Biomedical subjects

A Prokop

Publications and source records attributed to A Prokop.

At least 73 records · Page 4Linked to original sources

PubMed1998

Batch foam recovery of sporamin from sweet potato.

The major sweet potato root protein, sporamin (which comprises about 80-90% of the total protein mass in the sweet potato) easily foams in a bubble/foam-fractionation column using air as the carrier gas. Control of that foam fractionation process is readily achieved by adjusting two variables: bulk solution pH and gas superficial velocity. Varying these parameters has an important role in the recovery of sporamin in the foam. Changes in the pH of the bulk solution can control the partitioning of sporamin in the foam phase from that in the bulk phase. A change in pH will also affect the amount of foam generated. The pH varied between 2.0 and 10.0 and the air superficial velocities (V0) ranged between 1.5 and 4.3 cm/s. It was observed in these ranges that, as the pH increased, the total foamate volume decreased, but the foamate protein (mainly sporamin) concentration increased. On the other hand, the total foamate volume increased significantly as the air superficial velocity increased, but the foamate concentration decreased slightly. The minimum residual protein concentration occurred at pH 3.0 and V0 = 1.5 cm/s. On the other hand, the maximum protein mass recovery occurred at pH 3.0 and at V0 = 4.3 cm/s.

Chemical Fractionation↗

PubMed1998

Batch foam fractionation of kudzu (Pueraria lobata) vine retting solution.

The aqueous protein solution from kudzu (Pueraria lobata) vine retting broth, without the addition of other surfactants, was foam-fractionated in a vertical tubular column with multiple sampling ports. Time-varying trajectories of the total protein levels were determined to describe the protein behavior at six positions along the 1-m column. The lowest two trajectories of this batch process represented a loss of proteins from the bulk liquid and tended to merge and decay together in time; the other trajectories displayed a gain in proteins in the foam phase. These upper column port protein concentration trajectories generally increased in time up to 45 mm, followed by a decrease, reflecting the removal of proteins from the column ports. The foam became dryer as it passed up the column to the top port. The protein concentration was about 5-8x higher in the top port foam than in the initial bulk solution, mainly as a result of liquid drainage from the foam along the column axis. This concentration increase in the collected foam was dependent on the initial pH of the bulk solution. The mol-wt profile of the proteins in the concentrated foam effluent was determined by one-dimensional gel electrophoresis. An analysis of the gel electropherograms indicated that the most abundant proteins could be cellulases and pectinases.

Aspergillus niger↗

PubMed1998

[Baker's cyst--current surgical status. Overview and personal results].

Baker's cysts were treated operatively in 19 patients in the Department of Traumatology of the University of Cologne from 1988 to 1997. The subjective and objective results were evaluated with a questionnaire and a clinical examination and sonography (follow-up: 95%). All patients were examined before surgery, sonography and X-ray of the knee were performed. We differentiated between the congenital primary cyst (39%), and the secondary form, which was always associated with an intraarticular lesion (61%). Arthroscopy was performed in all secondary forms of Baker's cyst. Postoperative complications were two reinterventions due to one hematoma and one effusion. Patient's evaluation of operation result was "excellent" in 61% and "good" in 39% of cases. All knee joints had a full range of motion. There was only one case of a recurrent cyst. The primary form of Baker's cyst has always to be extirpated, according to our clinical experience. The extirpation of the secondary Baker's cyst and the relevance of arthroscopy and treatment of the basic disease have to be discussed.

Adolescent↗

PubMed1998

[Candida spondylitis. Case report and review of the literature].

Candida species have emerged as important pathogens in human infection. Although a variety of deep-seated candidal infections have been reported, Candida spondylitis has rarely been described. One patient with candida tropicalis spondylitis L I and L II in combination with candida coxitis is presented, and the 31 adult cases with vertebral involvement previously reported are reviewed. Candida spondylitis is noted as a simultaneous occurrence or late manifestation of hematogenously disseminated candidiasis. Spondylitis may not be prevented by a course of Amphotericin B adequate to control the acute episode of disseminated candidiasis, particularly in immune suppressed patients. Spondylitis does not present as a postoperative wound infection. The insidious progression of infection, the nonspecificity of laboratory data, and the failure to recognise Candida as a potential pathogen may lead to diagnostic delay. Diagnosis can be made by either open biopsy or CT controlled needle aspiration. Successful therapeutic regimes have employed combinations of antifungal therapy (Amphotericin B or fluconazole) with radical surgical debridement. Ventral and facultatively dorsal instrumentation is required to stabilize the spine. It is anticipated that the spondylitis will become a more commonly recognised manifestation of hematogenously disseminated candidiasis. A increasing significance of candida species as etiologic agents of infection immune compromised humans has been recognised in the recent years. In those patients whom an antecedent Candida septicaemia was documented, a striking delay of 3.3 months was found between the septicaemia and the onset of symptoms as well as the time of diagnosis.

