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Biomedical subjects

G Heimann

Publications and source records attributed to G Heimann.

At least 19 recordsLinked to original sources
PubMed2001

Association of apnea and nonacid gastroesophageal reflux in infants: Investigations with the intraluminal impedance technique.

An association of apnea and gastroesophageal reflux (GER) was proposed previously. However, pH metry as the standard diagnostic tool for GER only measures acid reflux (pH < 4). It is difficult to interpret studies in infants with a presumed association between apnea and GER based on pH metry because the buffering effect of feeding may result in predominantly nonacid GER. The aim of this study was to investigate the temporal association of apnea and GER with the pH-independent intraluminal impedance technique (IMP). Infants with recurrent regurgitation or respiratory symptoms suggestive of apnea were investigated simultaneously with IMP, pH monitoring, and polygraphy. IMP patterns, pH, oronasal flow, and chest wall movement were recorded and analyzed. In 22 infants, 364 GER episodes were recorded by IMP. One hundred and sixty five apneas were documented by visual validation of polygraph records. Forty-nine apneas (29.7%) were associated with GER; 11 (22.4%) of these showed acid reflux (pH < 4). A significant correlation between the time spent apneic and GER was found (P < 0.001). There is marked association between apnea and gastroesophageal reflux in infants. Patients potentially at risk cannot be reliably identified by pH metry. Its exclusive use is therefore not suitable for the detection of all GER-associated apneas in infants. The pH-independent intraluminal impedance technique has proven to be a sensitive diagnostic tool for this approach.

Apnea↗
PubMed2000

Effect of cisapride on acid gastro-oesophageal reflux during treatment with caffeine.

About 50% of preterm infants and neonates receiving methylxanthines for respiratory stimulation will develop a pathological gastro-oesophageal reflux (GOR) pattern. In the face of potential GOR-related complications the effect of a concomitant treatment with a prokinetic agent, such as cisapride, should be evaluated. In this study 32 formerly preterm infants were studied simultaneously by 24-hour oesophageal pH monitoring and cardio-respirogram before the presumed end of caffeine treatment. In 14 of these infants a reflux index (RI; percentage of recording time) of more than 4% could be detected (pH <4). Ten of them were treated orally with cisapride (0. 2 mg/kg t.i.d.). Data of pH monitoring, cardio-respirogram and caffeine serum concentrations were obtained before and 5 days after introducing cisapride. The RI and the frequency of GOR decreased significantly with cisapride. The steady-state serum concentrations of caffeine were not influenced by cisapride and the extent of periodic breathing remained unchanged. In conclusion, cisapride has a positive influence on GOR parameters during caffeine treatment without impairing the oral bioavailability or therapeutic effect of caffeine.

Caffeine↗
PubMed2000

Idiopathic growth hormone deficiency: a vanishing diagnosis?

Some non-organic causes for growth hormone (GH) deficiency (GHD) can be attributed to genetic defects within the hypothalamo-pituitary axis. Using modern molecular biology techniques micromutations within the GH and GH-releasing hormone receptor genes have been detected as a rare cause of isolated GHD. Combined pituitary hormone deficiencies (CPHD), on the other hand, are associated with defects that manifest during the organogenesis of the anterior pituitary gland. In recent years an increasing number of patients with CPHD has been reported, showing mutations within pituitary transcription factors Pit-1, Prop-1 and HesX1. Such defects can be observed with different frequencies in patients. Some disorders, such as CPHD due to Pit-1 mutations, display a hormonal phenotype that seems more or less invariable. In most other forms of genetic CPHD both the combination and severity of anterior pituitary hormone deficiencies vary considerably. Ongoing research concentrates on factors involved in the differentiation and proliferation of cells that belong to the hypothalamo-pituitary growth axis. As not every possible candidate turns out to be a frequent cause of GHD or CPHD in humans, it will be many more years before the term 'idiopathic' becomes a vanishing attribute to the clinical diagnosis of pituitary insufficiency.

Animals↗
PubMed1999

Procedure for the semi-automatic detection of gastro-oesophageal reflux patterns in intraluminal impedance measurements in infants.

