Biomedical subjects
Publications and source records attributed to M Lucas.
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Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Pittillo, Robert F. (Southern Research Institute, Birmingham, Ala.), Mary Lucas, Robert T. Blackwell, and Carolyn Woolley. Modification of radiation damage of bacteria by folic acid antagonists. J. Bacteriol. 90:1548-1551. 1965.-The folic acid analogues, 2,4-diamino-6-methylpteridine, amethopterin, and aminopterin, have been found to sensitize certain bacteria, especially Escherichia coli, to the lethal action of ionizing irradiation. Data are presented which indicate that (i) the compounds must be present during the irradiation period for maximal sensitization to be observed, (ii) the sensitizing effect can be nullified by cysteine or cysteamine, (iii) the sensitizing effect occurs in a number of diverse bacterial genera, and (iv) folic acid neither sensitizes bacteria to irradiation nor prevents the sensitization caused by these antifolic agents.
Estimation of maternal serum alpha-fetoprotein (AFP) was used as a screening method for the detection of neural tube defects (NTDs) in 6344 women over three years. Of 88 (1.4 per cent) who had one or more serum AFP levels equal to, or greater than, 2.5 multiples of the median (MoM) for the relevant gestational age, 43 (0.68 per cent) underwent amniocentesis. There were eight NTDs. Four of these were screened by serum AFP, and all cases of spina bifida had serum AFP levels greater than 3.0 MoM, including one small open defect which was not seen on ultrasound. The other four cases of NTD, which were not screened, were identified by ultrasound. Of 64 singleton pregnancies 32 (50 per cent) had serum AFP levels between 2.5 and 3.0 MoM, and low birthweight (less than or equal to 2500 g) occurred in 29 per cent. Because of improvements in ultrasound techniques and the apparent falling incidence of NTD, the role of serum AFP as the primary screening procedure should be regularly reviewed. Effective screening is dependent on mothers booking early.
The electroencephalographic (EEG) effects of the ICV administration of neurotensin (NT 1-13), NT 1-8 (an inactive neurotensin fragment) and D TYR-11 NT (a long-lasting analog of neurotensin) were studied in rats. In awake rats, NT 1-13 (30 micrograms) and D TYR-11 NT (10 micrograms) induced an increase of the power spectrum in the theta range activity (4-7 Hz). In rats recorded during the sleep-wakefulness cycles, NT 1-13 (10 and 30 micrograms) and D TYR-11 NT (10 micrograms) had an awakening effect and also induced an increase of latency to the first episode of the different sleep stages (intermediate stage and slow wave sleep). NT 1-8 (30 and 90 micrograms in awake rats, 10 and 90 micrograms for sleep-wakefulness cycles) was inactive in all these experiments. Thus, it seems that all these effects can be linked to neurotensin receptors; indeed only fragments which recognize receptors possess an EEG activity.
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PURPOSE: Ferumoxtran-10 (ultrasmall superparamagnetic iron oxide; Combidex, AMI-7227) is a long-circulating MR contrast agent with reticuloendothelial uptake known to enhance tissue T1 and T2 relaxation rates. The purpose of this study was to assess the effect of ferumoxtran-10-enhanced MRI in evaluating focal splenic lesions. METHOD: Eighteen patients underwent MR evaluation of the spleen. Two of these patients with exophytic normal splenic tissue (splenules) and 13 of these patients with 24 focal splenic lesions (7 cysts, 2 hemangiomas, 7 metastases, 1 infarct, 7 lymphoma) were assessed by T1-weighted gradient echo and T2-weighted fast SE MRI following intravenous administration of ferumoxtran-10 (1.1 mg of Fe/kg). Qualitative analysis involving improved lesion detection and/or characterization, additional information from postcontrast images affecting staging, and patient management was performed. Quantitative measurements of lesion-to-spleen contrast-to-noise ratio were also performed. RESULTS: Additional information was provided by ferumoxtran-10-enhanced images in 15 of 18 patients. In 8 of 15 (53%) patients, improved lesion detection (i.e., number of lesions) was obtained on contrast-enhanced images. Improved lesion visualization (i.e., conspicuity) was noted in 11 of 15 (73%) of patients. In 10 of 15 (67%) patients, postcontrast imaging provided additional information leading to lesion characterization. Staging of disease and patient management were affected in 5 of 15 (33%) and 6 of 15 (40%) patients, respectively. CONCLUSION: Ferumoxtran-10 is a promising contrast agent for the evaluation of focal splenic lesions.
A heart transplant patient undergoing a combined cyclosporine and prednisone treatment was monitored during the 18 months following transplantation. A complete oral and dental examination was performed in each of the first six months after transplantation, and then in the 9th, 12th, 15th, and 18th months. The data collected included gingival hyperplasia secondary to cyclosporine use, and clinical and periodontal variables. Histological studies were also conducted on gingival tissue samples in months 1, 3, 9, 15, and 18. Cyclosporine treatment was replaced by azathioprine treatment in month 10 because the patient was experiencing nephrotoxicity. Between months 9 and 18, gingival hyperplasia regressed by 26.5% due to a reduction in the fibrous connective tissue mass, fibroblasts, and inflammatory infiltration. The control group included 13 heart transplant patients subject to equivalent conditions except discontinuance of cyclosporine treatment; seven of the patients had developed hyperplasia by month 9. Average hyperplasia in the control group increased by 2% between months 9 and 18; only one patient showed a 6.2% decrease in hyperplasia. This provides further evidence for the causal relationship between cyclosporine therapy and gingival hyperplasia, and suggests that this side-effect is reversible.
