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Biomedical subjects

M S Kramer

Publications and source records attributed to M S Kramer.

At least 91 records · Page 5Linked to original sources
PubMed1997

Etiologic determinants of abruptio placentae.

OBJECTIVE: To quantify the roles of suspected sociodemographic, anthropometric, behavioral, and pathologic determinants in the etiology of abruptio placentae. METHODS: We performed a hospital-based cohort study of 36,875 nonreferred births between January 1978 and March 1989. Gestational age was based on menstrual dates confirmed (within 7 days) by early ultrasound. RESULTS: Parity, maternal education, pre-pregnancy weight, and the rate of net gestational weight gain did not have significant independent associations with abruption. Significant determinants included the following: severe small for gestational-age (SGA) birth (odds ratio [OR] 3.99; 95% confidence interval [CI] 2.75, 5.77), chorioamnionitis (OR 2.50; 95% CI 1.58, 3.98), prolonged rupture of membranes (OR 2.38; 95% CI 1.55, 3.65), preeclampsia (OR 2.05; 95% CI 1.39, 3.04), pregnancy-induced hypertension without albuminuria (OR 1.57; 95% CI 1.00, 2.46), pre-pregnancy hypertension (OR 1.77; 95% CI 1.05, 2.99), maternal age at least 35 years (OR 1.50; 95% CI 1.14, 2.01), unmarried status (OR 1.50; 95% CI 1.13, 1.98), cigarette smoking (OR 1.40; 95% CI 1.00, 1.97 for ten to 19 cigarettes per day and OR 1.13; 95% CI 0.81, 1.59 for at least 20 cigarettes per day), and male fetal gender (OR 1.38; 95% CI 1.12, 1.70). Removal of SGA from the regression model resulted in little change in the magnitude of the other associations. CONCLUSIONS: Severe fetal growth restriction, prolonged rupture of membranes, chorioamnionitis, hypertension (before pregnancy and pregnancy-induced), cigarette smoking, advanced maternal age, unmarried status, and male fetal gender are significant etiologic determinants of placental abruption. Non-SGA determinants appear to operate largely independently of their effects on fetal growth.

Abruptio Placentae↗
PubMed1997

Schizophrenia and L-745,870, a novel dopamine D4 receptor antagonist.

The discovery of a novel high-affinity and selective dopamine D4 receptor antagonist, L-745,870, and the results of clinical trials with this compound are reviewed. Despite several lines of evidence which suggest that a selective D4 receptor antagonist may be an effective antipsychotic agent with a lower propensity to induce extrapyramidal side-effects, L-745,870 was ineffective as an antipsychotic in humans.

Animals↗
PubMed1997

Double-blind, placebo-controlled, dose-finding study of rizatriptan (MK-462) in the acute treatment of migraine.

Rizatriptan (MK-462) is a potent 5HTID receptor agonist. This multicenter, double-blind, placebo-controlled, outpatient study investigated the clinical efficacy, safety, and tolerability of rizatriptan (2.5, 5, and 10 mg) as a function of dose for acute migraine. Patients with moderate or severe migraine (n = 417) were treated with placebo (n = 67), rizatriptan 2.5 mg (n = 75), 5 mg (n = 130), or rizatriptan 10 mg (n = 145). Headache severity, functional disability, and migraine symptoms were measured immediately before dosing (0) and at 0.5, 1, 1.5, 2, 3, and 4 h post-dose. Patients were permitted to take a second dose of test drug at 2 h if their headache pain was moderate or severe (i.e., placebo initially-->rizatriptan 10 mg as optional second dose; rizatriptan 2.5 mg, 5 mg, or 10 mg initially-->placebo as optional second dose). An upward dose-response relationship was observed among placebo, rizatriptan 2.5 mg, 5 mg, and 10 mg in the primary efficacy measure of proportion of patients reporting pain relief, i.e., a change in headache severity to "no pain or mild pain" at 2 h post-dose. The relationship was evident even at the first recorded timepoint, 30 min, and was statistically significant at 1.5 h and beyond. At the primary timepoint of 2 h after the initial dose, the proportion of patients reporting pain relief was 47.6% for rizatriptan 10 mg; 45.4% for rizatriptan 5 mg; 21.3% for rizatriptan 2.5 mg; and 17.9% for placebo. Seventy percent of patients on rizatriptan 10 mg reported pain relief at 4 h. Patients who took rizatriptan 5 mg and 10 mg were significantly less functionally disabled than those who took placebo at 1.5 and 2 h post-dose. Rizatriptan 10 mg was consistently more effective than 5 mg, although the differences were not statistically significant. The most frequent clinical adverse events were dizziness, somnolence, and asthenia/fatigue. No patients were discontinued for any adverse experiences and there were no serious adverse experiences.

