Search PubMed⌕ Search

Biomedical subjects

J F Clark

Publications and source records attributed to J F Clark.

At least 55 records · Page 3Linked to original sources
PubMed1991

Evidence that gonadal hormone levels in amniotic fluid are decreased in males born to alcohol users in humans.

Biochemical evaluation of amniotic fluid content is often used to monitor fetal secretory and excretory functions. It is known that alcohol freely passes through the placenta and enters the fetal tissues. The study was designed to investigate whether alcohol use during pregnancy affects amniotic fluid steroid and peptide hormone levels. Five alcohol users who drank between 40 and 45 drinks per month and consumed approximately 1 oz. of alcohol per day from beer drinking participated in the study. Thirteen controls with no history of alcohol use including essential and non-essential drugs were selected for the study. The final selection of participants was made among those who delivered male offsprings. Amniotic fluid was aspirated between 16 and 20 weeks of gestation by amniocentesis and an aliquot was used to assay steroid hormones (4-androstenedione [-4-AD], testosterone [T], estradiol [E2], dehydroepiandrosterone sulfate [DHEA-S]), and peptide hormones (FSH and LH). Birth weights, placental weights and gestation age were recorded at birth. The results showed that -4-AD, T and E2 levels were significantly decreased (P less than 0.01) in alcohol users; DHEA-S, FSH and LH levels were unaffected. Birth weights were significantly decreased (P less than 0.05) in alcohol users, the placental weights and gestation age were not affected. We conclude that alcohol passes through the placenta and affects fetal testes, capacity to synthesize steroids and the effect appears to be direct and not via the hypothalamic-hypophyseal axis.

Adult↗
PubMed1991

Primary peritoneal pregnancy: a case report.

Primary peritoneal pregnancy has been reported and debated for almost a century. Case reports using Studdiford's criteria and later modified criteria have substantiated the entity, but the pathogenesis remains an enigma. This article fulfills both criteria and discusses the factors related to the pathogenesis.

Adult↗
PubMed1991

Cocaine intoxication associated with abruptio placentae.

Acute cocaine intoxication has been associated with elevated blood pressure and placental abruption. A retrospective analysis was performed comparing gestational age at the time of placental abruption and response to conventional therapy for elevated blood pressure between patients known to have ingested cocaine and those who were drug free. Data suggest that cocaine ingestion during pregnancy increases the risk of early placental abruption and an elevation of blood pressure that is not as responsive to conventional therapy as pregnancy-induced hypertension.

Abruptio Placentae↗
PubMed1990

The theory of diazymes and functional coupling of pyruvate kinase and creatine kinase.

The physical-chemical principles governing the interactions of enzymes having common metabolic products are presented. Methods for comparing the dissociation rates of the metabolic product and the rates of enzyme-enzyme interaction are given. Using muscle pyruvate kinase (PK) and creatine kinase (CK) as an example, it is shown that the probability of forming an enzyme-product-enzyme complex is much greater than the rate of ATP dissociation from either enzyme. Experimental evidence using 31P-NMR demonstrates that in the presence of both pyruvate kinase and creatine kinase, there is exchange of phosphate between phosphocreatine and phosphoenolpyruvate without a change in the intermediate, ATP. This confirms the formation of a PK.ATP.CK complex in an aqueous solution without enzyme attachment to a substructure. Enzymes capable of forming these mobile clusters are defined as diazymes, and the criteria for their formation are given. The metabolic implications of diazymes are discussed.

Adenosine Diphosphate↗
PubMed1989

Mechanical and metabolic toxicity of 3-(trimethylsilyl)propanesulfonic acid to porcine carotid arteries.

3-(Trimethylsilyl)propanesulfonic acid (TMSPS) is used as a water-soluble NMR frequency marker. It has its major resonance at 0.00 ppm relative to trimethylsilane, and smaller resonances at 0.62, 1.77 and 2.85 ppm. Its toxicity was tested by exposing contracted porcine carotid strips to increasing concentrations of TMSPS. Up to 3 mM, no statistical change in tension was found. Tension decreased 94 +/- 2% (S.E.) after 30 min in 10 mM TMSPS. An intermediate concentration of TMSPS (6 mM) caused a small fall in phosphocreatine in unstimulated perfused porcine carotid arteries (82 +/- 2% S.E.). A larger decrease (59 +/- 6% S.E.) occurred during K+ contractures in the presence of 6 mM TMSPS. From those experiments it appears the TMSPS is non-toxic in concentrations up to 3 mM, but at greater concentrations inhibits both contraction and phosphorus metabolism.

Alkanesulfonates↗
PubMed1989

The use of 31P-NMR to study smooth muscle.

The use of 31P NMR to study smooth muscle is hindered by low metabolite concentrations and low tissue mass. These disadvantages can be overcome due to low rates of energy utilization and the temporal stability of smooth muscle. Smooth muscle free Mg++, ADP, and the creatine analogue beta-guanidinopropionate can be studied in ways distinctive from 31P NMR of striated muscle. The pharmacological effects of naturally occurring agents such as insulin, glucose, or norepinephrine, and of NMR markers such as phenylphosphonate or 3-(trimethylsilyl)-1-propane-sulfonate on both vascular smooth muscle and perfused smooth muscles can be measured. Given sufficient collection time, 31P NMR is as useful in assessing the behavior of smooth muscle as it is of other muscle types.

