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Biomedical subjects

K Dietrich

Publications and source records attributed to K Dietrich.

At least 19 recordsLinked to original sources
PubMed1992

Filtration of buffy coat free red cell concentrates in additive solution.

Leukocyte poor RCC's (LP-RCC) are indicated in chronically transfused patients in order to prevent non-hemolytic transfusion reactions and HLA alloimmunization. In this study buffy coat free red cell concentrates (BCF-RCC) in additive solution (SAG-M) stored for four weeks were leukocyte depleted by filtration with three different filter systems (Erypur Optima (E), Sepacell R500 B (S) and, Pall RC, 50 TM (P)). The BCF-RCC's were prepared using 'bottom and top (BAT)' systems and automatic separation containing about 20% leukocytes and 5% platelets of fresh whole blood. The leukocyte concentration could be reduced to less than 5 x 10(6) per RCC with all filter systems equally: Leukocytes/RCC's: E .58 +/- .94, S .36 +/- .55, P .55 +/- .69 x 10(6). The leukocyte depletion was even in case of filtering two RCC's through one filter (double filtration) efficient enough in order to keep leukocyte contamination below the 'critical immunogenic load for leukocytes (CILL)'. But significant differences concerning the damage of red cells (free hemoglobin, LDH, HBDH) were measured which were even considerable: free hemoglobin E = 3.69 +/- 2.28, S = 1.31 +/- 1.24, P = 3.58 +/- 2.34 g/l. Double filtration was only performed with filter system S showing the best blood compatibility. But the second BCF-RCC also showed considerable hemolysis. Therefore, double filtration of RCC's only seems to be indicated under optimal conditions with blood compatible filters for selected patients. Bed side filtration cannot be recommended because of the risk of hemolysis that makes quality control necessary.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Component Removal↗
PubMed1992

[Filtration of buffy coat-free erythrocyte suspensions in additive solution].

Buffy coat-free red cell concentrates in SAG-M (RCC) were produced by BAT system (leukocyte content 132 x 10(6)/RCC). They were stored for 4 weeks and filtered by Erypur Optima (E), Sepacell R 500 B (S) und PALL RC 50 TM (P). Leukocyte depletion was very effective (E: 0.56 x 10(6)/RCC; S: 0.36 x 10(6)/RCC; P: 0.55 x 10(6)/RCC) but hemolysis was remarkable (E: 301 +/- 195; S: 127 +/- 123; P: 368 +/- 256 mg/RCC). Therefore preparation of two RCC per filter was only acceptable with S. In S and P loss of red cells was tolerable (E: 90.5; S. 41.8; P: 38.2). In contrast, E should be rinsed with sodium chloride at the end of the preparation. In E and S filtration times were short without additional pressure (E: 6.6 min; S: 4.7 min; P: 20.3 min). We conclude from our results that the use of buffy coat-free red cell concentrates in additive solution considerably reduces the problems of filtration, e.g. storage interval, leukocyte reduction, hemolysis, filtration flow. Despite this, bedside filtration is not recommended because quality assurance is necessary.

Blood Component Transfusion↗
PubMed1991

Extracellular matrix preparation of expanded polytetrafluoroethylene grafts seeded with endothelial cells: influence on early platelet deposition, cellular growth, and luminal prostacyclin release.

