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Biomedical subjects

M H Schmidt

Publications and source records attributed to M H Schmidt.

At least 109 records · Page 6Linked to original sources

Light-emitting diodes as a light source for intraoperative photodynamic therapy.

The development of more cost-effective light sources for photodynamic therapy of brain tumors would be of benefit for both research and clinical applications. In this study, the use of light-emitting diode arrays for photodynamic therapy of brain tumors with Photofrin porfimer sodium was investigated. An inflatable balloon device with a light-emitting diode (LED) tip was constructed. These LEDs are based on the new semiconductor aluminum gallium arsenide. They can emit broad-spectrum red light at high power levels with a peak wavelength of 677 nm and a bandwidth of 25 nm. The balloon was inflated with 0.1% intralipid, which served as a light-scattering medium. Measurements of light flux at several points showed a high degree of light dispersion. The spectral emission of this probe was then compared with the absorption spectrum of Photofrin. This analysis showed that the light absorbed by Photofrin with the use of the LED source was 27.5% of that absorbed with the use of the monochromatic 630-nm light. Thus, to achieve an energy light dose equivalent to that of a laser light source, the LED light output must be increased by a factor of 3.63. This need for additional energy is the difference between a 630- and 677-nm absorption of Photofrin. Using the LED probe and the laser balloon adapter, a comparison of brain stem toxicity in canines was conducted. LED and laser light showed the same signs of toxicity at equivalent light energy and Photofrin doses. The maximal tolerated dose of Photofrin was 1.6 mg/kg, using 100 J/cm2 of light energy administered by laser or LED. This study concludes that LEDs are a suitable light source for photodynamic therapy of brain tumors with Photofrin. In addition, LEDs have the potential to be highly efficient light sources for second-generation photosensitizers with absorption wavelengths closer to the LED peak emission.

Animals↗

[4 1/2 years later: Mannheim risk children of preschool age].

The present investigation was concerned with the impact of prenatal and perinatal complications (biological risks) and of family adversity (psychosocial risks) on developmental status at age 4 1/2. In a prospective study the developmental course of 362 children (including 210 high-risk children) was followed from birth to age 4 1/2 years. A multilevel approach was used to assess all relevant domains of functioning (i.e. motor, cognitive and social-emotional development). The goal was to obtain information about the effects of biological and psychosocial risks alone and together on outcome in the different domains of functioning. The results show that psychosocial risk factors posed the greatest threat to normal development. Children with psychosocial risks were significantly behind those without such risks in all areas of functioning. Biological risks mainly affected motor development, their negative effects on cognitive and social-emotional functioning having been largely compensated for by age 4 1/2. The extent of an adverse outcome was related to both the degree of risk load and the number of risk factors, whereas interactions among risks were of only minor relevance. An adverse outcome is not inevitable, however: Despite the risks most of the at-risk children showed normal development at age 4 1/2.

Affective Symptoms↗

[Evaluation of disruptive behavioral disorders: how situation specific and temporally accurate are behavior observations?].

The stability of expert behavior ratings was analyzed in an unselected inpatient sample of 49 children admitted for disruptive behavior disorders. Expert behavior ratings were obtained for two highly standardized situations (play behavior on ward, on-task behavior during tests) at two time points (T1: 1 week and T2: 4 weeks after admission). These scores were compared with initial diagnostic assessments (clinical judgement) and objective behavior data (actometer) in the test situation. A comparison of the standardized behavior ratings over time showed that in both settings problem behavior was more pronounced at T2 than at T1. Actometer data indicating a higher activity level at T2 were significantly correlated with behavior ratings. There was only a weak association between expert behavior ratings and an initial diagnosis of conduct disorder; the correlation between an initial diagnosis of attention-deficit hyperactivity disorder and the behavior ratings was statistically significant. In general, T2 behavior ratings corresponded better to the initial clinical judgement. Implications for the use of multiple sources of information and of repeated measurements are discussed.

Attention Deficit Disorder with Hyperactivity↗

[Treatment of hyperkinetic children in the home environment].