Adenosine Triphosphate↗
PubMed1989

Adenomyosis: a retrospective view.

Adenomyosis has been referred to as diagnostically elusive due to the difficulty of clinical identification and unknown etiology. In a retrospective study of 178 consecutive uteri removed or biopsied at Howard University Hospital significant differences in the average age and peak incidence, correct preoperative diagnosis, and association with leiomyoma was noted when compared with the current literature. The data suggest that in black Americans symptomatic essential adenomyosis occurs earlier and that dilation and curettage may have an etiologic role. In general, adenomyosis is more frequently associated with leiomyoma but essential adenomyosis was diagnosed most consistently when uterine enlargement was noted during the menstrual period. The authors conclude that adenomyosis should be considered in all cases of abnormal uterine bleeding and dysmenorrhea. Early diagnosis by ultrasonographic testing may lead to an identifiable cause of this disease and result in methods of prevention or early medical therapy.

Adult↗
PubMed1987

Developmental outcome of children born from extrauterine pregnancies.

From 1947 to 1984, 45 advanced ectopic pregnancies were delivered at Freedmen's Hospital and its successor, Howard University Hospital. Four patients of extrauterine pregnancies were contacted to determine their developmental outcome. At the time of the study, their ages ranged from infancy to adulthood. Results are presented of two children who received in-depth interdisciplinary evaluations at the Howard University Child Development Center. The authors reviewed the literature and questioned other authors, who, based on single examinations, reported normal function in children born after extrauterine pregnancies.

Adolescent↗
PubMed1987

Adolescent pregnancy: a 25-year review.

A five-year update of a previous 20-year study of adolescent pregnancy is presented. For the 25-year period, data were collected on 2,789 adolescents. Prematurity and low birth weight infants continue to have a high incidence in adolescent pregnancy. This study found that there has been a significant decrease in preeclampsia and toxemia of pregnancy and a large increase in the incidence of cesarean section.

Adolescent↗
PubMed1984

Fetal heart monitoring in detection velamentous insertion of the umbilical cord.

Velamentous insertion of the umbilical cord is a high-risk obstetrical condition that is rarely diagnosed before delivery of the placenta. The fetal mortality rate from this condition has been estimated to be as high as 70 percent. Criteria used to aid in the diagnosis of this condition include (1) vaginal bleeding accompanied by fetal heart irregularities, (2) vaginal blood determined to be of fetal origin, (3) palpation of vasoprevia through a dilated cervix, (4) visualization of vasoprevia through the amnioscope, and (5) marked fetal bradycardia when the membranes are unruptured and there is no evidence of vaginal bleeding.

Adult↗
PubMed1982

Adolescent pregnancy: a twenty year review.

In 20 years, from 1957 through 1977, there were 2,280 cases of adolescent pregnancy. The number one problem was low birth weight which occurred in 17 percent of all patients. The second significant obstetrical risk was toxemia of pregnancy, occurring in 15 percent of the cases. The cesarean section rate was 6.7 percent. There were 1.8 percent stillbirths and one maternal death.

Adolescent↗
PubMed1982

Embryo transfer in vivo.

Records of 44 patients with advanced ectopic pregnancy were reviewed. The author demonstrates that in vivo embryo transfer can reimplant later than one week of gestation and that implantation does not require endometrium as the only implantation site. Other tissues and organs can support implantation, but adequate hormonal secretion is necessary.

Diagnosis, Differential↗
PubMed1982

Pathogenesis of tubal pregnancy.

A review was made of 706 ectopic pregnancies treated at Howard University Hospital over a 20-year period. Comparison of two 10-year periods was made with special regard to the association of an inflammatory process in the involved tube. It is not the intention of this study to deny chronic pelvic inflammatory disease as a factor in the etiology of ectopic pregnancy, but it is not considered the main cause.An inflammatory process was associated in 40.1 percent of cases during the first 10 years, and 16.7 percent of cases in the second 10 years. Further study is necessary to elucidate the cause of ectopic pregnancy, probably in the direction of functional disturbances rather than structural defects.

Adolescent↗
PubMed1980

The juvenile parturient.

The juvenile parturient causes concern and apprehension about the method of delivery and perinatal outcome. The author presents a study which evaluates the delivery methods on 99 such patients.

Adolescent↗
PubMed1979

A study of tubo-ovarian abscess at Howard University Hospital (1965 through 1975).

Unruptured tubo-ovarian abscess was diagnosed in 40 patients over ten years. This was three percent of 1,154 patients admitted to Howard University Hospital for pelvic inflammatory disease. The admitting diagnosis was 33 percent correct.The treatment was individualized with 23 percent receiving total abdominal hysterectomy with bilateral salpingo-oophorectomy. Twelve young women received unilateral salpingo-oophorectomy.We feel that early detection and aggressive medical treatment for pelvic inflammatory disease will decrease the incidence of tubo-ovarian abscess and the necessity for surgery.

Abscess↗
PubMed1978

Ulcerative vaginitis due to Torulopsis glabrata: a case report.

A patient with ulcerative vaginitis is presented. The differential diagnosis included malignant ulcer, chancroid, and granuloma venereum. Torulopsis glabrata vaginitis, which was subsequently proven, responded successfully to clotrimazole suppositories. Predisposing and related factors and isolation and identification procedures are discussed.

Candida↗