Functional and morphological characteristics of neuronal substance P in the canine gastroesophageal junction.

The specific functions of the numerous substance P (SP) nerve fibers present within the gastrointestinal tract are not clearly defined. This study examines both functional aspects and distribution of immunoreactive SP (IR-SP) in the canine gastroesophageal junctional (GEJ) region. Lower esophageal sphincter pressure (LESP), mean arterial pressure (MAP), pulse rate (PR), and respiratory rate (RR) were monitored before and after topical application of 2 ml capsaicin (8-methyl-N-vanillyl-6-nonenamide) to the distal esophageal mucosa of anesthetized dogs. Animals then underwent a capsaicin desensitization protocol over a 12-day period. The responses of monitored variables were compared on Day 1 and Day 12 of repetitive capsaicin application. Immunohistochemistry and radioimmunoassay (RIA) were performed on GEJ segments to study the distribution and content of IR-SP in both control (untreated) and capsaicin-treated dogs. The IR-SP was extracted from tissue for RIA and analysis by reverse-phase high-performance liquid chromatography (HPLC). On Day 1, a 2-ml capsaicin application stimulated increases in LESP (44.3 +/- 7.8 cm H2O; P < 0.05), MAP (48 +/- 8.7 mm Hg; P < 0.05), PR (52.6 +/- 20.5 beats/min; P < 0.05), and RR (26.3 +/- 15.6 breaths/min; P > 0.2). No response was observed on Day 12 of treatment. This was accompanied by a 43.3% decrease of IR-SP content in the mucosa of the distal esophagus of desensitized animals. Capsaicin applied at greater concentrations on Day 12 stimulated a return of responses (P < 0.05). Ganglia, cell bodies, nerve fascicles, and neurites stained positively for IR-SP. IR-SP content was markedly higher in esophageal mucosa than in gastric mucosa (P < 0.05). The authenticity of the IR-SP molecule was confirmed by elution time on HPLC. In conclusion, repetitive capsaicin application induced a state of homologous desensitization which was accompanied by a partial depletion of mucosal SP. The GEJ region contains a high SP content with a broad neural distribution. These findings are consistent with the hypothesis that SP may act as a neurotransmitter for chemonociceptive stimuli in the canine distal esophagus.

Tachykinins in the canine gastroesophageal junction.

Lower esophageal sphincter (LES) effects produced by the mammalian tachykinins were evaluated in anesthetized dogs. The distribution and content of substance P (SP) and neurokinin A (NKA) in the region of the canine gastroesophageal junction was also studied. SP and NKA stimulated a linear dose-dependent contraction of the LES after intra-arterial administration. Neurokinin B (NKB) failed to stimulate an increase in LES pressure (LESP). SP was characterized by an immediate but short-lived contraction followed by a period of relaxation. NKA stimulated a potent LES contraction that was slow in onset but long-lasting. On an equimolar basis, both SP and NKA were approximately 100 times more potent LES stimulants than bethanechol or phenylephrine. Pretreatment with atropine (muscarinic blockade) or tetrodotoxin (neural blockade) inhibited the effect produced by SP. NKA appeared to stimulate LES contraction independent of neural or cholinergic mechanisms. Radioimmunoassay revealed a regional variation in tachykinin content in the gastroesophageal junction. Ganglia, cell bodies, nerve fascicles, and neurites stained specifically for both SP and NKA. The variable effects, potencies, and mechanisms of action observed in this study suggest the presence of specific tachykinin receptor subtypes in the gastroesophageal junction. Both SP and NKA were found to have a broad neural distribution in this region. These findings suggest that the tachykinins may play an important role in neuroregulation of LES smooth muscle.

Linkage, expression, and distribution of the pyrethroid resistance gene in the horn fly (Diptera: Muscidae).

A sex-linked gene for pyrethroid resistance in the horn fly, Haematobia irritans (L.), showed complete linkage to the male-determining gene in a laboratory colony that had been inbred for 10 generations. Within susceptible, heterozygous, and resistant populations, the level of resistance that was expressed was greater for females than for males. The increase in level of resistance conferred by the gene was similar for females and males. Preliminary synergism and allelism tests supported our supposition that the same gene was responsible for resistance in California, Florida, and Texas populations.

