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Biomedical subjects

S Parker

Publications and source records attributed to S Parker.

At least 163 records · Page 9Linked to original sources
PubMed1990

Does stimulus context affect loudness or only loudness judgments?

Marks (1988) reported that when equal-loudness matches were inferred from magnitude estimates of loudness for tones of two different frequencies, the matches were affected by changes in the stimulus intensity range at both frequencies. Marks interpreted these results as reflecting the operation of response biases in the subjects' estimates; that is, the effect of range was to alter subjects' judgments but not necessarily the perception of loudness itself. We investigated this effect by having subjects choose which of two tone pairs defined the larger loudness interval. By using tones of two frequencies, and varying their respective intensity ranges, we reproduced Marks' result in a procedure devoid of numerical responses. When the tones at one frequency are all soft, but the tones at the other frequency are not all soft, cross-frequency loudness matches are different from those obtained with other intensity range combinations. This suggests that stimulus range affects the perception of loudness in addition to whatever effects it may have on numerical judgments of loudness.

Adult↗
PubMed1990

Maternal depressive symptoms during pregnancy, and newborn irritability.

Maternal depression is associated with a wide range of adverse outcomes for children, including poor mother-infant interactions at 3 months post-partum. The aim of this study is to determine whether maternal depressive symptoms during pregnancy are associated with neonatal neurobehavioral functioning, as measured by the Neurologic and Adaptive Capacity Scale. The study population consists of 1,123 mothers and their term infants who were participants in a larger study of maternal health and infant outcomes. Women were administered the Center for Epidemiologic Studies-Depression (CES-D) questionnaire for depressive symptoms during their pregnancy. Their infants were subsequently assessed by a pediatrician blind to their CES-D scores. The CES-D score was associated with unconsolability and excessive crying (p less than 0.01). The higher the mother's CES-D score, the more likely it was that the infant would be unconsolable or cry excessively. Mothers with CES-D scores at the 90th percentile were 2.6 times more likely to have unconsolable newborns, compared with women with CES-D scores at the 10th percentile (95% C.I. = 1.54, 4.23). When potentially confounding variables, such as cigarette smoking, alcohol, marijuana, and cocaine use, poor weight gain, income, birth weight, and other drug use, were controlled, the relationship between CES-D score and newborn unconsolability and excessive crying remain unchanged. The results of this study suggest that the relationship between early childhood problems and maternal depressive symptoms may be part of a sequence that starts with depressive symptoms during pregnancy.

Adolescent↗
PubMed1990

Jitteriness in full-term neonates: prevalence and correlates.

The prevalence and correlates of jitteriness were evaluated in a sample of 936 healthy full-term infants. Jitteriness was seen in 44% of this sample: 23% were classified as mildly jittery, 8% as moderately jittery, and 13% as extremely jittery. Jitteriness was seen most commonly in infants who were sleepy or active and least commonly in infants who were quietly wakeful during the neonatal examination. Jittery infants were more likely to be difficult to console when crying (P less than .01) and less visually alert (P less than .001) than were nonjittery infants. Jitteriness was seen more commonly in slightly smaller (P less than .05) and shorter (P less than .001) infants, in those more than 12 hours old (P less than .01), and in those not exposed to general anesthesia (P less than .05). In an expanded sample of 1054 healthy and sick full-term infants, jitteriness was observed more commonly in neonates who had been exposed prenatally to maternal marijuana use (P less than .01), but not to cocaine use (P = .1), and whose mothers had a positive postpartum urine assay for marijuana (P less than .05) or cocaine (P = .06). The magnitude of these drug effects, however, was small. These findings have important implications for the early parent-infant relationship, pediatric practice, and future research.

Child Behavior↗
PubMed1989

Epidemic of nosocomial Legionnaires' disease in renal transplant recipients: a case-control and environmental study.

An outbreak of Legionella pneumophila pneumonia occurred in 6 of 49 new renal transplant recipients over the course of 13 months. We compared infected patients (cases) and uninfected patients (controls) with respect to potential risk factors. Corticosteroid use, need for hemodialysis and number of days of hemodialysis were significantly greater among the cases. Logistic regression analysis identified corticosteroid dosage and number of days of hemodialysis as independent risk factors. Lymphopenia and monocytopenia were correlated with the amount of corticosteroid administered and occurred to a greater degree in the cases. All clinical isolates were of L. pneumophila serogroup 1, subtype Philadelphia 1, which was also cultured from a recovery room sink outside the operating room where the transplants were done. Other areas of the hospital were colonized with other, heterogeneous strains of L. pneumophila. The organism was not eliminated from the hospital water supply despite shock chlorination and superheating of water tanks. The epidemic ended when new transplant recipients routinely received prophylactic trimethoprim-sulfamethoxazole (160-800 mg given orally once daily) while in hospital after transplantation. Corticosteroid-induced monocytopenia and lymphopenia and the complement activation and monocyte depletion effects of hemodialysis may combine to increase susceptibility to Legionnaires' disease.

Adult↗
PubMed1989

Effects of maternal marijuana and cocaine use on fetal growth.

