Turbo-screening of bacterial colonies using microwave denaturation on paper filters.
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Autoradiography↗
Biomedical subjects
A Forster
Publications and source records attributed to A Forster.
Correction of prolonged bleeding time in von Willebrand's disease with Humate-P.
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Bleeding Time↗
Predictive value of FRC and respiratory compliance on pulmonary gas exchange induced by high frequency jet ventilation in humans.
To determine if functional residual capacity (FRC), compliance of the respiratory system (C), or underlying pulmonary disease are predictive for the efficacy of high frequency jet ventilation (HFJV) on pulmonary gas exchange, we investigated six adult patients within 4 h of abdominal surgery and six patients with severe adult respiratory distress syndrome. Gas exchange during intermittent positive pressure ventilation (IPPV) was compared with that during HFJV at frequencies of 100 b.p.m. (HFJV100) and 200 b.p.m. (HFJV200), resulting in a minute ventilation of about 400 ml kg-1 with both ventilatory frequencies, and in both groups of patients. Baseline FRC and C were measured during IPPV with the multiple-breath nitrogen washout method and from expiratory pressure-volume curves, respectively. Changes in the alveolar-arterial oxygen difference (PAO2 - PaO2): FIO2 ratio induced by HFJV correlated negatively with C (HFJV100: r = -0.78, P less than 0.005; HFJV200: r = -0.84, P less than 0.005); that is, greater oxygenation was obtained in patients with a better compliance. Similarly, changes in arterial partial pressure of carbon dioxide (PaCO2) induced by HFJV correlated negatively with C (HFJV100: r = -0.77, P less than 0.001; HFJV200: r = -0.61, P less than 0.05). In contrast, there was no significant correlation between FRC measured during IPPV and changes in (PAO2 - PaO2): FIO2 ratio or PaCO2 induced by HFJV, as these changes were influenced more by the patient's pulmonary disease than by baseline FRC. These results should be interpreted in the context of different underlying pathophysiological mechanisms reducing FRC in both groups of patients.
Abdomen↗
Preoperative sedation before regional anaesthesia: comparison between zolpidem, midazolam and placebo.
The quality of premedication induced by oral midazolam and zolpidem, a new imidazopyridine hypnotic, was assessed in a controlled, double-blind study in 93 patients undergoing elective surgery under spinal or extradural anaesthesia. The patients were allocated randomly to three groups. Each group received the same treatment twice at two different doses. The night before operation, patients received zolpidem 10 mg, midazolam 7.5 mg or placebo and, 1 h before operation, zolpidem 20 mg, midazolam 15 mg or placebo. The sleep inducing effects of the drugs were comparable. Zolpidem and midazolam were significantly more effective sedatives than placebo 45 min after administration, but no difference was noted between the drugs. There was a comparable incidence of anterograde amnesia with zolpidem and midazolam, but the onset was shorter after zolpidem. Side effects were comparable in the three groups. Zolpidem is an effective hypnotic with a rapid onset and short duration of action which may be an alternative to midazolam for premedication.
Adult↗
High frequency jet ventilation and intermittent positive pressure ventilation. Effect of cerebral blood flow in patients after open heart surgery.
Attenuation of ventilator-synchronous pressure fluctuations of intracranial pressure has been demonstrated during high frequency ventilation in animal and human studies, but the consequences of this effect on cerebral blood flow have not been investigated in man. We compared the effects of high frequency jet ventilation and intermittent positive pressure ventilation on CBF in 24 patients investigated three hours after completion of open-heart surgery. The patients were investigated during three consecutive periods with standard sedation (morphine, pancuronium): a. IPPV; b. HFJV; c. IPPV. Partial pressure of arterial CO2 (PaCO2: 4.5-5.5 kPa) and rectal temperature (35.5 to 37.5 degrees C) were maintained constant during the study. The CBF was measured by intravenous 133Xe washout technique. The following variables were derived from the cerebral clearance of 133Xe: the rapid compartment flow, the initial slope index, ie, a combination of the rapid and the slow compartment flows, and the ratio of fast compartment flow over total CBF (FF). Compared to IPPV, HFJV applied to result in the same mean airway pressure did not produce any change in pulmonary gas exchange, mean systemic arterial pressure, and cardiac index. Similarly, CBF was not significantly altered by HFJV. However, important variations of CBF values were observed in three patients, although the classic main determinants of CBF (PaCO2, cerebral perfusion pressure, Paw, temperature) remained unchanged. Our results suggest that in patients with normal systemic hemodynamics, the effects of HFJV and IPPV on CBF are comparable at identical levels of mean airway pressure.
