Abnormal gastric motor function in viral gastroenteritis.

Nausea and vomiting occur commonly with gastroenteritis caused by parvovirus-like agents. Infection results in histologic injury to the small bowel mucosa, but the gastric mucosa remains unaffected. We have studied gastric emptying of liquids serially in 10 volunteers before and after ingestion of the parvovirus-like agents, Norwalk and Hawaii viruses. The five subjects who developed illness all showed marked delays in gastric emptying, while the five well subjects had no alteration of emptying. Five addition volunteers who developed Norwalk virus gastroenteritis underwent serial studies of gastric secretion of hydrochloric acid, pepsin, and intrinsic factor. No change was detected in either basal or betazole-stimulated secretion of these three substances during the course of illness. The nausea and vomiting accompanying this type of viral gastroenteritis may result from abnormal gastric motor function.

Immune response and prevalence of antibody to Norwalk enteritis virus as determined by radioimmunoassay.

A solid-phase microtiter radioimmunoassay was established for the detection of Norwalk virus and its antibody, with clinical materials from human volunteers previously studied in Massachusetts as reagents. A study of 308 Massachusetts residents showed that serum antibody to Norwalk agent was rarely present during childhood but was detectable in approximately 50% of adults. All volunteers inoculated with Norwalk virus who developed illness seroconverted (10/10), whereas only one-third (5/15) of nonill volunteers seroconverted (P = 0.0009). The 10 nonill, nonseroconverting subjects had undetectable to low preexisting antibody levels. Paradoxically, 10/13 subjects with preexisting antibody became ill, whereas 17/25 lacking antibody did not (P = 0.009). All 3 subjects with preexisting anti-Norwalk radioimmunoassay blocking activity in duodenal intraluminal fluids became ill, whereas only 5/11 lacking such activity developed illness (P = 0.15). These data further support the unique concept that some individuals are susceptible to repeated infections with this agent, whereas others are incapable of developing infection.

Paneth cells in Barrett's esophagus.

Paneth cells were identified in esophageal biopsies from 4 patients with Barrett's epithelium of the specialized columnar type. These cells were identical to human intestinal Paneth cells by light microscopy, electron microscopy, and histochemical staining reactions. Retrospective review of biopsies from 8 additional cases with esophageal specialized columnar epithelium yielded 2 further cases with Paneth cells. The presence of Paneth cells, along with goblet cells, suggests that specialized columnar type epithelium in the esophagus may be a form of highly differentiated intestinalization.

Clinical immunity in acute gastroenteritis caused by Norwalk agent.

To examine immunity in viral gastroenteritis, we challenged and then rechallenged 12 volunteers with Norwalk agent and evaluated symptoms, jejunal biopsies and serum antibody. With the first challenge, gastroenteritis developed in six volunteers but not in the others. When rechallenged 27 to 42 months later, the six who became ill initially again had gastroenteritis with jejunal lesions; in the six previously immune volunteers illness or jejunal lesions did not develop. Four of five ill volunteers had increases in serum antibody to Norwalk agent after both challenges. Serum antibody did not increase in three immune volunteers after either challenge. Four volunteers who had twice become ill underwent a third challenge four to eight weeks after their second illness. In one gastroenteritis developed; in three, it did not. These findings indicate two forms of immunity for viral gastroenteritis, one of short and the other of long duration. Factors other than serum antibody appear important in immunity to Norwalk gastroenteritis.

Structure of the gastric mucosa in acute infectious bacterial gastroenteritis.

It is now well documented that a characteristic mucosal lesion of the proximal small intestine is present in acute nonbacterial gastroenteritis. To determine whether a gastric mucosal lesion also accompanies this illness, stool filtrate containing Norwalk agent was given orally to 15 volunteers after base line biopsies of gastric fundal and/or antral mucosa had been obtained. Gastric fundal and/or antral biopsies were then obtained serially between 24 and 168 hr after administration of the inoculum. Nine volunteers developed symptoms of gastroenteritis. gastric biopsies from those with normal base line fundal and/or antral biopsies remained normal during and after clinical illness. Those volunteers who had mild to moderate gastritis in their base line biopsies showed persistence but no progression of the lesion during illness. In 4 of the volunteers who became ill, intestinal biopsies were available and showed the typical gastroenteritis lesion. These results indicate that acute infectious nonbacterial gastroenteritis induced by Norwalk agent is not associated with histologically detectable gastric mucosal lesion.