To investigate the effects on infants of the use of marijuana and cocaine during pregnancy and to compare the importance of urine assays with that of interviews in ascertaining drug use, we prospectively studied 1226 mothers, recruited from a general prenatal clinic, and their infants. On the basis of either interviews or urine assays conducted prenatally or post partum, 27 percent of the subjects had used marijuana during pregnancy and 18 percent had used cocaine. When only positive urine assays were considered, the corresponding values were 16 percent and 9 percent, respectively. When potentially confounding variables were controlled for in the analysis, the infants whose mothers had positive urine assays for marijuana, as compared with the infants whose mothers were negative according to both interviews and urine assays, had a 79-g decrease in birth weight (P = 0.04) and a 0.5-cm decrement in length (P = 0.02). Women who had positive assays for cocaine, as compared with nonusers, had infants with a 93-g decrease in birth weight (P = 0.07), a 0.7-cm decrement in length (P = 0.01), and a 0.43-cm-smaller head circumference (P = 0.01). To compare our findings with those of other investigators who did not use urine assays, we repeated the analyses, considering only self-reported use of marijuana (23 percent) and cocaine (13 percent). There were no significant associations between such use as determined by interviews alone and any of the measures of outcome. We conclude that the use of marijuana or cocaine during pregnancy is associated with impaired fetal growth and that measuring a biologic marker of such use is important to demonstrate the association.

Adolescent↗
PubMed1989

Water absorption of methacrylate soft lining materials.

The water absorption of soft methacrylate prosthetic materials is very high compared with rigid methacrylates and is not at an equilibrium value even after 6 yr. This very high and prolonged uptake can be explained qualitatively in terms of the presence of water soluble impurities which form sites for the formation of water droplets. These droplets grow until the osmotic and elastic forces balance; this mechanism can be accompanied by creep or even rupture under the osmotic pressure. Desorption on the other hand, is rapid and obeys diffusion laws, giving diffusion coefficients of 5-7 X 10(-8) cm2 s-1.

Absorption↗
PubMed1989

Do chest physicians follow-up too many patients?

We have examined the pattern of attendance of 750 randomly selected regular attenders at a chest outpatient clinic and sought the patients' views on the frequency of their follow-up appointments and the possible consequences of discharge to the care of the general practitioners. In addition, the clinic doctors and the patients' general practitioners were asked about the appropriateness of the frequency of follow-up and whether the pattern of attendance should change or the patient be discharged. Patients were most commonly seen at three monthly intervals. Clinic doctors felt that 24% and general practitioners that 9% of patients attended too often while only 2% of patients felt that this was the case. Clinic doctors recommended discharge for 28% and general practitioners for 21% of patients. Sixty-nine per cent of patients felt that their condition would be unchanged or would improve if they were discharged to the care of their general practitioners. Our findings suggest that at least 20% of our patients should be discharged to the care of their general practitioners, and, if the patients are correct in their interpretation of the consequences of discharge, that as many as 70% could safely be discharged.

Adolescent↗
PubMed1989

Double-blind, crossover placebo controlled trial of selegiline in Parkinson's disease--an interim analysis.

The response to selegiline was assessed in ten (2 females, 8 males) idiopathic parkinsonian patients with the wearing off response. Selegiline was compared to placebo in each patient in a double blind crossover study carried out over ten months. After 16 weeks of therapy selegiline significantly prolonged response to levodopa, extending response to 3 hours (p less than 0.05) in most patients and to 4 hours (p less than 0.001) in some patients. Baseline scores (zero time: 12 hours after their previous dose of medication) were also significantly better after selegiline therapy (p less than 0.05). Selegiline did not improve peak response (1 hour after medication) to levodopa indicating that these patients were on optimum therapy prior to receiving selegiline. Adverse effects (nausea (2), dyskinesia (2), fear reaction (1) and postural dizziness (1] occurred in 5 patients during the trial.

Aged↗
PubMed1989

A ration of care, a measure of doubt.

With limited dollars and skyrocketing costs, Medicaid programs around the country are feeling the squeeze. While some hope to guarantee basic health services by withholding access to certain high-ticket procedures, the question remains: Should we deny any level of care to the poor?

Health Care Rationing↗
PubMed1989

Antigenic stimulation during ultraviolet therapy in man does not result in immunological tolerance.

People receiving therapy with either 8-methoxypsoralen plus long wavelength ultraviolet radiation (PUVA) or medium wavelength ultraviolet radiation (UVB) have been studied to see whether their unresponsiveness to the contact sensitizer dinitrochlorobenzene (DNCB) is a form of immunological tolerance. It was confirmed that both PUVA and UVB therapy impair sensitization by DNCB:4/13 PUVA-treated and 9/29 UVB-treated psoriatic subjects became sensitized by a dose of DNCB which sensitizes 100% of untreated patients. Subjects unsuccessfully sensitized during PUVA therapy could subsequently be sensitized perfectly normally. Subjects unsuccessfully sensitized during UVB therapy showed slight impairment of subsequent sensitization which was not statistically significant, and which was probably a persistent effect of UVB exposure. In conclusion, the temporary unresponsiveness seen in human subjects exposed to antigens during PUVA or UVB therapy is not due to immunological tolerance.

Antigens↗