Acute Disease↗
PubMed1997

Improvement in migraine-specific quality of life in a clinical trial of rizatriptan.

A validated migraine-specific questionnaire (24-h Migraine Quality of Life Questionnaire: 24-h MQoLQ) was used to assess the impact of migraine and migraine therapy on health-related quality of life during an acute migraine attack. Male and female migraineurs aged 18-55 years were randomized to placebo (n=41), rizatriptan 2.5 mg (n=47), 5 mg (n=74), or 10 mg (n=85) in a triple-blind, placebo-controlled clinical trial. Rizatriptan 5 mg and 10 mg were significantly more efficacious than placebo on pain relief and functional disability. After accounting for multiple comparisons to placebo, rizatriptan 10 mg showed significantly better responses compared to placebo on three of five domains of 24-h MQoLQ (social functioning, migraine symptoms, and feelings/concerns). The O'Brien's Rank Sum Test statistic showed a statistically significant overall difference on the 24-h MQoLQ between the 10 mg rizatriptan and placebo groups (p=0.005) and for the overall dose trend (p< or =0.001).

Adult↗
PubMed1997

A comparison of perinatal mortality between ethnic Chinese and ethnic whites: why the Chinese rate was lower.

OBJECTIVES: To confirm the observation that has been occasionally reported in the literature that perinatal mortality rate is lower in ethnic Chinese than in ethnic whites, and to assess the reasons for this lower perinatal mortality rate. METHODS: Secondary-analysis based on published data. RESULTS: This exercise demonstrates that the perinatal mortality rate was lower in ethnic Chinese than in ethnic whites. The birth weight distribution in ethnic Chinese was more favourable with reduced births at two extremes of the distribution, and the exposure to risk factors for perinatal death by their mothers was also lower. CONCLUSION: Perinatal mortality rate is lower in ethnic Chinese than in ethnic whites, and the lower perinatal mortality rate in ethnic Chinese is probably caused by their favourable birth weight distribution and lower exposure to risk factors of perinatal death by their mothers.

Adult↗
PubMed1996

Recent trends in Canadian infant mortality rates: effect of changes in registration of live newborns weighing less than 500 g.

OBJECTIVE: To ascertain whether the increase in the crude infant mortality rate in Canada in 1993 was due to a recent increase in the registration of newborns weighing less than 500 g as live births. DESIGN: Ecological study, with Poisson regression analysis. SETTING: Canada. SUBJECTS: All live births and infant deaths in Canada between 1987 and 1993, as reported by Statistics Canada. Data from Newfoundland were excluded because they were incomplete for 4 years. OUTCOME MEASURES: Proportion of live births by low-birth-weight category; and annual crude and adjusted infant mortality rates. RESULTS: Over the study period the proportion of newborns weighing less than 500 g registered as live births increased significantly (chi 2 for trend = 71.26, p < 0.01). This trend was an isolated phenomenon rather than a general increase in all low-birth-weight categories (chi 2 for trend in the proportion of newborns weighing 500 to 2400 g registered as live births = 1.14, p = 0.28). The crude infant mortality rate per 1000 live births decreased from 6.4 in 1991 to 6.1 in 1992 and then increased to 6.3 in 1993. Poisson regression analysis revealed that the apparent increase in the infant mortality rate was caused by the increased registration of infants weighing less than 500 g as live births. The adjusted infant mortality estimate for 1993 was lower than that for 1992. CONCLUSIONS: The increased infant mortality rate in Canada in 1993 appears to be due to increased registration of infants weighing less than 500 g as live births. Comparisons of infant mortality rates by place and time should be adjusted for the proportion of such live births, especially if the comparisons involve recent years.

