Biomedical subjects

M S Dietrich

Publications and source records attributed to M S Dietrich.

18 recordsLinked to original sources

PubMed2006

MDMA use is associated with increased spatial BOLD fMRI visual cortex activation in human MDMA users.

Previous animal studies have demonstrated that 3,4-methylenedioxymethamphetamine (MDMA) exposure causes serotonin axotomy that is greatest in occipital cortex (including primary visual cortex) where serotonergic axons innervate neurons and blood vessels. Human MDMA users have altered serotonergic function and reduced gray matter density in occipital cortex. The fMRI BOLD method is potentially sensitive to both the neuronal and vascular consequences of MDMA-induced serotonin toxicity. To test the hypothesis that MDMA users have altered visual system function, we used the fMRI BOLD technique to assay visual cortical activation after photic stimulation in a group of adult MDMA users. Because MDMA users worldwide are polydrug users and therefore difficult to match to comparison groups in terms of polydrug exposure, we conducted a primary within-group analysis examining the correlation between lifetime episodes of MDMA exposure and measures of visual cortical activation. The within-group correlational analysis in the MDMA user group revealed that the degree of prior MDMA exposure was significantly positively correlated with the number of activated pixels for photic stimulation (r=0.582, p=0.007). A secondary between-group comparison of MDMA users with non-MDMA users found overall greater levels of polydrug exposure in the MDMA user cohort but no significant differences in visual cortical activation measures between the two groups. Additional research is needed to clarify the origin and significance of the current findings.

Adolescent↗

PubMed2006

Continent catheterizable channels and the timing of their complications.

PURPOSE: We reviewed our experience with continent catheterizable channels with interest in the timing of conduit related complications. MATERIALS AND METHODS: A retrospective review was performed of the outcome of continent catheterizable channels in all patients between 1998 and 2003 who had undergone construction of an antegrade continence enema and/or a Mitrofanoff procedure using appendix, small bowel or continent cutaneous vesicostomy. We performed a total of 117 such stomas in 37 male and 41 female patients 2.5 to 20 years old (mean age 8.9). For the antegrade continence enema we used appendix in 92% of cases, an ileal Yang-Monti tube in 6% and a cecal tube in 2%. For the continent catheterizable channel we used appendix in 43% of cases, a Yang-Monti tube in 38% and continent cutaneous vesicostomy in 19%. RESULTS: Continence was achieved in 98% of patients. Followup was 6 to 71 months (mean 28.4). There were 27 channel related complications (23%). Stomal stenosis occurred in 7 antegrade continence enema procedures (14%) within 1 to 10 months (mean 6.2) and in 9 continent bladder channels (13%), including 5 continent cutaneous vesicostomies, within 1 to 24 months (mean 9.4) after surgery. False passages occurred in 5 antegrade continence enema procedures (10%) within 1 to 13 months (mean 3.6) and in 4 continent catheterizable channels (6%) within 1 to 13 months (mean 6.5) after surgery. Of patients with stomal stenosis 50% were treated with surgical revision, while the remainder was successfully treated with dilation. Most false passages were managed by catheter drainage alone. Reasons for revision were contained perforation, colovesical fistula and inability to catheterize. Patient noncompliance appeared to have a role in stomal stenosis. CONCLUSIONS: Continent catheterizable stomas help patients achieve bowel and bladder continence. Stomal incontinence after reconstruction is rare. In our experience most stoma related complications occurred in the first year after reconstruction. Experience with more patients and longer followup will help determine whether such problems continue to accumulate with time or whether continent stomas function well with time, particularly after the initial period of healing.

Adolescent↗

PubMed2001

Information needs of clinical teams: analysis of questions received by the Clinical Informatics Consult Service.