Twenty children with hyperkinetic disorders with or without conduct disorders were treated in a home-treatment setting, as an alternative to inpatient treatment, by nurses specialized in child psychiatry and under the constant supervision of an experienced child psychiatrist. Conduct disorders were influenced positively in the child's natural surroundings. Parents were trained as co-therapists. Good cooperation by the family is required for therapy to have positive effects. Case studies serve to illustrate how treatment can be conducted at home.

Attention Deficit Disorder with Hyperactivity↗

Clitoral blood flow increases following vaginal pressure stimulation.

The vascular responses of clitoral arteries to vaginal pressure stimulation in 10 volunteer women were evaluated by Doppler ultrasonography. Pressure stimulations (20-160 mm Hg) along the lower third of the vagina increased blood velocity and flow into clitoral arteries in 9 of the 10 women. The latency and duration of the Doppler responses ranged from 0.1 to 1.6 sec and from 3.2 to 9.5 sec, respectively, and the response was associated with a blood flow increase of 4 to 11 times the baseline prestimulation level. This response parallels that recorded in the cavernous arteries in men when a similar range of pressure stimulations are applied to the glans penis. Similar responses evoked in the male and female suggest a sexual synergy that may occur during intercourse in that such physiological responses and reflexes may be reciprocally reinforced.

Adult↗

Munchausen syndrome by proxy and factitious illness: symptomatology, parent-child interaction, and psychopathology of the parents.

The term Munchausen syndrome by proxy is used to diagnose children presenting symptoms of an organic disorder resulting from manipulations initiated by their caretakers. Even in early infancy it happens that injuries are induced, and that drugs, poisons or medicine are administered in order to provoke and feign clinical symptoms of severe diseases. Exact data on prevalence are not available but it is obvious that Munchausen syndrome by proxy is a rare psychiatric disorder. There is a body of evidence that Munchausen syndrome by proxy is nothing but the extreme of a broader clinical entity for which the term factitious illness has been introduced. In this group children are included whose mothers invent a history of disease in order to produce symptoms without actually damaging their children. It is not well established whether such a distinction is necessary and whether there are differences in long-term outcome. Onset of symptoms is as early as three weeks up to twelve years, and mean age of diagnosis according to a more comprehensive study is 3 1/4 year. The estimated mortality rate of children with Munchausen syndrome by proxy is 9 percent. In three of the four cases of children reported here clinical presentations were dominated by symptoms of central nervous disorders. All mothers showed unsure and inconsistent parental behaviour and inefficient coping. None of them received support from their partners, if present. In interaction the children always wanted to dominate their mothers. The high amount of personality disorders observed in the caretakers might be the reason for the often reported failure of psychotherapeutic interventions.

Child↗

Case report: concordant traumatic brainstem contusion delayed diagnosis in a young man with Wilson's disease.

Wilson's disease is a hereditary autosomal recessive disorder of copper metabolism. The corresponding gene locus has been localized on the long arm of chromosome 13. Three different clinical variants of the disease can be distinguished: hepato-cerebral, abdominal/hepatic, and central nervous type. The heterogeneity of symptoms can cause problems in differential diagnosis, especially when another concordant disorder can also explain the pathogenesis of symptoms. The case report of a young man who suffered from brainstem contusion demonstrates the possibilities of misinterpretation because presenting symptoms could be attributed either to traumatic brain injury followed by adjustment disorder or Wilson's disease. Clinical signs included leftsided hemiparesis, bilateral gaze direction nystagmus, marked dysarthria with consecutive pervasive mutism, choreo-athetoid movements, spasmodic torticollis and diplopia dependent on gaze direction. Slit lamp examination showed Kayser-Fleischer's corneal ring. EEG- and computer assisted tomography investigations revealed non-specific findings. The patient was treated with D-Penicillamine. Alternative treatment with oral zinc preparations is discussed.

Adolescent↗

Benzodiazepine administration induces exogenic psychosis: a case of child abuse.

An 11-year-old boy with psychiatric symptoms was brought to the pediatric clinic by his father. The boy exhibited anxiety, sometimes exaggerating to panic reactions, rage, and disorientation. Because of the boy's behavior it was presumed he was having delusions. Careful physical examination revealed evidence of physical abuse. This article alerts readers to the possible combination of physical abuse and purposeful drug administration.

