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PubMed2006

The use of rapid assessment of enteric ICC and neuronal morphology may improve patient management in pediatric surgery: a new clinical pathological protocol.

Alterations in interstitial cells of Cajal (ICC) distribution and density may seriously influence gut motility. We and others have documented a disturbance of ICC and neurons in Hirschsprung's disease (HD), intestinal ischemia, and inflammation. The ability to remove intestine with permanent dysmotility improves significantly the prognosis. This may be important in the developing intestine especially in HD. More complete pathological information increases the accuracy of surgical decisions. Therefore we sought to develop a rapid, intraoperative immunohistochemical protocol for ICC and neurons in surgical specimens for routine diagnostic and therapeutic assessment of pediatric patients. To date, cKit is the only reliable immunohistochemistry for ICC identification. There are multiple antibodies in use for neuronal identification. A comparison of fixation methods and immunostaining using cKit and multiple intestinal neuronal antibodies was done. Fresh segments of surgically resected intestine were sectioned and stained using antibodies for ICC cell identification (anti-cKit) and for neuronal characterization. By carefully changing tissue fixation methods, different neuronal antibodies were tested to determine an optimal rapid protocol. Each suggested protocol was tested on normal and pathological intestinal tissue and compared to the previous overnight immunostaining of the same tissue. A new rapid tissue fixation and immunostaining protocol using cKit for ICC identification and NF 68 was developed. By employing this protocol, we could obtain ICC and neuro-immunohistochemistry in unfixed frozen sections within 1 h with tissue vibration to diminish the time for immunostaining. Without vibration the protocol takes 3 h. ICC and enteric neuronal changes could be readily observed and the quality of staining was comparable to standard immunohistochemistry. Each gut pathology displayed characteristic changes in ICC and neuronal density/distribution in the affected bowel. The time-scale of the 1-h immunoprocessing is still longer than the standard clinical pathological "quick" sections using H&E staining; however, the protocol duration is within the surgery timescale. Standard H&E stain used in combination with our rapid neuronal and ICC immunohistochemistry protocol enables a fast, comprehensive, and accurate assessment of the pathophysiology of signaling networks controlling gut motility while the patient is still in the operating room. We propose that the addition of this simple and rapid immunohistochemical assessment in the pathologist evaluation of surgical specimens would result in a more complete characterization for diagnosis and prognosis of the pediatric patient. Specifically, we propose that this test will differentiate good versus poor prognosis HD patients based on their neuron/ICC ratio and present a rapid, standardized method for use in general pathology.

Colon↗

PubMed2001

Use of GnRH antagonists in ovarian stimulation for assisted reproductive technologies compared to the long protocol. Meta-analysis.

The use of GnRH antagonists has revolutionized ovarian stimulation for assisted reproduction. Two GnRH antagonists are clinically available, namely, cetrorelix and ganirelix. Several studies have directly compared these new stimulation protocols against the long GnRH agonist protocol. To evaluate whether there is a reduction in cases of ovarian hyperstimulation syndrome (OHSS) and/or a reduction in pregnancy rates, a meta-analysis was performed. There was a significant reduction of OHSS cases in the cetrorelix studies (odds ratio, OR, 0.23; 95% confidence interval, CI, 0.10-0.54), but no reduction for ganirelix (OR 1.13; 95% CI 0.24-5.31). The incidence of OHSS degree III cases was reduced in the cetrorelix protocols as compared to the long protocol to a nearly significant degree (OR 0.26; 95% CI 0.07-1.01). Ganirelix did not reduce the incidence of OHSS degree III at all (OR 1.08; 95% CI 0.27-4.38). The pregnancy rate per cycle was significantly lower in the ganirelix protocols than in the long protocol (OR 0.76; 95% CI 0.59-0.98). The studies using cetrorelix showed quite similar, not significantly different results for the antagonist and the long protocol groups for the pregnancy rate per cycle (OR 0.91; 95% Cl 0.68-1.22). From the data one can conclude that cetrorelix but not ganirelix will reduce the incidence of cases of OHSS and that cetrorelix but not ganirelix will result in the same pregnancy rates as the long protocol. Several possibilities to explain this phenomenon are discussed.