Differential survival of male and female partially resistant horn flies (Diptera: Muscidae) on steers treated with permethrin.

Males and females from a heterozygous, resistant strain (SR) of the horn fly, Haematobia irritans (L.), were tested for survival until reproductive maturity on steers with ear tags in outdoor, screened enclosures and on steers sprayed on the neck in an indoor isolation room. After 6 d, female SR flies on outdoor steers with one tag had 10 times greater survival than males; almost no SR flies on steers with two ear tags survived. Survival of male and female SR flies on steers sprayed on the neck was reduced during the first 24 h, but not thereafter. Lower survival of males compared with females on treated steers reflected differential survival of the sexes during exposure to treated cloths in a laboratory bioassay. Hair samples from neck, back, rump, and lower legs of steers with ear tags in outdoor pens were tested for toxicity to the SR flies. These bioassays indicated high localization of insecticide on the neck of steers with ear tags.

Chronology of permethrin resistance in a southern Illinois population of the horn fly (Diptera: Muscidae) during and after selection by pyrethroid use.

From 1985 through 1988, horn flies (Haematobia irritans (L)) collected at the Dixon Springs Agricultural Center (DSAC) in southern Illinois were tested in 22 h bioassays for permethrin resistance with residues on cotton cloths. The LC90 for a susceptible field population collected in June 1985 was 0.19 micrograms/cm2. In comparison, flies collected from pyrethroid-tagged cattle in 1985 and 1986 exhibited 25- to 116-fold resistance to permethrin. A 25-fold level of resistance allowed survival on treated cattle 8 wk after pyrethroid tag application. Flies representing the local background population were collected periodically from an untreated herd 2.4 km from the nearest cattle treated with a pyrethroid; these flies exhibited up to 18-fold resistance. Although pyrethroids were not used on DSAC animals after October 1986, all bioassays done in 1987 and 1988 indicated resistance levels of greater than or equal to 7-fold. The 95% confidence intervals for LC90s from all 1987 bioassays overlapped the confidence interval from the corresponding July 1986 estimate for resistant flies collected from pyrethroid-tagged cattle. Although some decline in resistance was evident in 1988, bioassays done at the end of the season produced resistance ratios of 7.4 and 15.3. Survivorship at a diagnostic dose indicated that resistance frequencies remained at 4-8% throughout 1988. Two years' abstinence from pyrethroid use was insufficient to allow an adequate decline in resistance levels.

Computer-assisted medical direction of respiratory care.

As medical technology and the increased demand for respiratory care make concurrent monitoring of all respiratory care services more difficult, computers are coming to the aid of medical directors and quality assurance committees. The respiratory care staff at LDS Hospital, Salt Lake City, has used computers to enhance patient care and quality assurance.

Longitudinal pulmonary function changes in pigeon breeders.

We studied 15 subjects (14 men and one woman; seven symptomatic and eight asymptomatic) at three- to four-year intervals from 1967 through 1985 (18 years) to determine if continued pigeon antigen exposure in these groups was associated with a decline in pulmonary function greater than expected in healthy individuals. We collected immunologic studies at the initial visit, performed sequential pulmonary function studies and obtained chest radiographs. After compensating for the normal changes expected with increasing age, we found the declines in FVC, FEV1, and Dsb in the symptomatic group were nearly four times greater than expected. There was no significant difference in the decline of pulmonary function between asymptomatic subjects and the normal predicted declines with increasing age. We conclude that, if an individual has episodes of acute hypersensitivity pneumonitis, long-term exposure to pigeon antigens will result in an accelerated decline in pulmonary function.

A decision-driven system to collect the patient history.

