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Biomedical subjects

I Dawidson

Publications and source records attributed to I Dawidson.

At least 37 records · Page 2Linked to original sources
PubMed1992

The effect of acupuncture on salivary flow rates in patients with xerostomia.

Of 21 patients with severe xerostomia, 11 were treated with acupuncture and 10 patients received placebo acupuncture. Those patients who received acupuncture treatment showed increased salivary flow rates during and after the acupuncture treatment. The improved salivary values persisted during the observation year, whereas the patients who received placebo acupuncture showed some improvement of salivary flow rates only during the actual treatment. The results of the present study indicate that acupuncture may be a useful adjunct for the stimulation of salivary flow in some patients with xerostomia.

Acupuncture Points↗
PubMed1992

Septic shock in rats treated with terbutaline alone and in combination with chemotherapeutics, dexamethasone, and infusion of 3% albumin.

The effects of a beta 2-receptor agonist, terbutaline, on haematocrit and survival were studied in rats in which septic shock had been induced by intraperitoneal injection of a mean (SD) dose of 6.0 (4.5) x 10(8) live E. coli. Untreated septic animals developed haemoconcentration, the mean (SD) haematocrit increasing from 47.5 (1.4) to 53.1 (2.2). Mean (SD) survival time was 8.9 (0.6) hours, and no animal survived for 24 hours. Terbutaline given as the only treatment in doses of 0.1, 0.5, and 2.5 mg/kg before injection of E. coli significantly reduced the haemoconcentration, with haematocrit of 51.9, 46.6 and 47.9, respectively, at 4 hours. Survival was not significantly prolonged. When terbutaline was started 5.5 hours after injection of E. coli and given in addition to a chemotherapeutic drug (trimethoprim + sulphamethoxazole) and dexamethasone, haematocrit were reduced, 24 hour survival improved from 44% to 68%, and 7 day survival improved from 20% to 48%. We conclude that terbutaline given alone counteracts the loss of plasma volume during septicaemia and, when combined with a chemotherapeutic and dexamethasone, significantly improves long term survival.

Albumins↗
PubMed1991

Improvement of cadaver renal transplantation outcomes with verapamil: a review.

Although cyclosporin A (CsA) has allowed substantial advances in organ transplantation due to its immunosuppressive properties, its use is complicated by its direct nephrotoxic effects. Initial studies with mice confirmed that CsA caused a dose-related inhibition of the subcapsular microcirculation; subsequent clinical investigations have confirmed this inhibitory effect. Efforts to circumvent CsA-induced nephrotoxicity have focused on calcium antagonists. For example, when the calcium antagonist verapamil was administered before the initiation of CsA, renal blood flow was maintained. Verapamil therapy was also associated with significantly fewer rejection episodes (3 of 22; 14%) within 4 weeks of transplantation than CsA therapy alone (10 of 18; 56%). In a current study, verapamil 10 mg was injected into the renal artery during surgery, followed by 120 mg tid orally for 14 days. This regimen reduced delayed function incidents (the need for dialysis) during the first post-transplant week. Excluding nonfunctioning kidneys and technical failures, there were no graft losses secondary to rejection in patients treated with verapamil. The beneficial effects of verapamil therapy on transplant outcome may be related to its ability to protect cells from ischemia, the selective vasodilation of the efferent arteriole, elevated CsA blood levels, and inherent immunosuppressive properties.

Administration, Oral↗
PubMed1991

Improved outcome of cadaveric renal transplantation due to calcium channel blockers.

Calcium channel blockers (CCB) administered to recipients of cadaveric renal transplants have been shown to improve graft function, decrease the incidence of delayed function, prevent acute cyclosporine toxicity, and lessen the number of rejection episodes in the first several weeks posttransplant. In order to determine whether CCB provide a similar long-term benefit, a retrospective analysis of 83 first cadaveric renal transplants performed in 1987 and 1988 was performed. The clinical course of 17 patients who were discharged and maintained on CCB therapy for 1 year was compared with that of 24 patients who never received CCB during the same 1-year period. The remaining 42 patients were excluded for failing to meet these inclusion criteria. The two groups were similar with respect to age, sex, cold ischemia time, degree of sensitization, HLA matching, DR matching, and DR mismatching. The no CCB group did receive a significantly greater number of pretransplant transfusions. In the 1 year of follow-up, graft loss in the CCB group was less than in the no CCB group (1/17, 5.9% vs. 6/24, 25%). There was a striking decrease in the percentage of first rejection episodes in the CCB group as compared with no CCB therapy (35% vs. 83%, P less than 0.005). In addition, a similar decrease in second rejection episodes was found in the CCB group (18% vs. 33%, P less than 0.05). The two groups also were compared with respect to graft function. Despite similar serum creatinine levels at 1 month (CCB 1.8 mg% vs. no CCB 2.2 mg%, P = 0.37) and 1 year (CCB 1.7 mg% vs. no CCB 2.4 mg%, P = 0.19), the CCB group had a significantly higher glomerular filtration rate at 1 month (53.9 vs. 38.7, P less than 0.05) and 1 year (57.0 vs. 35.0, P less than 0.001) as measured by clearance of radiolabeled iothalamate. These results suggest that the short-term improvements noted in both graft function and rejection episodes with CCB are maintained for the first year posttransplant. More importantly, CCB use results in improved 1-year graft survival.

