[Remember malaria].
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Biomedical subjects
Publications and source records attributed to H Berg.
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Bennett and Xie (1988) described an experimental peripheral neuropathy that is produced by loosely ligating a rat's left sciatic nerve with chromic gut suture. Four ligations, which are tied tightly enough to constrict the nerve and retard epineurial blood flow, produce a chronic constriction injury (CCI). Maves et al. (1993) reported that if the ligations are tied more loosely (i.e., no retardation of blood flow) than those that produce the CCI, rats exhibit postural changes only when the ligations are of chromic gut. We decided to evaluate effects of different suture materials on the abnormalities in paw position associated with the CCI (Attal et al., 1990). Five groups of rats were included in this study. In three of the groups, the CCI was produced with chromic gut, plain gut, or polyglactin (Vicryl) suture. Rats in the fourth group served as sham injury control animals, and rats in the fifth group served as unoperated control animals. Our results indicate that the position in which the rats held the affected hindpaw varied significantly among treatment groups. Rats whose CCI was induced with chromic gut suture spent more time with the hindpaw in an abnormal position than rats in the other treatment groups. And as compared to rats in the unoperated control group, rats whose CCI was induced with either plain gut or polyglactin suture also spent more time with the hindpaw in an abnormal position. Though these different suture materials produced similar degrees of nerve constriction, the effects on paw position were greater with chromic gut suture. These results suggest that chromic gut suture, when used to produce the CCI, may have more than just a constrictive effect on the sciatic nerve. However, since all suture materials produced changes in paw position, constriction is likely to play an important role in the development of abnormalities in paw position observed in rats with the CCI.
Various nuclear proteins are the major targets of autoimmune responses in various rheumatic disorders. In particular, autoantibodies directed against a 68-kDa protein associated with the (U1) RNA-containing small nuclear ribonucleoprotein complexes typically occur in sera of patients with mixed connective tissue disease and related rheumatic disorders, such as systemic lupus erythematosus, and therefore are very useful as a serological marker. For establishing powerful immunoassays, it was necessary to generate recombinant human P68 antigen as the antigenic target. In this study we demonstrated that the cDNA coding for the full-length human P68 antigen could not be expressed by a traditional bacterial vector system due to a putative inhibitory sequence designated as inhibitory sequence X which is located between the autoreactive domains C' and D' of the human P68 antigen. The construction of corresponding hybrid plasmids carrying two functional and independent gene blocks indicated the trans-active function of the inhibitory sequence X, which could be localized by expression studies of various deletion constructs. Comparable Northern blot analysis clearly demonstrated that the inhibitory sequence X could act on the translation of the P68 mRNA. After excision of the inhibitory sequence X a dramatic increase in the production of recombinant human P68 antigen was observed.
Patients with endometriosis significantly develop autoantibodies directed against endometrial proteins, which may be involved in the aetiology of this gynaecological disease. Based on standard Western blot analysis, a 48 kDa protein was localized in the soluble protein extract of endometrial adenocarcinoma cells using sera from patients with clinically staged endometriosis and identified as the glycolytic enzyme alpha-enolase. The corresponding cDNA coding for the human alpha-enolase was isolated from a human endometrial cDNA library and cloned into the vector pH6EX3, allowing the efficient expression of recombinant human alpha-enolase with an N-terminal histidine-hexapeptide as affinity ligand in Escherichia coli. The purified recombinant human alpha-enolase was evaluated as a specific antigenic tool for the diagnostic measurement of antiendometrial antibodies in sera from patients with endometriosis. With selected endometriosis sera, two linear autoreactive epitopes were localized within the recombinant human alpha-enolase using epitope mapping techniques, and they were characterized.