Canada↗
PubMed1996

Does home visiting prevent childhood injury? A systematic review of randomised controlled trials.

OBJECTIVE: To quantify the effectiveness of home visiting programmes in the prevention of child injury and child abuse. DESIGN: Systematic review of 11 randomised controlled trials of home visiting programmes. Pooled odds ratios were estimated as an inverse variance weighted average of the study specific odds ratios. SETTING: Randomised trials that were available by April 1995. SUBJECTS: The trials comprised 3433 participants. RESULTS: Eight trials examined the effectiveness of home visiting in the prevention of childhood injury. The pooled odds ratio for the eight trials was 0.74 (95% confidence interval 0.60 to 0.92). Four studies examined the effect of home visiting on injury in the first year of life. The pooled odds ratio was 0.98 (0.62 to 1.53). Nine trials examined the effect of home visiting on the occurrence of suspected abuse, reported abuse, or out of home placement for child abuse. Because of the potential for bias in outcome reporting in these studies, pooled effect estimates were not calculated. CONCLUSIONS: Home visiting programmes have the potential to reduce significantly the rates of childhood injury. The problem of differential surveillance for child abuse between intervention and control groups precludes the use of reported abuse as a valid outcome measure in controlled trials of home visiting.

Child↗
PubMed1996

Recurrent respiratory distress syndrome in successive preterm pregnancies.

BACKGROUND: Earlier studies suggesting an increased recurrence risk of respiratory distress syndrome (RDS) among the subsequent infants of women with a previously affected infant were based on low birth weight inclusion criteria that did not differentiate between preterm and growth-retarded infants. METHODS: We therefore carried out two cohort studies of women who delivered two singleton preterm (gestational age < 37 completed weeks) infants: 1978 to 1989 at the Royal Victoria Hospital (RVH) in Montreal and 1959 to 1966 in the United States Collaborative Perinatal Project (CPP). We compared the relative risk (RR) of the development of RDS in the second infant according to the RDS status of the first. The diagnosis of RDS was based on respiratory distress of more than 24 hours' duration and a reticulogranular pattern on a chest radiograph. RESULTS: The RVH study sample comprised 284 infants born to 142 women, and the CPP sample 642 infants born to 321 mothers. In the RVH cohort the crude RR of RDS in the second sibling was 3.3 (95% confidence interval = 1.0 to 15.1) in women whose first preterm infant had RDS versus those whose first preterm infant did not have RDS. In the CPP cohort the corresponding RR was 2.5 (95% confidence interval = 0.8 to 7.9). These elevated risks were not altered substantially when multiple logistic regression was used to control for potentially confounding factors known to influence the risk of RDS (gestational age, sex, route of delivery, antenatal corticosteroids, and respiratory depression of birth). CONCLUSIONS: We conclude that preterm infants born to women with a previous preterm infant affected by RDS are at an increased risk of RDS, which suggests an important genetic (or other familial) tendency in its origin.

Cohort Studies↗
PubMed1996

Comparison of cerebral blood flow measured by laser-Doppler flowmetry and hydrogen clearance in cats after cerebral insult and hypervolemic hemodilution.

