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Biomedical subjects

R Paul

Publications and source records attributed to R Paul.

At least 145 records · Page 8Linked to original sources
PubMed1993

Congenital yellow fever virus infection after immunization in pregnancy.

To determine whether yellow fever (YF) vaccine administered in pregnancy causes fetal infection, women who were vaccinated during unrecognized pregnancy in a mass campaign in Trinidad were studied retrospectively. Maternal and cord or infant blood were tested for IgM and neutralizing antibodies to YF and dengue viruses. One of 41 infants had IgM and elevated neutralizing antibodies to YF virus, indicating congenital infection. The infant, the first reported case of YF virus infection after immunization in pregnancy, was delivered after an uncomplicated full-term pregnancy and appeared normal. Congenital dengue 1 infection may have occurred in another case. The frequency of fetal infection and adverse events after such exposure could not be estimated; however, the neurotropism of YF virus for the developing nervous system and the now documented possibility of transplacental infection underscores the admonition that YF vaccination in pregnancy should be avoided.

Cross Reactions↗
PubMed1993

Private sector response against the cholera threat in Trinidad and Tobago.

During the first half of 1992 the threat of cholera to Trinidad and Tobago prompted a strong health education effort by public authorities and the private sector. To help assess the private sector effort, the cost of cholera-related advertisements and private announcements placed in the country's two leading newspapers during January-June 1992 were reviewed. The review indicated that an estimated TT$ 540,660 was spent on these ads and announcements, that they contributed strongly to keeping cholera prevention continuously in the public eye, and that most of the messages published were accurate, specific, and safe. The strength and success of the private contribution to cholera prevention in this case suggests that similar approaches could be applied to other health problems and to the cholera problem outside Trinidad and Tobago. Overall, the lesson appears to be that if one can find congruence between private sector motives and public health interests, then the potential prospects for a successful partnership are great.

Advertising↗
PubMed1993

Technetium-99m-HMPAO-labeled leukocytes and technetium-99m-labeled human polyclonal immunoglobulin G in diagnosis of focal purulent disease.

To evaluate the usefulness of 99mTc-HMPAO-labeled leukocytes and 99mTc-labeled polyclonal human immunoglobulin G (Technescan HIG) in the diagnosis of focal purulent disease, 31 comparative scintigraphies were done in 30 patients with known or strongly suspected focal infection. Focal purulent disease was the final diagnosis in 19 patients. Technetium-99m-labeled leukocytes showed 16 true-positive, no false-positive, 11 true-negative and 3 false-negative findings. The corresponding figures for 99mTc-labeled HIG were 11, 2, 9 and 8. The sensitivity and specificity of imaging with labeled leukocytes were 84% and 100%, respectively, and with labeled HIG, 58% and 82%, respectively. The overall accuracy of the leukocyte scan was significantly better than that of the HIG scan (90% versus 67%, p < 0.001). Thus, if focal infection is suspected, scintigraphy with 99mTc-labeled leukocytes is the preferable method. No cases exhibited a better imaging result with 99mTc-HIG scintigraphy than with 99mTc-labeled leukocytes.

Female↗
PubMed1992

Phonological behavior in toddlers with slow expressive language development.

Toddlers with slow expressive language development were compared to normally speaking age-mates on three global measures of phonological behavior: the average level of complexity of their syllable structures, the number of different consonant phonemes produced, and the percentage of consonants correctly produced in intelligible utterances. The groups were found to differ significantly on all three variables. Further analyses were done, breaking the groups down into narrower age ranges. These comparisons also revealed differences between late-talking and normal youngsters. Detailed analyses of the range of phonemes and syllable structures produced, as well as the appearance of phoneme classes within syllable structures and positions, revealed that late talkers showed a delayed rather than a deviant pattern of phonological development. The implications of these findings for identifying and monitoring expressive delay in toddlers are discussed.

Articulation Disorders↗
PubMed1992

Role of the PU.1 transcription factor in controlling differentiation of Friend erythroleukemia cells.

Both viral and cellular genes have been directly implicated in pathogenesis of Friend viral erythroleukemia. The virus-encoded gp55 glycoprotein binds to erythropoietin receptors to cause mitogenesis and differentiation of erythroblasts. However, if the provirus integrates adjacent to the gene for the PU.1 transcription factor, the cell loses its commitment to terminally differentiate and becomes immortal, as indicated by its transplantability and by its potential for indefinite growth in culture (C. Spiro, B. Gliniak, and D. Kabat, J. Virol. 63:4434-4437, 1989; R. Paul, S. Schuetze, S. L. Kozak, and D. Kabat, J. Virol. 65:464-467, 1991). To test the implications of these results, we produced polyclonal antiserum to bacterially synthesized PU.1, and we used it to analyze PU.1 expression throughout leukemic progression and during chemically induced differentiation of Friend erythroleukemia (F-MEL) cell lines. This antiserum identified three electrophoretically distinct PU.1 components in extracts of F-MEL cells and demonstrated their nuclear localization. Although PU.1 proteins are abundant in F-MEL cells, they are absent or present in only trace amounts in normal erythroblasts or in differentiating erythroblasts from the preleukemic stage of Friend disease. Furthermore, chemicals (dimethyl sulfoxide or N,N'-hexamethylenebisacetamide) that overcome the blocked differentiation of F-MEL cells induce rapid declines of PU.1 mRNA and PU.1 proteins. The elimination of PU.1 proteins coincides with recommitment to the program of erythroid differentiation and with loss of immortality. These results support the hypothesis that PU.1 interferes with the commitment of erythroblasts to differentiate and that chemicals that reduce PU.1 expression reinstate the erythropoietic program.