Adult↗

PubMed1998

Homeotic regulation of segment-specific differences in neuroblast numbers and proliferation in the Drosophila central nervous system.

The number and pattern of neuroblasts that initially segregate from the neuroectoderm in the early Drosophila embryo is identical in thoracic and abdominal segments. However, during late embryogenesis differences in the numbers of neuroblasts and in the extent of neuroblast proliferation arise between these regions. We show that the homeotic genes Ultrabithorax and abdominal-A regulate these late differences, and that misexpression of either gene in thoracic neuroblasts after segregation is sufficient to induce abdominal behaviour. However, in wild type embryos we only detect abdominal-A and Ultrabithorax proteins in early neuroblasts. Furthermore, transplantation experiments reveal that segment-specific behaviour is determined prior to neuroblast segregation. Thus, the segment-specific differences in neuroblast behaviour seem to be determined in the early embryo, mediated through the expression of homeotic genes in early neuroblasts, and executed in later programmes controlling neuroblast numbers and proliferation.

Abdomen↗

PubMed1998

Salmeterol prevents aspirin-induced attacks of asthma and interferes with eicosanoid metabolism.

We determined the effect of a long acting beta2-agonist, salmeterol, on aspirin-induced asthma (AIA) attacks and urinary release of eicosanoids in a double-blind, placebo-controlled, crossover study in 10 asthmatics sensitive to aspirin. The patients inhaled 50 microgram of salmeterol or placebo 15 min prior to a cumulative challenge with increasing doses of lysine-aspirin (L-ASA) (Part I), and before a single, predetermined dose of L-ASA that caused a 20% fall in FEV1 (PD20) (Part II). Salmeterol significantly attenuated aspirin-precipitated bronchoconstriction and the increase in urinary LTE4. Salmeterol also prevented the decrease in blood eosinophils, and abolished the correlation between the urinary levels of LTE4 and provocative doses of aspirin. In addition, PGD-M, the major urinary metabolite of PGD2, increased after L-ASA inhalation in six of nine subjects; this increase was blocked in all six by salmeterol. The protective effect of salmeterol on aspirin-induced attacks and mediator release suggests that it may be efficacious in aspirin-sensitive asthma.

Administration, Inhalation↗

PubMed1997

Purification of polymers used for fabrication of an immunoisolation barrier.

A multistep extraction procedure has been tested for purification of natural and semi-synthetic polymers used for fabrication of an immunoisolation barrier for implanting animal cells. This procedure, originally described by Klock et al. for alginates, has been adapted for other gelling polymers to remove pyrogens (endotoxins) and mitogens. Several other steps have also been tested, resulting in a new and simple procedure for polymer purification, giving satisfactory levels of contamination. Endotoxin levels have been quantified by means of chromogenic and gelclot LAL methods. A simple calculation of the endotoxin permissible levels shows that the quality of purified polymers exceeds FDA specifications for implantable polymers.

Animals↗

PubMed1997

An encapsulation system for the immunoisolation of pancreatic islets.

Over a thousand combinations of polyanions and polycations were tested to search for new polymer candidates that would be suitable for encapsulation of living cells. The combination of sodium alginate, cellulose sulfate, poly (methylene-co-guanidine) hydrochloride, calcium chloride, and sodium chloride was most promising. In parallel, a novel multiloop chamber reactor was developed to control the time of complex formation and to negate gravitational effects such as pancreatic islet sedimentation and droplet deformation during the encapsulation process. Encapsulated rat islets demonstrated glucose-stimulated insulin secretion in vitro, and reversed diabetes in mice. This new capsule formulation and encapsulation system allows independent adjustments of capsule size, wall thickness, mechanical strength, and permeability, which may offer distinct advantages for immunoisolating cells.