The diagnosis of gastro-oesophageal reflux (GOR) is of great interest for paediatric gastroenterologists. pH monitoring is the commonly used procedure for GOR diagnosis but a major amount of postprandial GOR is missed due to the mostly non-acidic gastric contents in infants. The multiple intraluminal impedance technique is based on the recording of the impedance changes during bolus transport inside the oesophagus. It is the first method which allows the pH-independent, long-term registration of GOR. The use of the impedance technology in clinical practice has been limited so far by the time-consuming, visual evaluation of the impedance traces. The new approach of a semi-automatic analysis of the impedance measurements allows the automated detection of reflux patterns. It is based on event marking and an optimised feature description of the impedance traces combined with a fuzzy system for pattern recognition. The classifier is developed and tested on 50 investigations in infants. Compared to the comprehensive, multiple visual evaluation the achieved precision is 75% sensitivity and 48% positive prediction. In comparison to a single visual evaluation the analysis of the automatically proposed patterns corresponds to a 96% reduction of the evaluation time with no loss of precision. Thus the applicability of the impedance technology is enhanced significantly. A combined measurement of pH and impedance gives evidence about the occurrence of GOR, its pH and the acidic exposure of the oesophagus.

Algorithms↗
PubMed1999

Gastroesophageal reflux and respiratory phenomena in infants: status of the intraluminal impedance technique.

BACKGROUND: The coincidence of recurrent respiratory symptoms and gastroesophageal reflux (GER) is a well-known phenomenon in infants. Twenty-four-hour pH metry is the presumed gold standard of diagnostic tools for this symptom complex, but with this method, only acid (pH <4) and alkaline (pH >7) GER can be detected. Gastroesophageal reflux with an esophageal pH in the physiological range (pH 5-6.8) may represent many cases of clinically relevant GER unrecognized by pH metry. In this study the intraluminal multiple electrical impedance (IMP) procedure for complete registration of GER was compared with pH metry for its diagnostic value in the presence of respiratory symptoms. METHODS: Twenty-two infants with recurrent regurgitation or pulmonary problems were investigated simultaneously with IMP, pH metry, and polygraphy during two feeding periods. Heart rate, oxygen saturation, sleep states, and oronasal flow were recorded, among other parameters. RESULTS: Three hundred sixty-four occurrences of GER were detected by IMP; only 11.4% had a pH less than 4 and were therefore recognized by pH metry. Three hundred twelve (84.8%) occurrences were associated with breathing abnormalities, and 11.9% of these were detected by pH metry. Nineteen instances were accompanied by a decrease of oxygen saturation of more than 10% of the initial value. Only three (15.8%) of these had a pH less than 4. The remaining 16 reflux episodes were recognized by IMP only. After software-aided preselection, 165 instances of apnea were visually validated, 49 of which were accompanied by GER. Thirty-eight (77.6%) of these were exclusively recorded by IMP. CONCLUSIONS: The use of pH metry alone cannot detect most GER incidents accompanied by respiratory symptoms and therefore does not appear to be suitable for this approach. The pH-independent IMP technique promises to be a reliable tool for presumably GER-associated respiratory symptoms.

Electric Impedance↗
PubMed1999

Neonatal diabetes mellitus with hypergalactosemia.

We report the case of a male, small-for-gestational-age newborn who presented with failure to thrive, severe fluctuation of blood glucose concentrations, and increased serum concentrations of galactose. The infant responded well to a lactose-free diet supplemented with fructose, inulin and corn starch. The metabolic disorder disappeared within 6 months. The transient course, and results of a molecular analysis of the glucose transporter 2 (Glut2) gene seem to rule out Fanconi-Bickel syndrome.

Diabetes Mellitus↗
PubMed1998

Early and late onset manifestations of cerebral vasculitis related to varicella zoster.

Varicella-zoster associated cerebral vasculitis (VZCV) as a cause of cerebral infarction has hitherto been considered a rare condition. Ischemic stroke in previously healthy children has occurred during recovery from chickenpox or has been attributed to virus reactivation among immunosuppressed patients. The clinical, radiologic and immunologic findings in four children with VZCV will be reported. Clinical manifestations included sudden onset of hemiparesis, motor aphasia and disturbed consciousness in previously healthy children. Only one child had a history of chickenpox six weeks prior to the onset of stroke, whereas a latency period of up to four years between chickenpox and the onset of stroke was found in the other three children. Diagnosis of VZCV was confirmed repeatedly by demonstrating intrathecal production of varicella-zoster IgG antibodies in three children or a four-fold increase of varicella-zoster serum IgA-antibodies in one child. Intrathecal production of antibodies against other latent viruses and borreliosis could be excluded. PCR for varicella on CSF, performed in two patients, remained negative. No intrathecal production of varicella-zoster antibodies has been found in a control group of twenty clinically healthy children (age range from 2-18 years) with a previous varicella infection. During follow-up two children recovered completely whereas two children still suffer from serious neurological deficits. Immunological investigations, performed in three children, showed circulating immune-complexes with slightly lowered complement concentrations in two patients. In addition a lowered T-helper/T-suppressor cell ratio of unknown origin was found in three children. These immunological findings will be discussed in the light of the pathophysiology of VZCV.