Chorionic Gonadotropin↗

PubMed2005

Detection of atherosis in preeclamptic placentas: comparison of two gross sampling protocols.

Two standardized gross sampling protocols were compared with the intention of maximizing the histologic detection rate of atherosis in at-risk (i.e., preeclamptic) placentas. The first, 4-block, protocol was designed to be broadly representative of good current practice (central, edge, en face shave, and membrane roll blocks). A second, 5-block, protocol incorporated all of protocol 1 with the addition of a block composed of multiple flat membrane leaves stacked and sectioned 5 times at 200-mum intervals. Data were available on the first protocol from 80 consecutive accessioned cases of singleton preeclamptic placentas and on the second protocol from 40 cases. Criteria for diagnosis for atherosis were relatively rigorous and excluded "burnt-out" fibrinoid lesions in which foam cells were not positively identified. With the first protocol, atherosis was detected in 30 of 80 (37.5%) of placentas studied. With the second protocol, atherosis was detected in 25 of 40 (62.5%) of placentas studied. This increase was related to a high detection rate of 50% in the flat membrane stack block. Evaluation of the more traditional forms of block produced atherosis detection rates of 2.5% for central full-thickness blocks, 14% for edge blocks, 10% for en face shave blocks, and 25% for membrane rolls. The flat membrane stack was found to be the single most sensitive block for detection of atherosis. When used in conjunction with traditional blocking techniques, it offers significantly increased reliability for detection of atherosis in placentas when maternal vascular compromise is suspected.

Adult↗

PubMed1991

Use of bromoergocryptine in the validation of protocols for the assessment of mechanisms of early pregnancy loss in the rat.

Validated protocols for evaluating maternally mediated mechanisms of early pregnancy failure in rodents are needed for use in the risk assessment process. To supplement previous efforts in the validation of a panel of protocols assembled for this purpose, bromoergocryptine (BEC) was used as a model compound because it is known to inhibit pituitary prolactin secretion. BEC was tested using the early pregnancy protocol (EPP), the decidual cell response technique (DCR), the pre- vs postimplantation protocol (PPP), and embryo transport rate analysis (ETRA). These protocols evaluate the effects of chemicals on multiple endpoints following exposure during (a) the first 8 days of pregnancy, (b) early pseudopregnancy accompanied by decidual induction, (c) the pre- and postimplantation intervals of early pregnancy, or (d) the period of embryo transport. In the EPP, dosing with BEC during Days 1-8 of pregnancy reduced the number of implantation sites found on Day 9 as well as serum progesterone. The DCR technique revealed a dose-dependent inhibition of decidual growth concomitant with decreased serum progesterone as a result of BEC treatment. A modified DCR technique using hormone-supplemented ovariectomized rats demonstrated that BEC did not impair decidual growth in the presence of adequate progestogenic support. Pre- vs postimplantation dosing indicated that implantation is vulnerable to BEC effects at least through Day 4. BEC had no effect on embryo transport rate. Data from these protocols identified BEC as having adverse maternal effects during early pregnancy. While the pituitary was not identified by these protocols as the site of BEC's primary action, the protocols did identify a reduction in serum progesterone and impaired uterine function as toxicological mechanisms mediating the reduced fertility seen following BEC exposure.

Abortion, Veterinary↗

PubMed1994

Optimizing the time course of brachytherapy and other accelerated radiotherapeutic protocols.