Animals↗

PubMed1997

[Treatment strategies in bite injuries].

Animal and human bites are a extremely common problem. Despite the prevalence of this problem, few systematic studies have been done. There is astounding sparsity of factual information in the literature to aid the therapeutic decision. Crucial questions regarding suturing, antibiotics, and other matters have been left unanswered. Therefore the literature was reviewed and therapeutic guidelines extracted.

Animals↗

PubMed1996

Hip fracture.

Explore the source record for details and available documents.

Femur Head Necrosis↗

PubMed1996

A Drosophila neurexin is required for septate junction and blood-nerve barrier formation and function.

Septate and tight junctions are thought to seal neighboring cells together and to function as barriers between epithelial cells. We have characterized a novel member of the neurexin family, Neurexin IV (NRX), which is localized to septate junctions (SJs) of epithelial and glial cells. NRX is a transmembrane protein with a cytoplasmic domain homologous to glycophorin C, a protein required for anchoring protein 4.1 in the red blood cell. Absence of NRX results in mislocalization of Coracle, a Drosophila protein 4.1 homolog, at SJs and causes dorsal closure defects similar to those observed in coracle mutants. nrx mutant embryos are paralyzed, and electrophysiological studies indicate that the lack of NRX in glial-glial SJs causes a breakdown of the blood-brain barrier. Electron microscopy demonstrates that nrx mutants lack the ladder-like intercellular septa characteristic of pleated SJs (pSJs). These studies identify NRX as the first transmembrane protein of SJ and demonstrate a requirement for NRX in the formation of septate-junction septa and intercellular barriers.

Amino Acid Sequence↗

PubMed1996

[Segmental displacement by callus distraction in extended tibial defects].

In open tibial fractures with defects over 4 cm, spongiosaplasty is considered to be insufficient. Since 1988 we have tried to apply Ilisarov's ideas of callus distraction in combination with modern external fixation devices and AO/ASIF implants. By August 1995, 15 patients with severe tibial fractures had been treated. The bone defect averaged 7 cm. Thus, more than 1 m of tubular bone was produced. Eleven male and 4 female patients, averaging 21.3 years in age, were given this treatment. The defect was caused by resection of a malignancy in 3 cases and a second- or third-degree open fracture in 12 cases, accompanied by osteomyelitis in 6 cases. Reconstruction required an average of 5.3 operations. The complication rate was 53%, and the median duration of treatment was about 1 year. The final results were excellent or good. Amputation could be avoided in all instances. This treatment is contra indicated if the patient exhibits a lack of compliance. There is a realistic chance of salvaging the limb in cases of severe soft tissue and bone defects. In terms of economical considerations, this treatment is cost effective. Physical integrity and mobility without aid is the important motivation for these patients.

Adolescent↗

PubMed1996

[Partial median sternotomy in resection of metastases of the upper thoracic spine].

A modified method of access to the upper thoracic spine is presented based on a case report. The third and fourth thoracic vertebral bodies can be reached by partial upper sternotomy. This approach takes the local anatomic situation into account, thus avoiding the typical complications of complete sternotomy and reducing the postoperative pain. Closure was done using biodegradable sutures, achieving satisfactory stabilisation and a low rate of complications. In only 4 of 130 cases (3%) did a superficial wound infection occur. There was no case of deep infection, osteomyelitis or dehiscence of the sternum.

Aged↗

PubMed1996

[Roentgen image presentation in the patient's room. Simple equipment for demonstration and storage of roentgen images].

Immediate presentation of the more significant X-ray pictures facilitates planning and supervision of therapy in trauma surgery and orthopedics. If a wire rope is stretched in front of the window X-ray pictures can be clipped onto it, which avoids time-consuming searches. Suspended filing boxes placed in each sickroom make appropriate storage of each patient's X-ray pictures possible. The expenditure for all this amounted to 100 DM for each two-bedded room. Wire ropes and boxes were technically easy to install with a minimum investment of time. The presentation of X-ray pictures considerably increased the patients' understanding of their illness. It was also very rare for X-ray pictures to get mixed up once this system had been instituted.

Equipment Design↗

PubMed1996

Value of bronchoscopic pneumonia diagnosis: prospective study.