OBJECTIVES: To examine the types of questions received by Clinical Informatics Consult Service (CICS) librarians from clinicians on rounds and to analyze the number of clearly differentiated viewpoints provided in response. DESIGN: Questions were retrieved from an internal database, the CICS Knowledge Base, and analyzed for redundancy by subject analysis. The unique questions were classified into ten categories by subject. Treatment-related questions were analyzed for the number of viewpoints represented in the librarian's response. RESULTS: The CICS Knowledge Base contained 476 unique questions and 71 redundant questions. Among the unique queries, the top two categories accounted for 67%: treatment (36%) and disease description (31%). Within the treatment-related subset, 138 questions (59%) required representation of more than one viewpoint in the librarian's response. DISCUSSION: Questions generated by clinicians frequently require comprehensive, critical appraisal of the medical literature, a need that can be filled by librarians trained in such techniques. This study demonstrates that many questions require representation of more than one viewpoint to answer completely. Moreover, the redundancy rate underscores the need for resources like the CICS Knowledge Base. By critically analyzing the medical literature, CICS librarians are providing a time-saving and valuable service for clinicians and charting new territory for librarians.

Artificial Intelligence↗

PubMed1997

Cadmium-induced apoptosis in the urogenital organs of the male rat and its suppression by chelation.

Cadmium-induced apoptosis is shown to occur, in vivo, in several organs of the male Wistar rat urogenital system, 48 h after cadmium administration i.p. at a dose of 0.03 mmol/kg. Characteristic DNA fragmentation (as measured by an enzyme-linked immunosorbent-assay, ELISA) and histopathologically observed changes characteristic of apoptosis are found in the kidney, prostate, seminal vesicles, testes, and epididymis. TUNEL assay also demonstrates the apoptosis. Such changes are absent from bladder and vas deferens tissue. Timely administration of an appropriate chelating agent capable of reaching intracellular cadmium binding sites can suppress the processes leading to apoptosis. Administration of monoisomyl meso-2,3-dimercaptosuccinate (Mi-ADMS, 0.5 mmol/kg i.p.) to cadmium-treated rats is effective in greatly reducing typical histopathologic signs of apoptosis and the associated chromatin DNA fragmentation as revealed by ELISA when the antagonist is administered 1 h after cadmium. Administration of the chelating agent at law times results in greater degradation of DNA into oligonucleotides and more prominent histopathological evidence of apoptotic changes in the affected organs of the rat urogenital system. There is also a progressive increase in apoptotic changes indicated by TUNEL assay, as the antagonist is administered at progressively greater intervals after cadmium.

Animals↗

PubMed1997

Psychological effects of chronic injury in elite athletes.

Many athletes train in a constant state of pain or injury while meeting the demands of an elite level program. It is hypothesized that the emotional distress experienced by athletes with chronic injuries is not inconsequential. A self-report battery, the Impact of Event Scale, was administered to 280 inter-collegiate athletes at a division I institution in an attempt to examine their response to chronic injury. Of the 280, 134 (48%) had been injured by study definition, with 117 (42%) meeting the criteria for chronic injury. Athletes with chronic injury scored on the Intrusion subscale of the Impact of Event Scale in the range of those who had experienced natural disasters, but scored higher (P < .05) on the Avoidance/Denial subscale. Their Avoidance subscale scores were similar to those of a group of orthopedic patients who required hospital admission with surgical fixation. Female athletes' Avoidance scores were significantly higher than those of their male peers (P < .05), but no gender differences were seen in intrusive thoughts. Subsets of athletes defined by the duration of injury showed no significant differences on subscale scores. It appears extraordinary that athletes should score in the realm of groups traumatized by natural disasters in intrusive thought and higher in avoidance thought when referring to their chronic injury. Although some attention has been focused on psychiatric intervention for acutely injured athletes or those who have undergone surgical treatment, the psychological needs of athletes struggling with chronic "minor" injuries also appear to merit consideration.

Adult↗

PubMed1995

Evidence for specific effects of childhood sexual abuse on mental well-being and physical self-esteem.

