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Biomedical subjects

W Weigel

Publications and source records attributed to W Weigel.

At least 19 recordsLinked to original sources
PubMed2001

Thin layer molecularly imprinted microfiltration membranes by photofunctionalization using a coated alpha-cleavage photoinitiator.

A novel approach towards thin-layer molecularly imprinted polymer (MIP) composite membranes was developed based on using benzoin ethyl ether (BEE), a very efficient alpha-scission photoinitiator. The triazine herbicide desmetryn was used as the template, and a mixture of the functional monomer 2-acrylamido-2-methyl-1-propane sulfonic acid (AMPS) and the cross-linker N,N'-methylene-bis-acrylamide (MBAA) in methanol was copolymerised via photoinitiation followed by deposition on the surface of either hydrophobic or hydrophilically precoated polyvinylidene fluoride (PVDF) microfiltration membranes. Blanks were prepared under identical conditions, but without the template. Especially, the degree of functionalization (DF) of the PVDF membranes with poly(AMPS-co-MBAA), the membrane permeabilities and non-specific vs. MIP-specific template binding from aqueous solutions during fast filtration were studied in detail to evaluate the effects of the preparation conditions, in particular the coating of the membrane surface with the photoinitiator prior to UV irradiation and the influence of the precoated hydrophilic layer on PVDF. Significant template specificities of the MIP membranes compared with the blanks were only achieved for the preparations including coating the two types of PVDF membranes with BEE. In contrast, a homogeneous photoinitiation of the copolymerisation in the membrane pore volume yielded functional layers with similar DF but with only non-specific desmetryn binding. All data clearly indicate the significant contribution of MIP stabilization by the support material in layers of optimum thickness to the MIP specificity. Main advantages of the novel approach are the potential to synthesize MIP composite membranes by controlled deposition onto any kind of polymer support, and the very fast MIP preparations due to a very efficient photoinitiator and small MIP layer thickness. Due to the mechanical and chemical stability in combination with high permeabilities, thin-layer MIP composite membranes have a large application potential, e.g., in solid phase extraction.

Journal Article↗
PubMed1992

[Experiences with digital luminescence radiography (DLR) in pediatric radiology].

X-ray examinations represent a variety of indications with different demands on exposure latitude, spatial and contrast resolution of screen-film-system combinations in paediatric radiography. The value of digital luminescent radiography (DLR) was compared to conventional x-ray examinations carried out with screen-film-systems, speed class 200, by analysing matched digital and conventional exposures in 200 abdominal, 600 skeletal and 300 chest examinations. The exposure of DLR was reduced to 50% of conventional exposure. Analysing the results in abdominal and skeletal radiography, DLR proved to be diagnostically equivalent to conventional radiography despite the reduction in exposure dose. DLR of the newborn chest compared to conventional x-ray studies was not always sufficient due to lower digital spatial resolution.

Adolescent↗
PubMed1992

[Imaging and functional parameters in diagnosis of obstructive nephropathy].

Obstruction of the kidney leads to terminal kidney failure within a few years. Therefore, early recognition of such obstruction is of importance. Non-invasive diagnostic ultrasound examination now allows intrauterine visualization of a suspected obstruction. However, the implications of such a dilated ureteral pelvic system are obscure. Whether there is obstruction or dilatation can only be evaluated postnatally by a nuclear technique. The aim of our study was to measure the recovery of kidney function. We investigated 13 kidneys of 9 newborns or small infants (up to 2 years). The follow-up was continuous for up to 29 days. The parameters were: urine output (24-h clearance), glomerular filtration rate, fractional excretion of sodium and potassium, free water clearance, total protein excretion, albumin and alpha 1 microglobulin excretion. The urine output fell from 0.3 to 0.12 ml/min within 14 days after relief of obstruction. The glomerular filtration rate rose from nearly 30 ml/min to about 50 ml/min within a week. The fractional excretion of sodium and potassium indicated recovery of the proximal tubli. The fractional sodium excretion fell below 1% within 4 days. The free water clearance reflects the concentrating ability of the kidney, and in kidneys from newborns it had only positive values, while in kidneys of children older than 6 months there were also negative values. The protein excretion and the albuminuria showed recovery of the glomerular as well as the tubular system.(ABSTRACT TRUNCATED AT 250 WORDS)

Alpha-Globulins↗
PubMed1986

[Corrective craniofacial surgery in the acrocephalosyndactylia syndrome (Saethre-Chotzen syndrome)].

The possibility of plastic surgery in acrocephalosyndactylia syndrome during infancy is shown. Due to her main signs and symptoms and the mode of inheritance the patient suffered from an acrocephalosyndactylia syndrome type III (Saethre-Chotzen). Craniofacial surgery with frontal craniotomy, turn of frontal bone and frontal orbital advancement were performed at the age of eight months, using bone plates developed by Luhr. The reconstruction gave an aesthetically satisfactory result, and further development was normal. The condition for a good result is the cooperation between plastic surgeons, neurosurgeons, anaesthesiologists and paediatricians in specialised centres.

Acrocephalosyndactylia↗
PubMed1981

Pneumatosis intestinalis in children with leukaemia; report of three cases.