In a prospective clinical study we examined whether bronchoscopically controlled suctioning is preferable to the blind suctioning of mucus aspirates for bacterial identification of intensive care unit patients with pneumonia. Forty patients with clinical and radiologic signs of pneumonia underwent both bronchoscopically controlled and blind endotracheal lavage. Bronchoscopically controlled suctioning did not demonstrate greater sensitivity for identifying organisms than the results obtained from blind suctioning (58 organism were bronchoscopically identified, compared to 57 organisms identified by blind suctioning; p = 0.32, NS). Arterial and mixed venous partial oxygen pressure and shunt also showed no significant differences 15 minutes before and after examination, nor did the blood pressure or pulse. The use of four of the bronchoscopes resulted in preinterventional contamination with Pseudomonas. Bronchoscopically controlled lavage shows no advantages over blind endotracheal lavage for diagnosing pneumonia. Blind suctioning with single-use sterile catheters can be done more quickly and inexpensively with fewer personnel and a lower complication rate.

Adult↗

PubMed1996

Presynaptic development at the Drosophila neuromuscular junction: assembly and localization of presynaptic active zones.

We describe the extent to which presynaptic structures at the embryonic neuromuscular junction of Drosophila can form in mutants where development of postsynaptic somatic muscles is affected. Although twist mutant embryos lack mesoderm, motor axons still grow out of the CNS and form morphologically normal presynaptic active zones, independent of their target cells. In myoblast city mutant embryos, myoblasts do not fuse but form fully differentiated mononucleate muscles, which make functional neuromuscular synapses with correctly localized presynaptic active zones. Myoblasts also fail to fuse but still attract appropriate innervation in mef2 mutant embryos. However, these myoblasts fail to differentiate into muscles and presynaptic active zones fail to localize at neuromuscular contacts. Thus, the process of synapse formation can be genetically separated from the process of target recognition, revealing that localization of presynaptic active zones requires mef2-dependent muscle differentiation.

Animals↗

PubMed1996

Validity of SEP monitoring in carotid surgery. Review and own results.

OBJECTIVE: The sensitivity of intraoperative monitoring by means of somatosensory evoked potentials (SEP) in carotid surgery is to be examined. EXPERIMENTAL DESIGN: Prospective clinical investigation. In addition, the influence of circulatory parameters on SEP curves will also be tested. SETTING: Department of Surgery of a university clinic. MATERIALS AND METHODS: A total of 200 patients underwent intraoperative monitoring by means of somatosensory evoked potentials (SEP) during carotid endarterectomy between March 1, 1991 and August 1, 1994. MEASURES: In order to exclude blood pressure variations as a cause for amplitude changes the blood pressure and pulse were documented during the entire phase of preparation and clamping. RESULTS: A significant correlation could not be established between parameters of circulation and amplitude changes (r = 0.0026; p = 0.62). In seven cases of intraoperative amplitude reduction of more than 50% a stroke has been avoided by inserting a shunt. Despite the lack of an amplitude reduction, a watershed stroke of A.cerebri media and A.cerebri posterior occurred in two instances. Taking this into consideration the sensitivity of monitoring is 99.0% at a specificity of 100%. CONCLUSIONS: SEP-monitoring in carotid endarterectomy is simple to execute and is superior in sensitivity to EEG analysis. To avoid artefaction by anesthesia, a standard injection anesthesia is recommended. Farfield potentials should also be derived to avoid watershed infarctions.

Blood Pressure↗

PubMed1996

[Trauma in the last trimester of pregnancy].

Although accidents during pregnancy are fairly rare, besides endangering the mother, they nearly always mean a vital threat to the fetus: lethality rates are up to 8% for the mother and up to 34% for the fetus. Besides depression of the circulatory system in the mother, coupled with fetal hypoxy, injury to the placenta and uterus is also possible. Moreover, the unborn child may be injured by direct trauma. If the fetus sustains a direct injury, the head of the child is affected in the majority of instances. In addition, the risk of an intrauterine death is very high. If the injured baby survives after a section, permanent damage must be taken into account. Pregnant women who are injured in an accident should quickly be checked by sonography and cardiotocography. If no danger is expected for the child, the usual therapeutic rules that apply for traumatology should be followed. If the mother and child are endangered, a cesarean section must be undertaken along with simultaneous accident-related surgery on the mother. Case reports are presented on three cases in our clinic last year, and the current literature is discussed. All three mothers and newborns survived because of the cooperation between surgeons, gynecologists and pediatricians.

Adult↗