Biomedical subjects
Publications and source records attributed to B Thomas.
Using a static B scanner, 203 pregnant patients underwent cholecystosonography at the time of a routine 24-week ultrasound study. The incidence of asymptomatic cholelithiasis, 2.5%, was less than that reported by others. This low incidence and the increased time needed for cholecystosonography suggest that studies should be done on symptomatic patients only.
Of 104 patients with arthrogryposis multiplex congenita treated between 1952 and 1982, 74 had significant knee contractures, instability, or recurvatum. The minimum follow-up period was two years. Nonoperative treatment modalities included physical therapy, bracing, and serial casting in 43 patients (78 knees). Thirty-one other patients (46 knees) had 62 operative procedures, including hamstring and posterior capsular release, epiphysiodesis, distal femoral or proximal tibial osteotomy, arthrodesis, and knee disarticulation. Surgery was reserved for the more resistant causes and was recommended only as part of an overall treatment plan including the correction of foot and hip deformities. The average follow-up period for the surgically treated patients was 11 years, with a range of two to 20 years. Recurrence of deformity was frequent, with no one procedure being clearly favored. Physiotherapy alone rarely resulted in clinically significant improvement unless accompanied by prolonged casting and bracing. The most useful surgical procedure in the growing child was posterior capsular release performed in conjunction with hamstring tenotomy. Contractures treated by osteotomies before the completion of growth had a high rate of recurrence.
In vitro mutagenic techniques have generated an asp-->glu substitution at residue 198 adjacent to the carbamate-divalent metal ion binding site of Rhodospirillum rubrum ribulose 1,5-bisphosphate carboxylase. A single C-->A nucleotide change in the coding strand created the mutant and introduced a new EcoRI restriction site on the expression plasmid pRR2119. Although the carboxylase:oxygenase ratio remained the same, the mutant enzyme had slightly altered kinetic properties. The e.p.r. spectra of the quaternary complexes enzyme.activator carbamate.Mn.2-carboxyarabinitol 1,5-bisphosphate and enzyme.activator carbamate.Mn.4-carboxyarabinitol 1,5-bisphosphate for mutant and wild-type enzymes were different, indicating that the metal ion was in a slightly altered environment. These findings are consistent with the hypothesis that, besides the carbamate at lys 201, the carboxyl group of asp 198 contributes to the formation of the divalent metal ion binding site.
A "fast" egg-killing human strain of Chlamydia trachomatis was inoculated into normal CBA and congenic CBA/nu mice, which have an impairment of T-cell function and do not produce anti-chlamydial antibodies. The mice were inoculated by the intra-uterine, intra-articular, or intravenous routes. Some of the mice were first treated with progesterone, which allows successful chlamydial infection of the mouse genital tract when the organisms are introduced genitally. Mice were sacrificed up to 27 days after inoculation. Homogenates of joints, genital tract, spleen, liver, kidneys, eyes and lungs were prepared and tested for chlamydiae in cycloheximide-treated McCoy cell cultures. Chlamydiae were detected in the genital tracts and spleens, but not in the joints, of mice inoculated via the intra-uterine route. They were found in the joints and spleens of mice inoculated intra-articularly, and were detected also in spleens and, from the 4th to 6th day after inoculation, in joints of mice given the organisms intravenously. These results were obtained irrespective of whether or not the mice had received progesterone. The numbers of chlamydiae in the spleens and joints of the nude mice were larger and they persisted longer than in the corresponding immunocompetent animals, although this was not true for chlamydiae in the genital tract of mice inoculated via the intra-uterine route. Compartmentalisation of chlamydiae was evident although the spleen was infected consistently irrespective of the route of inoculation and, as mentioned, chlamydiae were found transiently in the joints following intravenous inoculation. This suggests that chlamydiae might also enter the human joint.(ABSTRACT TRUNCATED AT 250 WORDS)
The effects of cimetidine and indomethacin on the growth of dimethylhydrazine induced or transplanted intestinal tumours in the rat have been studied. Cimetidine is a histamine type 2 receptor antagonist and indomethacin is an inhibitor of prostaglandin synthesis. Two models of rat intestinal tumours were used: a colon carcinoma line transplantable in syngeneic animals and intestinal tumours induced by dimethylhydrazine treatment of Sprague-Dawley rats. Cimetidine and indomethacin were given in drinking water, alone or in combination. Cimetidine had no effect on the growth of transplanted colon cancer but significantly increased the incidence of chemically-induced tumours, with a tendency toward more invasive and metastatic tumours than in the control animals. Indomethacin did not significantly modify the incidence or other characteristics of the tumours in any of the models. This result is at variance with a protective effect of indomethacin on chemically-induced rat colon cancer previously reported by others.
