Biomedical subjects

A Kaiser

Publications and source records attributed to A Kaiser.

At least 91 records · Page 5Linked to original sources

PubMed1994

[Preventive digitalis therapy in open thoracotomy].

Prophylactic digitalization is still recommended after open lung surgery in order to prevent cardiac arrhythmias in the postoperative period. Since a beneficial effect of this potentially harmful medication is only poorly documented, we conducted a prospective randomized trial. Patients undergoing elective open lung surgery were divided into two groups one of which received digoxin postoperatively, the other not. Randomization was performed independently in three groups with regard to the extent of surgery, i.e. pneumonectomies in patients of any age, (bi-)lobectomies in patients > 50 and other (less extended) operations in patients > 60. Patients who were either too young for either group or who had already taken digoxin before surgery were followed separately. Monitoring was performed continuously in the ICU and conventional ECG was registered after 24, 48 and 72 hours and weekly until dismission.--Cardiac arrhythmias are very frequent in the early postoperative period with a maximum between the third and the fifth postoperative day. Any kind of arrhythmias were present in 19 of 30 patients (63%) compared to 14 of 35 patients (40%) in the control group. Symptomatic arrhythmias that needed treatment occurred in 11.4% of the control group, but in 33.3% of the patients with prophylactic digitalization. We therefore conclude that a general prophylactic digitalization after open lung surgery is not indicated, but that arrhythmias should be treated individually.

Adolescent↗

PubMed1994

[The value of defecography for diagnosis of rectocele and rectal prolapse].

The role of defecography with respect to rectoceles and to any grade of rectal prolapses has not been defined so far. Therefore, we studied 42 out of 45 patients that were submitted to a defecography between 1988 and 1992 for defecation disorders of unknown origin. In particular, we compared the diagnosis obtained by anamnestic data and the physical examination with the defecographic results and the definitive diagnosis with regard to the chosen therapies and the results. Rectocele and rectal prolapse were very frequent pathologies with 69% and 33% respectively. Of 23 patients with a clinically palpable rectocele, defecography was false negative in 4 and moreover, it did not provide any information about the functional relevance of the rectocele. Yet, it disproved the clinically diagnosed prolapses in 6 of 15 subjects, but revealed one in 5 of 27 patients that were presumed normal. On the other hand, a previously not diagnosed rectocele was detected in 6 out of 19 patients by means of defecography, but none of them proved to be of any clinical relevance. Of all rectoceles, only 48% were regarded responsible for the patients' symptoms and were therefore operated. Hereby, the indication for a surgical approach based more on anamnestic data and the proctological examination than on radiographic findings. Contrarily, the indication for a rectopexy--even if given only in 4 of those 14 patients with any grade of invagination--mainly based on the dynamics during defecation as documented by defecography.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1993

Cranioplasties for congenital and acquired skull defects in children--comparison of new concepts with conventional methods.

From 1974 to 1992 fifty-two patients with congenital or acquired skull defects were operated at the Department of Pediatric Surgery of the University Children's Hospital of Zurich. By 1988, in 26 patients conventional methods with PMMA (polymethyl methacrylate) plasties or rib plasties were performed. After 1988, in 26 patients skull reconstruction was done by skull splitting, application of lyophilized bone or cartilage or a combination of both. In the latter period, stabilization and fixation was always provided by biodegradable screws and bands. The results of the different techniques were compared in a retrospective fashion. PMMA plasties provided immediately full stability and good cosmetic results. Another advantage was their availability. In one patient (= 4.8%), a wound infection required the removal of the plasty. In two other patients (9.5%), an increasing mobility of the plasty could be observed during skull growth. Rib plasties were not satisfying. Skull splitting or reconstruction with lyophilized bone or cartilage showed good results with a stable integration within 3-4 months. In one patient (4%), a superficial wound infection occurred, but it did not affect the plasty. From the present study, we conclude that skull splitting or the reconstruction of skull continuity by means of lyophilized bone or cartilage with fixation through biodegradable screws and bands are the methods of first choice in children, because they are fully integrated, avoid foreign material and might have a slightly lower risk of infection. In addition, removal of the implants may be avoided.(ABSTRACT TRUNCATED AT 250 WORDS)

Biodegradation, Environmental↗

PubMed1993

Evaluation of a social interaction coaching program in an integrated day-care setting.