PURPOSE: It is likely that early-responding tissues, such as tumors, repair sublethal damage more rapidly than do late-responding tissues. This difference can be exploited to design protocols with a significantly improved therapeutic advantage for accelerated radiotherapeutic regimens, including brachytherapy. METHODS AND MATERIALS: The time course of potential protocols is computer optimized, maximizing the therapeutic difference between tumor-control probability (TCP), and normal-tissue complication probability (NTCP). These quantities are evaluated with the linear-quadratic model, using clinically derived parameters. The optimization is performed by individually adjusting doses in different parts of the treatment, maximizing the therapeutic advantage. In the main calculations, half times for damage repair were T1/2(late) = 4 h, T1/2(early) = 0.5 h. Two component (fast/slow) repair processes were also investigated. RESULTS: Protocols determined by optimization have significantly greater therapeutic advantage than continuous low-dose rate (CLDR) protocols of the same overall dose and time. The optimized protocols are either (a) acute-dose/gap/CLDR/gap/acute-dose; or (b) a series of acute doses separated by 3-4 h. As a typical example, results are given for 60 Gy/120 h CLDR brachytherapy, which is assumed to give NTCP = 0.2 and TCP = 0.8. Under our assumptions, optimized regimes, with the same overall time and dose, produce an NTCP of approximately 0.11 and TCP of approximately 0.83, a significant therapeutic gain over CLDR. CONCLUSION: Difference in repair rates between early- and late-responding tissues can be exploited to produce clinically practical protocols that are significantly superior to current regimens. Such optimized protocols produce slightly better tumor control than CLDR with the same overall dose and time, significantly less late damage, and similar early normal-tissue sequellae. Temporal optimization, thus, promises to be a powerful tool in designing better treatment protocols.

Animals↗

PubMed2005

Thermal characterization of Nakagata's mouse sperm freezing protocol.

This paper reports the results of an experimental study of the warming and cooling rates achieved using the popular Nakagata Protocol for murine sperm cryopreservation. Problems with the storage and maintenance of the huge number of genetically engineered mouse strains have led to an increased need for murine sperm preservation. Recent studies have begun to focus on optimizing the cryopreservation of murine sperm by carefully studying the effects of cooling and warming rates on sperm survival. In current practice, however, the Nakagata protocol is widely used. The actual cooling and warming rates achieved using the Nakagata protocol have not previously been determined; and the Nakagata protocol has a number of unspecified parameters which we have found can significantly affect cooling rates, warming rates and sperm survival. A detailed study of the thermal response of samples frozen and thawed using the Nakagata protocol reveals that the cooling rates range from 30 to almost 300 degrees C per minute depending on the exact manner in which the Nakagata protocol is implemented. Warming rates range from 160 degrees C/min to about 1000 degrees C/min. Sperm survival depended significantly on the particular cooling rate achieved, and less strongly on the warming rates. Overall, it was found that the particular manner in which the Nakagata protocol was implemented could strongly affect cooling rates and sperm survival; and, consistent with the findings of Mazur and Koshimoto, an optimal cooling rate appears to exist in the range of cooling rates that can be achieved using the Nakagata protocol.

Animals↗

PubMed2005

Comparison between "short" and "long" protocols in an ICSI programme.

In the present retrospective study we compare the efficacy of gonadotropin-releasing hormone (GnRH) agonist in a long protocol and a GnRH agonist in a short protocol administration for controlled ovarian hyperstimulation (COH) in an ICSI program. A total of 424 consecutive patients with a history of male factor were included in the present study. Three hundred and three patients were included in the long protocol and 121 in the short protocol. Patients treated with the short protocol were stimulated in a shorter time and achieved lower estradiol levels. A significantly higher percentage of oocytes transferred were found in the long protocol. The clinical pregnancy rate per embryo transfer was 39.3% in the long protocol and 19.2% in the short protocol (p=0.001).

Adult↗

PubMed2005

The blind protocol and its place in consciousness research.

