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At least 19 recordsLinked to original sources

PubMed1998

A comparison of electrophysiologic properties between responders and non-responders to DL-sotalol among patients with ventricular tachyarrhythmia. Importance of the lack of a reverse use-dependent effect on ventricular refractoriness to responders.

This study was undertaken to determine whether dl-sotalol can prevent ventricular tachyarrhythmia inducibility that can be predicted from electrophysiologic parameters. The effects of dl-sotalol in 16 patients (ventricular tachycardia (VT) in 11 and fibrillation (VF) in 5) were determined in electrophysiologic studies before and after dl-sotalol (320 mg/day). In 9 of 16 patients (56%) after dl-sotalol, ventricular tachyarrhythmia could not be induced by the entire stimulation protocol (responders). There were significant differences in QT interval (462 +/- 52 vs. 415 +/- 34 msec; p < 0.05) and ventricular effective refractory period (VERP) at 600, 400 and 300 msec (302 +/- 28 vs. 262 +/- 20 msec; p < 0.001, 280 +/- 23 vs. 240 +/- 21 msec; p < 0.001, 256 +/- 24 vs. 222 +/- 12 msec; p < 0.005, respectively) between responders and non-responders. The percentile increases in VERP (% VERP) at 600, 400, and 300 msec in responders were 25%, 26%, and 27%, whereas those in non-responders was 9%, 7%, and 7%, respectively. Isoproterenol administered to responders did not fully reverse the dl-sotalol-induced prolongation of VERP (delta VERP) at 600, 400, and 300 msec, which remained significantly prolonged compared to the baseline (281 +/- 18 vs. 241 +/- 16 msec; p < 0.01, 258 +/- 20 vs. 223 +/- 21 msec; p < 0.01, 247 +/- 22 vs. 202 +/- 16 msec; p < 0.01, respectively). % VERP did not exhibit significant differences at 600 (16%), 400 (15%), and 300 (20%) msec, indicating the lack of a reverse use-dependency. The results suggest that delta VERP in responders did not show reverse use-dependency, and that the phenomenon may account for the efficacy of dl-sotalol.

Action Potentials↗

PubMed1981

Antigen-reactive T clones. III. Low responder antigen-presenting cells function effectively to present antigen to selected T cell clones derived from (High Responder x Low Responder)F1 mice.

Long-term-cultured poly(Tyr, Glu)-poly-D,L,-Ala-poly-Lys [(T,G)-A--L]-reactive T cells and clones derived from (high responder x low responder)F1 [(C57BL/6 x A/J)F1] mice were shown to recognize (T,G)-A--L presented by cells from low responder strain A/J mice. The antigen-presenting determinant(s) that allowed recognition of (T,G)-A--L by such T cell clones was controlled by the I-A subregion of the major histocompatibility complex. These results suggest that there is no functional defect in the ability of low responder Ir gene products (I-A antigens) to associate with (T,G)-A--L for effective recognition by T cells. Although these results might tentatively be interpreted to suggest that Ir gene-controlled low responsiveness is due to the inability of the T cell to recognize the association between (T,G)-A--L and low responder I-A gene products, it is similarly possible that there might be a defect in the functional capabilities of low responder antigen-presenting cells to effectively process (T,G)-A--L into immunodominant epitopes.

Animals↗

PubMed1972

Characteristics and response-displacement effects of shock-generated responding during negative reinforcement procedures: pre-shock responding and post-shock aggressive responding.

Bar-pressing (Experiment I) or key-pressing (Experiments II and III) responses of monkeys were reinforced according to a fixed-interval schedule of negative reinforcement: the first response after a fixed interval of time terminated regularly spaced shocks for a fixed time designated as the reinforcement period. During extinction, shocks continued during the reinforcement period. That there were two types of responding generated by shock alone was indicated by (1) the level of responding maintained during extinction relative to conditions without shock, (2) the stability of two between-shock response patterns across reinforcement and extinction conditions, and (3) the development of these two between-shock patterns without a history of reinforcement. Subjects developed either a pre-shock or a post-shock response pattern when only the bar was available. However, when both a bite tube, an operandum requiring an aggressive topography, and a recessed key, an operandum that did not require an aggressive topography, were provided, the post-shock pattern was observed in tube biting and the pre-shock pattern was observed in key pressing. Removal of the bite tube produced post-shock key responding similar to that observed when only the bar was available. The displacement of post-shock, aggression-motivated responding confirmed the confounding effect of shock-generated responding in negative reinforcement procedures, and suggests that the use of concurrent response alternatives would reduce such confounding.