We used a multiple baseline design across teachers (with a reversal phase for 1 teacher) to evaluate the direct and indirect effects of a structured coaching procedure on the teaching behaviors of 3 day-care teachers. Structured coaching preceding daily caregiver routines resulted in (a) substantial increases in adult delivery of behavioral support of social interaction during group activities with 2- and 4-year-old children and (b) marked collateral increases in positive interactions of socially withdrawn children. Long-term maintenance effects were demonstrated by both the teachers and target children, and social validity measures indicated that the teachers rated coaching very positively on several dimensions. The results are discussed in relation to in-service training of day-care staff, the concept of coaching as a setting event, and the dissemination of teaching technology related to social interaction of young children.

Adult↗

PubMed1993

[Proximo-distal course of the diameter of the great saphenous vein and distribution of the number of side branches as an inherent difficulty in infra-inguinal arterial in situ bypass].

The greater saphenous vein is still the best material for infrainguinal arterial bypasses, particularly if they have an infrapopliteal distal anastomosis. Although a lot of advantages have been presumed for the in-situ bypass, the reported results are not significantly better than with the reversed technique. To find some additional explanations, we studied post mortem the anatomy of 20 greater saphenous veins with regard to the diameter and the number of side branches and compared the results with 10 phlebographies. A minimal diameter (2.6 mm) and a maximum of side branches and venous valves were found at the proximal calf. Furthermore, this region was characterized by a lot of anatomic variants such as double systems (25%) or cross over variants (5%). These findings are surgically relevant and may reduce the bypass patency: 1. There is an increased hemodynamic resistance in longer bypasses, 2. The small diameter (particularly if smaller than 2 mm) means a risk for the patency of the distal anastomosis, 3. The high frequency of side branches requires a comparable exposition of the GSV as for the reversed technique, 4. The introduction of the valvulotomy from distally may overestimate the proximal diameter and underestimate the frequency of variants and may therefore cause significant endothelial damages or even perforation.

Humans↗

PubMed1993

[Acute pancreatitis after local infusion of divalent cations].

The association of hypercalcemia and acute pancreatitis had been experimentally reproduced in cats by local infusions of the divalent cation calcium whereas the monovalent cation potassium did not induce any pancreatic pathology. The purpose of the present study was therefore to investigate the role of further divalent cations in order to determine the relevance of ion valency for pancreatitis induction. Anesthetized male SIV-rats received divalent cations, of which a role in the pancreas had already been reported in the literature, through retrograde infusions into the splenic artery at a dose of 0.6 mmol/kgh for 3 hours and at a flow of 0.5-1.0 ml/h. The pancreas was then removed for morphologic studies. In the animals treated with calcium and manganese, pancreas showed a hemorrhagic necrosis of the acinar lobuli with leucocytic infiltrates. The barium treated animals spontaneously died after 49 +/- 15 minutes and revealed acute pancreatitis in the perfused, but not in the residual pancreas. Zinc at the initial dose induced an immediate heparin-refractory blood-clotting with subsequent ischemic necrosis whereas a lower dosis (0.002 mmol/kgh) led to an acute pancreatitis as seen after calcium. The magnesium treated animals and the controls did not reveal any pathology. We conclude that some divalent cations may induce an acute pancreatitis, but that the induction is not dependent on the cation valency.

Acute Disease↗

PubMed1992

Laminin binding in membranes of a rat pancreatic acinar cell line are targets for glucocorticoids.

The adhesive properties of tumor cells to basement membranes are known to play a crucial role in the complex process of tumor invasion and metastasis. Therefore, the interaction between the rat pancreatic acinar cell line AR42J and various extracellular matrix components along the route of differentiation induced by glucocorticoids was investigated. AR42J cells displayed a significantly higher affinity to laminin than to type IV collagen and fibronectin. Flow cytometric analysis showed expression of the 67-kilodalton laminin receptor and the integrin VLA-6 as potential laminin binding proteins in AR42J cells. Cell adhesion inhibition studies revealed that binding of undifferentiated AR42J cells to laminin was mediated predominantly by the 67-kilodalton laminin receptor. Dexamethasone pretreatment, which results in a more differentiated phenotype of AR42J cells, reduced the adhesion to laminin. In contrast to undifferentiated cells, interaction of differentiated AR42J cells to laminin was mediated by VLA-6. Dexamethasone-induced differentiation of pancreatic AR42J cells was paralleled by a decreased expression of 67-kilodalton laminin receptors, most likely because of a downregulation of the steady-state concentration of 67-kilodalton laminin receptor messenger RNA induced by dexamethasone. The hormonal modulation of cell matrix interactions opens interesting perspectives to the potential regulation of infiltrative growth and metastasis in pancreatic cancer.

