Biomedical subjects

C Hamer

Publications and source records attributed to C Hamer.

15 recordsLinked to original sources

PubMed1991

The secretory kinetics of the G cell in omeprazole-treated rats.

Prolonged achlorhydria leads to hypergastrinemia which must be matched by increased gastrin production. The extent to which the balance between synthesis and storage or secretion is shifted in achlorhydria remains uncertain. In the present study, rats were treated for 14 days with the hydrogen-potassium-stimulated ATPase inhibitor omeprazole, and the effects on plasma and tissue gastrin concentrations and on the abundance of gastrin messenger RNA were examined. To calculate the fractional release rates of gastrin, the metabolic clearance rate of synthetic unsulfated rat heptadeca peptide gastrin in anesthetized rats was also measured. Treatment with omeprazole for 14 days led to a profound hypergastrinemia, a twofold increase in antral gastrin stores, and a tenfold increase in messenger RNA. Calculations based on the metabolic clearance rate for rat heptadecapeptide gastrin suggested that in control rats, about 0.08% of stored gastrin was released per minute compared with about 0.4% in omeprazole-treated rats. No evidence was observed to suggest that changes in the efficiency of conversion of Gly-extended gastrins to amidated peptides were of any significance in accounting for the increased production of amidated gastrin. The increased gastrin synthesis in achlorhydria is therefore attributable to increased messenger RNA levels; most of the increase in gastrin production is directly secreted as changes in the stores of gastrin appear to be of lesser importance.

Animals↗

PubMed1990

The contribution of symptomatology and/or uterine activity to the incidence of unscheduled visits.

Home uterine activity monitoring and perinatal nursing support have been shown to be associated with a decrease in preterm births with no increase in the number of unscheduled patient visits. This prospective, randomized multicenter study compared the frequency of unscheduled visits in patients receiving home uterine activity monitoring and perinatal nursing support with that of patients receiving education regarding the detection and reporting of preterm labor symptomatology. The contribution of patient-reported signs and symptoms versus objective uterine activity data to unscheduled visits is assessed. The overall frequency of unscheduled visits was similar in both groups. In the home uterine activity monitoring and perinatal nursing support group, the contributions of uterine activity versus signs and symptoms to the diagnosis of preterm labor were equal, with 36% of patients diagnosed with preterm labor sent to the physician for increased uterine activity and 36% for signs and symptoms. The sensitivity for the group receiving monitoring and nursing support in detecting preterm labor was 93%. The majority of false-positive visits were associated with patient symptoms. These data show that this combination service does not lead to a clinically significant increase in unscheduled visits. Further, the visits resulting from the combination service provide a sensitive predictive method to aid physicians in detecting early labor.

Clinical Trials as Topic↗

PubMed1990

Home uterine activity monitoring is associated with a reduction in preterm birth.

The value of home uterine activity monitoring plus perinatal nursing support in the prevention of preterm birth among high-risk patients has been demonstrated by several studies. Other reports with less stringent guidelines and less intensive nursing contact have questioned the contribution of home uterine activity monitoring and perinatal nursing support to a preterm birth prevention program. In this large, prospective, randomized multicenter study, patients were assigned to receive either daily monitoring and nursing contact or a preterm birth prevention program including intensive education and more frequent prenatal visits. Among the monitored patients, there was a significant increase in early detection of preterm labor (2 cm or less), successful tocolysis, and prolongation of pregnancy to term. Thirty-one percent of these diagnoses of preterm labor resulted from evaluation of increased uterine activity without associated patient-perceived symptoms. We conclude that a program of daily uterine activity monitoring and perinatal nursing support results in earlier diagnosis of preterm labor and subsequently more effective tocolysis.

Cardiotocography↗

PubMed1990

Antepartum uterine activity characteristics differentiating true from threatened preterm labor.

Daily antepartum nursing contact and ambulatory uterine activity monitoring have been used for the early detection of preterm labor. However, it may be difficult to separate true labor from false labor. In this study, the uterine activity records of 110 women at risk for preterm birth with excessive contraction frequencies were evaluated by blinded reviewers. Maternal symptomatology and uterine activity characteristics such as low-amplitude high-frequency contractility, contraction amplitude, contraction duration, contraction interval, and contraction rhythmicity were assessed for their ability to differentiate true from threatened preterm labor. Neither maternal symptomatology nor any uterine activity characteristic other than contraction frequency could differentiate true from threatened preterm labor. Antepartum uterine activity monitoring should continue to rely on contraction frequency to identify the woman at risk for premature labor.