The importance of blood and extracellular matrix precoating of expanded polytetrafluoroethylene (ePTFE) grafts on the effectiveness of endothelial cell (EC) seeding was assessed in a canine experimental model. Part I of the study documented ex vivo platelet deposition in 256 ePTFE grafts, 6 cm x 4 mm internal diameter, after implantation as femoral artery-femoral vein or carotid artery-jugular vein arteriovenous shunts. These conduits were precoated with blood, fibronectin, laminin, or collagen type IV with laminin, after which they were seeded with enzymatically derived and cultivated venous canine endothelium at a density of 30,000 to 40,000 EC/cm2 of graft surface. Luminal deposition of Indium 111-labeled platelets, expressed as 10(8) platelets/cm2, at 30 minutes (n = 176) and 24 hours (n = 80), respectively, was 2.29 and 0.30 for blood, 2.83 and 0.37 for fibronectin, 0.99 and 0.08 for laminin, and 0.98 and 0.11 for collagen type IV with laminin. Part II of the study documented in vivo luminal EC coverage at 14 days of 6 cm x 4 mm internal diameter ePTFE femoral or carotid arterial grafts (n = 8) prepared in the same manner as part I ex vivo shunt grafts. EC coverage with blood, fibronectin, laminin, and collagen type IV with laminin preparation was 42%, 49%, 44%, and 52%, respectively. The graft:carotid artery ratio of luminal 6-keto-PGF1 alpha release at 14 days with these same four preparations was 0.38, 0.31, 0.35, and 0.32, respectively. Precoatings of ePTFE prostheses with fibronectin, laminin, and collagen type IV are known to enhance the initial attachment of seeded EC. Fibronectin caused an insignificant increase in early platelet accumulation; laminin or laminin with collagen type IV preparations were associated with significantly less (p less than 0.005) deposition of platelets when compared to whole blood preparations. Most importantly, none of the four preparation techniques resulted in different in vivo rates of EC growth or luminal release of prostacyclin from conduits studied 14 days after implantation.

Animals↗
PubMed1990

Effect of tamoxifen and high-dose medroxyprogesterone acetate (MPA) on cell-mediated immune functions in breast cancer patients.

In 48 postmenopausal patients with non-disseminated breast cancer an adjuvant therapy with tamoxifen, and in 17 breast cancer patients with disseminated disease a therapy with high-dose medroxyprogesterone acetate (MPA) was performed and the results obtained were compared to a control group of 35 postmenopausal patients with non-disseminated disease receiving no further adjuvant treatment and 9 patients with disseminated disease, who were not treated by hormonal therapy or chemotherapy. Before therapy was started and at the end of therapy reactivity in the leukocyte migration inhibition test (LMI-Test) against autologous and homologous tumor tissue, serum levels of TNF alpha, IL-2 and IFN alpha, as well as the differentiation of different lymphocyte subsets in the peripheral blood, were determined. In patients undergoing adjuvant therapy with tamoxifen an increase of reactivity in the LMI test against tumor tissue (14.6% before and 22.9% after tamoxifen therapy) and increase of the percentage of NK cells (13.6% before and 19.8% after therapy) could be observed, whereas with TNF alpha, IL-2 and IFN alpha serum levels, as well as the differentiation of other lymphocyte subsets, no differences were found. In breast cancer patients with disseminated disease treated with high-dose MPA no changes of LMI reactivity and cytokine serum levels could be observed. We only found a decrease of T-helper cells from 38.4% before to 22.7% (p less than 0.05) at the end of therapy. These results indicate that tamoxifen has no severe suppressive side effects on different parameters of cell-mediated immunity and possibly leads to an increase in the number of NK cells. Contrary to this, high-dose MPA must be considered as a depletor of T-helper cells.

Aged↗
PubMed1989

[Treatment of acute stomach ulcer with H2 receptor antagonists. A direct therapy comparison with 300 mg nizatidine nightly and 2 times 150 mg nizatidine with twice daily 150 mg ranitidine].

In this endoscopically controlled, double-blind study involving 242 patients with acute benign gastric ulcer, it was shown that the selective inhibition of nocturnal gastric acid secretion with 300 mg nizatidine administered on retiring represents an effective and reliable form of therapy. After four weeks of treatment, 90% of the patients receiving 300 mg nizatidine, no longer experienced nocturnal pain, in comparison with 83% receiving 2 X 150 mg nizatidine daily (n.s.). The total healing rates after four weeks were 60% in the patients receiving 300 mg nizatidine, 60% in those on 2 X 150 mg nizatidine daily, and 58% in those receiving 2 X 150 mg ranitidine daily. After eight weeks, the respective figures rose to 85%, 84% and 84%. Clinically relevant side effects were observed in none of the three groups. With a dose on retiring of 300 mg nizatidine, it is possible to accelerate the healing of a benign gastric ulcer, simply by the nocturnal suppression of gastric acid production, and, during the day, preserving physiological gastric function, thus avoiding the possible risks of protracted hypochlorhydria.

Adolescent↗
PubMed1989

Ethnic differences in the demand for physician and hospital utilization among older adults in major American cities: conspicuous evidence of considerable inequalities.

