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Biomedical subjects

R Marion

Publications and source records attributed to R Marion.

18 recordsLinked to original sources
PubMed1995

Spectrophotometry of amniotic fluid: a simple and rapid method for distinguishing between gestational sacs in second-trimester amniocentesis of twin pregnancies.

OBJECTIVE: To evaluate the use of an alternative and simple spectrophotometric method that could replace the intraamniotic injection of dye in the second-trimester amniocentesis of twins. METHODS: Optical densities (OD) of amniotic fluid (AF) obtained at second-trimester genetic amniocentesis were measured at 360 nm. Comparison was made between 36 twin pregnancies and 60 singleton controls. RESULTS: The mean difference in OD between two samples taken from the same sac of singleton pregnancies was very small (mean 0.004, standard deviation [SD] 0.003). However, samples drawn from each of the twin pairs' amniotic sacs varied widely (raw mean 0.176, SD 0.223; median 0.096, range 0.011-0.943). The difference between the groups was highly significant statistically (P < .001). CONCLUSION: Our preliminary experience with spectrophotometry of AF in twin amniocentesis suggests that this simple test may be useful in ascertaining that the AF samples were obtained from each of the two gestational sacs.

Amniocentesis↗
PubMed1994

Nasal pyriform aperture stenosis and the holoprosencephaly spectrum.

Recent reports have described congenital nasal pyriform aperture stenosis, but do not address its etiology in detail. We describe a child with nasal pyriform aperture stenosis, submucus cleft palate, and hypoplastic maxillary sinuses. Chromosome analysis revealed a ring chromosome 18. Awareness of the association of midline facial defects with midline brain defects allowed us to predict that features of the holoprosencephaly sequence would be found. Subsequent evaluation revealed growth hormone deficit. Eventually the child manifested a single central incisor. We review the association between midline facial defects and holoprosencephaly to remind the otolaryngologist of the need to look at the whole patient as he treats specific upper airway problems.

Chromosomes, Human, Pair 18↗
PubMed1994

Intracellular ionic consequences of dietary salt loading in essential hypertension. Relation to blood pressure and effects of calcium channel blockade.

To study the ionic basis of salt sensitivity in hypertension, 19F-, 13P-, and 23Na-nuclear magnetic resonance techniques were used to measure cytosolic free calcium (Cai), pH (pHi), free magnesium (Mgi), and sodium (Nai) in erythrocytes of essential hypertensive subjects (n = 19). Individuals were studied for 2 mo each on low- (UNaV < 50 meq/d) and high- (UNaV > 200 meq/d) salt diets, with the concomitant administration of nifedipine (10 mg t.i.d.) or placebo tablets for 1 mo of each diet. Salt loading elevated Cai and Nai while suppressing Mgi and pHi; these changes occurred predominantly in salt-sensitive subjects (n = 9). Nifedipine blunted the pressor response to salt loading > 50% (delta diastolic BP [high-low salt vs placebo] = 5 +/- 2 vs 14 +/- 2 mmHg, P < 0.05) and reversed salt-induced ionic changes, lowering Cai and elevating Mgi and pHi. Regardless of the definition of salt sensitivity, continuous relationships were observed between the pressure response to salt loading, the levels of Cai (r = 0.726, P < 0.001), Nai (r = 0.747, P < 0.001), and pHi (r = -0.754, P < 0.001), and the salt-induced change in Mgi (r = -0.757, P < 0.001). Altogether, these results emphasize the reciprocal and coordinate nature of intracellular ionic changes in response to dietary salt loading and calcium channel blockade in essential hypertension. They suggest that salt sensitivity is mediated by cellular calcium accumulation from the extracellular space, in association with magnesium depletion and acidification. Lastly, interpretation of intracellular ion measurements in the future will require concurrent assessment of dietary salt intake.

Analysis of Variance↗
PubMed1994

Progressively intractable seizures, focal alopecia, and hemimegalencephaly.

We report a 3-year-old boy with the neurocutaneous combination of unilateral alopecia, ipsilateral hemimegalencephaly, and intractable seizures. He was born with an asymmetric hair pattern consisting of absent patches of hair, a small left eyebrow, and less eyelashes on the left eye; he had normal development until age 17 months, when he experienced right focal seizures with fever. Two months later, fever triggered new seizures characterized by flurries of head and body flexion and adduction of the right arm. He had left hand preference and language regression. EEG manifested left hemihypsarrhythmia, and MRI showed left hemimegalencephaly with marked enlargement of the temporal lobe with ventriculomegaly. Seizures were refractory to treatment with phenobarbital, adrenocorticotropic hormone, pyridoxine, sodium valproate, clonazepam, carbamazepine, phenytoin, and felbamate. This may represent a previously undescribed neurocutaneous syndrome.