Cardiac Surgical Procedures↗
A rapid procedure for colony screening using nylon filters.
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Bacteria↗
Alternating purine-pyrimidine tracts may promote chromosomal translocations seen in a variety of human lymphoid tumours.
Chromosomal abnormalities which are prevalent in human lymphoid tumours are believed to be involved in tumour pathogenesis and their formation may be the result of erroneous activity by the V-D-J recombinase. Frequently, recombinase accessibility is provided by prior transcription of the chromosomal regions involved. However, this may not always be so and in those cases DNA structural features must be involved. Here we examine the breakpoints of three different tumour-specific translocations in the proximity of which we can detect no transcription; two of the translocations involve regions of chromosome 11, (t[11;14] [p13;q11] and t[11;14] [q13;q32]), and the third is a newly described translocation, t[7;10] [q35;q24], involving the T cell receptor beta-gene on chromosome 7. In each case, a purine--pyrimidine tract (potential Z-DNA) occurs near the translocation breakpoints. Four independent tumours with translocation t[11;14] [p13;q11] reveal a 2 kb breakpoint cluster region at 11p13 with an adjacent potential Z-DNA region of 62 bp in length; the analogous purine--pyrimidine tract at 10q24 is 32 bp long. The purine--pyrimidine tract at the 11q13 chromosome breakpoint, however, is very large as it covers approximately 800 bp. The position, surrounding sequence and potential Z-DNA tract of the human 11p13 TALLber is conserved in rodents. These results suggest that the purine--pyrimidine tracts, presumably in the Z-DNA form, can influence chromatin structure giving access for recombinase-mediated translocations. Such putative alterations of chromatin organization are supported by the observation of DNase I hypersensitive sites near to translocation breakpoints on 10q24 and 11p13.
Animals↗
Changes in muscle fiber conduction velocity, mean power frequency, and mean EMG voltage during prolonged submaximal contractions.
Average muscle fiber conduction velocity, mean power frequency, and mean EMG voltage have been measured in human vastus lateralis during prolonged isometric knee extensions at 10, 20, 30, and 40% of the maximum knee extension force. During contractions at 10 and 20% of maximum force, conduction velocity and mean power frequency rose as the contraction progressed, whereas the conduction velocity and mean power frequency fell at 30 and 40% of the maximum force. The mean EMG voltage rose during the contractions, with steeper increases for higher forces. It is argued that two principal factors influence the EMG during prolonged submaximal contractions: firstly, the fatigue of current active motor units, and, secondly, recruitment of fresh motor units. These factors act in opposition to muscle fiber conduction velocity. Recruitment gives an increase in average conduction velocity, whereas fatigue provokes a slowing in conduction velocity.
Adult↗
Chromosomal translocations involving the T-cell receptor delta chain locus and two loci on the short arm of chromosome 11.
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Chromosome Mapping↗
[Accidental catheterization of the subdural space: a complication of continuous spinal anesthesia and continuous peridural anesthesia].
Two cases of subdural catheter placement following continuous spinal and continuous epidural anaesthesia are presented. In the first, despite an easy reflux of clear cerebrospinal fluid through the catheter, the injection of 4 ml bupivacaine 0.5 per cent with epinephrine 1:200,000 followed by 3 ml tetracaine 0.5 per cent showed a failure of spinal anesthesia. In the second, the administration through the catheter of 20 ml lidocaine 2.0 per cent CO2 plus epinephrine 1:200,000 and of ten ml bupivacaine 0.5 per cent lead to an insufficient, patchy and asymmetrical analgesia. The clinical signs observed in these two cases are compared with previous publications. The importance of an x-ray contrast study to confirm the diagnosis of subdural catheter insertion is stressed.