Adult↗
PubMed1991

Verapamil improves the outcome after cadaver renal transplantation.

Because of their favorable effects on renal hemodynamics, calcium antagonists may have a major role in the prevention and management of certain types of acute renal dysfunction. In fact, verapamil (VP) was shown to prevent cyclosporin A (CsA)-induced decreases in RBF in mice and in cadaver renal transplant (CRT) recipients. The study presented here of 59 cadaver renal transplant patients evaluates the outcome from perioperative treatment with VP (N = 30) administered intraoperatively into the renal artery (10 mg) followed by oral administration of 120 mg every 8 to 12 h for 14 days versus no drug (N = 29). Early immunosuppression included azathioprine, corticosteroids, and antilymphocyte globulin with subsequent overlapping with CsA on days 5 and 6. Actuarial graft survival at 1 yr was different when the two groups were compared (P less than 0.05). Estimated graft survival at 1 yr for VP patients was 93.3 compared with 72.4% in control patients. The improved graft survival was most striking in repeat transplants with 90% graft survival at 1 yr for VP recipients versus 37.5% for controls. Compared with controls, VP recipients had significantly improved renal parenchymal diastolic blood flow velocities on the first day after surgery (7.8 versus 5.8 cm/s). By day 7, GFR were greater with VP (44 +/- 29 mL/min) versus controls (28 +/- 22 mL/min). Of VP patients, 67% (18 of 24) had GFR greater than 30 mL/min versus 33% (9 of 26) for control patients. Similarly, on the seventh day, 77% (21 of 30) of VP patients had serum creatinines less than 2.0 mg% versus 34% (10 of 29) for controls.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

Cardiac output and organ blood flow in experimental septic shock: effect of treatment with antibiotics, corticosteroids, and fluid infusion.

Septic shock from intraperitoneal (i.p.) injection of live Escherichia coli bacteria in rats induces marked pathophysiological changes, including 40% decrease in plasma volume (PV), cardiac output, and oxygen consumption with 100% mortality within 24 hr. The present study evaluates cardiac output and organ blood flow before and after treatment of septic shock with an effective antibiotic (AB), plasma volume (PV) expansion, and corticosteroids (CS), alone and in combination. Treatment was initiated at 5.5 hr after bacterial injection, at a time when AB therapy did not improve 24 hr survival rate. Cardiac output decreased from 28.6 +/- 3.1 (SD) to 15.4 +/- 2.8 ml/min/kg (P less than .01) in septic rats concomitant with redistribution of blood flow from carcass to the heart, brain, intestines, liver, and adrenal glands. Absolute arterial blood flow increased only to the adrenal glands and the liver to 158% (P less than .01) and 167% (P less than .01) of control values, respectively. AB, CS, and Ringer's lactate (RL) alone or in combination did not significantly improve any organ blood flow compared to untreated septic animals but increased survival significantly to about 60% (P less than .01). Albumin (ALB) and CS in combination expanded PV to 138% (P less than .01), restored cardiac output to 100%, and achieved supranormal blood flow values to the brain (109%), liver (125%), small intestine (147%) (P less than .01), and kidneys (190%) (P less than .01) of preshock levels. More importantly, survival at 24 hr was 90% (9/10) (P less than .001). It is concluded that a colloid diluted in an electrolyte solution, combined with CS, and an effective antibiotic agent are necessary therapeutic ingredients for the successful recovery of experimental E. coli sepsis.

Adrenal Cortex Hormones↗
PubMed1990

The impact of extended preservation on clinical liver transplantation.

The introduction of UW solution into clinical transplantation has permitted extended cold storage preservation of the liver. Over a 46-month period, we have performed 308 orthotopic liver transplants (266 primary, 42 retransplants) in 266 recipients. Our experience is divided into cold-storage preservation in Eurocollins (163 transplants in 140 recipients) and UW (145 transplants in 131 recipients) solutions. Donor and recipient factors were comparable between the two groups. The use of UW solution has permitted an increase in the mean preservation time from 5.2 +/- 1.0 [EC] to 12.8 +/- 4.3 [UW] hr (P less than 0.001). The mean total operating time was reduced but intraoperative blood loss was unchanged with UW preservation. The number of transplants performed during the daytime hours has increased dramatically (21.5% [EC] vs. 71% [UW], P less than 0.001). The incidence of primary nonfunction, hepatic artery thrombosis, 1-month graft survival, and early retransplantation were similar in the 2 groups. Initial allograft function as determined by bile production, histology, and clinical assessment were likewise similar. Mean serum bilirubin, transaminase, and prothrombin levels were virtually identical by 5 days posttransplant. The enhanced margin of safety afforded by extended preservation has increased the capability for distant organ procurement and sharing, minimized organ wastage, and improved the efficiency of organ retrieval. With the relaxation of logistical constraints, our rate of liver import has nearly doubled (20.9% [EC] vs. 39.3% [UW], P less than 0.001). Extended preservation has permitted the development of reduced-size liver grafting (n = 12), resulting in a significant reduction in the number of deaths occurring while awaiting transplantation. Therefore, we advocate the use of UW solution with selective extension of preservation based not only on donor and recipient factors but also on manpower, resource, and logistical considerations.