Women who are sexually abused are at increased risk for having mental health problems long after the abuse. Other nonexploitive experiences can also be psychologically detrimental, may coexist with sexual abuse, and may explain some portion of subsequent mental health problems. This study addresses the association between childhood sexual abuse and a woman's psychological functioning, independent of the quality of parental nurturance received during childhood and other variables which may influence mental health. Of 609 women completing mental health and self-concept measures, 98 reported sexual abuse; 110 of the remaining women were selected as comparisons. Women sexually abused as children scored lower on measures of mental health status. Both sexual abuse and fewer years of education were related to lower scores on a psychological well-being scale after variance accounted for by family and demographic variables was removed. Sexual abuse was not a predictor of general self-concept scores after the removal of family and demographic variables, but sexual abuse was independently associated with the subscale measuring the physical aspect of self-concept. These findings lend support to theorized causal links between child sexual abuse and some aspects of later psychological difficulties.

Adaptation, Psychological↗

PubMed1994

The prospective assessment of self-concept in neglectful and physically abusive low income mothers.

Maternal self-esteem has long been associated with the quality of maternal-child interactions and many assume that low self-esteem contributes to the cause of maltreatment. Assessments of the self-concepts of maltreating parents, however, have been done only after maltreatment has occurred. Prospective measurement of self-concept would help to clarify its role in the etiology of maltreatment. In this study, 471 pregnant women completed the Tennessee Self-Concept Scale (TSCS). State protective services' records were reviewed 3 years after these children were born. When records of the 459 women with a known live-born child were reviewed, 29 were found to have maltreated their children (neglect n = 22; physical abuse n = 11; four women found to have both neglected and abused their children). Neglectful mothers had lower scores on scales measuring overall self-esteem, moral self-worth, personal and social adequacy, and perception of self-worth in family relationships than matched nonreported mothers. They described their identity and behavior more negatively and had greater general maladjustment and neurotic symptoms. Physically abusive mothers had lower scores on self-worth in family relationships. When measured prospectively, low self-esteem appears to be a risk factor for child neglect, but is not a strong predictor for physical abuse. Implications for prevention programs are discussed.

Adult↗

PubMed1993

Differential reactivity of cortical and juxtamedullary glomeruli to adenosine-1 and adenosine-2 receptor stimulation and angiotensin-converting enzyme inhibition.

A recently developed modification of the technique of the split hydronephrotic rat kidney enables intravital assessment of vascular reactivity of cortical and juxtamedullary (JM) glomeruli and their vascular network. Effects of the adenosine-1 receptor agonist N6-cyclohexyladenosine (CHA) and the adenosine-2 receptor agonist N-ethylcarboxamide-adenosine (CHA) and the adenosine-2 receptor agonist N-ethylcarboxamide-adenosine (NECA) on these renovascular structures were examined before and after angiotensin II-converting enzyme (CE) inhibition by quinapril (0.9 mg kg-1 iv). CE inhibition was undertaken to test for an interdependence of adenosine and angiotensin II, as we have previously demonstrated for cortical glomeruli and CHA. In the first series of experiments (n = 7), CHA (in local dosages from 10(-8) to 10(-6) mole liter-1 produced a dose-dependent vasoconstriction of all preglomerular vessels and a decrease of cortical glomerular blood flow that was markedly attenuated by CE inhibition. In JM glomeruli, CHA also led to a dose-dependent vasoconstriction, but these effects were, on the contrary, unchanged or even increased by CE inhibition. In the second series (n = 6), NECA (in local dosages from 10(-8) to 10(-5) mole liter-1) led to a vasodilation and an increase in glomerular blood flow both before and after CE inhibition in both cortical and JM glomeruli. The reactions induced by NECA alone in the principal preglomerular vessel segments were significantly larger than those under NECA and simultaneous CE inhibition, thereby demonstrating an attenuation of NECA effects induced by CE inhibition. In additional series, we demonstrated a dose-dependent vasoconstriction of all pre- and postglomerular cortical vessel segments by local application of angiotensin I (dosage 10(-8) to 10(-6) mole liter-1) and the abolition of these effects by quinapril. Our findings demonstrate a differential reactivity of cortical and juxtamedullary glomeruli to adenosine receptor agonists and, additionally, an interdependence of adenosine-and angiotensin II-induced renovascular effects.

Adenosine↗

PubMed1993

A prospective study of secondary prevention of child maltreatment.