Reinterpreting ethnicity's role in the prevailing behavioral model of health services usage reveals among older Americans a patient pattern of inequality favoring the Anglo-American population. Demand for hospital and physicians' care among minority elderly is far more constrained and sensitive to health needs than it is for their Anglo-American counterparts. The findings underscore the importance of examining ethnic differences in determinants of health behavior as well as in health service utilization. Such results also appear to strengthen the grounds for developing new programs aimed at eliminating inequalities of access to health care that older members of minorities now face.

Black or African American↗
PubMed1988

Postural disequilibrium quantification in children with chronic lead exposure: a pilot study.

Previous studies reported that some children who survive acute lead encephalopathy suffer from ataxia and have difficulties maintaining postural equilibrium. More recent studies have failed to quantify postural imbalance in association with lower levels of lead exposures, perhaps due to the insensitivity of the clinical measure. In our study, we noninvasively measured postural disequilibrium with a microprocessor-based force platform. The test provides a real time quantification of the body's center of gravity movement pattern. Measurements were made in a cohort of 33 inner city children (mean age: six years +/- 0.4 SD) with well documented blood lead histories. The average maximum blood lead of these children during their first six years of life was 23.5 micrograms/dl (range = 8.5 to 49.4). The children performed four postural tests [i.e., standing eyes open (EO) and closed (EC), on firm surface and standing on a compliant foam surface with eyes open (FO) and closed (FC)]. The results indicated that the maximum blood lead incurred during the second year of life was significantly positively related to postural sway, and the body balance was most affected in the EC test where visual cues were eliminated and proprioceptive feedback was not modified. Fetal Pb exposure levels as well as Pb exposures during the first year of life were not correlated with postural sway of six year olds. However, the maximum blood lead concentration beyond two years of life was significantly associated with the postural sway at six years of age.

Child↗
PubMed1988

[Peptone stimulation of the lower esophageal sphincter in patients with reflux disease].

Twenty patients with gastroesophageal reflux disease (10 with compensated and 10 with decompensated gastroesophageal incompetence) were examined to determine if there was a correlation between the ability of physiological stimuli to tonicize the lower esophageal sphincter (LES) and the response to pentagastrin stimulation (Gastrodiagnost). The pressure of the lower esophageal sphincter as well as blood levels of the hormones/neurotransmitters gastrin, PP and VIP were determined after giving a 300 ml intragastral bolus of either 0.9% NaCl or 20% peptone solution. All patients exhibited per definitionem a positive common-cavity phenomenon on abdominal compression. Intravenous pentagastrin stimulated the LES in patients with compensated gastroesophageal incompetence (GI) but not in those with decompensated GI (p less than or equal to 0.0005). Esophagoscopy revealed a severe esophagitis in 80% of the patients with decompensated GI but in only 10% of the patients with compensated GI. Peptone stimulated the LES in patients with compensated GI (p less than or equal to 0.005) at 5, 10 and 15 minutes, pepton vs. NaCl). Neither NaCl nor peptone increased the tone of the LES in patients with decompensated GI. Peptone but not NaCl caused a significant increase of serum gastrin in all patients: there was no difference between the two groups. Neither NaCl nor peptone influenced VIP levels in peripheral blood. PP levels increased significantly in both groups following peptone. Physiological responsiveness of the LES can be inferred from the manometric data and the results of the pentagastrin test. A negative reaction to pentagastrin is associated with a loss of response to physiological stimuli.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1985

Studies on the intracerebral metabolism of anticonvulsant drugs--II. Disposition of carbamazepine in the isolated perfused rat brain.

Carbamazepine (CBZ) was perfused (85 nmoles/ml) through the isolated brains of rats. After 2 hr the mean regional concentrations of the drug were between 170 and 234 nmoles/g wet weight. The total brain content of CBZ was 390 nmoles. During perfusion 82 nmoles epoxycarbamazepine (E-CBZ) were formed, most of which were found in perfusion medium. Tissue levels of E-CBZ were between 0.3 and 2.8 nmoles/g wet weight. No dihydroxycarbamazepine (DH-CBZ) could be found. Pretreatment of the rats with phenobarbital neither influenced the uptake of CBZ into the brains nor increased the formation of E-CBZ significantly.