The frequency of postoperative residual neuromuscular block following the use of the long-acting non-depolarizing muscle relaxants is high, and manual evaluation of the response to nerve stimulation does not eliminate the problem. In this prospective and randomized study we evaluated the hypothesis that perioperative use of acceleromyography would allow for a more rational and precise administration of the long-acting muscle relaxant pancuronium resulting in a decrease in 1) the incidence and severity of postoperative residual neuromuscular block, 2) the amount of pancuronium used, and 3) the time from end of surgery to tracheal extubation. Forty adult patients were randomized into two groups, one managed without the use of a nerve stimulator, the other monitored using train-of-four (TOF) nerve stimulation and acceleromyography. All patients were anaesthetized with diazepam, fentanyl, thiopentone, nitrous oxide, and in some patients halothane, and they all received pancuronium 0.08-0.1 mg kg-1 for tracheal intubation, and 1-2 mg for maintenance of neuromuscular block. Neostigmine 2.5 mg preceded by atropine 1 mg was administered for reversal. In the patients managed without a nerve stimulator, the trachea was extubated when the anaesthetist judged the neuromuscular function to have recovered adequately for upper airway protection and spontaneous ventilation. In patients monitored with acceleromyography, the trachea was extubated when the TOF ratio was above 0.70. In all 40 patients, TOF ratio was measured using mechanomyography immediately after tracheal extubation and the patients were evaluated for clinical signs of residual neuromuscular block.(ABSTRACT TRUNCATED AT 250 WORDS)
This study made a longterm (72 hours) evaluation of the efficacy and possible side-effects of transdermal delivery of fentanyl (TTS-system) for post-operative pain relief. The study was double-blind, placebo-controlled with either a TTS-system delivering fentanyl 100 micrograms.h-1 and rescue analgesic on demand or a placebo system and analgesic on demand. Analgesic consumption, pain, general satisfaction, respiratory rate, and levels of SpO2 and tcCO2 (pulse oximetry and transcutaneous CO2 measuring) were evaluated. Recruitment was stopped after enrolment of 24 patients, on safety grounds. The Fentanyl group was more satisfied with postoperative pain relief (P = 0.008); they had a lower analgesic demand (P < 0.05) but also a lower respiratory rate (P < 0.05) and a higher level of tcCO2 23 hours after application (P < 0.05). There were three cases (25%) of increased PaCO2 (> 6.5 kPa) in the Placebo group but without low PaO2 levels, sedation or bradypnoea. Conversely, there were three cases (33%) in the Fentanyl group with bradypnoea (< 10 breaths/minute), two without influence on PaO2 or PaCO2, but one (no. 24) with bradypnoea, heavy sedation, a marked decrease in PaO2 (5.8 kPa) and increased PaCO2 (7.5 kPa). These findings terminated the study. The 100 micrograms transdermal fentanyl system is agreeable to the patients, but apparently too potent for routine postoperative pain relief due to a risk of respiratory depression. Respiratory frequency can not be relied upon as sole indicator of insufficient respiration.
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The human insulin domains, signal peptide, B-chain, C-peptide, and A-chain, were highly expressed in Escherichia coli as recombinant proteins N-terminally fused to glutathione-S-transferase and a histidine-hexapeptide. The recombinant proteins were purified from insoluble cell fraction by affinity chromatography using metal chelating matrix, which was charged with Ni+2 ions. ELISA screening for autoantibodies directed to preproinsulin were performed with sera from patients with recently diagnosed insulin-dependent diabetes mellitus in order to localize the antigenic epitopes within the human preproinsulin. Of the patients, 14% had developed autoantibodies that recognized either the recombinant C-peptide or the signal peptide. No reaction was observed with the A-chain or B-chain.
A novel prokaryotic expression vector pGEX-6T was designed for high-level expression of recombinant fusion protein with a histidine-hexapeptide and glutathione-S-transferase at its N-terminus and the recombinant human preproinsulin at its C-terminus. Efficiency of expression was investigated in the Escherichia coli strain CAG456. The synthesized protein was sequestered in an insoluble form in inclusion bodies and was purified to homogeneity by one-step affinity chromatography based on the specific complex formation of the histidine-hexapeptide and a chelating matrix which was charged with Ni2+ ions. The antigenic nature of the purified recombinant preproinsulin fusion protein was evaluated by ELISA screening for insulin autoantibodies in selected sera from patients with recent-onset type 1 (insulin-dependent) diabetes mellitus classified by the existence of additional autoantibodies reactive against glutamic acid decarboxylase. 14% of the tested sera (n = 43) contained insulin autoantibodies which strongly recognized the recombinant human preproinsulin. Comparable measurements with both recombinant human preproinsulin and mature insulin suggested that the observed autoantigenicity of preproinsulin was mediated by the C-peptide or/and signal peptide.