Alopecia↗
PubMed1993

Variable phenotypes in velocardiofacial syndrome with chromosomal deletion.

Velocardiofacial syndrome (VCF) has overlapping features with DiGeorge sequence; both result from a developmental field defect and probably represent contiguous gene deletion syndromes. The association of chromosome 22q11 deletion with DiGeorge sequence led us to do molecular analysis of chromosome 22 in 18 patients with VCF, who ranged in age from 6 to 42 years. All 18 patients had monosomy for the chromosome region 22q11. Retrospectively, we correlated the presence of the deletion with various clinical findings: 100% had cleft palate, 67% the facial phenotype, 83% cardiac disease, 94% learning disabilities, 70% ophthalmologic findings, 50% short stature, 22% psychiatric disorders, and 17% hypocalcemia. Both severely phenotypically affected and mildly affected patients had the deletion. These findings stress the importance of continued surveillance of all patients with VCF for the many medical problems that may not be present at initial diagnosis. We conclude that the presence of the gene deletion does not predict the phenotypic expression in VCF. Further studies to characterize the size of the gene deletion may facilitate better prediction of the phenotype.

Abnormalities, Multiple↗
PubMed1992

Duodenal atresia presenting as hematemesis in a premature infant with Down syndrome. Case report and review of the literature.

Congenital duodenal obstruction, a common complication of Down syndrome, most often presents as neonatal bilious vomiting. We report the first premature infant with Down syndrome whose duodenal atresia presented with a massive hematemesis secondary to duodenitis. Since a plain radiograph of the abdomen is diagnostic in the case of duodenal obstruction, it should be included in the diagnostic workup of hematemesis in newborn infants.

Down Syndrome↗
PubMed1990

Voluntary control of submaximal grip strength.

Stokes (J Occup Med; 1983;25:683-684) proposed that feigned weak hand grip can be distinguished from sincere efforts by examining force measurements for the different handle positions of the Jamar hand dynamometer. Sincere efforts yield a curvilinear relationship between grip force and handle position; feigned efforts yield a horizontal, linear relationship. The purpose of the present set of three experiments was to investigate the degree of control normal subjects have over submaximal effort and their ability to feign weakened grip. In Experiment 1 we found that subjects instructed to exert a specific amount of submaximal effort (50%) did not produce a response pattern of grip force consistent with Stokes' hypothesis. In Experiment 2 we found a linear relationship between the degree of submaximal effort and grip force for efforts of 30, 50, 70, and 90% of maximal effort. In Experiment 3 we found that subjects, with proper instruction as to the amount of effort to exert, can produce feigned submaximal efforts similar to the sincere, maximal efforts of injured people. Simple maximal grip force measurements are insensitive to the different motor strategies used in maximal and submaximal efforts and may provide little evidence for the detection of feigning.

Adult↗
PubMed1988

Pregnancy termination after detection of fetal chromosomal or metabolic abnormalities.

In 3400 midtrimester amniocenteses, 68 fetuses had abnormal findings. Three women elected to continue their pregnancies and the remainder chose terminations. Of these, 29 were cared for in our hospitals. Pregnancy termination was carried out in gestations averaging 21.6 +/- 2.3 weeks and fetal weights averaging 531 +/- 351 g. Three prostaglandins techniques were used, two of which proved to be effective. Dosages employed were comparable to those used in early second trimester pregnancy terminations. Side effects were similar; one retained placenta occurred. We have used a multidisciplinary counseling approach for these couples and have restricted ourselves to the medical aspects of their problems. Techniques are described for the psychologic support of the couple during this stressful period.

Abortion, Induced↗
PubMed1987

Detecting sincerity of effort when measuring grip strength.

The purpose of the present study was to determine whether sincere and faked grip strength measurements could be distinguished from one another by the patterns of measurements obtained for the five handle (hand size) positions of the Jamar dynamometer. Healthy subjects were instructed on different trials to give a sincere, maximal effort or to fake weakness of grip. Results were that the patterns did differ for sincere and fake trials, but not as strongly as expected. The recommendation is made that further research be done using patients with upper extremity injury.