Animals↗

PubMed1992

The ontogeny of homeothermic regulation in post-hatching chicks: its influence on the development of hearing.

1. The maturation of homeothermy in chicks from day 0 to day 30 after hatching (P0-P30) was studied by measuring rectal temperatures following different environmental exposures. 2. Body temperature regulation and an adult-like temperature (41.5 degrees C) develop with different time courses, being mature on days P4 and P23, respectively. After 1 hr at 20 degrees C, P0 chicks were 4.5-6.5 degrees C cooler than P30 animals. 3. A temperature effect shifts frequency in the auditory pathway up to 0.5 octaves to lower values. Some shifts in tonotopic maps observed in developmental studies of frequency representation in awake chicks can be fully explained by this temperature effect.

Animals↗

PubMed1992

Dietary fat and cholesterol modulate the plasma lipoprotein distribution and production of pigment or cholesterol gallstones in hamsters.

To evaluate the impact of key dietary factors on plasma lipoproteins and gallstone induction, male Syrian hamsters were fed either cholesterol and fat-supplemented purified diets containing glucose or lactose, or cholesterol and fat-free diets with or without fiber, for 13 wk. Fat-supplemented hamsters were hyperlipidemic in comparison to those fed fat-free diets. The former group revealed a greatly expanded VLDL fraction, whereas a normal HDL2 pool predominated in the latter group. Plasma fatty acids indicated that hamsters fed the fat-free diet were essential fatty acid deficient whilst the hamsters fed the fat-supplemented diet were subnormal in essential fatty acids. Ninety-three percent of the hamsters fed the fat-supplemented diet had gallstones (mostly cholesterol), whereas 62% of hamsters fed the fat-free diet had gallstones (almost all pigmented). Lactose increased cecal weight and prevented pigment stone formation in the fat-supplemented hamsters, whereas adding fiber to the fat-free diet contributed essential fatty acids, eliminated cholesterol stones and enhanced pigment stone formation. Thus, diets containing casein, rice flour, glucose and fiber with minimal essential fatty acids but no cholesterol promoted pigment stones (associated with a normal lipoprotein profile); a low fat diet limited in essential fatty acids but containing cholesterol and lactose, promoted cholesterol gallstones (associated with an expanded VLDL pool).

Adipose Tissue↗

PubMed1992

Long-term Antabuse treatment: tolerance and reasons for withdrawal.

We studied 210 alcoholics, who were re-admitted to a disulfiram treatment programme after having voluntarily discontinued disulfiram therapy, primarily to ascertain whether illness, hospitalization, or serious adverse effects were the cause of the withdrawal. A simple 9-item questionnaire was used. About 70% of the patients gave either "a wish to drink again" or "no need for further treatment" as the reason. Withdrawal in the remaining patients was in no case related to adverse effects of disulfiram. The low incidence of adverse effects was confirmed in another group comprising 93 patients treated under supervision with disulfiram 600-800 mg twice a week for at least a year (i.e. total dose at least 70 g disulfiram). They were monitored by standard laboratory blood and urine tests. There were no clinically significant changes in the measures used. Indeed, many of the patients improved during the year of abstinence. These two studies add weight to the evidence that disulfiram is not a drug with a high incidence of adverse effects.

Alcoholism↗

PubMed1992

Depletion of proton motive force by nisin in Listeria monocytogenes cells.