A 2.0-kb cDNA coding for the full-length 64-kDa human glutamic acid decarboxylase (GAD64) was isolated from a pancreatic carcinoma cDNA library by oligonucleotide screening, polymerase-chain-reaction amplification and subsequently characterized by sequence analysis. Five overlapping fragments of GAD64 cDNA were constructed into the vector pH6EX3, allowing the highly efficient expression of corresponding fusion proteins with a histidine hexapeptide as an affinity ligand at their N-termini in Escherichia coli. The recombinant GAD64 fragments were analysed by Western blotting using sera from patients with early onset of insulin-dependent diabetes mellitus (IDDM). We found that at least 20% of the patients with an onset of IDDM have developed autoantibodies which can specifically recognize a linear antigenic epitope within the GAD64. With a selected IDDM serum, an antigenic epitope was localized in a region of 31 amino acids located at the C-terminus of GAD64, using epitope mapping techniques, and it was characterized. The possibility of using recombinant GAD64 for the development of an immunoassay for a predictive diagnosis of IDDM is discussed.
The crew of a disabled submarine can be rescued by means of free ascent through the water to the surface. Pulmonary gas exchange was studied during simulated rapid free ascent in subjects standing immersed to the neck in a pressure chamber. The pressure was rapidly increased to 1.1 MPa [100 meters seawater (msw)] followed by decompression at 0.03 MPa/s (3 msw/s). Effective inspired tidal volume, as estimated by an Ar dilution method, fell gradually to zero during decompression from 20 to 0 msw. Directly determined expired tidal volumes were increased up to two to three times at the time of return to surface pressure compared with pre- and postdecompression volumes. End-tidal PCO2 was increased on compression and fell to a nadir of 3.4 kPa (25 Torr) at the time of return to surface pressure. Thus, intrapulmonary gas expansion caused simultaneous inspiratory hypoventilation and expiratory hyperventilation. If O2-enriched gas is to be used to reduce the risk of decompression sickness, it should be administered early during decompression to alter the intrapulmonary gas composition. The time course of arterial PCO2 changes as reflected by end-tidal values during short-lasting compression/decompression would act to promote inert gas supersaturation in the brain.
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This retrospective study deals with the outcome of 401 patients with laryngeal carcinoma who were treated between 1975 and 1986 either by operation alone or by operation and irradiation. The patients as a group, the concepts of treatment, and the course of disease as found retrospectively are described. T and N categories are compared with the respective pT and pN categories: T and pT categories corresponded in 83.3% of the cases while there was only a 67.4% correspondence between each N and pN category. The survival rates using the Kaplan-Meier estimation according to the localization and extension of laryngeal tumor, pN category and method of resection are discussed in detail.
We have investigated 296 inpatients in a single-blind observer study to determine the incidence, degree and duration of hypoxaemia during anaesthesia. The clinical recognition of hypoxaemia, period of time until recognition and risk factors were studied. Oxygen saturation (Spo2) was monitored continuously with a pulse oximeter (Ohmeda, model 3700). One or more episodes of mild hypoxaemia (Spo2 86-90%) were recorded in 53% of patients. Severe hypoxaemia with Spo2 values less than 81% were recorded in 20% of patients. The mild hypoxaemic episodes lasted up to 34.6 min (mean 2.3 min) and 70% were not detected by the anaesthetist. In the remaining 30% of episodes, the anaesthetist diagnosed the complication with a mean time delay of 70 s. After intervention a mean time delay of 57 s was recorded until Spo2 exceeded 90%. Utilizing a stepwise multiple logistic regression analysis, we found that risk factors associated with a greater incidence of hypoxaemia were patient age (P less than 0.005) and anaesthetic technique (P less than 0.00001). We conclude that hypoxaemic episodes in our operating rooms are common during anaesthesia and suggest preoxygenation in all patients in addition to administration of supplementary oxygen during arousal from anaesthesia and during transfer to the recovery room.
