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Biomedical subjects

G M Harbert

Publications and source records attributed to G M Harbert.

At least 37 records · Page 2Linked to original sources
PubMed1981

Biorhythms of the nonpregnant human uterus.

Uterine activity was monitored continuously for periods of three or five days in two subjects. Biorhythms in the spontaneous variations of intrauterine pressure and frequency of contraction were demonstrated in both phases of the menstrual cycle. Statistically, the patterns conformed to 24-hour Fourier curves, with higher values synchronized by the periods of light. Positive statistical correlations were present between uterine activity and the circadian patterns of intrauterine temperature and norepinephrine concentrations in both urine and peripheral arterial plasma.

Activity Cycles↗
PubMed1980

Biorhythms of the primate uterus (Macaca mulatta) during labor and delivery.

The association between the documented spontaneous biorhythms of uterine activity, uterine artery blood flow, and aortaic blood pressure and the processes of labor and delivery was explored in 17 nonmedcated rhesus monkeys for 18 pregnancies. The characteristic circadian variations of higher hourly average values of uterine activity during periods of light than during periods of darkness were incorporated in a statistically distinct, predictable, and repetitive manner into the events of parturition. Variations in uterine artery blood flow reflected changes in intra-amniotic pressure. In those animals in which delivery occurred at night, a shift in maximal values of uterine activity from periods of light to periods of darkness occurred 48 to 60 hours prior to delivery. Progressive linear increases in hourly average values of frequency of contraction and aortic blood pressure consistently began 24 to 36 hours prior to delivery. These changes suggest that specific, directly related prodromal events occur within the maternal organism hours before parturition in the nonhuman primate.

Amniotic Fluid↗
PubMed1979

Effects of biorhythms on blood flow distribution in the pregnant uterus (Macaca mulatta).

Ten rhesus monkeys were studied between 143 and 161 days of gestation. The unanesthetized animals were confined to restraining chairs and maintained in a controlled environment with continuous monitoring of spontaneous uterine dynamics. Forty-five determinations of blood flow distribution were made using radionuclide-labeled microspheres. The microsphere injections confirmed a circadian pattern of uterine blood flow. These biorhythms are related to alterations in distribution of blood flow to placental and nonplacental portions of the uterus. Myometrial blood flow is highest during the period of light. It is correlated positively to aortic blood pressure (r = 0.490, p less than 0.05) and inversely to uterine artery blood flow (r = -0.508, p less than 0.05). Placental blood flow is highest during the period of darkness. The flow rates are significantly correlated to intra-amniotic pressure (r = -0.602, p less than 0.05) but not to aortic blood pressure (r = -0.185, p less than 0.05). The data indicate that blood flow distribution in the primate uterus is modulated by factors in addition to physiologic pressure-flow relationships. Extrapolation to the human has potential significance.

Animals↗
PubMed1979

Cervical cerclage: twenty years' experience.

During a 20-year period, 40 pregnancies were managed in 32 patients with a diagnosis of an incompetent cervix, a ratio of 1:775 deliveries. Diagnosis before development of symptoms produced a 92% fetal salvage, with 68% reaching 36 weeks of gestation. Development of symptoms before cerclage resulted in only a 40% fetal salvage. Fetal salvage was reduced in cases where membranes bulged beyond the cervix, the cervix was more than 3 cm dilated, or the gestational age was greater than 26 weeks at the time of suture placement. No difference was noted between the Shirodkar and McDonald procedures. Major complications included uterine rupture in three patients and acute chorioamnionitis in two. Because of complications, treatment is contraindicated based on history alone or where close follow-up is not available.

Adolescent↗
PubMed1977

Conservative management of pre-eclamptic and eclamptic patients: a re-evaluation.