Aggression↗

PubMed1998

Characteristics of responders and non-responders in an infant feeding study.

BACKGROUND: Few studies have fully investigated and described the characteristics of non-responders in infant breast feeding studies. Examination of the characteristics of non-responders enhances this understanding and provides information on the representativeness of the sample actually investigated. METHODS: As part of a larger local longitudinal study, couples whose babies were due to be born during the three months of the study in the autumn of 1995, at two local maternity hospitals, were approached by midwives to participate in the study of infant feeding patterns and determinants, including interviews, questionnaires and postal survey. From the 648 eligible mothers, 91 (14 per cent) were not approached, 233 (35.9 per cent) consented but were not interviewed, 256 (39.5 per cent) consented and were interviewed and 68 (10.5 per cent) refused to participate (non-responders) in the longitudinal study. To make a comparison between the 'responders' (i.e. the 233 who consented but were not interviewed and the 256 who consented and were interviewed) and non-responders (the 68 who refused to consent), appropriate data were collected on their socio-demographic characteristics, their feeding intentions and their feeding behaviour. RESULTS: Univariate analysis revealed a number of significant differences between responders and non-responders. However, log-linear analysis of these differences indicated that the main factors that differentiated between responders and non-responders were social class, smoking habit and actual feeding behaviour. When comparing the feeding intention at the time of 'booking', the non-responders compared with the responders were less likely to intend to breastfeed and more likely to be uncertain about their feeding intentions. Following delivery non-responders compared with responders were more likely to bottle feed their babies. By the time of discharge, of the non-responders, 83.6 per cent were bottle feeding in comparison with 47.3 per cent of responders who were also bottle feeding. CONCLUSIONS: In this study non-responders were found to be more similar to bottle-feeding responders than to breastfeeding responders. Furthermore, non-responders were more likely to be smokers, from lower social class and to bottle feed. This study also showed that the non-responders were more undecided about their feeding intention at the time of the booking visit. Invariably a higher percentage of mothers who were undecided at the booking visit chose to bottle feed their babies at discharge. These results highlight the impact of failing to include information from non-responders when conducting research which examines patterns of infant breastfeeding and attitudes towards it.

Adult↗

PubMed1982

Genetic control of the immune response to myoglobins. Both low and high responder T cells tolerant to the other major histocompatibility complex help high but not low responder B cells.

We sought to examine the role of immune response (Ir) genes in helper T cells. To eliminate allogeneic effects, we used neonatally tolerized mice. The results bear not only on the mechanism of Ir genes, but also on the development of the T cell repertoire. B 10.BR (H-2(k)) or C57BL/10 (H-2(b)) mice, which were low responders to myoglobin (Mb), were neonatally tolerized to high responder H-2(d) alloantigens, and B10.D2 mice, which were high responders to Mb, were neonatally tolerized to low responder H-2(k) or H-2(b) alloantigens. Spleen cells from these tolerized mice did not show any reactivity in mixed-lymphocyte reaction or cell-mediated lympholysis against alloantigens used in tolerization. Mb-immune F(1) B cells were helped comparably by Mb-immune tolerized low or high responder T cells. Thus, low responder T cells functioned equivalently to high responder T cells. The failure of nonimmune T cells from tolerized low responder mice to help F(1) B cells and antigen-presenting cells (APC) indicated that collaboration between B10.BR or C57BL/10 T cells and F(1) B cells was not caused by a positive allogeneic effect. Spleen cells from tolerized mice were contaminated with 2-4 percent chimeric F(1) cells, as judged by fluorescence-activated cell sorter analysis, and no F(1) alloantigens were detectable in the thymus. However, removal of chimeric F(1) T cells from the tolerized cell population by treatment with anti-H-2 and complement did not change the helper activity of tolerized low responder T cells. These data indicated that helper activity in the T cell population from low responder mice was not due to F(1) cells. Also, the level of contamination was not sufficient to quantitatively account for the help. In examining the genetic restriction of these tolerized T cells, we found that T cells from tolerized low responder B10.BR or C57BL/10 mice helped F(1) or high responder B10.D2 B cells and APC but not syngeneic B10.BR or C57BL/10 B cells and APC, which were immunized with Mb-coupled fowl gamma globulin instead of Mb to prime low responder B cells with Mb. On the other hand, high responder B 10.D2 tolerized T cells helped syngeneic B 10.D2 B cells but not allogeneic low responder B10.BR B cells. These data indicated that clones of helper T cells specific for Mb exist in low responder mice, and these are not phenotypically different from those in high responder mice, in that both help high responder and F(1) but not low responder B cells and APC. These data are discussed in terms of the mechanism for Ir gene control, and the mechanism of T cell repertoire development- whether intra- or extrathymically-in neonatally tolerized mice.