This paper describes the development of the blind protocol, and its place in this history of consciousness research. It was first devised by Croesus, King of the Lydians (BCE 560-547) and reported by Herodotus ( approximately BCE 484 - approximately 424), and was created to protect against fraud in assessing an Anomalous Perception (AP) event; a Remote Viewing (RV) experiment little different from those conducted today. Its next use in the 17th century was to study a peasant farmer, Jacques Aymar, who solved crimes with Anomalous Perception, using dowsing. Not only was a blind protocol employed, but the rudiments of controls were introduced to assess Aymar. The next documented use of a blind protocol in consciousness research occurred in 1784, when it was explicitly employed in the interest of science, and its history as a research technique can be said to have formally begun. King Louis the XVIth created a commission to evaluate Franz Anton Mesmer's claims concerning healing through "animal magnetism," administered while people were in a trance, and asked Benjamin Franklin to be the commission's head. The paper proposes that Franklin be considered the first parapsychologist. He created the blind protocol to answer the king's question as to whether "animal magnetism" was real, and he not only introduced demographic variables and controls, but literally blindfolded people, which is why today we call it the blind protocol. Franklin's observations also present the first recorded Western description of psychosomatic illness. An unintended consequence of Franklin's Mesmer study was the loss of the idea of psychophysical self-regulation (PPSR) as a research vector, although the English surgeon John Eliotson (1791-1868) apparently saw through the failure of Mesmer's explanatory model to the deeper insight in the form of hypnosis that was Mesmer's real discovery. He seems to have avoided all attempts at explaining how it worked but conducted a considerable number of surgeries using hypnosis as the anesthetic, anticipating its usage in this capacity a century later. So great was the disapproval of Mesmer, however, that no one seems to have gotten Eliotson's point. Franklin's protocol, though, rapidly became the gold standard of science. Rupert Sheldrake, however, carried out a survey of the leading scientific journals and discovered that the main use of the blind protocol is not in medicine per se, but parapsychology and consciousness research, in which it is used for the same purposes it was originally conceived: to winnow out fraud in anomalous consciousness events and to avoid introducing experimenter effects. Ultimately, though, the protocol may be based on a false assumption, because increasingly research in areas such as therapeutic intent/healing and remote viewing suggest that all consciousness from single-celled organisms to human beings may be interlinked through a nonlocal aspect of awareness they all share.

Autosuggestion↗

PubMed2005

Comparison of three ELISA protocols to measure antibody responses elicited against serogroup C meningococcal polysaccharide in mouse, monkey and human sera.

In this study we compared the following ELISA protocols to measure antibody levels against serogroup C meningococcal polysaccharide: a traditional protocol using poly-L-Lysine mixed with the polysaccharide as coating antigen, a second protocol coating with a mixture of methylated human serum albumin with the C polysaccharide, a modified protocol coating with derivatized polysaccharide and a modification to the last one, specifically without adding ammonium thiocyanate to the sample buffer. Serum bactericidal activity of mouse, monkey and human sera were measured and correlation coefficients were calculated. For all serum types the modified ELISA protocol showed the highest correlation coefficients while the traditional protocol showed the lower ones. We demonstrated that the traditional protocol measures non-specific antibodies to the C polysaccharide, because no differences were detected between pre-immune and post-immune human sera (P>0.05), while the modified protocol detected the highest difference (P<0.01).

Animals↗

PubMedDate not supplied

Estimation of potency of HERG channel blockers: impact of voltage protocol and temperature.

INTRODUCTION: The HERG channel is widely used for the assessment of proarrhythmic risk for new drugs. HERG channel blockers obstruct channel functions through various mechanisms, which usually show time dependence, voltage dependence, and state dependence. The voltage protocol and temperature may affect the estimation of drug potency, but limited information is available in this regard. The purpose of this study was to evaluate the influence of voltage protocol and temperature on predicting the potency of HERG channel blockers, and to determine electrophysiological approaches for new drugs screening studies. METHOD: Whole-cell patch-clamp electrophysiology was carried out by utilizing different voltage step protocols to examine the potency of compounds known to preferentially block the channel in the closed (ketoconazole and BeKm-1), open, and/or inactivated states (E-4031, astemizole, and terfenadine) in HEK293 cells transfected with HERG cDNA at room temperature and near-physiological temperature. RESULTS: Drug potency determined using different voltage protocols varied dependent on the mechanisms of drug actions. For most compounds, the IC(50) values obtained with a long pulse step protocol at room temperature were close to those determined with the voltage protocols designed to disclose their intrinsic potency. Relative to room temperature, the potency of E-4031, terfenadine, and ketoconazole was not changed at approximately 35 degrees C, but potency of astemizole was reduced. DISCUSSION: The long pulse step protocol with room temperature can be selected for HERG channel safety screening studies. Alternative voltage protocols or temperatures should be considered if HERG study results are not consistent with other cardiac safety assessments.