We determined the sequence of a Drosophila tRNA gene cluster containing a tRNAHis gene and a tRNAHis pseudogene in close proximity on the same DNA strand. The pseudogene contains eight consecutive base pairs different from the region of the bona fide gene which codes for the 3' portion of the anticodon stem of tRNAHis. The tRNAHis gene is transcribed efficiently in Drosophila Kc cell extract, whereas the pseudogene is not. The pseudogene is also a much poorer competitor than the real gene in a stable transcription complex formation assay, even though the sequence alteration in the pseudogene does not affect the sequence or spacing of the putative internal transcription control regions. Recombinant clones were constructed in which the 5'-flanking regions are exchanged. The transcription efficiencies and competitive abilities of the recombinant clones resemble those of the genes from which the 5' flank was derived; for example, the tRNAHis pseudogene with the 5'-flanking sequence of the tRNAHis gene is now efficiently transcribed. Deletion analysis of the pseudogene 5' flank failed to uncover an inhibitory element. Deletion analysis of the real gene showed very high dependence on the presence of the wild-type 5'-flanking sequence for factor binding to the internal control regions and stable complex formation. The 5'-flanking sequence of a Drosophila tRNAArg gene active in the Drosophila Kc cell extract does not restore transcriptional activity or stable complex formation. The tRNAHis gene and pseudogene behave atypically in HeLa cell extract. Both genes compete for HeLa transcription factors, but neither of them is efficiently transcribed. Removal of the 5'-flanking sequences of each gene and replacement with various sequences, including the tRNAArg gene 5' flank, does not allow increased transcription in HeLa cell extract.
In order to study the humoral immune response of rats against a colonic tumor, we developed an immuno-enzymatic technique for quantitating specific anti-tumoral antibodies. This technique which uses a monolayer of intact cancer cells as antigen produces objective and reproducible results. Applied to eleven rats carrying grafted colon carcinomas, it allowed the characterization of three different types of evolution of the concentration of circulating antibodies.
Subject of our examination are emotional-affective, vegetative and psycho-sexual disturbances which are possibly caused by oral contraceptives. 511 women, taking different oral contraceptives, were questioned. For that purpose we used a schedule of sociological dates, attitudes and complaints devised by ourself and connected with a part of Böttcher's Introversion-Neurotizism-Rigidity-Questionnaire. Neurotic and introverted persons are tending to suppose a connection between the "Pill" and certain inconvenient sensations as affective disturbances, diminished concentration, dyssomnia and an avoidance behavior in sexuality. But the results of investigation gave also evidence for a distinct increase of sexual unaffectedness without disadvantageous uninhibition. A classification of the disturbances relative to the particular drugs did not reveal any differences within our cases. The sample "Gravistat" had significantly raised scores of neurotizism and here can also be observed an increase of inconvenient psychical disturbances. We recommend to give better information on the mode of action of the respective contraceptives. In cases of neurotic attitude a psychotherapeutical consultation between doctor and patient may diminish psychosexual disturbances as symptoms of the application of oral contraceptives.
Isoflurane was selected as the main agent for induction and maintenance of anesthesia in two patients scheduled for resection of pheochromocytoma. The inspired concentration was calculated with a pocket computer (Sharp PC 1401) and adjusted to maintain an alveolar concentration of 1.5 to 1 MAC. With this technique, a stable heart rate was observed, without arrhythmias. The blood pressure stabilised at normal levels before surgery and only moderate hypertension was seen during tumor manipulation. No specific antihypertensive medication was needed. Transient hypotension after tumor resection was treated with ephedrine and volume replacement. Recovery of anesthesia was rapid and uneventful.
To analyze the prognostic significance of renal involvement, data from 24 cases of necrotizing angeitis, with renal involvement in 16, is studied. Associated disorders are described. Patients are divided into four groups: acute renal failure, progressive renal failure, renal involvement with normal renal function, and no renal involvement. Acute renal failure et onset appears to be a poor prognosis factor in necrotizing angeitis. Progressive renal failure seems to have no bearing on the short-term and medium-term vital prognosis. The value of plasma exchange therapy in these indications is discussed.
A double-outlet left ventricle (LV), with a valved conduit interposed between the LV apex and the aorta, was created in 7 dogs with subaortic stenosis. Of 8 dogs in which the implantation was attempted, 1 died following thoracotomy but before conduit implantation could be performed, 1 died from hemorrhage 24 hours after surgery, 1 died from septicemia as a sequel to pneumonia 10 days after surgery, 1 died from "shock-lung" 4 days after surgery, and 4 were functionally normal 22, 12, 6, and 2 months after surgery. In the 7 dogs in which the implantation was completed, the mean LV to aorta (LV-Ao) pressure gradient was significantly (P less than 0.01) reduced by the implantation. Diastolic and systolic murmurs were detected over the prosthetic valve area in 3 of the 4 surviving dogs 1 to 4 days postoperatively, but the murmurs gradually decreased in intensity until they disappeared after 1 month. The 4 survivors had no angiographic evidence of prosthetic valve insufficiency at 2 months or at 1 year. In 3 of the survivors, the LV-Ao pressure gradients 2 months postoperatively were 45, 20, and 0 mm of Hg, as compared with 120, 90, and 50 mm of Hg preoperatively. Postoperative pressure measurements were not obtained on 1 surviving dog.
The authors report a case of a patient with an ENT granuloma, treated successfully with cyclophosphamide and prednisone in 1976. After a complete remission lasting three years, the condition recurred in the form of Wegener's disease, presenting as a renal tumour. The authors discuss the relationship between these two conditions.
