Læknablaðið - 15.08.1995, Page 42

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LÆKNABLAÐIÐ 1995; 81
Nýr doktor í
Þann 24. nóvember 1994 varði Einar Stefán
Björnsson, læknir á lyflækningadeild Sahlgren-
ska sjúkrahúsins í Gautaborg, doktorsritgerð í
læknisfræði við Háskólann í Gautaborg. Rit-
gerðin nefnist Interdigestive gastrointestinal
motility in humans. Studies with special refer-
ence to small intestinal peristalsis. Agrip úr rit-
gerðinni fer hér á eftir:
The interdigestive motility of the upper gut
is characterized by the migrating motor com-
plex (MMC), which is a cyclic pattern of activ-
ity of both motility and secretion. The MMC
consists of phase I with motor quiescence,
phase II with irregular contractions, and phase
III with motor activity at the maximal rate of
the stomach and the small intestine. The func-
tional significance of the MMC still remains
uncertain and the specific function of the dif-
ferent phases has yet to be explained. In partic-
ular, little is known about the characteristics of
individual contractions in the different phases
of the MMC, their direction of migration and
velocity of migration.
The present study was initiated to analyse
the MMC in detail by computerized recordings
of the stomach and the proximal small intes-
tine, with special focus on individual contrac-
tions in the duodenum. Pressure recordings
were performed in the upper gut by antroduo-
denojejunal manometry in healthy subjects.
Multichannel pressure catheters were used
with tightly spaced side holes, constructed for
the study of individual contractions.
In the proximal duodenum the mean pro-
portion of retroperistaltic pressure waves, out
of all propagating waves, was significantly in-
creased in the last part of phase III of the
MMC (85%), compared with early phase III
(6%), late phase II (6%) and the feeding phase
(10%), irrespective of gender, order of the
MMC cycle and previous tubeexperience of
the subjects. This retroperistaltic pattern was
Key words; Computerized recording; erythromycin; duo-
denum; gastrointestinal motility; hyperglycemia; insulin;
manometry; motilin; pancreatic polypeptide; peristaisis;
propranolol; time window.
læknisfræði
also found in
the distal duo-
denum but not
in the proximal
jejunum. In the
last part of
phase III in the
proximal duo-
denum, the
motility index
decreased in
orad direction
(p<0.01) and
the contraction
frequency had
a marked orad
gradient
(p<0.05). The phase III-like activity in the
duodenum induced by the macrolide erythro-
mycin was also characterized by retroperistal-
sis in the last part of the phase, similar to the
naturally occurring one. The phase III-related
retroperistalsis was not altered by acute hy-
perglycemia, by euglycemic hyperinsulinemia,
or by beta adrenergic blockade by proprano-
lol. However, hyperglycemia was shown to re-
duce the motility index in late phase II, not
only in the gastric antrum (p<0.01) but also in
the small intestine (p<0.01). Furthermore,
during euglycemic hyperinsulinemia, similar
effects were obtained as during hyperglyce-
mia, with a complete absence of phase III in
the antrum and a shorter duration of phase III
in the proximal duodenum (p<0.05).
The present findings show that the last part
of phase III behaves like a retroperistaltic
pump. This distinct retroperistaltic pattern
seem to be confined to the duodenum, since it
was not observed in the proximal jejunum.
This cyclic retroperistalsis was not affected by
the different pharmacological and metabolic
conditions studied and may be the motility
phenomenon behind the recently reported cy-
clic alkalinization of the gastric antrum. Its
role in functional and organic motility disor-
ders warrants more experimental and clinical
studies.