This study sought (1) to retest an approach to the prediction of risk of child maltreatment and (2) to test the effect of a comprehensive prenatal and pediatric health services program on the rate of maltreatment. Of 2585 women screened at their first prenatal visit, 1154 qualified for the study. Risk assignment was determined by a structured interview. High-risk women (n = 314) were assigned to receive standard (high-risk control group; n = 154) or intervention (high-risk intervention group; n = 160) services throughout the prenatal period and during the first 2 years of their infants' life. A third group (low-risk control group; n = 295) was selected among low-risk women and received standard care without intervention services. State records were searched for substantive reports of child maltreatment up to 36 months after birth. Physical abuse was found for 5.1% of the study population; neglect was substantiated for 5.9%. Prediction efforts were effective in identifying risk of physical abuse but not of neglect. Comprehensive health services did not alter the reported abuse rate for high-risk parents and was associated with an increased number of neglect reports. Intervention reduced subject attrition and appeared to serve as a bias for detection of maltreatment. Thus this long-term, prospective approach was ineffective for child abuse prevention, perhaps because of detection biases and societal changes.

Adult↗

PubMed1993

Endothelin and endothelium-derived relaxing factor control of basal renovascular tone in hydronephrotic rat kidneys.

1. In order to investigate the control of renal vascular tone by endothelin (ET) and endothelium-derived relaxing factor (EDRF) under basal conditions, we infused intravenously anti-ET-1/3 antibodies (a-ET-1/3) and NG-nitro-L-arginine methyl ester (L-NAME) in split hydronephrotic rat kidneys. 2. A 25 min I.V. infusion of a-ET-1/3 (4.0 x 10(-13) mol kg-1 min-1) induced a time-dependent vasodilatation of arcuate (16.5%) and interlobular arteries (18.6%) as well as an increase of glomerular blood flow (GBF) by 32%. 3. Inhibition of EDRF synthesis by L-NAME produced a marked vasoconstriction of arcuate arteries (17.1%) and efferent (20.1%) arterioles and a decrease of GBF by 43%. 4. Co-infusion of a-ET-1/3 and L-NAME induced efferent vasoconstriction by 19.5%, whereas preglomerular vessel diameters remained unchanged. 5. The specificity of a-ET-1/3 effects was confirmed by simultaneous I.V. application of a-ET-1/3 and ET-1 (160 ng I.V.) which produced no significant vascular effects. Injection of ET-1 alone constricted arcuate arteries and decreased glomerular blood flow by 25%. 6. Experiments in normal rat kidneys with a-ET-1/3 I.V. revealed an increase of renal blood flow by 21%. 7. Our results demonstrate a physiological control of basal vascular tone in larger preglomerular arterioles by ET and EDRF. Efferent arteriolar tone is predominantly controlled by EDRF.

Animals↗

PubMed1992

Antecedents of child neglect in the first two years of life.

To determine the prenatal antecedents of child neglect by low-income women, data from a prospective study of child maltreatment were reviewed. Mothers determined to be at high risk prenatally for maltreatment were more likely to be identified as neglectful within 24 months of the interview. Neglectful mothers were less likely to have completed high school, had more children younger than 6 years of age, and had more aberrant responses on parenting skills and support systems scales. Neglected children were lower in birth weight, were rated more difficult temperamentally, and had poorer mental and motor developmental scores.

Child Abuse↗

PubMed1992

Randomized trial of comprehensive prenatal care for low-income women: effect on infant birth weight.

The effect of comprehensive prenatal care on birth weight was examined using a prospective randomized design. A total of 428 pregnant women were randomly assigned to comprehensive prenatal care (n = 217) or standard prenatal care (n = 211). Comprehensive care was provided by a multidisciplinary team of nurse-midwives, social workers, a nutritionist, paraprofessional home visitors, and a psychologist. Standard prenatal care consisted of medical care provided by obstetric residents. Multiple regression analysis using behavioral, demographic, and medical variables showed a strong relationship between the set of predictors and birth weight. Comprehensive care was related to higher birth weights for primiparous but not multiparous mothers. Separate analyses of variance for primiparas and multiparas similarly showed a favorable effect of comprehensive care on birth weight for primiparous but not multiparous mothers.