Adolescent↗
Comparison of continuous spinal and continuous epidural anaesthesia for lower limb surgery in elderly patients. A retrospective study.
This retrospective study compared continuous spinal anaesthesia with continuous epidural anaesthesia for lower limb orthopaedic surgery in the elderly. The anaesthetic records of 457 patients who received continuous spinal anaesthesia and 274 who received continuous epidural anaesthesia over a 5-year period were analysed. The patients who had continuous spinal anaesthesia were at a higher anaesthetic risk (ASA 3-4, 76% as compared with 37%, p less than 0.001), but the incidence of failures was significantly lower (1.7%, as compared with 9%, p less than 0.001) and fewer patients showed a decrease in mean arterial pressure of more than 30% (44%, as compared with 65%, p less than 0.001) and (or) received vasopressors (65%, as compared with 77%, p less than 0.01). Our data show continuous spinal anaesthesia to be more reliable and to provide better cardiovascular stability.
Aged↗
Effect of the knee-chest position on cerebral blood flow in patients undergoing lumbar spinal surgery.
The cerebral haemodynamic effect of the knee-chest position was evaluated in 15 anaesthetised patients undergoing elective lumbar disc surgery and divided into a control group (n = 8) where cerebral blood flow (CBF) was measured twice in the supine position and an experimental group (n = 7) where the first CBF was measured in the supine position and the second in the knee-chest position. CBF was measured by a modified intravenous 133xenon washout technique. Mean global CBF did not change in control group (56.1, SD 9.2 versus 52.8, SD 10.8 units) and was not significantly modified by the knee-chest posture, 51.8, SD 8.8 units versus 53.9, SD 7.4 units in the supine position. The results indicate that mean global CBF in the knee-chest position is not different from CBF in the supine position in healthy patients.
Adult↗
Electromyography.
Electromyography is a useful extension of the neurological examination. This article reviews the range of methods available to the electromyographer and the types of abnormalities that can be detected.
Acquired Immunodeficiency Syndrome↗
[Dose-response relation of gallopamil in comparison with nifedipine, diltiazem and tiapamil in patients with coronary heart disease].
For effective treatment of coronary heart disease with calcium antagonists, knowledge of both the dose-response relationship of a remedy and equipotent dosage for comparison of different drugs is necessary. We performed controlled studies to evaluate the influence of single oral doses of calcium antagonists on ischemic ST-depression (calculated as the mean of all exercise and recovery minutes = mean ST-depression) in exercise ECGs of patients with proven CHD and stable angina pectoris. Ergometries were carried out under constant conditions, particularly with individually constant work load and duration. All calcium antagonists reduced ischemic ST-depression during ergometry dose-dependent when compared to placebo. Diltiazem: 90 mg: 6% (n.s.), 120 mg: 19% (n.s.) und 180 mg: 26% (p less than 0.025); gallopamil: 25 mg: 19% (n.s.), 50 mg: 34% (p less than 0.01) und 100 mg: 57% (p less than 0.0025); nifedipine-Cps.: 5 mg: 17%, 10 mg: 33% und 20 mg: 42%; nifedipine-Tbl.: 20 mg: 8% (p less than 0.05), 40 mg: 23% (p less than 0.057 und 60 mg: 31% (p less than 0.05); tiapamil: 300 mg: 30% (p less than 0.05) und 600 mg: 60% (p less than 0.01). As the result of our findings, comparable antiischemic effects can be expected with 120 mg diltiazem, 50 mg gallopamil, 20 mg nifedipin as capsule or 60 mg nifedipin as tablet and 600 mg tiapamil.
Adult↗
Surgical repair of hip fractures using continuous spinal anesthesia: comparison of hypobaric solutions of tetracaine and bupivacaine.