Animals↗

PubMed1998

["Responders and non-responders" to PGE1 and alpha-cyclodextrin].

BACKGROUND: In this study we evaluated a group of 76 patients (mean age 66 +/- 12) treated with the short-term PGE1 alpha-ciclodestrina protocol (60 micrograms/die for 2 days). Responders to PGE1 alpha-ciclodestrina treatment were considered patients with an increase in flow/perfusion and an associated improvement in signs/symptoms. Moderate responders were considered patients with only flow/perfusion increase or only sign/symptoms improvement. Non-responders were characterised by no increase in flow/perfusion and no clinical improvement. METHODS: Signs/symptoms variations were measured on an analogue scale line. Perfusion measurements (laser Doppler, transcutaneous PO2, arterial inflow with straingauge plethysmography) were recorded after the two days of the short term treatment. RESULTS: In the group of 38 patient with claudication (200-600 m) 54% were considered responders, 12% non responders and 34% moderate responders. In the more severe claudication group (distance < 200 m) including 18 patients, 66% were responders, 8% non responders and 26% were considered moderate responders. In the rest pain group (13 patients) there were 63% responders, 9% non-responders and 28% moderate responders. In the gangrene group (10 patients) 60% were considered responders, 10% non-responders and 3% moderate responders. The overall percentages were 61.25% of responders, 10% of non-responders and 28.75% moderate responders. CONCLUSIONS: The evaluation of the response to PGE1 alpha-ciclodestrina treatment may indicate which group of patients will benefit from the treatment and which group will have no benefits or only limited benefits. This may induce changes in treatment (i.e. increasing doses, more prolonged treatment) or other solutions (revascularisation if possible, arterial infusion or amputation).

Alprostadil↗

PubMed1991

Comparison of 'poor' responders with 'good' responders using a standard buserelin/human menopausal gonadotrophin regime for in-vitro fertilization.

This study identifies a group of 87 patients, who demonstrated a 'poor' response to a standard buserelin/human menopausal gonadotrophin (HMG) regime. The subsequent outcome in 61 of these 'poor' responders when treated with a higher dose of HMG to achieve a satisfactory response was compared with 250 patients, who showed a 'good' response to the standard regime. 'Poor' responders were significantly older than 'good' responders (P less than 0.001), but no significant difference was demonstrated in the indication for in-vitro fertilization (IVF). Even on higher doses of HMG, 'poor' responders took longer for their follicles to achieve maturity than the 'good' responders (P less than 0.01). 'Poor' responders produced 8.9 oocytes per oocyte collection compared to 11.8 in the 'good' responders (P less than 0.01). The fertilization rate was significantly lower in the 'poor' responders compared to the 'good' responders (P less than 0.01). Although there was no significant difference in morphometric grading between 'poor' responder embryos and 'good' responder embryos, the rate of cell division was significantly slower in embryos of the 'poor' responders than the 'good' responders (P less than 0.01). The pregnancy rate per oocyte retrieval was 9% in the 'poor' responders compared to 29% in the 'good' responders (P less than 0.01). The implantation rate in the 'poor' responders was 4.4% compared to 16.1% in the 'good' responders (P less than 0.001).

Adult↗

PubMed1996

The response of breeding doses to nematodiasis: segregation into "responders" and "non-responders".