The basal proton motive force (PMF) levels and the influence of the bacteriocin nisin on the PMF were determined in Listeria monocytogenes Scott A. In the absence of nisin, the interconversion of the pH gradient (Z delta pH) and the membrane potential (delta psi) led to the maintenance of a fairly constant PMF at -160 mV over the external pH range 5.5 to 7.0. The addition of nisin at concentrations of greater than or equal to 5 micrograms/ml completely dissipated PMF in cells at external pH values of 5.5 and 7.0. With 1 microgram of nisin per ml, delta pH was completely dissipated but delta psi decreased only slightly. The action of nisin on PMF in L. monocytogenes Scott A was both time and concentration dependent. Valinomycin depleted only delta pH, whereas nigericin and carbonyl cyanide m-chlorophenylhydrazone depleted only delta psi, under conditions in which nisin depleted both. Four other L. monocytogenes strains had basal PMF parameters similar to those of strain Scott A. Nisin (2.5 micrograms/ml) also completely dissipated PMF in these strains.

Energy Metabolism↗

PubMed1991

Regulation of a modified CaMV 35S promoter by the Tn10-encoded Tet repressor in transgenic tobacco.

We have investigated the use of the Tn10-encoded tet repressor-operator system to regulate the expression of a suitably engineered cauliflower mosaic virus (CaMV) 35S promoter in transgenic tobacco plants. First, a transgenic plant was generated which constitutively synthesizes 600,000 Tet repressor monomers per cell. In a second transformation step, the beta-glucuronidase (gus) gene under the control of a modified CaMV 35S promoter, containing two tet operators, was stably integrated into the plant genome of a tetR+ plant. Expression of the gus gene is repressed 5-fold, if the operators are located flanking the TATA box, and 50- to 80-fold when both operators are positioned downstream of the TATA box. This indicates that Tet repressor-operator complexes can form on plant chromosomes and interfere with transcription. Maximal induction is achieved after 0.5 h upon application of only 0.1 mg/l tetracycline. This fast and efficient induction makes the system useful for specifically inducing expression of transferred genes at different stages of plant development.

Base Sequence↗

PubMed1991

Activity patterns of primary auditory-nerve fibres in chickens: development of fundamental properties.

We have examined the activity patterns of single auditory-nerve fibers in the chicken and tested for possible changes during post-hatching development. For this purpose, we recorded from fibres in the cochlear ganglion of chickens of two age groups (about P2 and P21) and investigated their spontaneous and sound-evoked activity patterns under nembutal-chloralhydrate anaesthesia. The spontaneous activity of primary auditory neurones was irregular, the average rates were between 20.5 (P2) and 23 (P21) spikes/s. Many low-frequency fibres from both age groups showed preferred intervals in their spontaneous activity. Tuning characteristics, including the range of characteristic frequencies, the presence of primary and two-tone suppression, the slopes of tuning-curve flanks and Q10dB values were similar to those previously reported for the starling and were statistically indistinguishable between the two age groups. However, there was a difference in fibre thresholds at the highest frequencies. Systematic differences were also present between the two age groups with regard to some characteristics of the rate-intensity functions. These data indicate that whereas the tuning properties of primary auditory fibres of the chicken cochlea are mature as early as post-hatching day 2, the intensity functions are not.

Acoustic Stimulation↗

PubMed1991

Inhibition of food-borne bacterial pathogens by bacteriocins from lactic acid bacteria isolated from meat.

Ten strains of bacteriocin-producing lactic acid bacteria were isolated from retail cuts of meat. These 10 strains along with 11 other bacteriocin-producing lactic acid bacteria were tested for inhibitory activity against psychotrophic pathogens, including four strains of Listeria monocytogenes, two strains of Aeromonas hydrophila, and two strains of Staphylococcus aureus. Inhibition due to acid, hydrogen peroxide, and lytic bacteriophage were excluded. The proteinaceous nature of the inhibitory substance was confirmed by demonstration of its sensitivity to proteolytic enzymes. Eight of the meat isolates had inhibitory activity against all four L. monocytogenes strains. Bacteriocin activity against L. monocytogenes was found in all of the strains obtained from other sources. Activity against A. hydrophila and S. aureus was also common.

Aeromonas↗

PubMed1991

[Electron microscopy of the exocrine pancreas in experimental acute hypercalcemia].

