Research Publications - College of Medicine and Health Science

Department of Physiology
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M.Sc. programs. Professor Howarth has ongoing
collaborations with researchers in other
departments in FMHS and various international
research laboratories in U.S.A., U.K., Ukraine and
other countries. Recent projects have included
the progressive changes in expression of genes
encoding Ca2+ signalling proteins and remodelling
of Ca2+ proteins in type 2 diabetic heart,
the effects of exercise training on heart function
in the Goto-Kakizaki type 2 diabetic rat, remodelling
of Ca2+ transport proteins and cardiac
muscle dysfunction in the Zucker diabetic fatty
rat and the effects of nanoparticles on myocyte
electrophsyiology. Work in the laboratory has
been generously supported by Sheikh Hamdan
Bin Rashid Al Maktoum Award for Medical
Sciences, Emirates Foundation, United Arab
Emirates University and the Faculty of Medicine
& Health Sciences.
Mapping laboratory
Work has proceeded very well in 2011 with
major research developments obtained both
Khawla Salem (PhD Student) and Anwar Qureshi (Technician) working with
cardiac myocytes on one of our electrophysiology systems
in the mapping lab in Al Ain and through our
collaborations with other laboratories around
the world.
We have continued our work in the emerging
field of gastric arrhythmias with our analysis and
publication of spontaneous arrhythmias and
propagation disturbances that occur in the pig
in vitro and in gastroparetic patients. This work
is again part of a successful collaboration with
the Pullan/Cheng group at the Bioengineering
department at Auckland University, New
Zealand and expands on our initial concepts of
several mechanisms in gastric arrhythmias such
as circus movements, reentries, ectopic pacemaking,
complete and incomplete conduction
blocks.
In Al Ain, we have continued our collaborative
work with Dr Hamad Fayez on the origin and
propagation of impulses in the normal and
blocked ureter of the rat and the propagation
pattern in the isolated bladder in guinea pigs.
And, this year, we finalized and published a first
analysis of the propagation of the slow wave in
diabetic small intestines, in collaboration with
Professor Sherif Karam (Anatomy) (see figure).
It must be noted that this work actually started
as a Student Research Summer activity (Al-
Bloushi HM, Al-Eisae SA, Al-Dhaheri FA). In this
work, we showed a significant decrease in the
interstitial cells of Cajal (= ICC) in the myenteric
plexus at 3 months diabetes and, surprisingly, a
re-population of the ICC’s at 7-months diabetes.
This is important because the ICC’s are responsible
for the propagation of the electrical impulse
(= slow wave) in the intestine, which in turn
dictates the motility of that organ. Furthermore,
we showed that the velocity of propagation
was not affected by this level of depletion at
3-months diabetes and we explained this by developing
a cellular automaton model to analyze
the relationships between number of cells and
the pattern of propagation.
Finally, we discovered in this same model the
occurrence of circus movement arrhythmias in
the diabetic small intestine, a first in this organ.
This discovery led to several invitations for
presentations in the USA, Canada, Australia and
New Zealand and a first paper describing this
phenomenon is now in press.
Other collaborative achievements, in Al Ain or
elsewhere have been:
a) A visit by Dr Wing-Chiu Tong, from the Institute
of Cellular Medicine, Newcastle University,
Newcastle, UK for a 2-week training in mapping
technology in the mapping lab in Al Ain.
b) Several visits by Dr Sandeep (Ras Al Khaima
College of Medical Sciences, RAK) to develop a
new project (effects of Imatinib on slow wave
propagation in the small intestine).
c) With Professor Sherif Karam, the study of the
propagation of the slow wave in diabetic small
intestine of the rat. In this study, we recently discovered
the occurrence of functional re-entries
in these small intestines, which could be the
substrate for functional bowel obstruction. A first
paper describing this phenomena is in press.
d) Following on our successful presentation on
the origins of myometrial contractions in the
pregnant guinea-pig uterus (Glasgow 2009),