Deception↗
PubMed1985

Relationship of blood pressure response and the renin-angiotensin system to first-dose prazosin.

It has been reported that the first-dose response to prazosin is more common in patients who are salt-depleted or already receiving beta blockers. The relationship between the first-dose blood pressure and plasma renin responses to oral administration of 1 mg prazosin in 13 (seven male, six female) patients with essential hypertension (average blood pressure = 150/100 +/- 5/2 mm Hg) was studied. Eight of 13 patients experienced marked orthostatic decreases in blood pressure associated with nausea and dizziness. The degree of the orthostatic depressor response was inversely correlated with the baseline plasma renin activity (p less than 0.005). This unique sensitivity of low-renin essential hypertension to prazosin may reflect an underlying increased alpha tone and/or an attendant blunted renin reactivity in this form of human essential hypertension.

Blood Pressure↗
PubMed1985

The redundancy of student comments and numerical ratings in evaluations of teaching.

Student evaluation of teaching effectiveness is widely used in undergraduate institutions as one element of determining overall faculty effectiveness. The evaluation format typically consists of (1) a number of questions the student answers by indicating a numerical rating and (2) an open-ended section for written comments. Some faculty members believe that the numerical ratings are not taken seriously by the students, and that the written comments impose greater accountability on the part of students. On the other hand, numerical ratings are necessary to minimize the fear that unfavorable written comments will be taken out of context in promotion decisions. Tabulation of numerical ratings is essential if a computerized data base for faculty evaluation is to be established. This study was designed to examine the relationship between student's numerically based ratings and written comments by evaluating allied health instructors using a standard, schoolwide evaluation form. Written comments were categorized according to a five-point scale and compared to mean values obtained from numerical ratings. Twenty-two faculty and 1,311 student evaluations were included. Significant positive correlations were found between the numerical student ratings and the written comments. The highest correlations were between student comments and two items related to overall teaching effectiveness. Students who evaluated instructors at either extreme on the spectrum of effectiveness were most likely to include written comments. Based on the consistency of numerical ratings and written comments we recommend that only the numerical ratings be used as part of the promotion and tenure decision-making process.(ABSTRACT TRUNCATED AT 250 WORDS)

Allied Health Personnel↗
PubMed1985

Achondroplasia and obstructive sleep apnea: correction of apnea and abnormal sleep-entrained growth hormone release by tracheostomy.

Severe obstructive sleep apnea in a patient with achondroplasia syndrome was found to result in a definitive deficiency of overnight growth hormone secretion related to absence of slow-wave sleep. Resolution of the apnea by tracheostomy resulted in normalization of growth hormone release and normal growth rates postoperatively. Sleep-related growth hormone deficiency may contribute to the short stature so often seen in a variety of craniofacial syndromes. Furthermore, this short stature may be reversible.

Achondroplasia↗
PubMed1979

Experience with sonography as an adjunct to amniocentesis for prenatal diagnosis of fetal genetic disorders.

This report summarized our experience with a consecutive series of 800 women referred for midtrimester amniocentesis for prenatal diagnosis of a fetal genetic abnormality. The results are compared before and after introduction of sonography immediately prior to the tap as a routine adjunct of the procedure. Following use of sonography there was a statistically significant reduction in the frequency of bloody taps, and an increase in the proportion of successful and informative initial taps. Moreover, in many instances sonography provided information useful for identification of fetal abnormalities or for management of pregnancy. These findings support the recommendation that examination by sonography should be utilized routinely as an adjunct to amniocentesis, despite the uncertainities relating to possible long-term adverse effects of intrauterine exposure to ultrasound.

Amniocentesis↗
PubMed1977

Testing for the Tay-Sachs gene in the Atlanta Jewish population.

In May 1975, three mass screening clinics for the asymptomatic Tay-Sachs carrier were held in Atlanta, Georgia. Ninety percent of the 2,330 adults screened were of Ashkenazi Jewish ancestry. One hundred seventy-six people were identified as possible carriers, 145 returned for retesting, and 74 were diagnosed as carriers. The Tay-Sachs heterozygote frequency estimated from this tested population was 0.043 or 1 in 23. Retesting of all possible carriers and assessment of their first-degree relatives were emphasized as saids in diagnosis of the carrier state. Our results indicated that the hexosaminidase A values in the white celll lysates used for the retest procedure provided a more reliable diagnosis of the carrier state than did enzyme values obtained from screening sera alone. Test results from first-degree relatives in all cases supported the assigned genotype of probands.

Europe↗