Birth Weight↗

PubMed1991

Interaction between adenosine and angiotensin II in renal microcirculation.

In order to examine the possibility of an interaction between adenosine and angiotensin II (A II) in the control of the renal microcirculation, we studied the effects of agonists and antagonists of both substances by means of in vivo microscopy in the split hydronephrotic rat kidney. In a first series of experiments (n = 6), local application of the A II receptor antagonist saralasin (10(-6) mol.liter-1 abolished the vasoconstriction and the reduction of glomerular blood flow induced by the A1-adenosine receptor agonist N6-cyclohexyladenosine (CHA, local concentration 10(-7) mol.liter-1). Without saralasin (second series, n = 6), CHA reduced glomerular blood flow and decreased vessel diameters as previously reported from our laboratory. In a third series of experiments (n = 6), A II significantly reduced vessel diameters and glomerular blood flow both alone and during blockage of the A1-adenosine receptor by the selective antagonist 1,3-dipropyl-8-cyclopentylxanthine (DPCPX, 10(-5) mol.liter-1). In additional experiments, we excluded nonspecific receptor effects of saralasin and confirmed the inhibitory action of DPCPX on the adenosine-induced vasoconstriction. We suppose that adenosine needs a functioning A II receptor system for its vasoconstrictor action, whereas A II can induce a nonadenosine-dependent vasoconstriction.

Adenosine↗

PubMed1991

Effects of neuropeptide-Y on renal function and its interaction with sympathetic stimulation in conscious dogs.

1. The effects of neuropeptide-Y (NPY) on renal function were investigated in conscious foxhounds. 2. Dose-response curves (n = 7) were obtained for NPY by measuring renal blood flow (RBF), glomerular filtration rate (GFR), urine excretion (VU), sodium excretion (VNa), potassium excretion (VK) and plasma renin activity (PRA) at different infusion rates. All variables decreased with increasing infusion rates except for PRA, which surprisingly did not change during the different infusion rates. 3. The influence of the non-constrictor dose of NPY at control pressure, and after servo-controlling renal arterial pressure at 80 mmHg, was determined for these parameters (n = 6). 4. This was repeated during a reflex sympathetic activation via carotid sinus hypotension, in order to quantify a possible interaction between the sympathetic transmitter and co-transmitter (n = 6). 5. The subthreshold NPY dose raised plasma NPY-like immunoreactivity (NPY-LI IR) significantly (renal venous plasma: 54 +/- 13 vs. 405 +/- 117 pg ml-1; P less than 0.05) and enhanced the pressure-dependent (80 mmHg) antidiuresis (0.48 +/- 0.06 vs. 0.24 +/- 0.02 ml min-1; P less than 0.05), antinatriuresis (46 +/- 11 vs. 25 +/- 3 mumol min-1; P less than 0.05), antikaliuresis (19 +/- 4 vs. 9 +/- 0.7 mumol min-1; P less than 0.05) and pressure-dependent renin release (0.95 +/- 0.27 vs. 3.0 +/- 1.1 ng angiotensin I ml-1 h-1; P less than 0.05). These effects are consistent with a non-uniform vasoconstrictor action of NPY in the renal vascular bed (see accompanying papers). 6. The effects of NPY plus sympathetic activation were less than the sum of the two individual effects, which may rely on a presynaptic mechanism.

Animals↗

PubMed1991

Renovascular effects of neuropeptide-Y in the split hydronephrotic rat kidney: non-uniform pattern of vascular reactivity.