Laser-Doppler flowmetry provides a continuous measurement of blood flow without violating the natural state of circulation. The linearity of the laser-Doppler and hydrogen clearance methods of blood flow measurement were compared using a protocol that produced changes in cerebral blood flow that might be experienced in a neurosurgical setting. Cerebral blood flow was measured in both hemispheres of 12 adult cats during the snaring of one common carotid artery, the intracisternal injection of 5 mg of 5-hydroxytryptamine creatinine sulfate, and hypervolemic hemodilution, which produced a 25% reduction in blood hematocrit. The percentage of baseline laser-Doppler flowmetry and hydrogen clearance flows showed an acceptable degree of correlation (R2 = 0.762) over the range of cerebral blood flows measured. More rigorous analysis using Bland and Altman's difference against mean test showed that 10 minutes after hemodilution, the two methods displayed a level of variation outside the limits of agreement (-21.85 to 22.03%). Laser-Doppler flowmetry provided a noninvasive and continuous measure of blood flow, increasing the ability to observe instantaneous changes in cerebral microcirculation. However, laser-Doppler flowmetry did not record absolute blood flow, was affected by cerebral tissue shrinkage, and did not accurately measure flow under conditions of changed blood hematocrit.

Animals↗
PubMed1995

Maternal asthma and idiopathic preterm labor.

Previous studies suggest that women with asthma are at increased risk of preterm birth. Moreover, drugs (especially beta-agonists) used to treat asthma are also used to treat preterm labor. The authors carried out a case-control study of 555 women from three hospital centers with idiopathic preterm labor (< 37 weeks), including two overlapping (i.e., non-mutually exclusive) subsamples: cases with early idiopathic preterm labor (< 34 weeks) and cases with idiopathic recurrent preterm labor (< 37 weeks plus a previous history of preterm delivery or second-trimester miscarriage). Controls were matched to cases according to race and smoking history prior to and during pregnancy. All subjects responded in person to questions about atopic, respiratory, obstetric, and sociodemographic histories. Subjects in the early and recurrent preterm labor subsamples were also asked to undergo spirometric testing with methacholine challenge 6-12 weeks after delivery. Cases were significantly more likely to report histories of asthma symptoms and physician-diagnosed asthma (matched odds ratios of 2-3) than controls, particularly those cases with recurrent preterm labor. No significant associations were observed, however, with methacholine responsiveness. These results could not be explained by residual confounding by smoking or other variables, nor by selective recall of asthma symptoms and histories by cases. Women with asthma are at increased risk of idiopathic preterm labor. The fact that no such association was seen with methacholine responsiveness suggests that nonatopic, noncholinergic mechanisms may link bronchial and uterine smooth muscle lability.

Adult↗
PubMed1995

Comparison of birth weight distributions between Chinese and Caucasian infants.

To assess the reasons for the Chinese-Caucasian differences in birth weight distributions, a cohort study was carried out involving 18,665 Caucasian and 1,597 immigrant Chinese infants born at Montreal's Royal Victoria Hospital from January 1978 to March 1990 and 1,862 native Chinese infants born at Hefei Maternal and Infant Hospital in Hefei, People's Republic of China, from September 1990 to August 1991. Mean (standard deviation) birth weights in grams were 3,369 (567), 3,195 (493), and 3,171 (428) (p < 0.01 for differences in mean and variance), and mean (standard deviation) fetal growth ratios (ratio of observed birth weight to average birth weight at the same gestational age) were 0.994 (0.124), 0.963 (0.114), and 0.935 (0.112) (p < 0.01 for differences in mean and variance), respectively, in the Caucasian, immigrant Chinese, and native Chinese groups. No important or consistent Chinese-Caucasian differences in gestational age were found. When mothers with extreme values for demographic, anthropometric, nutritional, and lifestyle determinants of fetal growth were excluded, the mean fetal growth ratio in Caucasian infants remained significantly higher (p < 0.01), but the standard deviations became more similar (p > 0.05): Mean (standard deviation) fetal growth ratios were 1.001 (0.111), 0.966 (0.108), and 0.946 (0.114), respectively. The race-specific rate of growth differed according to period of gestation, with Chinese infants showing more rapid fetal growth early in the third trimester but slower growth near and after term. The authors conclude that the lower mean birth weight in Chinese infants is due to differences in fetal growth (rather than gestational duration) and by their inherently slower growth at or after term. The tight distribution of birth weight among the Chinese is caused partly by their reduced exposure to extremes of maternal determinants of fetal growth (mediated largely by environmental mechanisms) and partly by their inherently different growth pattern, with faster growth at earlier gestations but slower growth at later gestations.