Adolescent↗
PubMed1998

First adult patient with fibrosing colonopathy.

An adult patient with cystic fibrosis and chronic abdominal complaints developed symptomatic fibrosing colonopathy several months after the beginning of high dose pancreas enzyme therapy. Despite the absence of a stricture, surgical resection was performed. Since then the abdominal complaints have not recurred.

Abdominal Pain↗
PubMed1998

Permutational distribution of the log-rank statistic under random censorship with applications to carcinogenicity assays.

In the random censorship model, the log-rank test is often used for comparing a control group with different dose groups. If the number of tumors is small, so-called exact methods are often applied for computing critical values from a permutational distribution. Two of these exact methods are discussed and shown to be incorrect. The correct permutational distribution is derived and studied with respect to its behavior under unequal censoring in the light of recent results proving that the permutational version and the unconditional version of the log-rank test are asymptotically equivalent even under unequal censoring. The log-rank test is studied by simulations of a realistic scenario from a bioassay with small numbers of tumors.

Animals↗
PubMed1998

[Lipoma of the corpus callosum in a newborn infant: misinterpretation of cranial ultrasound by coincidence with thrombocytopenia].

Among the very rare intracerebral lipomas, those of the corpus callosum are the most frequent. Due to the advanced technology and the frequent use of ultrasonography these lesions are diagnosed more and more often. A female neonate was admitted to our hospital because of a progressive thrombocytopenia. Pregnancy was complicated by an autoimmune thrombocytopenia of the mother. While there were no remarkable findings on clinical presentation, a sonogram of the brain revealed an area of increased echogenicity in the midline which was interpreted as an intracerebral hemorrhage. In absence of any respective clinical signs a magnet-resonance-tomography of the brain was performed leading to the hypothesis of a lipoma of the corpus callosum (LCC) that could be verified by a densitometry in a cranial computer tomography (CT). Obviously, the initially performed sonogram was misinterpreted as an intracerebral hemorrhage due to the coincidence with the thrombocytopenia. At last the discrepancy of clinical and ultrasonographical findings led to the diagnosis by magnet-resonance-tomography and CT scan. Knowledge of the typical sonographic appearance of an LCC may be helpful for the differential diagnosis of this rare lesion even in fetal ultrasound.

Brain Neoplasms↗
PubMed1997

Nasopharyngeal carcinoma in childhood and adolescence: concept and preliminary results of the cooperative GPOH study NPC-91. Gesellschaft für Pädiatrische Onkologie und Hämatologie.

BACKGROUND: The increasing use of chemotherapy has improved the prognosis of patients with nasopharyngeal carcinoma (NPC), and the authors demonstrated the beneficial effect of adjuvant interferon (IFN)-beta in a previous pilot study of children with advanced stage NPC. The current multi-institutional, cooperative GPOH (Gesellschaft für Pädiatrische Onkologie und Hämatologie) study NPC-91 was begun in 1992 to determine the efficacy of preradiation chemotherapy, radiotherapy, and adjuvant IFN-beta, in the treatment of advanced stage NPC. METHODS: Of a total of 22 patients, 21 had American Joint Committee on Cancer Stage III or IV disease, and 1 had Stage II disease. The median age was 12 years (range, 8-16 years). Twenty of 22 received 3 courses of preradiation chemotherapy consisting of methotrexate 120 mg/m2 on Day 1, cisplatin 100 mg/m2 on Day 1, and 5-fluorouracil 1000 mg/m2 for five days as well as 6 doses of leucovorin 25 mg/m2 every six hours beginning on Day 2. The Stage II patient received no chemotherapy, and chemotherapy was terminated for another during the first course. All patients had radiation therapy, stratified by stage. The cumulative dose to the primary sites was 59.4 gray (Gy), with single doses of 1.8 Gy. A total of 45 Gy was delivered to the neck area. Finally, all patients were treated with recombinant IFN-beta (10(5) U per kg of body weight) 3 times a week for 6 months. RESULTS: The response rate was 91%. These patients stayed in first remission during a median follow-up of 32 months. With the exception of one reversible cardiotoxicity, moderate chemotherapy-related toxicity was observed. CONCLUSIONS: In this study, patients with advanced stage NPC had a good prognosis with treatment consisting of neoadjuvant cisplatin and 5-fluorouracil, radiotherapy, and adjuvant IFN-beta. It is particularly noteworthy that distant metastases did not develop.

