natal cleft shaving, improved perineal hygiene, and limited lateral incision and drainage for abscess) with initial comparison to excisional procedures. MAIN OUTCOME MEASURES: Occupied-bed days for conservative vs excisional therapy during a 3-year pilot study and the number of admissions and procedures performed for pilonidal sinus disease at an institution dedicated to conservative treatment alone. RESULTS: Complete healing over 83 occupied-bed days was demonstrated in 101 consecutive cases managed during 1 year with the conservative method, whereas slower healing over 4760 occupied-bed days was observed in 229 patients undergoing 240 operative procedures during the preceding 2 years. With application of conservative treatment over 17 years, only 23 excisional operations were performed. CONCLUSIONS: Conservative therapy effectively controls pilonidal sinus disease in the nonoperative outpatient setting while promoting near-normal work status and is preferred over excisional operations.

Roentgenographic evaluation of the cervical spine. A selective approach.

BACKGROUND: To determine if routine radiographic evaluation of the cervical spine could be eliminated in the alert, sober trauma patient who has no neck pain, tenderness, or other major injuries without a significant increase in missed occult injury. DESIGN: Prospective cohort study. SETTING: Emergency department and general surgery service at a military tertiary medical center. MAIN OUTCOME MEASURE: Those patients with cervical spine injuries. RESULTS: Sixteen patients (2%) had cervical spine injuries, all had signs and/or symptoms of their injury on presentation. Ninety-six patients (14%) who were not intoxicated and had no neck pain, tenderness, or other major injuries were evaluated. None of these patients had abnormal cervical spine studies. Two hundred ninety patients (43%) were followed up between 30 to 150 days. No missed injuries were noted. CONCLUSIONS: These results indicate that blunt trauma patients may not require cervical spine roentgenography if they meet the following criteria: absence of mental status changes, intoxication, neck pain or tenderness, neurologic signs or symptoms, or simultaneous major distracting injury. Because of the small incidence of cervical spine injuries, further studies are necessary to evaluate the positive predictive value of history and physical examination of the cervical spine in a trauma patient.

Femoral hernia in children: an infrequent problem revisited.

Femoral hernias are of very rare occurrence at any age, but are exceedingly rare in the pediatric population. A 10-year survey, 1979-1989, of our experience with pediatric hernias produced a total of 1,134 inguinal hernias and 6 femoral hernias, supporting an incidence of 0.5% for femoral hernias in our population. The correct diagnosis was made in only two cases preoperatively. These two patients had undergone inguinal herniorrhaphies less than 6 months prior to presenting with recurrent groin masses. Femoral hernias were most frequently misdiagnosed as inguinal hernias. Inclusion of this entity in the differential diagnosis of groin masses, an accurate preoperative physical exam, and a careful surgical exploration will allow one to make the correct diagnosis and prevent unnecessary reoperations. In addition, early recurrence of a groin mass after inguinal exploration and herniorrhaphy should make one suspicious of a femoral hernia. At surgery, our recommendations include a simple infra-inguinal exploration medial to the femoral vessels when an inguinal hernia is unexpectedly not found at groin exploration and a Cooper's ligament repair when a femoral hernia is encountered. All six cases in our review were repaired with Cooper's ligament repair without complication.

Exploratory laparotomy for diagnosis of tuberculous peritonitis.

Tuberculous (TB) peritonitis is uncommon but may present at any age and socioeconomic group. We reviewed 14 patients with TB peritonitis diagnosed during a five year period (six were white and eight, Pacific Islanders). The mean age was 31 years (a range of three to 69 years). Symptoms, signs and laboratory and roentgenologic studies were not specific. Peritoneal tap and laparoscopic procedures gave positive results of Mycobacterium tuberculi in four of seven patients. Diagnosis was not suspected in two patients until autopsy. TB peritonitis was confirmed at exploratory laparotomy in the other eight patients. Several common misconceptions about TB peritonitis have been discussed and refuted.

Fatal poisoning from sodium phosphate enema. Case report and experimental study.

An overdose of a common over-the-counter sodium phosphate enema solution was fatal in an infant. The marked hypernatremia, acidemia, hyperphosphatemia, and hypocalcemia observed before death were also produced in a porcine model. A study using pigs showed that the enema solution was lethal if retained in doses above 20 mL/kg, equivalent to four pediatric-sized enemas in a 2-year-old child. Even normal doses of the enema solution caused measurable changes in serum phosphorus and calcium levels.

Neonatal zygomycotic necrotizing cellulitis.

Zygomycosis is a rare infection that should be suspected in any patient with a fulminant necrotizing cellulitis in an area recently covered with adhesive bandages or dressings. Early diagnosis and treatment are essential for patient survival.

Peritoneal lavage as an aid in the surgical management of neutropenic colitis.

Neutropenic colitis is a severe, often devastating complication of acute leukemia. The diagnosis can be difficult as the symptoms are often those of the leukemia itself or of the therapy being rendered. These anemic, thrombocytopenic, and severely immunosuppressed patients present great operative risks. Distinction between the surgical and nonsurgical abdomen can be a challenge for even the most experienced surgeon. Peritoneal lavage may serve as a means to help in this differentiation.

Total parenteral nutrition cholestasis: a cause of mechanical biliary obstruction.

In a newborn baby with Hirshsprung's disease obstructive jaundice developed following prolonged parenteral nutrition. At laparotomy, thick inspissated bile was flushed from the biliary tree and prompt resolution of the jaundice followed. To our knowledge, this is the first reported case in which inspissated bile appeared to be a complication of total parenteral nutrition. Mechanical obstruction must be recognized as an extreme in the spectrum of total parenteral nutrition cholestasis.

Nonaccidental burns in child abuse.

Nonaccidental or inflicted burns account for a significant subset of children hospitalized for the treatment of burns and are a form of child abuse. We review our experience with inpatient treatment of pediatric burns and examine the characteristics of patients with accidental and nonaccidental burns. Abused children were of a younger age group. Their burns more frequently involved the buttocks and perineum and were more often caused by hot tap water. Unstable social factors and chronic medical problems were more common among those with inflicted burns. We suggest guidelines to differentiate between accidental and inflicted burn victims.