Hypercalcemia has been associated with acute pancreatitis clinically and in the experimental animal. We studied the pancreatic ultrastructure in acute experimental hypercalcemia. Anesthetized cats (Pentobarbital, 0.55 mg/kg) received Ca++ (Calcium-Gluconate: 0.6 mmol/kgh; n = 4), K+ (KCl: 1.1 mmol/kgh; n = 4) or NaCl (0.9%; n = 4) locally through retrograde infusion into the splenic artery. Biopsies for electron microscopy (EM) were taken at three hours. Eight cats received intravenous Ca++ (0.6 mmol/kgh, 0.3 mmol/kgh after three hours) or NaCl (0.9%) for 12 hours. Biopsies were collected in two animals in three-hour intervals, and in all animals at twelve hours. After local calcium infusion necrotizing pancreatitis was seen macroscopically in the body of the pancreas. Biopsies for EM showed acinar cell necrosis, hydrops of nuclei and mitochondria and needle-like precipitates in the cytoplasma in the center of calcium perfusion. Biopsies taken from the peripheral region of the macroscopically altered tissue revealed desorganisation of the acinar polarisation and the endoplasmic reticulum, with zymogen granules appearing in the basolateral cell-portion. After intravenous calcium administration no macroscopical changes were seen. In EM acinar cells showed dilatation and proliferation of the golgi apparatus and increased number of condensing vacuoles indicating stimulation. Again, disorganisation of acinar cell polarisation was present. Control animals treated with K+ or NaCl showed normal pancreatic ultrastructure. The morphological changes after calcium infusion indicate direct damage to the acinar cell. Our results suggest that hypercalcemia induced pancreatitis could originate in the acinar cell.

Acute Disease↗

PubMed1990

Role of the entC gene in enterobactin and menaquinone biosynthesis in Escherichia coli.

Tn10 mutants of Escherichia coli MC4100 were screened for their inability to grow under iron deficiency and for their inability to grow under anaerobiosis in the presence of fumarate as an electron acceptor. A strain so obtained (E. coli PBB1) lacked the ability to convert chorismic acid to isochorismic acid. This shows that the gene (entC) encoding isochorismate synthase was mutated. E. coli PBB1 did not produce any detectable amounts of menaquinones (vitamin K2) or enterobactin. When supplemented with isochorismic acid this strain produced menaquinones, indicating that isochorismic acid is involved not only in enterobactin but also in menaquinone biosynthesis. The entC gene was isolated and was shown to be part of the enterobactin gene cluster: It was located on a DNA fragment (9 kb in length) which also carried the entA gene. The DNA fragment was identified by restriction site mapping and was compared to a previously published map of the enterobactin gene cluster. The entC gene on this fragment responds not only to conditions (iron deficiency) that stimulate enterobactin biosynthesis but also to anaerobiosis which results in increased isochorismic acid formation and increased menaquinone biosynthesis. We conclude that isochorismic acid, isochorismic synthase, and the gene (entC) encoding this enzyme are involved in catalytic events at a metabolic branch point from which both enterobactin and menaquinones originate.

DNA Transposable Elements↗

PubMed1990

[Qualitative marginal gap research on amalgam fillings].

Using x-ray spectroscopy the inorganic contents of the interface tooth restoration of conventional and gamma-2-reduced amalgam fillings were analysed after short and long clinical application. Qualitative difference did not exist between interface layer of both amalgam types. The amalgam elements mercury, silver and copper were not detected, but tin occurred everywhere. Zinc and oxygen were frequently analysed in the interface layer. Calcium, phosphorus, sodium and magnesium were detected, too.

Corrosion↗

PubMed1989

Auditory brain stem responses in infants with posthaemorrhagic ventricular dilatation.

Nineteen infants with posthaemorrhagic ventricular dilatation had auditory brain stem responses measured during the period of maximal ventricular dilatation. These showed various patterns ranging from normal, through various abnormalities, to complete absence of responses. When serial auditory brain stem responses were studied in parallel with the evolution of posthaemorrhagic ventricular dilatation it was seen that the abnormalities of auditory brain stem response usually resolved irrespective of the persistence or progression of ventricular dilatation. No correlation was found between cerebrospinal fluid pressure and prolonged interpeak intervals on the auditory brain stem response. In three patients with posthaemorrhagic ventricular dilatation improvement in the auditory brain stem response occurred when cerebrospinal fluid was withdrawn. Intermittent withdrawal of cerebrospinal fluid (by ventricular tap or lumbar puncture) in two of these infants was followed by improvement in the auditory brain stem response after a period of 24 hours (but not sooner). In one infant born at full term improvement in the auditory brain stem response was noted one week after shunting.

Brain Stem↗