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Biomedical subjects

G W Meyer

Publications and source records attributed to G W Meyer.

At least 19 recordsLinked to original sources
PubMed2000

Peristaltic pressure profiles of the human esophagus.

Using a low-compliance pneumohydraulic infusion system, we mapped the entire esophagus of nine volunteers with no history of esophageal disease, centimeter by centimeter, to see if there was pressure symmetry throughout the esophagus during 5 mL wet swallows. We found that esophageal length varied from 21-25 cm. The esophageal low-pressure zone (LPZ) varies in distance from the upper esophageal sphincter (UES) (4-8 cm). The length of this LPZ is 2-3 cm in most subjects but low pressures (<50 mmHg) may occur for longer intervals in some. The amplitudes of most paired swallows were within 10 mmHg of each other, and in only 10% of swallows was the pressure difference more than 15 mmHg. We conclude that there is radial pressure symmetry throughout the normal esophagus. The LPZ coincides closely to the 50-50 point where the percentage of striated and smooth muscle distribution in the circular and longitudinal muscles is equal.

Adult↗
PubMed1997

Antibiotic prophylaxis for orthopedic prostheses and GI procedures: report of a survey.

OBJECTIVE: To determine the practice recommendations of Program Directors of infectious disease training programs with regard to infection prophylaxis for patients with prosthetic orthopedic devices who undergo gastrointestinal procedures. METHODS: We surveyed Program Directors of infectious disease training programs to determine what they recommend when asked about antibiotic prophylaxis for patients with orthopedic prostheses who undergo gastrointestinal procedures. RESULTS: More than 50% of the respondents agreed that prophylaxis is not indicated at any time for these procedures, although there was an almost even split when confronted with colonoscopy and polypectomy within 6 months of prosthesis insertion. CONCLUSIONS: Most Program Directors agree with the recommendations of the American Society for Gastrointestinal Endoscopy and do not recommend prophylactic antibiotics for these patients. If antibiotics are chosen, they should be the same ones that are recommended for infectious endocarditis by The American Heart Association.

Anti-Bacterial Agents↗
PubMed1991

Hyperbaric oxygen therapy for acute smoke inhalation injuries.

Hyperbaric oxygen therapy is an important adjunct in the management of respiratory injuries secondary to smoke inhalation, especially when injury is complicated by inhalation of a toxic chemical such as carbon monoxide or cyanide. For carbon monoxide poisoning, such therapy has become a standard of practice. As more information becomes available concerning the ability of hyperbaric oxygen to reduce reperfusion injuries, we anticipate that this therapy will become a standard of practice for managing smoke inhalation injuries and cyanide poisoning as well.

Antidotes↗
PubMed1987

Metoclopramide effect on esophageal peristalsis in normal human volunteers.

There is relatively poor documentation of the effect of metoclopramide on the human esophageal body. We, therefore, studied several parameters of esophageal function in 19 normal volunteers both before and after 20 mg intravenous metoclopramide. Contraction amplitude, wave duration, velocity, and propagation time were increased after metoclopramide. These changes were more pronounced in the distal esophagus. At the most distal manometric recording level located 2 cm above the lower esophageal sphincter, contraction amplitude increased 39% (p less than 0.01) and duration increased 22.5% (p less than 0.01) after metoclopramide. We conclude that in normal subjects metoclopramide has an effect predominant in the distal body of the esophagus.

Adult↗
PubMed1986

Muscle anatomy of the human esophagus.

We studied the esophageal musculature of 11 cadavers to assess the distribution of striated and smooth muscle. The lower 54-62% of the esophagus was found to be exclusively smooth muscle, the proximal 4.1-5.6% to be exclusively striated, and the remainder to be mixed. The area in which striated and smooth muscle portions were approximately equal, the 50/50 point, was found to be 4.7 +/- 0.6 cm from the proximal portion of the cricopharyngeus muscle. This point corresponds to the previously described physiologic low pressure zone in the proximal esophagus.

Adult↗
PubMed1983

In vivo migration of 111In radiolabeled mouse-spleen lymphocytes and tumor cells.

Mouse-spleen lymphocytes, mouse mammary adenocarcinoma cells (MMA-67) and mouse lymphoma cells (S49.1) were radiolabeled with 111In and their in vivo migration patterns studied over a 24-72 h period after i.v. injection into syngeneic mice. All three cell lines showed different in vivo migration patterns. Initially, some trapping of the cells occurred in the lungs at 15 min. More MMA-67 cells were initially trapped in the lungs than S49.1 cells or lymphocytes. At 24 h, most of the 111In labeled cells had left the lungs and accumulated in various tissues and organs. At 48 and 72 h, only slight changes in the localization patterns of the 111In radiolabeled cells in vivo were noted when compared to the 24 h patterns. About 35% of the injected 111In was excreted from the animals over the 72 h period of these experiments. In vitro studies compared the growth and/or viability of 111In radiolabeled lymphocytes or tumor cells to nonradiolabeled lymphocytes or tumor cells. The percentage of 111In released from the cells in culture was also determined. Similar values for growth and/or viability were obtained between non-radiolabeled cells and MMA-67 cells radiolabeled with 1.35 dpm 111In per cell; S49.1 cells, 0.51 dpm111In per cell; and lymphocytes, 0.04 dpm 111In per cell.

Adenocarcinoma↗
PubMed1983

Efficacy of atropine as an endoscopic premedication.

To determine the efficacy of atropine as an endoscopic premedication, we prospectively evaluated in double-blind fashion 196 elective endoscopies performed on 189 consecutive consenting patients. Group 1 (95 endoscopies) received meperidine, 1.5 mg/kg, intramuscularly 30 min prior to endoscopy. Group 2 (101 endoscopies) additionally received atropine, 0.6 mg, in the same injection. Endoscopy was performed by one of two investigators using a 13-mm fiberoptic instrument. Endoscopists and patients filled out postendoscopy questionnaires. Both endoscopists (p less than 0.01) and patients (p less than 0.05) noted less oral secretions after atropine. Endoscopists noted less gastric motility after atropine (p less than 0.05) and guessed correctly whether or not atropine had been given in two thirds of cases. They noted no overall difference, however, in the ease of the endoscopy (p greater than 0.05). Moreover, there were no differences in the patients' assessments of the acceptability of the procedure between the two groups (p greater than 0.05). We concluded that although atropine does not improve patients' tolerance for the examination or the endoscopists' ability to do an adequate examination, it does objectively decrease the amount of gastric motility and oral secretions. This latter effect could potentially decrease the hazard of aspiration, but such a benefit could not be demonstrated in our series.

Adolescent↗
PubMed1983

Effect of atropine and upper gastrointestinal endoscopy on serum gastrin.

To determine if atropine alone, gastric distension alone, or atropine plus gastric distension affected serum gastrin levels, we obtained serum gastrins on 45 consecutive patients who were randomized into two groups. Group 1 (27 patients) was premedicated with meperidine alone, 1.5 mg/kg I.M. Group 2 received atropine 0.6 mg I.M. in addition to meperidine. Blood samples were drawn: 1) before premedication, 2) 30 minutes after premedication, and 3) immediately after endoscopy. We found: 1) no statistical difference between mean basal gastrin levels for groups 1 and 2, 2) no change in basal serum gastrin levels after premedications in either group, and 3) that endoscopy caused no significant increase in mean serum gastrin levels. We conclude that endoscopy does not lead to a significant elevation of basal serum gastrin in patients premedicated with meperidine or meperidine and atropine.

Atropine↗