Adenosine↗
PubMed1990

Islet isolation from human pancreas stored in UW solution for 6 to 26 hours.

1. Viable and functional islets can be recovered from human pancreata stored for prolonged periods (up to 18 hours) with either the UW solution or EC. 2. Function of islets from pancreas stored in UW solution appeared superior. However, the difference in these preliminary studies does not appear nearly so dramatic as in transplantation of vascularized pancreas. 3. Function of islets from human pancreas stored for longer than 18 hours after UW in situ flush was uniformly poor. 4. Considerable room for improvement in the storage of human pancreas before isolation exists. Progress in this area will be important for the development of any large-scale program of clinical islet transplantation.

Adenosine↗
PubMed1990

Predictive value of intraoperative liver biopsies of donor organs in patients undergoing orthotopic liver transplantation.

The evaluation of prerevascularization and postrevascularization biopsies in comparison with clinical and laboratory data has revealed a direct correlation between elevated PT and AST levels and pericentral and panlobular individual hepatocyte necrosis. No other significant correlations were determined when comparing selected histologic features to selected clinical laboratory values. In conclusion, these biopsies are of limited use in predicting subsequent allograft function in the absence of prominent individual hepatocyte or pericentral necrosis.

Adult↗
PubMed1989

Oxygen consumption and central hemodynamics in septic shock treated with antibiotics, fluid infusions, and corticosteroids.

The multidimensional pathophysiology of septic shock is poorly understood and treatment modalities are controversial. The present study evaluates the relative importance of three therapeutic measures: antibiotics (trimethoprim and sulphamethoxazole [TS]); fluid infusions (lactated Ringer's solution [RL] and 3% albumin [Alb]), and pharmacologic doses of corticosteroids (CS) (dexamethasone [DM]), using central hemodynamics (plasma volume [PV], cardiac output, oxygen consumption [VO2]), and survival as end-points. Septic shock was induced by intraperitoneal injection of live Escherichia coli bacteria. At 5 h in untreated septic rats, PV had dropped to 76%, cardiac output to 69%, and VO2 to 71% of preshock levels. Untreated septic animals had a mean survival time of 9.7 +/- 1.7 (SD) h, with none surviving 24 h. Regardless of therapy, cardiac output and VO2 at 10 h were predictors of survival time (p less than .01). Treatment was initiated at 5.5 h after bacterial injection, at a time when TS therapy alone had not improved the 24-h survival rate. Animals treated with DM, RL, and Alb, in this order, exhibited progressively improved central hemodynamics, and 24-h survival rate increased to 60% compared with 0 in untreated animals (p less than .001). The combination of DM and RL produced no further improvement. However, DM combined with 3% Alb restored VO2, cardiac output, and PV to 81%, 100%, and 125%, respectively, increasing the 24-h survival rate to 97% (29/30), significantly greater than that achieved by any other treatment modality (p less than .05).

Animals↗
PubMed1989

Prevention of detrimental effect of cyclosporin A on vascular ingrowth of transplanted pancreatic islets with verapamil.

The revascularization of pancreatic islet clusters transplanted beneath the renal capsule was studied in a syngeneic mouse model. The degree of vascular ingrowth was visualized by in vivo fluorescence microscopy (fluorescein isothiocyanate-dextran) and judged by a semiquantitative method from coded video recordings. The recipients of isografts were divided into four groups, depending on their daily immunosuppressive treatment: 1) none (controls), 2) 15 mg/kg cyclosporin A (CsA), 3) 0.4 mg/kg verapamil + 15 mg/kg CsA, and 4) 20-30 mg/kg methylprednisolone. In control animals, capillary ingrowth was first demonstrated on day 6, followed by progressive vascularization up to day 34. After 6 mo, the vascular architecture was similar to that seen in normal islets in situ. CsA alone significantly decreased vascular ingrowth on day 14 compared with controls (P less than .02). Verapamil prevented the detrimental effect of CsA (P less than .01), probably by improving renal subcapsular blood flow. Methylprednisolone did not affect revascularization compared with control animals at day 14. We conclude that CsA inhibits vascular ingrowth into transplanted pancreatic islets, which is likely to have clinical implications. The prevention of CsA vascular ingrowth inhibition by a calcium antagonist indicates a possible approach to the correction of this problem, particularly when the renal capsule is used as the recipient's transplant site.

Animals↗