Responder and non-responder does were identified from a flock of 95 Scottish cashmere 2-6 year-old does exposed to natural nematode infection over a 12-month period. Every 5 weeks, the does were faecal sampled for worm-egg counts prior to anthelmintic treatment. Responsive and non-responsive individuals were identified on the basis of their cumulative faecal egg count (FEC) rankings: the 8 lowest and 8 highest rankings were deemed to be responders and non-responders, respectively. Retrospective analysis showed that the mean egg count of the 8 responders was significantly lower than that of the 8 non-responders. The selected responders and non-responders were subsequently housed together with 8 randomly selected does from a control line, and given a mixed trickle challenge with Teladorsagia circumcincta and Trichostrongylus vitrinus larvae (L3). Mean responders FEC was significantly lower following artificial infection than that of non-responder and unselected does. Peripheral eosinophilia was significantly greater in responders in the first 3 weeks of this infection. On day 60, the infection was terminated with anthelmintic and 7 days later the goats were given a single challenge of 50,000 T. circumcincta L3. The mean responder worm burden was lower, and exhibited greater evidence of retardation of worm development, than those of non-responder and unselected does. Responders had significantly more mast cells and globule leukocytes post-challenge than did the other 2 groups. These results suggest that under the conditions encountered in this experiment, it is possible to segregate goats into responders and non-responders using simple parasitological criteria, as individual responsiveness is a relatively repeatable phenomenon.

Animal Feed↗

PubMed1998

Monosymptomatic primary enuresis: differences between patients responding or not responding to oral desmopressin.

OBJECTIVES: To evaluate the 24-h diuresis, urinary osmolality, plasma arginine vasopressin (AVP) and urinary prostaglandin E2 (PGE2) before and during desmopressin treatment in patients with monosymptomatic primary enuresis (MPE), and to investigate the possible depressor effect of desmopressin on the detrusor in such patients with urodynamically confirmed bladder instability. PATIENTS AND METHODS: Seven healthy children (control group) and 11 consecutive patients with MPE (mean age 10.4 years, range 7-15) were assessed using laboratory tests, renal and bladder ultrasonography, and video-urodynamic investigations. A 24-h inpatient assessment with a controlled water intake of 20 mL/kg per day included determinations of diuresis, urinary osmolality, AVP and PGE2 in both normal children and those with MPE. After 30 days of treatment at optimal doses of desmopressin, all children were hospitalized and re-evaluated during desmopressin treatment; all completed 3 months of treatment at optimal doses. At the end of this period, patients whose symptoms improved by > or = 80% were defined as 'responders' while those in whom they did not were defined as 'non-responders'. RESULTS: After treatment, six of the 11 patients with MPE were 'responders' and five 'non-responders'. Urodynamic evaluation showed bladder instability in seven of the 11 patients with MPE but in those with bladder dysfunction, urodynamic studies carried out during desmopressin treatment showed no changes in detrusor activity. There were significant differences in the morning values of AVP between normal children and responders (P < 0.03), and between responders and non-responders (P < 0.02); none of the non-responders had AVP levels of < 2.5 pg/mL, while none of the responders exceeded this value. At midnight, responders had the lowest mean AVP and non-responders the highest; this correlated with the highest PGE2 value in the nonresponders at 00.00-08.00 hours. Non-responders had an overnight mean PGE2 level greater than that in normal subjects or responders. CONCLUSIONS: Polyuria occurred in all patients with MPE, independently of the response to desmopressin. Responders had the lowest AVP values over the 24 h; the morning AVP levels differentiated normal subjects from enuretic patients and responders from non-responders. In patients with MPE, clinically undetected bladder instability was unrelated to the results of treatment and there were no urodynamic changes during desmopressin treatment. The differences between enuretic patients suggested a different aetiology of MPE, probably related to an increase in PGE2 concentration and an antagonistic mechanism of action of AVP or desmopressin.

Administration, Oral↗

PubMed2000

Characteristics of respondents and non-respondents from a case-control study of breast cancer in younger women.