Analysis of Variance↗
PubMed1995

A placebo-controlled trial of L-365,260, a CCKB antagonist, in panic disorder.

The functional role of cholecystokinin in the central nervous system is unknown. The tetra peptide CCK-4 was previously observed to induce panic attacks in a majority of normal volunteers and patients with panic disorder. Furthermore, it had been demonstrated that pretreatment with 10-50 mg of L-365,260, a selective CCKB antagonist, blocked CCK-4 induced panic in patients with panic disorder. Therefore, the present multicenter, placebo-controlled, double-blind trial was designed to investigate the efficacy of L-365,260, a CCKB antagonist, in patients with panic disorder with or without agoraphobia. Following a 1-week, single-blind placebo period, 88 patients were randomized to double-blind treatment in which they received either L-365,260, 30 mg qid, or placebo for 6 weeks. At the dose tested, there were no clinically significant differences between L-365,260 and placebo in global improvement ratings, Hamilton anxiety rating scale scores, panic attack frequency, panic attack intensity, or disability measures. The possible reasons for lack of effect with L-365,260 are discussed.

Adult↗
PubMed1995

Maternal anthropometry and idiopathic preterm labor.

OBJECTIVE: To assess the etiologic role of maternal short stature, low pre-pregnancy body mass index (BMI), and low rate of gestational weight gain in idiopathic preterm labor. METHODS: We carried out a three-center case-control study of 555 women with idiopathic onset of preterm labor (before 37 completed weeks), including two overlapping (ie, nonmutually exclusive) subsamples: cases with early preterm labor (before 34 completed weeks) and cases with recurrent preterm labor (before 37 completed weeks plus a history of prior preterm delivery or second-trimester miscarriage). Controls were matched to cases by race and smoking history. All subjects responded in person to questions about height, pre-pregnancy weight, gestational weight gain, and obstetric and sociodemographic histories. RESULTS: Maternal height, pre-pregnancy weight, and gestational weight gain demonstrated excellent test-retest reliability, with intra-class correlation coefficients of 0.97, 0.99, and 0.91, respectively. Based on matched analyses, women with a height of 157.5 cm or less had an increased risk of idiopathic preterm labor (odds ratio [OR] 1.85, 95% confidence interval [CI] 1.25-2.74), as did those with a pre-pregnancy BMI less than 19.8 kg/m2 (OR 1.63, 95% CI 1.09-2.44) or a gestational weight gain rate less than 0.27 kg/week (OR 1.74, 95% CI 1.16-2.62). Conditional logistic regression models containing all three anthropometric variables and controlling for parity, marital status, language, age, and education yielded virtually identical point estimates and CIs. CONCLUSION: Maternal short stature, low pre-pregnancy BMI, and low rate of gestational weight gain may lead to shortened gestation by increasing the risk of idiopathic preterm labor.

Anthropometry↗
PubMed1995

Etiologic fraction analysis for continuously distributed outcome variables and empirical analogy with dichotomized outcome variables.

BACKGROUND: It is not clear from the published literature whether R2 estimated from linear regression models for continuously distributed outcome variables is analogous to the etiologic fraction for dichotomized outcome variables. This article attempts to address this issue. METHOD: Continuous and dichotomous outcomes of the same underlying attributes (gestational age and fetal growth) were compared using data from a recent study of birthweight distributions in ethnic Caucasian infants. RESULTS: The relative magnitudes of the etiologic fraction and R2 were quite similar for the same underlying attributes. For example, R2 and etiologic fraction for weight gain rate ranked 2 and 3, respectively, for fetal growth and ranked 4.5 and 5, respectively, for gestational duration. CONCLUSIONS: R2 estimated from linear regression models for continuously distributed outcome variables appears analogous to the etiologic fraction for dichotomized outcome variables. If due consideration is given to the underlying biological mechanisms of the studied attributes, R2 can be used as a measure of public health impact.

Birth Weight↗