Astemizole↗

PubMed1983

Effect of exercise protocol on the left ventricular response to exercise.

The purpose of this study was to determine whether the left ventricular response during exercise radionuclide angiography would be influenced by exercise protocol. One hundred twenty healthy volunteers (aged 18 to 40 years) performed upright bicycle exercise using 1 of 5 protocols. Ejection fraction was measured using first-pass radionuclide angiography. Exercise protocols were as follows: (1) graded exercise (25 W increase every 2 minutes) to fatigue, heart rate greater than 85% of age-predicted maximum, n = 53; (2) graded exercise to 85% of age-predicted maximal heart rate or to fatigue with heart rate less than 85% of age-predicted maximum, n = 26; (3) graded exercise to fatigue, with "exercise" imaging performed immediately after exercise, n = 15; (4) abrupt presentation of a supermaximal work load (400 W), n = 10; (5) graded exercise to a work load of 75 W preceding the abrupt presentation of a supermaximal work load (300 to 400 W), n = 16. Protocols 2 and 3, representing less than maximal stress, yield higher ejection fractions than Protocol 1 and may reduce the sensitivity of exercise radionuclide angiography. Protocols 4 and 5, representing supermaximal stress, yield lower ejection fractions than Protocol 1 and may reduce the specificity of exercise radionuclide angiography. Thus, exercise protocol has a significant influence on the left ventricular response during exercise radionuclide angiography.

Adolescent↗

PubMed1992

Determination of electric field threshold for electrofusion of erythrocyte ghosts. Comparison of pulse-first and contact-first protocols.

Rabbit erythrocyte ghosts were fused by means of electric pulses to determine the electrofusion thresholds for these membranes. Two protocols were used to investigate fusion events: contact-first, and pulse-first. Electrical capacitance discharge (CD) pulses were used to induce fusion. Plots of fusion yield vs peak field strength yielded curves that intersected the field strength axis at positive values (pseudothresholds) which depended on the protocol and decay half time of the pulses. It was found that plots of pseudothreshold vs reciprocal half time were linear for each protocol; when extrapolated to reciprocal half time = 0 (i.e., t----infinity), these lines intersected the ordinate at values of the field strength considered to be the true electrofusion thresholds. In this fashion, the contact-first protocol gave an electrofusion threshold of 46.5 +/- 11.5 V/mm for hemoglobin-free ghosts (white ghosts) and 40.9 +/- 8.8 V/mm for ghosts with fractional hemoglobin (pink ghosts), while the threshold for the pulse-first protocol applied to pink ghosts was determined to be 93.4 +/- 11.0 V/mm. Although the thresholds depended on the electrofusion protocol, plots of critical field strength vs reciprocal time had the same slopes, i.e., approximately 24 Vs/mm. The results suggest that the fusogenic state induced by an electric pulse in either the contact-first protocol or the pulse-first protocol (long-lived fusogenic state) may in fact share a common mechanism, if the two states are not actually identical.

Animals↗

PubMed1991

Prospective randomized study of human menotropin versus a follicular and a luteal phase gonadotropin-releasing hormone analog-human menotropin stimulation protocols for in vitro fertilization.

