Neurogenic and myogenic patterns of electrical activity in isolated intact mouse colon

BACKGROUND

Relatively little is known about the electrical rhythmicity of the whole colon, where long neural pathways are preserved.

METHODS

Smooth muscle electrical activity was recorded extracellularly from the serosa of isolated flat-sheet preparations consisting of the whole mouse colon (n=31).

KEY RESULTS

Two distinct electrical patterns were observed. The first, long intense spike bursts, occurred every 349±256 seconds (0.2±0.2 cpm), firing action potentials for 31±11 seconds at 2.1±0.5 Hz. They were hexamethonium- and tetrodotoxin-sensitive, but persisted in nicardipine as 2 Hz electrical oscillations lacking action potentials. This pattern is called here neurogenic spike bursts. The second pattern, short spike bursts, occurred about every 30 seconds (2.0±0.6 cpm), with action potentials firing at about 1 Hz for 9 seconds (1.0±0.2 Hz, 9±4 seconds). Short spike bursts were hexamethonium- and tetrodotoxin-resistant but nicardipine-sensitive and thus called here myogenic spike bursts. Neurogenic spike bursts transiently delayed myogenic spike bursts, while blocking neurogenic activity enhanced myogenic spike burst durations. External stimuli significantly affected neurogenic but not myogenic spike bursts. Aboral electrical or mechanical stimuli evoked premature neurogenic spike bursts. Circumferential stretch significantly decreased intervals between neurogenic spike bursts. Lesioning the colon down to 10 mm segments significantly increased intervals or abolished neurogenic spike bursts, while myogenic spike bursts persisted.

CONCLUSIONS & INFERENCES

Distinct neurogenic and myogenic electrical patterns were recorded from mouse colonic muscularis externa. Neurogenic spike bursts likely correlate with neurogenic colonic migrating motor complexes (CMMC) and are highly sensitive to mechanical stimuli. Myogenic spike bursts may correspond to slow myogenic contractions, whose duration can be modulated by enteric neural activity.

Links between social understanding and social behavior in verbally able children with autism

This study investigated the relations between various measures of social understanding and social interaction competence in verbally able children with autism. Measures of social understanding included measures of verbalizable knowledge (false belief understanding, affective perspective taking), as well as measures of more intuitive forms of social responsiveness (empathy, concern to distress, and initiating joint attention). Two measures of social interaction competence were employed: level of engagement with peers on the playground, and prosocial behavior in a structured laboratory task. For children with autism, initiating joint attention and empathy were strongly related to both measures of social interaction competence. No understanding-behavior links were identified for a language-age matched comparison sample of developmentally delayed children. Several accounts of these understanding-behavior links are considered, including the possibility that for children with autism, more impaired forms of understanding are more closely linked to behavior because they serve as limits on competence.

Information Science for the Future: An Innovative Nursing Informatics Curriculum

Health care is increasingly driven by information, and consequently, patient care will demand effective management of information. The report of the Priority Expert Panel E: Nursing Informatics and Enhancing Clinical Care Through Nursing Informatics challenges faculty to produce baccalaureate graduates who use information technologies to improve the patient care process and change health care. The challenge is to construct an evolving nursing informatics curriculum to provide nursing professionals with the foundation for affecting health care delivery. This article discusses the design, implementation, and evaluation of an innovative nursing informatics curriculum incorporated into a baccalaureate nursing program. The basic components of the curriculum framework are information, technology, and clinical care process. The presented integrated curriculum is effective in familiarizing students with informatics and encouraging them to think critically about using informatics in practice. The two groups of students who completed the four-course sequence will be discussed.

Diabetic gastroparesis due to postprandial antral hypomotility in childhood

Nausea, vomiting, chronic abdominal pain, and constipation developed in three children with insulin-dependent diabetes mellitus beginning 1 to 7 years after the onset of diabetes. All three had considerable difficulty in achieving satisfactory glycemic control. All had delayed gastric emptying of solids and postprandial antral hypomotility. Diabetic autonomic neuropathy must be considered in the differential diagnosis of gastrointestinal symptoms even in the young diabetic patient.

Link between caudal regression and Vater syndromes

A variant between caudal and regression and Vater syndromes is presented which was significant anomalies of the genitourinary tract. The patient has a normal 46XX karyotype with the following urogenital anomalies: solitary pelvic kidney with megacalycosis, high ureteral bud or diverticulum, and ectopic insertion of the ureter into the proximal urethra; as well as, sacral agenesis, vaginal atresia, aberrant gonadal tissue, and uterine agenesis.

Nature of the Ultraviolet Absorber in the Venus Clouds: Inferences Based on Pioneer Venus Data

Several photometric measurements of Venus made from the Pioneer Venus orbiter and probes indicate that solar near-ultraviolet radiation is being absorbed throughout much of the main cloud region, but little above the clouds or within the first one or two optical depths. Radiative transfer calculations were carried out to simulate both Pioneer Venus and ground-based data for a number of proposed cloud compositions. This comparison rules out models invoking nitrogen dioxide, meteoritic material, and volatile metals as the source of the ultraviolet absorption. Models involving either small ( approximately 1 micrometer) or large ( approximately 10 micrometers) sulfur particles have some serious difficulties, while ones invoking sulfur dioxide gas appear to be promising.