A philosophy of conservatism in regard to termination of gestations complicated by pregnancy-induced hypertension has been practiced at the University of Virginia Hospital for many years. The advent of improved methods to evaluate the intrauterine fetal status prompted retrospective review of 246 pre-eclamptic and 13 eclamptic patients managed during the antepartum period. Continuous magnesium sulfate infusion for periods up to 144 hours (265 grams) was the therapeutic measure used for prevention or control of convulsions. Average duration of predelivery hospitalization increased 8.7 days, and the incidence of neonates requiring intensive care increased 10.9% with the use of tests to evaluate intrauterine fetal status. Frequency of spontaneous onset of labor and vaginal delivery decreased 18.6%. The uncorrected perinatal mortality rate for all antepartum patients was 7.0%. The mortality rate for infants of mothers with superimposed, severe or convulsive disease was significantly less in pregnancies in which tests of fetoplacental status were employed (8.2%) compared to pregnancies in which they were not (15.2%). The only maternal death was a 41-year-old patient with severe pre-eclampus who suffered a cerebral vascular accident on the fifth hospital day. These data reiterate the value of conservative management with meticulous individualized care.

Adolescent↗
PubMed1976

Thrombotic thrombocytopenic purpura associated with pregnancy.

Thrombotic thrombocytopenic purpura (TTP), a disorder of unknown etiology, appears to be a syndrome often associated with infectious, vascular, or autoimmune diseases. When it occurs in pregnancy, TTP can mimic other gestational complications. Two patients with TTP associated with pregnancy form the basis of this report. On patient is the second person known to have survived longer than 2 years after concurrent TTP and pregnancy. This patient had underlying glomerulonephritis and was treated with corticosteroids and heparin. The other patient, in whom an underlying disease process was not identified, was treated unsuccessfully with most of the recommended therapeutic modalities. Patients with concurrent TTP and pregnancy have the same prognosis as nonpregnant patient with TTP. Both groups have a prolonged survival rate of only 10 per cent. Primary treatment should consist of corticosteroids and inhibitors of platelet aggregation. If a rapid response does not occur, splenectomy is indicated. Care must be taken to recognize the pregnancy complicated by TTP, a circumstance which appears to occur more frequently than past reports have indicated.

Adolescent↗
PubMed1976

Actinomycosis of the female genital tract.

Four cases of actinomycosis involving the uterus and adnexal structures are reported. In 2 cases the infection was transmitted from a ruptured appendix. Ascending actinomycosis involving the endometrium and resulting in adnexal abscesses was associated with the use of an IUD in 2 patients. This infection should be suspected in any patient who develops a pelvic abscess with an IUD in place. Culture and histologic examination of tissue removed with the IUD may be a means of early diagnosis. The nature of these infections became apparent only after serious complications developed. Each patient required several surgical procedures. The diagnosis remained unsuspected until repeated laboratory examinations detected the fungus. The difficulty encountered identifying Actinomyces israeli indicates the infection is often undetected. Gallium scans were helpful in localizing occult abscesses in 2 patients.

Abscess↗
PubMed1975

Pharmacologic control of uterine contractility. In vitro human and in vivo monkey studies.

The exact cause and mechanism of the onset of labor are unknown but the theories are many. There is considerable evidence that prostaglandins are potent stimulants of uterine activity and may play a role in the onset of labor. Prostaglandin release may be the natural mediator of uterine contractions during labor. A group of anti-inflammatory compounds (aspirin-like compounds) that inhibit prostaglandin synthesis include indomethacin and fenoprofen. Inhibition of prostaglandin production is a reasonable approach to inhibiting premature labor. An excised muscle strip technique was used as a screening procedure for pharmacologic depression of human uterine activity in vitro, testing isoxsuprine, mesuprine, Alupent, ritodrine, indomethacin, and fenoprofen. The prostaglandin antagonists indomethacin and fenoprofen exhibited marked depressant activity. These drugs were further tested in an in vivo rhesus monkey preparation measuring uterine activity, maternal blood pressure, uterine blood flow, fetal heart rate, fetal blood pressure, and blood gases. Fenoprofen is effective in reducing uterine contractility without serious maternal or fetal side effects and shows promise as a clinically effective agent for pharmacologic control of premature labor.

Adrenergic beta-Agonists↗
PubMed1970

Diurnal variation of spontaneous uterine activity in nonpregnant primates (Macaca mulatta).

Diurnal variations in the average intrauterine pressure and in the average frequency of contraction were demonstrated in four nonpregnant rhesus monkeys. Uterine activity is lowest between 0400 and 0700 hours and highest between 1400 and 1700 hours. There is statistically significant correlation between uterine activity and diurnal variation in core temperature.

Analysis of Variance↗