In order to provide dentists with specific guidelines regarding appropriate oral treatments for transplant patients, their timing, and the prophylactic steps that must be taken in their handling, a two-phase study was undertaken. In the first phase, the effectiveness of an initial oral hygiene training and motivation program was evaluated by statistical testing of the observed differences in gingival overgrowth and plaque and gingivitis scores between a study group and a control group, each consisting of 46 heart and liver transplant patients. Significantly higher scores were observed in the control group. In the second phase, the effectiveness of a set of prophylactic measures was tested in 530 periodontal treatments and 380 dental treatments, applied in 120 heart, liver, and kidney transplant patients who showed no significant complications. It was concluded that all transplant patients should be monitored by a dentist, and that the recommended procedure is effective in preventing oral treatment complications.
Detailed measurement of lumbosacral evoked potentials is usually only feasible using sophisticated, multichannel neurophysiological equipment. This paper describes the recording technique, and the additional equipment developed for use with a high-quality two-channel recording system, the Dantec Neuromatic 2000M, to facilitate the routine measurement of these potentials. The characteristic feature is a microprocessor based control unit, which allows switching of multiple input channels prior to preamplification and detects the electrocardiogram to trigger the stimulus with a variable time delay.
INTRODUCTION: Myotonic dystrophy is an autosomal dominant hereditary disorder with variable expression, associated with expansion of the CTG triplet on the gene which codifies myotonia situated on chromosome 19q. We present an unusual case of myotonic dystrophy in a pair of monozygotic twin sisters, determination of CTG expansion in lymphocytes of members of their family and in their father's spermatozoids. CLINICAL CASE: The patients presented the phenomenon of anticipation of paternal transmission with an expansion of triplet CTG of lymphocyte DNA in a range of 300-1,400 identical repetitions in both. DNA of the paternal lymphocytes and spermatozoids showed a similar expansion of 75 repetitions. CONCLUSIONS: CTG expansion is not due to previous expansion of DNA in the paternal gametes but to instability of DNA in the cellular mitoses following formation of the zygote.
INTRODUCTION: Multiple sclerosis (MS) is a demyelinating and inflammatory disease of the central nervous system (CNS) with a clear proved genetic susceptibility. The real frequency and clinical features of familial MS is although not well established in Spain. OBJECTIVE: We studied the clinical and CSF features of familial MS (FMS) patients in comparison with the rest of our patients. PATIENTS AND METHODS: We reviewed 308 definite MS patients looking for patients with other familial members with MS. We analyzed clinical characteristics (age, age at onset, sex, evolution time, evolution course, symptoms at onset, disability measured by EDSS scale) and IgG synthesis measured by Tibbling-Link index. RESULTS: We found 23 patients (10 men and 13 women) in 18 independent families with at least other family member diagnosed of definite MS (7.47% of our total MS population). Age and age at onset were no different from non FMS cases. The clinical course was relapsing-remitting in 21 out of 23 FMS cases and secondary progressive in two. No primary progressive cases were found among FMS. At onset the symptom most frequently found in FMS was optic neuritis. Mean EDSS score was lower in FMS cases in comparison with the rest of cases. Link index was increase in 93.7% of patients with FMS. CONCLUSION: In comparison with non familiar forms FMS patients in Spain, present more often remitting courses, are less disabled, optical neuritis is more frequently seen as onset symptom and IgG synthesis is more often increased.
INTRODUCTION: Decrease in incidence of neurosyphilis over the last few decades implies that clinicians consider less frequently this diagnosis. On the other hand, some reports suggest an increase in atypical forms of this disease that represent an additional reason for missing this diagnosis. CLINICAL CASE: We report on a 16 year-old immunocompetent black female from Guinea-Bissau presented with headaches, ear pain, hearing loss and peripheral facial paralysis. A cranial CT scan showed a hypodense area in the left cortico-subcortical zone and a contrast enhancement on the left pontocerebellar angle and internal auditory meatus. On the third day of admission a diagnosis of meningitis was made, with high titles of VDRL and TPHA in CSF and serum, leading to a diagnosis of neurosyphilis. The epidemiological aspects of this case suggest either a late congenital syphilis or an infection as a result of a blood transfusion administered seven years earlier in Guinea-Bissau. CONCLUSION: This rare form of presentation of neurosyphilis emphasizes the importance of considering systematically this diagnosis, even in the context of atypical presentations.
Perianal fistula is a frequent complication of Crohn's disease. The diagnosis of the later may be difficult if cutaneous disease is dominant, and sometimes an important clinical challenge. The authors report a case of a 34 year old male complaining of painful perianal nodules for the three last years. Cutaneous histopathological examination was inespecific and colonoscopy normal. Pelvic CT scan and fistulography showed an intercommunicated fistular system invading both isquiorectal fossae, without intestinal communication. Repetition of colonoscopy showed normal mucosa, but in two of the biopsy samples noncaseous granulomas were found at the submucosa. The authors explain their main difficulties to reach the diagnosis of Crohn's disease and discuss the investigation and the evolution of the patient.