BACKGROUND: This study assessed the nature of potential biases by comparing respondents with non-respondents from a case-control study of breast cancer in younger women. METHODS: The case-control study was conducted in three regions in the US: Atlanta GA, Seattle/Puget Sound WA, and central New Jersey. An abbreviated interview or mailed questionnaire was completed by willing non-respondents, most of whom had refused participation in the main study. RESULTS: Respondents and non-respondents appeared similar with respect to age, race, relative weight, smoking, family history of breast cancer, number of births, age at first birth, and several dietary items. Compared to non-respondents, case and control respondents were of shorter stature, and reported less frequent consumption of doughnuts/pastries. Respondent cases, compared with non-respondent cases, were more highly educated and more likely to have consumed alcohol regularly; similar but not statistically significant tendencies were observed for controls. Respondent cases experienced menarche earlier than non-respondents. Respondent controls were more likely to have used oral contraceptives than non-respondents; a similar but not statistically significant tendency was observed in cases. Comparisons of crude and simulated relative risks using available non-respondents' data generally showed a low impact of non-response on relative risks in this study. CONCLUSIONS: Our results suggest that non-response would not greatly affect relative risk estimates in this study, except possibly regarding height. However, we were limited by the numbers of informative non-respondents and the amount of data collected. Collecting similar information in future studies would be useful, especially since varying methods used to encourage participation may lead to differences in respondents' characteristics.

Adult↗

PubMed1982

Genetic control of the antibody response to poly(L Tyr, L Glu)-poly(DL Ala)--poly(L Lys) in mice: analysis of (low responder x low responder)F1 hybrids.

The antibody response to the synthetic polypeptide poly (L Tyr, L Glu)-poly (DL Ala)--poly (L Lys) designated (T,G)-A--L, was investigated in inbred, congenic, F1 and F2 hybrid strains of mice. The antibody response was analysed at both low (10 microgram) and high (50 microgram) immunizing doses of (T,G)-A--L. Antibodies were measured using both a modified Farr assay and a plate binding assay. At low immunizing doses it was found that all of the congenic and non-congenic (low responder x low responder) F1 hybrids were low responders. However, the quantitative antibody response of one non-congenic (low responder x low responder) F2 hybrid segregated in a 1:1 ratio of high responders to low responders, suggesting some form of complementation of (T,G)-A--L Ir genes. At high immunizing doses it was found that congenic and non-congenic (low responder x low responder) F1 hybrids were all high responders, indicating a complementation of Ir genes to (T,G)-A--L. This complementation was confirmed using two different routes of immunization, namely footpad and intraperitoneal. Furthermore the quantitative antibody responses of (low responder x low responder) F2 hybrids segregate in a 1:1 ratio of high responders to low responders. The class of antibodies produced to (T,G)-A--L in (low responder x low responder) F1 hybrids was determined by gel filtration on Sephadex G-200, and found to be predominantly IgG, with lesser amounts of IgM.

Animals↗

PubMed1996

Studies on caprine responsiveness to nematodiasis: segregation of male goats into responders and non-responders.

Eighty-three 2-4-year-old intact male goats exposed to a combination of artificial and natural challenge were segregated into responders and non-responders by ranking of weekly faecal egg counts (FECs). Retrospective analysis of samples over a 15-week-period showed responders had a statistically lower mean FEC than non-responders. Estimates of repeatability between consecutive egg counts were significant in both groups. The 6 top responders and bottom non-responders were subsequently given an artificial trickle challenge with Teladorsagia circumcincta and Trichostrongylus vitrinus. Mean faecal egg output was significantly lower in responders than non-responders. Peripheral eosinophil numbers following challenge were significantly greater in responder than non-responder goats. Abomasal and intestinal worm burdens were considerably lower in responders, with evidence of retardation of worm development compared to non-responders. Both abomasal and jejunal tissue eosinophil numbers were significantly higher in responders, although there was no difference in mucosal mast cell or globule leucocyte numbers. These results suggest that under temperate climatic conditions, it is possible to segregate male goats into responders and non-responders on the basis of simple parasitological criteria.

Abomasum↗

PubMed1999

Responders and non-responders to post-operative pain treatment: the loading dose predicts analgesic needs.

The study compares responders and non-responders to post-operative patient-controlled analgesia (PCA) and evaluates factors that might differ between these two groups in order to identify non-responders during the early post-operative period. A prospective, randomized, double-blinded study design was used. Patients recovering from abdominal surgery were assigned to one of three treatment groups for a study period of 48 h. After titration of an individual loading dose, patients could self-administer 1 mL bolus doses (2 mg of morphine, 20 mg of tramadol or placebo) using a PCA device. Patients responding or not responding to the treatment were identified. In non-responders the escape medication was morphine. There were 96 responders and 65 non-responders. All responders showed similar pain scores, irrespective of the drug they received. Drug consumption of placebo responders was twice as high as that of opioid responders. Pain scores and analgesic consumption of non-responders were significantly higher compared with responders, although those patients received morphine. The loading dose correlated with subsequent analgesic consumption. Altogether, 89.2% of the non-responders were identified after the loading dose. Size of loading dose and pain scores during the first 30 min are useful for assessing the overall response to post-operative pain management. These factors may be valuable for predicting individual pain management.