Three children with leukaemia (one with acute myeloid, two with acute lymphoblastic leukaemia) developed pneumatosis intestinalis during cytostatic treatment. The aetiology of pneumatosis intestinalis in these children could not be elucidated. Pneumatosis intestinalis may be caused by entry of gas into a bowel wall which is altered by steroid or cytostatic treatment. Otherwise, anaerobic bacteria may produce gas in the intestinal walls, therefore we treated all children with metronidazole.

Adolescent↗
PubMed1981

[Pancreatic pseudocysts in children (author's transl)].

Pancreatic pseudocysts in children are mostly caused by blunt abdominal trauma. The clinical and radiologic diagnosis is difficult whereas ultrasonography, convenient, painless and accurate enables to differentiate a solid from a cystic process. It is the best diagnostic method to follow the "natural"course of the pancreatic pseudocyst which can eventually disappear spontaneously. Three patients are described with their clinical, laboratory, radiologic and sonographic diagnosis. Two of our patients had an operation, one had spontaneous regression of his pseudocyst as documented by ultrasonography.

Abdominal Injuries↗
PubMed1980

[Congenital cystic adenomatoid lung malformation of newborn (author's transl)].

The congenital cystic adenomatoid malformation (CCAM) of the newborn is a particular form among the cystic disorders of the lung. The clinical findings, illustrated by four cases, and especially the roentgenographic symptoms are typical. Different radiologic examinations, including the computer tomography, are discussed. The differential diagnosis of the disease is various, and therefore a correct and on time diagnosis is necessary, because the prognosis of the patient depends on an adequate therapy.

Diagnosis, Differential↗
PubMed1980

[Enteric mediastinal cysts in children (author's transl)].

Primary mediastinal tumors are rare, especially in children, one fifth of them being cystic. Clinical and radiographic findings in 7 patients with mediastinal cysts are reported. Emphasis is placed upon the role of the radiologist to properly place the lesion into one of the three compartments of the mediastinum, which should even be possible for a mass in the upper mediastinum--above the line of capeabody. If a mass is established as belonging to the middle mediastinum, then there the probability is high of it being cystic and benign; and aggressive extensive radiographic workup can be spared preoperatively without significant risk to the patient.

Child↗
PubMed1979

[Osteoarthritis in the neonate. Radiologic diagnosis and follow-up observations (author's transl)].

A fatally ending index case of septic osteoarthritis that was diagnosed retrospectively initiated this report. This patient had severe, asymmetrically distributed metaphyseal growth disturbances at many long bones. In order to determine the features of early radiologic diagnosis we report the findings of 7 further patients with neonatal septic osteoarthritis with clinical and radiological follow-up. The most important observation for early radiologic diagnosis of osteoarthritis is the displacement of fat layers along the metaphysis. Other findings of the soft tissues have the same diagnostic value as bone destruction and subperiosteal new bone formation found one to three weeks later on roentgenfilms. Detecting early signs of osteoarthritis helps in localizing the focus for bacteriologic diagnosis, which is said to be more successful than blood cultures. Diagnosing a joint empyema initiates surgical intervention for pressure relief in order to avoid necrosis of the epiphysis as seen in the femoral head in septic arthritis of the hip joint. Early diagnosis and treatment prior to destruction of the growing cartilage is necessary to avoid growth disturbances and length discrepancies of long bones. In cases of sepsis a so called "babygram" and a repeat examination 10 to 14 days later is mandatory.

Arthritis, Infectious↗
PubMed1979

[The radiolucent esophageal foreign body in children (author's transl)].

The symptoms of radiolucent esophageal foreign bodies in small children may be predominantly respiratory with stridor and dyspnea. In a 1 3/12 years old girl who suffered from inspiratory stridor and only later from dysphagia as well this diagnosis was delayed for 2.5 months. Air in the upper part of the esophagus was the first striking roentgenologic symptom of the foreign body which was then clearly outlined by a barium swallow examination. The foreign body was a plastic lid of a candy tube.

Age Factors↗
PubMed1977

Smooth muscle involvement in congenital myotonic dystrophy.

Dysfunction of smooth muscles is not unusual in adults suffering from myotonic dystrophy but has not yet been reported in patients with the congenital form of the disease. Of two brothers, the younger one presented with the typical features of congenital myotonic dystrophy at birth. He developed severe constipation due to megacolon during his second year of life. In the older brother disturbances of gastrointestinal motility, causing repeated bouts of subileus during the newborn period, sprue-like symptoms during early childhood, and megacolon with constipation and incontinence later on, remained the only manifestation of myotonic dystrophy until the age of eight years when the diagnosis could be finally established by electromyography.

Child↗
PubMed1975

[Child abuse and neglect (author's transl)].

In this paper the "verschleierter Pflegeschaden" is defined. The syndrome is well discribed by the English expression "child abuse and neglect". However the German expression is used to avoid prejudice and offense to the caretakers before the culprit is found. The clinical and mainly the radiological symptoms are listed with reference to recent literature dealing with the diagnostic value of these symptoms. The "verschleierter Pflegeschaden" includes problems of malnutrition and rickets as well as scurvy. They are partly evidence of neglect. Short reference is made to differential-diagnosis. Psychological, socioeconomical and family problems involved are briefly mentioned in respect to statistical data. They are included in this brief survey in order to lead from the mere collection of radiological symptoms to an understanding of the many different aspects of the clinical syndrome. The necessity of early diagnosis and rapid information of the referring physician and/or institution is pointed out. Both, the high incidence of reocurrence rate and the high risk for siblings requires immediate action.

Battered Child Syndrome↗