Adult↗

PubMed1990

Uterine activity and symptoms as predictors of preterm labor.

Women enrolled in a previously reported prospective trial of ambulatory tocodynamometry who developed preterm labor while using an ambulatory tocodynamometer were candidates for this analysis. Data from 51 women who met these entry criteria were evaluated and placed into four groups according to the initial reason for evaluation for preterm labor: monitored uterine activity, symptoms, both contractions and symptoms, or cervical examination at a routine office visit. Less than half (43%) had both subjective symptoms and an increase in monitored contraction frequency; 24% were initially identified by symptoms, 24% by uterine activity, and 10% at a routine office visit. We conclude that waiting for both an increase in uterine activity and subjective symptoms of labor will delay diagnosis in 50% or more of preterm labor patients and that women at risk of preterm birth should be evaluated promptly if either contractions or symptoms persist.

Adult↗

PubMed1990

Uterine activity in patients with cervical cerclage.

Cervical cerclage is the traditional management of cervical incompetence. Uterine activity among these patients has never been studied. This retrospective report details the contraction frequency in 96 patients with cerclage who underwent daily home uterine activity monitoring. Twenty-three percent (22) developed preterm labor and 12% (11) had preterm delivery related to failed tocolysis or rupture of the membranes. Uterine activity in the group who developed preterm labor was significantly greater than in those who labored at term. The objective contraction frequency data obtained by uterine activity monitoring are of clinical significance to physicians managing such patients.

Female↗

PubMed1990

The incidence of preterm labor and specific risk factors.

A retrospective review of patients at high risk for preterm delivery because of twin gestation, uterine malformation, incompetent cervix, or previous preterm delivery was carried out to assess the rates of preterm labor and spontaneous preterm birth. Among the 119 patients with multifetal gestation, 46% had preterm labor and 36% delivered before 37 weeks' gestation. In the 58 patients with an anomalous uterus, the rate of preterm labor was 19%, and 14% had early deliveries. Of those with incompetent cervices (115), one-fourth had preterm labor and 17% had an early birth. When a history of one or more preterm deliveries was present, the preterm labor rate ranged from 41-68%, with an early delivery rate of 30-47%. Prophylactic tocolytic therapy did not prolong gestations significantly. Maternal smoking did not have an adverse effect on the incidence of preterm labor except in twin pregnancies, for which early delivery was more likely. The percentages for preterm delivery are slightly lower than those found in the literature; this may be attributable to improvement in preterm birth prevention efforts including patient education, more frequent examinations, home uterine activity monitoring, and daily nursing contact.

Female↗

PubMed1989

Outpatient triplet management: a contemporary review.

The antepartum management of 198 women who were delivered of triplets between 1985 and 1988 is reviewed. Women were managed with the assistance of ambulatory perinatal nursing to provide outpatient surveillance. Modified bed rest, prophylactic tocolysis, and betamethasone were liberally used and patients were hospitalized only when obstetrically indicated. The most common antepartum complication was preterm labor (66.2%) and the success of therapy with tocolytic agents is described. The mean gestational age and birth weight at delivery were 33.6 +/- 3 weeks (mean +/- SD) and 1871 +/- 555 gm, respectively. Comparison of the gestational age distribution at delivery with previous reviews demonstrates fewer deliveries less than 29 weeks' gestation and significantly more deliveries between 32 and 37 weeks' gestation. Cesarean delivery occurred in 94% of the triplets, which eliminated birth order as a factor that affects survival. The corrected perinatal survival rate was 95% in this contemporary review of outpatient triplet management and represents a major improvement in the expected outcome for triplets.

Adult↗

PubMed1980

The effects of indoramin on histamine and antigen-induced changes in respiration in guinea-pigs.

Indoramin, a drug which blocks alpha-adrenergic, histamine and serotonin receptors, was tested as a protective agent during challenge with bronchoconstrictor agents in guinea-pigs. In conscious guinea-pigs, the time of onset of respiratory distress during continuous administration of aerosolized solutions of histamine, serotonin or ovalbumin (with animals pre-sensitized to this antigen) was measured using a force-displacement transducer applied to the animal's back. This time interval for each guinea-pig was compared with and without indoramin pre-treatment. Indoramin was administered by intraperitoneal injection or by aerosol treatment. In anaesthetized animals under artificial respiration respiratory distress was induced by intravenous injection of histamine and measured by the Konzett-Rössler technique. Indoramin treatment significantly protected guinea-pigs in both types of experiment from the effects of each challenging agent.

Anaphylaxis↗

PubMed1978