Animals↗
PubMed1979

[Miniaturized methods to monitor intracranial pressure. Technical and clinical results (author's transl)].

The prognosis of numerous diseases of the central nervous system is essentially determined by the intracranial pressure (ICP) and its therapeutic influencing. Long-term monitoring of the ICP must therefore be the objective in neurological and neurosurgical patients at risk. For this purpose, miniaturized methods were tested and developed. To monitor the intracranial pressure in patients who were not operated on, a miniature pressure transducer the size of a match head was used which was directly implanted 'percutaneously' in the intensive care unit: After a stab wound had been made in the skin, a 5-mm burrhole is made; the specially constructed miniature coaxial burr which disengages as soon as it touches the dura automatically enables coplanar epidural implantation of the transducer by means of an adapter capsule. The skin is closed without tension. For monitoring the pressure after trepanation, a spiralled miniature pressure transducer is implanted. The equally flattened receiver with lateral membranes is placed intracranially as desired, e.g., epidurally or subdurally, durin the operation. The zero point can be checked from outside without danger of infection. After the end of the measurements the recorder is easily extracted. Up to the present time, the epidural pressure has been reliably monitored for several weeks by this method in 86 patients. Ten comparative measurements showed corresponding cerebrospinal fluid pressures to within a few mm Hg with very good reproduction of frequency and amplitude. Small zero drift and the external zero control give an accuracy of measurement +/- 5 mm Hg independently of the time of measurement. The measurement permits early recognition of progressive intracranial space-occupying lesions. In 14 patients (16%) a measured rise in intracranial pressure was an essential basis for indication for neurosurgical operations. In addition, the pressure measurement provides an objective assessment of the effect of measures to lower the ICP; progressive increases in intracranial pressure which cannot be influenced conservatively can be brought for surgical decompression in good time before the brain has been irreversibly damaged by pressure. In craniocerebral traumata, monitoring the intracranial pressure permits the differentiation of primary damage to the brain stem with uniform, normal intracranial pressure from secondary constrictions of the brain stem with considerable rise of intracranial pressure and disturbed autoregulation. Only in chronic subdural haematomata are considerable displacements of intracranial masses to be seen with only slightly increased ICP ( less than 30 mm Hg). Besides space-occupying lesions, the measurement of pressure also detects generalised epileptic attakcs due to a considerable rise in intracranial pressure caused by hyperemia. Also disorders of respiration are recognised by supervision of ICP. The procedures described seem suitable for routine monitoring of ICP in patients at risk, with little operative effort and minimum danger...

Adolescent↗
PubMed1979

Comparison of the effects of surgical decompression and resection of local edema in the therapy of experimental brain trauma. Investigation of ICP, EEG and cerebral metabolism in cats.

The effect of decompressive trepanation was compared to that of surgical resection of the traumatized tissue in the course of traumatic brain edema in standardized experimental brain trauma. Following a right parietal cold injury, the following parameters were monitored continuously in 12 cats: ventricular pressure, epidural pressure over both hemispheres, arterial and central venous pressure and heart rate. The EEG was evaluated continuously, using a computer (power spectra). After catheterization of the superior sagittal sinus, cerebral arteriovenous differences of glucose, lactate, O2 and CO2 were calculated. 6 animals were treated surgically when showing elevated intracranial pressure ICP and markedly altered EEG. In 3 animals, the right hemisphere was decompressed by extensive resection of bone and dura. In 3 further animals, the softened brain tissue of the cold lesion was resected and the skull defect closed. 6 untreated animals were used in controls. A decompression by skull hemiresection for ablation of the injured cortex abolished the high intracranial pressure, but only the latter method seemed to prevent further damage. This could be demonstrated by the EEG registration, and by the normalization of arteriovenous metabolite differences. Only animals treated with edema resection had a normal arousal reaction and survived the trauma. The results indicate, that only an ablation of the local injury will prevent further damage to the brain. After decompressive trepanation alone, the progression of tissue edema is not interrupted. As can be seen from the literature, the poor results obtained even from extensive decompressive operations in traumatic brain edema, indicate that the further development of edema is independent of the intracranial pressure, whereas the favorable results of resection of lobar contusions show an interruption of the spread of dysbolism.

Animals↗