Aggression↗

Sleep in adolescents with primary major depression and schizophrenia: a pilot study.

The present study aimed at investigating the question whether abnormalities of sleep, especially disinhibition of rapid eye movement (REM) sleep, are already present in adolescents with primary major depressive disorder (MDD). Ten healthy controls assessed at home, 10 inpatients with MDD and 10 inpatients with schizophrenia (age range: 13-19 years) were investigated polysomnographically. REM latency was significantly shortened in MDD compared with the two other groups. Adolescents with MDD did not display disturbances of sleep continuity as typically observed in adults with major depression. The most pronounced impairment of sleep continuity was noted in schizophrenic patients. The results stress that shortened REM latency may already occur in adolescent depression.

Adolescent↗

Corpus spongiosum penis pressure and perineal muscle activity during reflexive erections in the rat.

This experiment represents the first simultaneous analysis of corpus spongiosum of the penis (CSP) pressure and perineal muscle activity during reflex-induced penile erections in the awake rat and provides new data on the coordination of muscular and vascular events in erection physiology. Nine male Sprague-Dawley rats were implanted with pressure transducers under pentobarbital anesthesia (60 mg/kg) for use in a new technique of chronic erection recording involving simultaneous CSP pressure monitoring and electromyography (EMG) of the ischiocavernosus (IC) and bulbospongiosus (BS) muscles. The association of these physiological measurements with visually scored ex copula erectile events was investigated. Reflexive erectile events were systematically associated with an increase in baseline CSP pressure. Glans erections were associated with dramatic suprasystolic CSP pressure peaks concurrent with BS muscle bursts. Indeed, measures of CSP pressure and BS EMG activity were found to vary significantly with the intensity of glans erection. Flips of the penile body, however, involved small CSP pressure increases and IC bursts. These data demonstrate for the first time that both CSP pressures and perineal muscle activity vary significantly with the intensity of penile erection.

Animals↗

[School refusal--a catamnestic study on the diagnostic concept ov "school phobia" and "school anxiety"].

Twenty-six patients diagnosed with school refusal were examined 2.4 years after inpatient treatment. The long-term course of patients with "school phobia" (school refusal unrelated to school) and that of patients with "school anxiety" (school refusal related to school) were compared. In addition, an attempt was made to identify variables predictive of a good outcome. The mean age of the 12 patients with "school phobia" and the 14 patients with "school anxiety" was 12.7 years at the start of inpatient treatment. The assessment of psychiatric disturbances was based on structured interviews for parents and adolescents (MEI and MADEL, 1989) and the dimensional assessment scales of functioning for children and adolescents (MSBF). The variables assessed for predictive value were taken from the patients' records during inpatient treatment and from the hospital documentation system. There was no difference in outcome between the two syndrome groups. There was a tendency to less autonomy in the patients with "school phobia". Girls had a better outcome than boys, as did patients with less absence from school prior to inpatient treatment. Overall there was no difference in the outcome of "school phobia" and "school anxiety". Therefore a new classification should be considered.

Adolescent↗

[Reversible changes in brain volume in anorexia nervosa].

Cranial computed tomography (CT) was performed in three different samples of young women with anorexia nervosa before and after treatment. The biggest changes in cerebrospinal fluid volume were observed in the supratentorial and extracerebral-subarachnoid area, with smaller changes in the ventricles. These changes, as assessed by different methods of volumetric and planimetric measurement, were statistically significant and were correlated with the changes in body weight. Two patient groups could be distinguished on the basis of the presence or absence of cerebellar pseudoatrophy in the initial CT, and these groups also showed differences in preclinical and clinical course.

Adolescent↗

[Feasibility of retroperitoneal pelvic lymph node exploration in cancers of the cervix treated by radiosurgery association or radiotherapy alone. Apropos of a series of 52 cases].