Abdomen↗

PubMed2007

Development of naltrexone supersensitivity during food-maintained responding enhances naltrexone's ability to reduce ethanol-maintained responding.

BACKGROUND: Similar doses of the opiate antagonist naltrexone (NTX) reduce responding maintained by food and ethanol. In animals responding for food, repeated administration of NTX produces supersensitivity to NTX. The purpose of this study was to determine whether the factors that produce enhanced sensitivity to NTX during food-maintained responding also contribute to NTX's ability to reduce ethanol-maintained responding. METHODS: Rats (n=12) were trained to lever press using food reinforcement. After responding stabilized, the rats were trained to respond for 10% ethanol. Before ethanol sessions, injections of 30 mg/kg NTX were given. Subsequently, weekly cumulative NTX dose-effect curves (1, 3, 10, 30, and 100 mg/kg), known to produce NTX supersensitivity, were determined during food-maintained responding in half the rats for 8 weeks while the other half of the rats received saline vehicle injections instead. To determine whether NTX supersensitivity would transfer to ethanol self-administration, ethanol-maintained responding was re-established and 30 mg/kg NTX was administered again. RESULTS: Initially, 30 mg/kg NTX had little effect on ethanol-maintained responding. During food-maintained responding, supersensitivity developed in rats receiving weekly cumulative NTX injections. After development of supersensitivity, 30 mg/kg decreased ethanol-maintained responding. Naltrexone's potency to reduce ethanol-maintained responding was unchanged in rats that received only vehicle injections for 8 weeks. CONCLUSION: The mechanisms that produce NTX supersensitivity during food-maintained responding may play a role in NTX's effect on ethanol consumption. Naltrexone's effect on responding for ethanol was much smaller than that reported in other studies. Further exploration may lead to techniques that maximize NTX's effect on ethanol while minimizing its effect on other behaviors.

Animals↗

PubMed1988

T cell response to myoglobin: a comparison of T cell clones in high-responder and low-responder mice.

Mice carrying the H-2b haplotype (e.g., inbred strains C57BL/6 and C57BL/10) are low responders to sperm whale myoglobin when tested in the T cell proliferation assay. Their response is improved by the removal of the Ly-2+ cells from the lymph node population, but it still remains significantly lower than that of cells cells from high-responder strains (e.g., DBA/2, H-2d). To determine whether T cells from the low and high-responder mice recognize the same or different epitopes on the immunizing antigen, we obtained sets of T cell clones from both strains and tested them against peptides representing different regions of the myoglobin molecule, as well as against myoglobins from species other than the sperm whale. Four types of T cell clones were obtained from the DBA/2 mice: 3 types responded to the peptide 107-120 (9 clones altogether), and 1 type responded to the peptide 133-149 (4 clones altogether). The 3 types responding to the peptide 107-120 could be distinguished by their response to horse myoglobin or by the restriction of the response (Ad vs. Ed). Similarly, 5 types of T cell clones were obtained from the C57BL/6 mice: 2 types responded to the peptide 10-22 (1 type, but not the other, responded to horse myoglobin); 1 type responded to the peptide 133-149; and 2 types did not respond to any of the peptides used (1 type, but not the other, responded to dog myoglobin). All 5 types (13 clones altogether) were presumably Ab restricted. These results demonstrate the diversity of epitopes in single antigenic regions and show equivalent heterogeneity of T cell repertoires in high and low responder mice. Attempts to demonstrate specific T cell suppression in the low responder mice failed; only partial, nonspecific suppression was observed.

Animals↗

PubMed2006

The relationship between regional cerebral blood flow and response to methylphenidate in children with attention-deficit hyperactivity disorder: comparison between non-responders to methylphenidate and responders.