Adenocarcinoma, Clear Cell↗
PubMed1997

Diagnostic yield of noninvasive high spatial resolution electromyography in neuromuscular diseases.

High Spatial Resolution electromyography (HSR-EMG), a new kind of noninvasive surface EMG based on a spatial filtering technique, was evaluated with respect to the diagnosis of neuromuscular diseases. HSR-EMG measurements were recorded from 61 healthy subjects and 72 patients with different neuromuscular diseases and analyzed quantitatively. The results indicate that a few parameters such as muscular conduction velocity, dwell time over root mean square, autocorrelation function, and chi-value are sufficient to recognize and classify specific signal alterations due to neuromuscular disorders. A diagnostic evaluation procedure calculating automatically the most probable diagnosis from the parameter results could assign the correct diagnosis to about 81% of the investigated patients and healthy subjects. Myopathic disorders were recognized with a sensitivity of 85% (specificity: 97%), neuropathic disorders with a sensitivity of 68% (specificity: 98%). We conclude that HSR-EMG shows a diagnostic validity similar to that described in literature for needle EMG. Moreover, the noninvasive technique provides the advantage of a simple and painless application.

Adolescent↗
PubMed1997

Combined pituitary deficiencies of growth hormone, thyroid stimulating hormone and prolactin due to Pit-1 gene mutation: a case report.

UNLABELLED: A child exhibited postnatal obstipation and icterus together with severe growth failure during the 1st year of life, a small facial skull and a prominent forehead. Endocrine work-up established the diagnosis of combined pituitary deficiencies of growth hormone, TSH and prolactin. Subsequently, the Pit-1 gene was analysed in the patient and both parents. A single point mutation was detected in exon 6 of the child: a C to G transversion on one allele, causing arginine in position 271 to be substituted by tryptophan (R271 W). This position is known as a "hot spot" for mutations. The inheritance is autosomal-dominant, as the mutated gene product interferes with DNA-binding of the wild-type protein. In contrast, other mutations in the PIT-1 gene are inherited in an autosomal-recessive mode. CONCLUSION: Diagnosing Pit-1 gene mutations as a rare cause of combined pituitary deficiency is important both for genetic counselling as well as for predicting the future course in the patient (spontaneous puberty, no glucocorticoid substitution necessary during stress periods).

Arginine↗
PubMed1997

Central pontine myelinolysis associated with acquired folate depletion.

After long-standing malnutrition a 15-month-old boy with signs of kwashiorkor was admitted in a moribund state with serious hyponatraemic dehydration, hypothermia, somnolence, and signs of a pontine disconnection syndrome. Folic acid levels were below the detection level in the presence of normal cobalamin levels. MRI of the brain showed global volume loss and signal abnormalities on the T2-weighted images suggestive for central pontine myelinolysis (CPM). Brainstem acoustic evoked responses have remained normal. The serious metabolic and nutritional derangements required substitution of folic acid, vitamins and trace elements as well as slow correction of hyponatraemic dehydration with return of the sodium level over a period of four days. This therapeutic regimen resulted in complete neurological recovery. Follow-up MRI documented normalisation of the initial pathologic findings. The hypothesis was put forward linking the pathogenesis of CPM with the combination of folate depletion and superimposed hyponatraemic dehydration. The previously acquired folate depletion could affect normal appositional function of myelin basic protein molecules due to insufficient methylation of arginine in position 107. The subsequent development of intramyelinic edema and CPM will then be triggered by the superimposed hyponatraemic dehydration. The verification of this hypothesis requires further investigations.

Dehydration↗
PubMed1997

Genetic disorders and cerebellar structural abnormalities in childhood.

Amongst 78 patients with either unilateral or bilateral (ponto-) cerebellar hypoplasia, atrophy or lesions on neuro-imaging (CT and/or MRI), 16 showed unilateral hypoplasia or lesions, 15 vermis defects, nine pontocerebellar hypoplasia, 10 non-progressive conditions with bilateral cerebellar hemisphere hypoplasia or lesions and 28 progressive cerebellar atrophy. Known genetic conditions did not occur with unilateral cerebellar involvement, whereas a high incidence of mostly autosomal recessively inherited diseases could be diagnosed in more than half of the patients with either pontocerebellar hypoplasia or progressive bilateral cerebellar atrophy. A minority of patients with vermis defects or non-progressive cerebellar hypoplasia suffered from genetic conditions. An overview of the literature is presented describing genetic and non-genetic syndromes, or metabolic disorders associated with cerebellar structural abnormalities. From these data, new proposals for improved diagnostic investigations will be presented.

Adolescent↗