From June 1980 to May 1993, 52 patients with a mean age of 49, underwent a retroperitoneal pelvic lymph node laparoscopic procedure for cervix carcinoma classified as stage IA (14), IB (12), IIA (6), IIB (14), IIIB (3), IVA (3). Two techniques were used: a retroperitoneoscopy in 16 cases and a panoramic retroperitoneal pelviscopy (PRPP) in 36 cases. The aim was to define, with a better accuracy, the pelvic lymph node status, to adapt the target volume, and to estimate the morbidity. More nodes were biopsied with PRPP than with retroperitoneoscopy (p < 0.05). There was a disagreement between the conventional radiologic assessment and the histological results in 28.6%. Specificity is 100%. Intra-operative and post-surgical morbidity was equivalent in the two procedures. One grade 3 urinary late morbidity (3%) was observed among the 33 patients who underwent a pelvic external irradiation. There was no morbidity of the gastro-intestinal tract. Discussion deals with the support offered by the two laparoscopic procedures to define the pelvic lymph node status, to choose the planning target volume, and to precise the lymph node boost.

Adenocarcinoma↗

Experimental evidence of penile erections during paradoxical sleep in the rat.

We have developed a new technique to chronically monitor penile erections in the rat across behavioural states. This technique, involving chronic erectile tissue pressure monitoring and simultaneous ischiocavernosus and bulbospongiosus (IC-BS) muscle electromyography, demonstrates for the first time that rats exhibit penile erections during paradoxical sleep (PS). No erectile events were observed during slow wave sleep. These PS-related erectile events were similar to visually confirmed, waking state, erections in that they were associated with an increase in baseline erectile tissue pressure and, with IC-BS muscle bursts, dramatic suprasystolic penile pressure peaks often greater than 1000 mmHg. PS-related erections were 11 +/- 7 s in duration and were observed in 28.5% of all PS episodes. This method of chronic penile erection monitoring in the rat provides a new animal model for investigating neural mechanisms of sleep-related erections.

Animals↗

Selective incorporation of 111In-labeled PHOTOFRIN by glioma tissue in vivo.

The use of PHOTOFRIN for photodynamic therapy of human gliomas has been studied by i.v. administration and laser photosensitization. Defining the uptake of PHOTOFRIN in the patient's tumor in comparison with the surrounding normal brain tissue is highly desirable for patient selection and study of in vivo kinetics. We utilized a non-invasive approach to the detection of PHOTOFRIN uptake in brain tumors with 111In-oxine radiolabeled PHOTOFRIN and external imaging and quantitation using a gamma camera. Biodistribution of 111In-labeled PHOTOFRIN in 13 organs was determined in four dogs and 15 mice with gliomas. 99mTc-DTPA was used as a control for nonspecific uptake. The greatest concentration of 111In-PHOTOFRIN in the brain tumor occurred at 24 hours post i.v. administration. The brain tumor PHOTOFRIN uptake was seven times greater than that of normal brain. The decreased blood background at 72 hours made this the optimum time for imaging. Specific tumor tissue uptake of 111In-PHOTOFRIN occurred, well beyond that resulting from blood-brain-barrier (BBB) breakdown.

Animals↗

Gallium nitrate delays the progression of microscopic disease in a human medulloblastoma murine model.

The goal of adjuvant chemotherapy is to treat postoperative microscopic disease in the hope of preventing tumor recurrence and/or metastasis. Since the introduction of chemotherapeutic agents, the disease-free survival of children with medulloblastoma has improved only modestly. Therefore, there is a need to develop and investigate new chemotherapeutic agents for this malignancy. Gallium nitrate has demonstrated significant antineoplastic activity toward human medulloblastoma in vitro and in vivo and may prove to be an optimal chemotherapeutic agent in treating medulloblastoma microscopic disease. The present study consisted of injecting medulloblastoma Daoy intradermally into both flanks of nude mice. A 15-day 50-mg/kg/day regimen was implemented the day after tumor inoculation. All treated and control mice received saline hyperhydration during the treatment period. The interval between tumor cell inoculation and first measurable tumor detection, tumor occurrence, growth rate, and size were recorded. Results indicated that gallium nitrate significantly prolonged the interval between tumor cell inoculation and measurable tumor detection.

Animals↗