OBJECTIVE: To determine whether gonadotropin-releasing hormone analogs (GnRH-a) initiated either in the luteal phase or in the early follicular phase immediately preceding menotropin will improve the fertilization, implantation, and pregnancy rates (PR) in all IVF patients, when compared with menotropins alone. DESIGN: In a prospective, controlled, randomized study we compared a pure follicle-stimulating hormone (FSH) human menopausal gonadotropin (hMG) protocol (group A = control) (n = 93 cycles) to two protocols in which GnRH-a pretreatment plus pure FSH and/or hMG was used in in vitro fertilization candidates. In group B (n = 64) GnRH-a was initiated during the luteal phase and in group C (n = 35) during the follicular phase. RESULTS: We found (1) no differences in fertilization and implantation rates between the three protocols; (2) similar pregnancy rates per transfer when similar number of conceptus were transferred (A = 30%, B = 22%, C = 21%); (3) an increase of the number of oocytes obtained; and (4) a reduction in the cancellation rate with both GnRH-a protocols. CONCLUSIONS: These findings suggest that there is no obvious superiority between the two GnRH-a protocols in the dosage schedule used and that the major advantage of GnRH-a over non-GnRH-a protocols is in decreasing the cancellation rate and increasing the number of oocytes and conceptus obtained. The follicular phase GnRH-a protocol required less hMG-pure FSH than the luteal phase GnRH-a protocol.

Adult↗

PubMed1995

Type of stimulation protocol affects oocyte maturity, fertilization rate, and cleavage rate after intracytoplasmic sperm injection.

OBJECTIVE: To compare oocyte maturity, fertilization rate and cleavage rate after a short and long GnRH agonist (GnRH-a) stimulation protocol and intracytoplasmic sperm injection (ICSI). DESIGN: Retrospective study of 34 sequential ICSI cycles stimulated with a short or long GnRH-a protocol. SETTING: A university-based tertiary care center for assisted reproductive treatment. RESULTS: Significantly more oocytes were mature (metaphase II) after a long GnRH-a protocol then after a short GnRH-a protocol (25.6% and 80.8%, respectively). The long protocol resulted in more cleaving embryos (36/152 versus 9/132) and more cycles of ET (12/17 versus 5/17) than the short group. CONCLUSION: A greater percentage of mature oocytes results from ovarian stimulation with a long GnRH-a protocol than a short GnRH-a protocol. Maturity could be assessed accurately after cumulus stripping that is required before ICSI. Fertilization rate and cleavage rate with ICSI was superior after a long GnRH-a stimulation protocol for superovulation.

Adult↗

PubMed1986

Effect of a treatment protocol on the efficiency of care of the adult acute asthmatic.

A treatment protocol for patients with acute bronchospasm was introduced to an adult emergency department in an attempt to decrease treatment time and potentially decrease need for admission. The charts of all patients seen in a control year (before any protocol was in place) and the first three years of the protocol were reviewed. All care was given by medical housestaff. The first year after the protocol was introduced showed no change in either admission rate or stay in the ED. During this time, however, the protocol was used only 33% of the time. In the following two years, the protocol was used 93% of the time, and the admission rate decreased from 36.4% to 23.3% (P less than .02). The length of stay for all patients seen fell from a mean of 3.6 hours to 2.8 hours (P less than .005). The length of stay for those discharged fell from an average of 4.3 hours to 3.6 hours (P less than .02). Among the patients admitted, there was also a less striking but similar decrease from 3.0 hours to 2.4 hours. An organized treatment protocol was effective in increasing the efficiency of care given by the housestaff. The routine use of the protocol was not immediate and required time for acceptance by the housestaff.

Adult↗

PubMed2000

Varied protocols of cadmium exposure produce different effects on nitric oxide production in macrophages.

Different protocols of cadmium (Cd) exposure in non-cytotoxic conditions (i.e. 10 microM Cd for 18 h), and their effect on nitric oxide (NO) generation induced by NO inductor agents (NOIA) in peritoneal macrophages (pM) were studied. In all cases, NOIA (i.e. bacterial lipopolysaccharide [LPS], phorbol ester [PMA], okadaic acid [OA] or their combinations [LPS/OA] and [LPS/PMA]) were added at the beginning of the first incubation, only. Simultaneously exposure with 10 microM Cd enhanced NO generation and inducible NO synthase (iNOS) expression evoked by LPS, OA, PMA; those induced by LPS/PMA were not modified; and those caused by LPS/OA in relation to culture without Cd (medium) decreased. Double incubation, either with or without Cd (Cd+Cd or medium+medium), or Cd added at the start of the first or second incubation only (Cd+medium or medium+Cd), were tested. After the second incubation, medium+Cd protocol produced the highest NO generation in relation to other exposure protocols. When NO production was measured at the end of the second incubation, Cd+medium protocol enhanced NO production induced by OA, and LPS/OA, while medium+Cd protocol enhanced the response to LPS, PMA, and LPS/OA, in both cases in relation to the first incubation. Cd+Cd incubation protocol decreases the response to all NOIA in relation to another protocols. Cd effect on NO generation in macrophages is dependent on protocol and timing of exposure.

