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Biomedical subjects

M Mohtashemi

Publications and source records attributed to M Mohtashemi.

13 recordsLinked to original sources
PubMed2001

Transient dynamics and early diagnostics in infectious disease.

To date, mathematical models of the dynamics of infectious disease have consistently focused on understanding the long-term behavior of the interacting components, where the steady state solutions are paramount. However for most acute infections, the longterm behavior of the pathogen population is of little importance to the host and population health. We introduce the notion of transient pathology, where the short-term dynamics of interaction between the immune system and pathogens is the principal focus. We identify the amplifying effect of the absence of a fully operative immune system on the pathogenesis of the initial inoculum, and its implication for the acute severity of the infection. We then formalize the underlying dynamics, and derive two measures of transient pathogenicity: the peak of infection (maximum pathogenic load) and the time to peak of infection, both crucial to understanding the early dynamics of infection and its consequences for early intervention.

Communicable Diseases↗
PubMed1987

Uterine-umbilical velocimetry in open heart surgery.

The effect of the nonpulsating cardiac pump in uterine and umbilical circulation has not been studied extensively by measuring the resistance of the uterine and umbilical circulation with velocimetry. During open heart surgery, we were able to demonstrate the effects of the nonpulsatile cardiac pump.

Adult↗
PubMed1984

Selective denervation of the S-A node in the treatment of progressive central vagal bradycardia.

The condition of central hypervagism and central vagal bradycardia, up to now, have been largely overlooked. Selective surgical vagal denervation of the SA node for progressive central and local episodic reflex arc bradycardia, via right thoracotomy, is a well-tolerated procedure even in the debilitated child. The bradycardia must, of course, be atropine-responsive. It appears to be a valuable alternative to pacemakers, especially because of the necessity of using the sequential type in this form of heart block. Our follow-ups are from 8 months to 13 years in seven children (five central and two peripheral). Up to now, in an admittedly small series, there has been only one recurrence of bradycardia. This was from crossover left vagal innervation of the SA node. The incidence of this is 10% to 15%. It responded to right cervical vagotomy, following a preliminary diagnostic novocain block. We hope that these findings may lead to more awareness and investigations of conditions due to autonomic dysfunction--both central and peripheral--which may help among other conditions in the elucidation and prevention of sudden infant death syndrome (SIDS) and other related problems, and that this surgical approach will be a definitive means for the control of refractory, persistent, or recurrent vagal bradycardia.

Atropine↗
PubMed1982

Delayed operative intervention in cardiogenic shock after myocardial infarction.

In a four-year period, 45 patients underwent counterpulsation for cardiogenic shock following myocardial infarction. Of these patients, 27 underwent angiography. Fifteen of them were not considered to be operative candidates because angiography demonstrated only single-vessel disease or diffuse distal coronary artery disease. Twelve patients were candidates for operation and were divided into three subgroups depending on the time of surgical intervention. One patient (Group 1) deteriorated while on counterpulsation, and underwent urgent angiography and operative intervention within 24 hours of balloon insertion. He is now in New York Heart Association (NYHA) Functional Class I. Group 2 consisted of 7 patients whose condition stabilized with use of the balloon but who could not be weaned. All underwent angiography from 7 to 14 days after insertion of the balloon. One patient died suddenly prior to operation. Six patients underwent coronary bypass from 8 to 21 days after balloon insertion. Five survived and are in NYHA Class II or III. Four patients were able to be weaned after angiography (Group 3). All had triple-vessel disease. Operation was undertaken six to eight weeks after infarction to treat persistent congestive heart failure or angina, or to improve chances of long-term survival. Two patients in this group survived. Our experience demonstrates that delayed intervention is an acceptable alternative to urgent operation.

Angiography↗
PubMed1979

Intra-aortic balloon pumping: two-year experience.

Experience with 29 patients who underwent intra-aortic counterpulsation between January, 1975, and December, 1977, was reviewed to determine (1) if the results of this method of treatment were similar at the community hospital and university hospital levels and (2) if earlier institution of counterpulsation made possible by easy availability of equipment resulted in improved survival. The balloon was successfully inserted in 27 patients. Arterial blood pressure was below 80 mm. Hg in all patients prior to institution of either pharmacologic or balloon therapy. Pulmonary capillary wedge pressure was greater than 12 mm. Hg in the 22 patients in whom it was measured. In 15 patients counterpulsation was instituted less than 12 hours after infarction (Group A), and in the 14 elapsed time was greater than 12 hours (Group B). There was no difference in precounterpulsation hemodynamic measurements between Group A and Group B. Ten patients in Group A were weaned and survived hospitalization. Seven (54 percent) are long-term survivors (6 months to 2 years). Four are in New York Heart Association Class I, two are in Class II, and one is in Class III. Ten patients in Group B were weaned, seven survived hospitalization, and five are long-term survivors (35 percent). Two are in N.Y.H.A. Class I, two are in Class II, and one is in Class III. These results indicate that counterpulsation is possible at the local hospital level and that early institution of the intra-aortic balloon pumping may improve long-term results.

Assisted Circulation↗