The thyroid function tests as well as evidence of thyroiditis were studied in 18 male patients with acquired immune deficiency syndrome (AIDS) and 12 healthy HIV1-positive persons compared with an age-matched control group. Serum total thyroxine was not significantly different between the groups, but both serum total triiodothyronine, triiodothyronine uptake test, and free thyroid hormone indices showed significantly decreasing values from HIV1-positive healthy persons to AIDS patients compared with controls (P value from less than 0.05 to less 0.001). Serum TBG was elevated in HIV1-positive subjects and in patients with AIDS, with a significant inverse correlation with the T3-uptake test (Spearman's rho = 0.657, P less than 0.01). There was no correlation between thyroxine binding globulin and the other measured variables. The serum level of thyrotropine was not significantly different in the groups, whereas serum thyroglobulin was significantly lowered in the AIDS group. There was no correlation between thyroid function variables and survival time, hepatic function and ratio of T-helper to T-suppressor cells. No evidence of thyroiditis was observed. In conclusion thyroid tests showed an atypical outcome in HIV1-positive patients with or without AIDS compared with the pattern normally seen in non-thyroid illness, and should, therefore, caution the interpretation of the biochemical changes when diagnosing abnormal thyroid function in these patients.
In an open-controlled, randomized trial over 24 weeks, the serum uric acid lowering effect of a daily dose of 100 mg allopurinol in combination with 20 mg benzbromarone compared to 300 mg allopurinol only was investigated on a total of 60 patients suffering from hyperuricemia. Both preparations led to a decrease of the serum uric acid value to normal. In those patients however, who had received the combination the reduction of the serum uric acid level was more pronounced. Tolerance was generally good. Side-effects were not reported.
Decanucleotide duplexes of the parent sequence d(GGCA6C).d(CCGT6G) containing various numbers of 2'-deoxytubercidin (c7Ad) in place of 2'-deoxyadenosine have been synthesized. Phosphoramidites of protected c7Ad (3a,b) were used in automated solid-phase synthesis together with those of regular nucleosides. Upon enzymic 5'-phosphorylation and ligation, multimers of 5 and 7-11 were analyzed by polyacrylamide gel electrophoresis and compared with regard to intrinsic, sequence-directed bending. Replacement of dA by c7Ad within the oligomers decreased bending, but the extent depends strongly on the position of incorporation: strong bending was still observed if the 3'- and 5'-terminal dA residues of the dA tract were replaced while the interruption of the d(A)6 tract by c7Ad reduced bending strongly.
In arterial blood from 250 patients we measured pH, pco2, and po2 (electrochemically) together with total-hemoglobin concentration, oxygen saturation, carboxy- and methemoglobin fractions (spectrometrically). With a previously published algorithm we calculated the effective hemoglobin concentration, total-oxygen concentration, half saturation tension, erythrocyte 2,3-diphosphoglycerate concentration, and two new oxygen parameters: uncompensated mixed venous oxygen tension and cardiac oxygen compensation factor. 11% of the patients have normal arterial oxygen tension, but nevertheless risk of tissue hypoxia judged from the two new oxygen parameters. This is due to a low hemoglobin concentration and/or low half saturation tension (increased hemoglobin oxygen affinity). Some patients have decreased arterial oxygen tension but normal uncompensated mixed venous oxygen tension (15%) or normal cardiac oxygen compensation factor (9%). This is due to a high hemoglobin concentration and/or increased half saturation tension. The latter varies from 2.6 to 5.2 kPa (ref.: 3.3-3.9 kPa); 36% have decreased, 27% increased values. The 2,3-diphospho-glycerate concentration varies from 2.0 to 7.9 mmol/l (ref.: 3.6-5.1 mmol/l); 14% have decreased, 30% increased values. Uncompensated mixed venous oxygen tension varies from 1.8 to 5.7 kPa (ref.: 4.5-5.5 kPaf). The cardiac oxygen compensation factor varies from 0.9 to infinity (ref.: 0.8-1.6). We conclude that the variation in the different oxygen parameters is so significant that it justifies routine calculation for all arterial blood samples where the measurement on a conventional blood gas analyzer is supplemented with measurement on one of the new multi-wavelength hemoximeters. The calculation algorithm permits calculation of all the oxygen parameters for the majority of arterial samples (84%) where the oxygen saturation is less than or equal to 0.970.