Animals↗
PubMed1992

Colour Doppler ultrasound in the management of a case of cranial arteritis.

Colour Doppler ultrasound allows simultaneous B scan and Doppler imaging and can be employed to determine the velocity of blood flow in the vasculature of the eye and orbit. We describe a case of cranial arteritis (giant cell arteritis) in which serial velocimetry recordings were obtained. At one stage in the disease process no blood flow was detectable in the orbit despite previously reliable recordings. This coincided with a deterioration of the clinical state of the patient as signified by recurrent anterior ischaemic optic neuropathy despite controlled symptomatology and erythrocyte sedimentation rate by prednisolone therapy. Subsequent increase in the immunosuppressive therapy was accompanied by a return of blood flow in the orbit. Colour Doppler ultrasound may prove to be a useful examination technique in the diagnosis and management of cranial arteritis.

Aged↗
PubMed1992

Venous thrombosis: a controlled study on the performance of scintigraphy with 99Tcm-HMPAO-labelled platelets versus venography.

Thirty-three patients with symptoms and signs of a deep venous thrombosis (DVT) were examined by contrast venography and radionuclide imaging with 99Tcm-hexamethylpropyleneamineoxime (99Tcm-HMPAO)-labelled autologous platelets. There were 13 patients on heparin therapy and 20 without anticoagulation during the scintigraphy. Scintigraphy consisted of blood pool imaging at 5 to 20 min and accumulation imaging at 2, 4-6 and 18-24 h. In scintigraphy a positive finding was either a defect of radioactivity in the immediate blood pool phase or a hot spot indicative of accumulation of platelets in later phases. Fifteen out of 23 patients positive by venography were also positive by scintigraphy. Five of the eight false negative patients were on heparin treatment, two probably had DVT which were not quite fresh. The venography negative patients were also negative on scintigraphy. Nine out of 12 patients without anticoagulation had positive platelet accumulation compared with two out of 11 patients on heparin therapy. This difference was statistically significant (P less than 0.025). The sensitivity and specificity of platelet scintigraphy were 65 and 100%, respectively, in all patients and 83 and 100% in patients without anticoagulation. Our results suggest that scintigraphy with 99Tcm-HMPAO-labelled platelets is a useful alternative in diagnosing DVT in patients in whom a standard contrast X-ray venograph is contraindicated or otherwise unsuccessful.

Adult↗
PubMed1992

The role of selection bias in comparing cesarean birth rates between physician and midwifery management.

OBJECTIVE: The midwifery service at our hospital has been observed to have a 2% cesarean birth rate consistently over a 10-year period. There are substantial differences in labor management style between the midwives and physicians. We sought to test the hypothesis that the low cesarean birth rate on the midwifery service was the result of patient selection bias. METHODS: A randomized blinded clinical trial was conducted in which 492 low-risk patients were assigned to either physician or midwifery management. The provider responsible for labor management was unable to determine group assignment. Patients in the midwifery group were managed by previously established protocols, and outcome was attributed to the midwives even if the patients subsequently required transfer to physician management. Route of delivery was the primary outcome measurement. Continuous variables were analyzed using Student t test and discrete variables using chi 2. RESULTS: There were no demographic differences between the groups, and the admission pelvic examinations were the same. The patients assigned to the midwifery group had a 2.1% cesarean birth rate, whereas those assigned to physician management had a 0.4% rate. The higher rate of operative vaginal deliveries in the physician group was statistically significant. There were no differences in neonatal outcomes. The physician-managed group had significantly more episiotomies and third- and fourth-degree extensions. CONCLUSIONS: The 2% cesarean birth rate observed on the midwifery service appeared to be the result of patient selection bias. A low cesarean birth rate can be achieved by either physician or midwifery management in a selected low-risk population.

Adult↗
PubMed1991

Neuronal activity in narcolepsy: identification of cataplexy-related cells in the medial medulla.

Narcolepsy is a neurological disorder characterized by sleepiness and episodes of cataplexy. Cataplexy is an abrupt loss of muscle tone, most often triggered by sudden, strong emotions. A subset of cells in the medial medulla of the narcoleptic dog discharged at high rates only in cataplexy and rapid eye movement (REM) sleep. These cells were noncholinergic and were localized to ventromedial and caudal portions of the nucleus magnocellularis. The localization and discharge pattern of these cells indicate that cataplexy results from a triggering in waking of the neurons responsible for the suppression of muscle tone in REM sleep. However, most medullary cells were inactive during cataplexy but were active during REM sleep. These data demonstrate that cataplexy is a distinct behavioral state, differing from other sleep and waking states in its pattern of brainstem neuronal activity.

Animals↗
PubMed1991

The theory of the frequency response of ellipsoidal biological cells in rotating electrical fields.

In this paper we have presented in as compact a form as possible the theoretical formalism that is needed to predict the frequency response of a biological cell of arbitrary ellipsoidal shape to a frequency dependant rotating external field. The formalism is much more complicated than that for a spherical or cylindrical cell where the radial vector is always parallel to the surface normal at each point of the surface. In addition to providing the theory we have demonstrated that the spin rate and its frequency dependance is very intimately related to the electrical properties of the cell interior and to that of the suspending fluid. It is possible to probe these properties of the cell and its environment by utilizing this technique. This aspect has been demonstrated by examining rotational changes as a function of the conductivity of both the cell interior and its suspending liquid. We also have shown, by considering a very simple model for the cell and the two dielectric constants, that the frequency spectrum is shape dependant. All our calculations have been carried out for "lossy" systems with frictional dissipation where energy minimization methods are no longer applicable. The invariant form of the Poynting vector forms the basis of the method.

Animals↗