Animals↗

PubMed1991

Comparison of the ramp versus standard exercise protocols.

To compare the hemodynamic and gas exchange responses of ramp treadmill and cycle ergometer tests with standard exercise protocols used clinically, 10 patients with chronic heart failure, 10 with coronary artery disease who were asymptomatic during exercise, 11 with coronary artery disease who were limited by angina during exercise and 10 age-matched normal subjects performed maximal exercise using six different exercise protocols. Gas exchange data were collected continuously during each of the following protocols, performed on separate days in randomized order: Bruce, Balke and an individualized ramp treadmill; 25 W/stage, 50 W/stage and an individualized ramp cycle ergometer test. Maximal oxygen uptake was 16% greater on the treadmill protocols combined (21.4 +/- 8 ml/kg per min) versus the cycle ergometer protocols combined (18.1 +/- 7 ml/kg per min) (p less than 0.01), although no differences were observed in maximal heart rate (131 +/- 24 versus 126 +/- 24 beats/min for the treadmill and cycle ergometer protocols, respectively). No major differences were observed in maximal heart rate or maximal oxygen uptake among the various treadmill protocols or among the various cycle ergometer protocols. The ratio of oxygen uptake to work rate, expressed as a slope, was highest for the ramp tests (slope +/- SEE ml/kg per min = 0.80 +/- 2.5 and 0.78 +/- 1.7 for ramp treadmill and ramp cycle ergometer, respectively). The slopes were poorest for the tests with the largest increments in work (0.62 +/- 4.0 and 0.59 +/- 2.8 for the Bruce treadmill and 50 W/stage cycle ergometer, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗

PubMed1998

Tc-99m tetrofosmin myocardial SPECT perfusion imaging: comparison of rest-stress and stress-rest protocols.

AIM: The purpose of this study was to evaluate the diagnostic value of Tc-99m tetrofosmin SPECT myocardial perfusion scintigraphy rest/stress and stress/rest protocols for the assessment of coronary artery disease (CAD). METHODS: 65 patients underwent both rest and stress SPECT imaging in a one-day protocol and coronary angiography within 2 months before or after scintigraphy. Scintigraphic data was obtained according to two different protocols; 1) rest-stress (n = 18) and 2) stress-rest (n = 47). RESULTS: Scintigraphic evidence for myocardial ischaemia was found in 36 patients (55%). The overall sensitivity to detect CAD (> 50% luminal stenosis) was 94% (34/36), specificity 66% (19/24), positive predictive value 77%, negative predictive value 90%. The sensitivity to detect CAD for protocols 1 and 2 were 100% and 93%, specificity 56% and 70%, positive predictive value 69% and 81% and negative predictive value 100% and 88%, respectively. The left anterior descending coronary artery showed a sensitivity (overall, protocol 1 & 2) of 78%, 75% (3/4) and 79% (15/19) and a specificity of 71%, 64% (9/14) and 75% (21/28). The right coronary artery showed a sensitivity (overall, protocol 1 & 2) of 91%, 100% (6/6) and 88% (14/16) and a specificity of 70%, 92% (11/12) and 61% (19/31). The left circumflex coronary artery showed a sensitivity (overall, protocol 1 & 2) of 50%, 67% (2/3) and 46% (6/13) and a specificity of 94%, 100% (15/15) and 91% (31/34). CONCLUSION: Tc-99m tetrofosmin appears to be a valuable tool in predicting significant CAD. The sensitivity and the positive predictive value are high, making this test highly appropriate for the diagnosis of CAD. The diagnostic value of the individual coronary arteries is high to moderate. No significant differences were found between both protocols.

Adult↗