The present experiments were designed to study the conditions under which failure would enhance or inhibit subsequent task performance. Based on the theory of Wortman and Brehm (1975), it was expected that small amounts of failure would produce reactance (manifested by improved performance at a subsequent task), whereas large amounts would lead to learned helplessness (i.e., impaired later performance). It was further expected that individual differences in self-esteem and private self-consciousness would serve as moderator variables for the above effects. In Experiment 1, subjects were exposed to either a small amount of failure or no failure before working on an anagrams task. As predicted, subjects high in self-consciousness, who have shown greater reactance arousal in attitude change studies, performed better on the anagrams task than subjects low in self-consciousness in the small-failure condition, but not in the no-failure condition. Further analyses revealed that this Self-Consciousness X Small Failure interaction was attributable to the performance data of the low, but not the high self-esteem subjects. Experiment 2 was designed to replicate and extend these results. Subjects were pretreated with either a small amount of failure, an extended amount of failure, or no failure before working on the anagrams task. A significant Self-Esteem X Helplessness Training interaction emerged. Relative to the no-failure condition, in which the two self-esteem groups did not differ, low self-esteem participants (low SEs) performed marginally better than did high self-esteem individuals (high SEs) in the small-failure condition but significantly worse than high SEs in the extended-failure condition. The effect of private self-consciousness was considerably weaker in this study, possibly because the sample included few low SEs (who are especially influenced by self-focused attention) who were also relatively low in self-consciousness. Questionnaire data from Experiment 2 were consistent with the notion that enhanced performance reflected reactance, whereas impaired performance signified helplessness.
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ESS-models are considered in the frame of adequate dynamical systems. This leads to a method of global representation of the dynamical characteristics, which allows for a comprehensive view on the relations among ESS-matrices. As an extension of ESS-models, the concept of ESS-models with changing matrix is introduced, which, in applications, makes use of such global representations. In particular, structurally stable and "catastrophic" cases can be identified and their significance in the context of ESS-models can be clarified. As a complete result for the case of two strategies a surface representation is obtained, which is an analogue to the elementary "cusp catastrophe". These concepts are applied in a model that describes directed evolution of a behavioural component to a certain limit.
The control of night-break timing was studied in dark-grown seedlings of Pharbitis nil (Choisy cv. Violet) following a single continuous or skeleton photoperiod. There was a rhythmic response to a red (R) interruption of an inductive dark period, and the phasing of the rhythm was influenced by the preceding light treatment.Following a continuous white light photoperiod of 6 hours or less, the points of maximum inhibition of flowering were constant in real time. Following a continuous photoperiod of more than 6 hours, maximum inhibition occurred at 9 and 32.5 hours after the end of the light period. The amplitude of the rhythm during the second circadian cycle was much reduced following prolonged photoperiods.Following a skeleton photoperiod, the time of maximum sensitivity to a R interruption was always related to the second pulse of the skeleton, R(2), with the first point of maximum inhibition of flowering occurring after 12 to 18 hours and the second after 39 hours. Without a second R pulse, the time of maximum sensitivity to a R interruption was related to the initial R(1) pulse. A ;light-off' or dusk signal was not mimicked by a R pulse ending a skeleton photoperiod; such a pulse only generated a ;light-on' signal and initiated a new rhythm.It is concluded that the timing of sensitivity to a R interruption of an inductive dark period in Pharbitis nil is controlled by a single circadian rhythm initiated by a light-on signal. After 6 hours in continuous white light, the phase of this rhythm is determined by the transition to darkness. Following an extended photoperiod, the timing characteristics were those of an hourglass; this seemed to be due to an effect on the coupling or expression of a single circadian timer during the second and subsequent cycles, rather than to the operation of a different timing mechanism.In addition to the effects on timing, the photoperiod affected the magnitude of the flowering response.
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In 2 groups of 25 patients 0.1 mg/kg vecuronium (Org NC 45) or pancuronium, according to a randomised basis, was injected during balanced anesthesia (thiopental, fentanyl, dehydrobenzperidol and N2O). Intubation conditions 120 seconds after injection were satisfactory. After intubation, a heart rate increase was present with pancuronium (p less than 0.01), but not with vecuronium (difference: p less than 0.05); heartrate decreased 15 and 30 minutes after injection of vecuronium (p less than 0.01). The clinical duration of action of vecuronium was 32.7 +/- 2.4 min (Mean +/- SEM) and of pancuronium 73.5 +/- 4.8 min (p less than 0.01). Successive maintenance doses of 0.025 mg/kg of vecuronium had a duration of action of 23.1 +/- 1.7, 26.8 +/- 2.1, 27.6 +/- 4.0 and 24.0 +/- 2.8 min (diff. NS), showing no cumulative activity. The duration of action of identical doses of pancuronium were 56.9 +/- 3.1, 52.1 +/- 7.2 and 61.3 +/- 17.6 min (diff. NS), values nearly +/- 220% above those of vecuronium (p less than 0.01). Reversion of neuromuscular blockade after vecuronium with small amounts of neostigmine was clinically adequate.