The aim of this study was to compare hypobaric solutions of tetracaine and bupivacaine in 30 geriatric patients undergoing surgical repair of hip fractures while under continuous spinal anesthesia. Tetracaine 1% and bupivacaine 0.5% were mixed with distilled water to prepare hypobaric 0.25% solutions. In a double-blind fashion, all patients received 3 ml (7.5 mg) of either solution in the lateral decubitus position with the operated side up, the table being kept horizontal for 30 minutes after injection. The mean highest sensory levels in both groups, and in both operated and non-operated sides in the same group, were comparable, ranging between T7 and T8.5. Duration of analgesia was 134 minutes with tetracaine and 130 minutes with bupivacaine (NS). In both groups, motor blockade was satisfactory in 29/30 patients on the operated side. The frequency of a decrease in systolic blood pressure of more than 30% was similar in the two groups. The authors conclude that hypobaric solutions of both tetracaine and bupivacaine are suitable for surgical repair of hip fractures in geriatric patients and produce comparable anesthetic and hemodynamic effects.
Anesthesia, Spinal↗
Immunoglobulin VH genes are transcribed by T cells in association with a new 5' exon.
We previously detected mRNAs in a number of human T cell lines with a probe from within the Ig VH gene locus. We now show these mRNAs consist of Ig VH genes expressed in T cells. In one human T cell line, two RNA species have been studied and found to come from transcripts of unrearranged VH segments in which the leader exon, normally associated with VH transcripts in B cells, is replaced by a novel 5' exon (ET) not encoding a hydrophobic leader peptide. In genomic DNA, this new ET exon is adjacent to a pseudo-VH gene that has not been observed in mature mRNA. This implies that RNA splicing controls association of the new exon with the expressed VH segments. Hence, VH transcription does indeed occur in T cells, but is qualitatively different from that in B cells.
Amino Acid Sequence↗
The mechanism of chromosomal translocation t(11;14) involving the T-cell receptor C delta locus on human chromosome 14q11 and a transcribed region of chromosome 11p15.
A chromosomal translocation t(11;14) (p15;q11) is described in a human acute T-cell leukaemia of immature phenotype (CD3-, CD4-, CD8-). The translocation occurs at a T-cell receptor joining J delta segment, 12 kb upstream of the constant C delta gene and 98 kb upstream of the C alpha gene at chromosome band 14q11. Nucleotide sequencing shows that both J delta and C delta are very conserved between mouse and man. The region of chromosome 11 involved in the translocation is transcriptionally active and produces a 4-kb mRNA. The DNA sequence at the chromosome 11 junction shows a perfect match to a recombinase signal sequence implying that this translocation occurred by recombinase error. The occurrence of the translocation breakpoint at the C delta locus, normally rearranged in immature T cells, and the structure of the translocation junctions suggests that the translocation occurred during an attempt at normal rearrangement of the J delta segment in an early thymocyte.
Amino Acid Sequence↗
The T-ALL specific t(11;14)(p13;q11) translocation breakpoint cluster region is located near to the Wilms' tumour predisposition locus.
A breakpoint cluster region (T-ALLbcr) has been previously described on 11p13 for T-ALL carrying t(11;14)(p13;q11). One further T-ALL breakpoint is described bringing to 5 out of 6 such translocations which are found to break within a maximum of 6.7 kb on chromosome 11p13. Studies of somatic cell hybrids derived from t(11;14)(p13;q11) T-ALL placed the T-ALLbcr between the genes for catalase (CAT) and the beta-subunit of follicle stimulating hormone (FSHB). This suggested a link between the T-ALLbcr and the Wilms' tumour predisposition locus (WT) since constitutional 11p13 deletions predispose to Wilms' tumour. Utilising somatic cell hybrids from patients with Wilms' tumours and aniridia, we show that while the T-ALLbcr maps distal to the catalase gene at 11p13, it maps outside the shortest region of overlap of a series of 11p13 deletions associated with Wilms'-Aniridia. The data suggest the order of genes at 11p13 to be: centromere-CAT-T-ALLbcr-WT-aniridia-FSHB-telomere. Therefore, the T-ALLbcr must lie very close to but may be distinct from the Wilms' predisposition locus at 11p13.
Aniridia↗