We have developed a computer-administered history designed to directly interview hospitalized patients with pulmonary disease. A frame-based decision system is used to direct the history and to generate a one- to five-member differential diagnostic list based on this history. This system incorporates a cognitive model of question selection and a Bayesian scoring algorithm. Structures to control the choice of questions are embedded in the diagnostic frames and in a QUERY program that makes the final choice of questions. We have compared the behavior of this decision-driven approach with a history taken using a paper questionnaire. The paper-based history presents 182 questions to every patient and captured 75% of 85 pulmonary diseases in its differential lists. The decision-driven system asks 50.7 +/- 31.0 (mean +/- standard deviation) and captured 74% of 61 pulmonary diseases. Our experience suggests that the use of a computerized diagnostic knowledge base to direct the selection of pertinent questions can substantially reduce the number of questions necessary to collect a diagnostically useful patient history.

[Measures for reducing complications in anus praeternaturalis repair]. / Massnahmen zur Reduktion der Komplikationen bei der Anus praeternaturalis-Rückverlagerung.

Colostomy closure has also today a complication rate between 20 and 30% in the literature, in which infectious complications are playing a substantial role. Increasing experience and standardization as well as better preoperative treatment, like whole gut irrigation and perioperative antibiotics and the additional use of a Gentamicin-PMMA-chain, led to a distinct reduction of the postoperative complication rate in a prospective study of 40 colostomy closures.

Prolonged mechanical ventilation for respiratory failure: a cost-benefit analysis.

To define the costs and benefits associated with prolonged mechanical ventilation, we studied retrospectively the records of 137 consecutive patients who required at least 48 h of ventilator support. The patients were physiologically unstable and required intensive care. Causes of respiratory failure included pulmonary diseases, post-operative complications, neuromuscular diseases, cardiac dysfunction, and GI disease. Forty-nine (36%) patients survived the hospitalization, and 38 (28%) patients were alive 3 yr after receiving prolonged mechanical ventilation. The mean total hospital cost was +16,930/patient (U.S. dollars, 1976-1977). The cost-benefit averaged +1826/yr of extended life. These costs varied from +460/yr of extended life for patients with respiratory failure complicating asthma to +8026/yr for patients with cardiac dysfunction. The cost-benefit ratio increased sharply for men older than 56 yr and for women older than 75 yr. These data document the importance of the basic disease process and the patient's age in the cost-benefit relationship.

[Colon surgery in old age]. / Kolonoperationen im Greisenalter.

Between 1975 and 1981, 632 patients with colon diseases underwent surgery. 93 (14.7%) patients were aged 80 or more. 90% of this age group had a colon cancer, 60% were in the tumour stage III or IV (TNM). An emergency operation was necessary in 37 (40%) cases, the postoperative mortality rate was nearly 60%. 62 patients underwent a selective colon operation with the postoperative mortality rate in this group amounting to 9.7%, impaired wound healing occurred in 25.8%. Preoperative treatment is described.

Comparison of two teaching methods for self-care training for patients with chronic obstructive pulmonary disease.

Group instruction in self care is a widely used adjunct to the medical management of chronic obstructive pulmonary disease (COPD). Such classes are neither convenient nor accessible to all COPD patients, however, especially those in rural areas. A self-teaching module could be a practical means of serving hard-to-reach patients. This study compares the results of a self-teaching module with those of an established group method in teaching 13 self-care skills to COPD patients. On referral from their physicians, patients in eight rural locations were randomly assigned to receive training through a group or a self-teaching process. Knowledge gain, skill attainment, skill implementation, and beneficial results were measured at the end of instruction and again six months later. The two teaching methods were compared by analyzing the data on 34 patients matched for the variables of smoking, diagnosis, and severity of disease. No statistically significant difference was observed between the two educational methods in any of the parameters measured. The fact that approximately three out of four patients benefited through either process suggests that the self-teaching module is as effective as group instruction.

Modified ventilator with liquid-oxygen system for transport of adult patients with acute respiratory failure.

The value of modern techniques of respiratory care for patients with acute respiratory failure in specialized intensive care units has been documented. Unfortunately, many patients needing this type of care are located far from such resources and require transportation over large distances. This paper describes a modified bird Mark 14 ventilator and a Linde liquid oxygen attachment used successfully in the air and ground transport of 84 patients over a five-year period.