In a sample of children with attention-deficit hyperactivity disorder (ADHD), a voxel based investigation of regional cerebral blood flow (rCBF) during resting state was conducted to identify functional differences between non-responders to methylphenidate (MPH) and responders. Thirty-four children with ADHD were examined by technetium-99m-hexamethylporphylenamine oxime (HMPAO) SPECT. According to clinical response after 8 weeks of treatment with MPH, they were classified as non-responders to MPH and responders. Using SPM analysis, we compared the SPECT images of non-responders to MPH with those of responders. Non-responders to MPH had higher rCBF in the left anterior cingulate cortex, the left claustrum, the right anterior cingulate cortex, and the right putamen relative to responders. In addition, lower rCBF was found in the right superior parietal lobule in non-responders to MPH relative to responders. Further stepwise discriminant analysis revealed that 88.2% could be correctly classified as either non-responders to MPH or responders when considering the extracted rCBF values in the left anterior cingulate cortex, the left claustrum, and the right superior parietal lobule. The current findings suggest that non-responders to MPH may have different patterns of rCBF in brain regions, which have been known as a part of frontal-striatal circuitry and posterior attentional system, respectively.

Attention Deficit Disorder with Hyperactivity↗

PubMed2007

Different hemodynamic responses by color Doppler ultrasonography studies between sildenafil non-responders and responders.

AIM: To determine if there are different penile hemodynamic patterns between sildenafil non-responders and responders by using color Doppler ultrasonography. METHODS: A total of 69 erectile dysfunction (ED) patients aged 22-79 years were enrolled into the present study. Thirty-eight (55.1%) men with ED who did not respond to four attempts of treatment with 100 mg sildenafil after re-education were classified as sildenafil non-responders. A combination of three vasodilator drugs, 1.25 mg papaverine, 0.4 mg phentolamine and 5 mg prostaglandin E1, was given by intracavernous injection before penile Doppler ultrasonography was carried out. The erectile response to intracavernous injection and vascular parameters including peak systolic velocity (PSV), resistance index (RI), end diastolic velocity (EDV) and cavernosa artery diameter (CD) were measured and the results between sildenafil non-responders and responders were compared. RESULTS: No statistical difference in vascular parameters measured by Doppler ultrasonography studies between non-responders and responders was noted. Sildenafil non-responders had a poorer penile rigidity response to intracavernous injection than responders (P < 0.05). Among patients with adequate PSV (>or=30 cm/s) and abnormal EDV (> 5 cm/s), individuals in the non-responder group had fewer positive responses to intracavernous vasodilator injection than in the responder group (35.3% vs. 72.2%, P < 0.05). Advanced age and comorbidity with diabetes mellitus were significantly associated with sildenafil non-response (P < 0.05). CONCLUSION: Sildenafil non-responders were characterized by a poorer penile rigidity response to intracavernous injection and had an associated impaired veno-occlusive mechanism. Advanced age and comorbidity with diabetes mellitus were two common factors associated with non-response.

Adult↗

PubMed2004

The effect of basic fibroblast growth factor on cell cycle in human gingival fibroblasts from nifedipine responder and non-responder.

It has previously been demonstrated that gingival fibroblasts derived from nifedipine-reactive patients (nifedipine responders) show a greater cell proliferation rate than those from nifedipine non-reactive patients (nifedipine non-responders) in the presence of 1 microM nifedipine. The aim of the present study was to characterize cell cycle differences between nifedipine responder and non-responder fibroblast cells and determine the effect of basic fibroblast growth factor (bFGF) on cell cycle progression. Further, the effect of bFGF on cyclins A, B1, D1, E, and CDKs 1, 2, 4, 6 mRNA expression in responder and non-responder cells was investigated. A population of nifedipine responder cells underwent progression to S and G2/M phases from G0/G1 phase in the presence of 10% fetal calf serum or 10 ng/ml bFGF was greater than nifedipine non-responder cells. mRNA expression of cyclins A, B1, D1, E and CDKs 1, 2, 4, 6 in the presence of 10 ng/ml bFGF was generally greater in nifedipine responder cells than non-responder cells. These results indicate that nifedipine responder cells may be more susceptible to growth factors such as bFGF with a resultant increase in expression of cyclins and CDKs in responder compared with non-responder cells.

CDC2 Protein Kinase↗