1. The renovascular effects of neuropeptide-Y (NPY) were examined in the split hydronephrotic rat kidney. 2. Systemic infusion of low non-pressor doses of NPY (0.2 micrograms kg-1 up to 5.0 micrograms kg-1) produced a non-uniform pattern of vascular reactivity. In general, a significant constriction of the proximal and distal arcuate artery was seen at all doses. No constriction was seen at the interlobular artery or the larger part of the afferent arteriole. These segments initially dilated during the lower dose infusions. The very distal part of the afferent arteriole adjacent to the glomerulus and the proximal efferent arteriole responded in a similar way to the arcuate arteries. 3. NPY, locally applied into the tissue bath at concentrations of 1 nmol l-1 up to 25 nmol l-1, produced non-uniform vascular reactions similar to those of intravenously infused NPY. At the considerably higher local dosage of 1.14 mumol l-1, all vascular segments revealed vasoconstriction. 4. NPY application did not attenuate effects of acetylcholine. This observation suggests that the mechanism of NPY-induced vasoconstriction does not rely upon antagonism of endothelium-derived vasodilatation. 5. The pattern of vascular reactivity to NPY was substantially different from that known for the vasoconstrictors noradrenaline and angiotensin II in our preparation.

Acetylcholine↗

PubMed1991

Differential effect of neuropeptide-Y on membrane potential of cells in renal arterioles of the hydronephrotic mouse.

1. The effects of neuropeptide-Y (NPY) on the membrane potential of vascular smooth muscle cells were studied in renal arterioles of hydronephrotic mouse kidneys. 2. Kidney vessels are only weakly coupled with length constants of less than 10 microns and are most probably 'multiunit' vessels. 3. The vasoconstrictor peptide NPY reversibly depolarizes only smooth muscle cells in arterioles at distances greater than 200 microns from the glomerulus, whereas no changes of the membrane potential can be evoked close to the glomerulus (distance less than 50 microns). 4. The depolarizations, when present, are dose dependent. 5. Regardless of distance from the glomerulus cells respond uniformly to application of the vasoconstrictor angiotensin II.

Angiotensin II↗

PubMed1991

Variation in the size and number of stone fragments after gallbladder lithotripsy.

Ninety-four gallbladder ultrasound examinations were carried out in 11 patients at intervals for the first 40 days after lithotripsy. No dissolution or other active therapy was carried out during this time. Fragment size and number were measured to determine the postlithotripsy variability. Analysis of variance (ANOVA) showed no significant changes in fragment size or number over time. The changes in fragment size and number compared to the previous measurements were then evaluated. Again, ANOVA showed no significant changes between times. The average change in absolute size was 3.1 +/- 0.6 mm, and the average change in absolute number was 1.4 +/- 0.5. We conclude that fragment size and number as determined by ultrasound do not vary significantly with time during the first 40 days. The absolute size change measured to the nearest millimeter should be at least 4 mm to surpass the 95% confidence interval. Similarly, the absolute change in number should be at least 2 to be regarded as significant.

Analysis of Variance↗

PubMed1989

Heart valve replacement with the Björk-Shiley monostrut valve in patients over 60 years of age.

Over a period of five years (1983-88) 210 Björk-Shiley monostrut mechanical tilting disc prostheses were implanted in 176 patients over the age of 60. There were 61 aortic valve replacements, 86 mitral valve replacements and 29 multiple replacements. Patients were aged between 61 and 78 years (mean 65.5 years), 89% were in NYHA grades III and IV preoperatively and 34.6% had had previous cardiac surgery. Concomitant coronary surgery was performed in 15.9%. Early mortality was 9.1%. Follow-up is 100% complete. There were eight late deaths (3.1 per 100 patient years) of which three were valve-related (prosthetic endocarditis 2, periprosthetic leak 1). Actuarial survival at five years is 98% for aortic valve replacement and 93% for mitral valve replacement. There were no major embolic events and four possible minor embolic events. Overall freedom from anticoagulant complications was 88.9% at five years. No deaths occurred because of anticoagulant-related haemorrhage. There were no episodes of valve failure (thrombotic obstruction or mechanical disruption). Six patients were reoperated for complications: two for periprosthetic leak and three for prosthetic endocarditis. These results compare favourably with those of other valve substitutes and justify the continuing use of the Björk-Shiley monostrut tilting disc prosthesis in the elderly.

Anticoagulants↗