Biomedical subjects
Publications and source records attributed to W J Watson.
The reported manifestations of thyrotoxicosis in the fetus include tachycardia, preterm birth, intrauterine growth retardation, and increased perinatal mortality. Presented is a twin pregnancy in a euthyroid mother with a history of Graves' disease and high levels of thyroid-stimulating immunoglobulin G antibodies, which resulted in nonimmune hydrops in one of the twins.
A sonographic standard for assessment of amniotic fluid volume in normal twin pregnancy is provided. In 210 uncomplicated twin pregnancies, amniotic fluid volume was assessed sonographically, by measuring the total amniotic fluid index (AFI), as well as the deepest single vertical pocket in each sac. The mean AFI was greater than values found in singleton gestations; the AFI increased up to 27 weeks' gestation, and decreased thereafter. It correlated well with measurement of the deepest vertical pocket in each sac (r = 0.71; p < 0.0001). In twin pregnancy at 26 to 32 weeks' gestation a fluid pocket of at least 8 cm was found in 9.8% of cases and did not indicate pathologic states. Either AFI or measurement of the deepest fluid pocket in each sac can be used to assess fluid volume in twin pregnancy. A table specific to twin pregnancy should be used when evaluating twin gestations sonographically.
Ninety-seven primigravid patients were prospectively studied to assess the predictive value of the pressor response to aerobic exercise as a screening test for preeclampsia. The blood pressure response to cycle ergometry exercise to a maternal pulse of 140 beats/min was recorded on each subject. Each subject was studied in the second trimester of pregnancy at a mean gestational age of 23 weeks (range, 18 to 27). Three of the study subjects developed hypertension with proteinuria in the third trimester. A rise in systolic blood pressure of at least 30 mm Hg occurred in 29 patients, but this did not predict third trimester preeclampsia (p = 0.21). A rise in diastolic blood pressure of 20 mm was observed in 18 patients, two of whom developed preeclampsia (p = 0.08). An increase of diastolic pressure of 20 mm Hg with moderate cycle ergometry exercise in the second trimester may predict a subset of patients at elevated risk of preeclampsia in the third trimester. However, the positive predictive value of this 20 mm Hg pressor increase (11%) limits its applicability as a screening test. Thus, we cannot recommend the use of an exercise screening test at this time.
Polyhydramnios and oligohydramnios in twin gestation is most often caused by twin-twin transfusion syndrome. Presented is a monozygotic twin pair with polyhydramnios and oligohydramnios, in which both twins had glomerulocystic kidney disease of differing severity. The more severely affected donor twin died of renal failure in the neonatal period. The surviving twin is well following unilateral nephrectomy. This case illustrates the varied spectrum of pathology in glomerulocystic kidney disease.
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Group B streptococcal (GBS) infection in the neonate is the most common infectious cause of perinatal morbidity and mortality. There is much confusion in the literature regarding screening and treatment for this disease. The authors review recent literature on perinatal GBS infection and present their clinical opinions in favor of routine screening during pregnancy. Treatment protocols for the GBS positive mother, as well as the infant delivered of a GBS positive mother are considered.
Family physicians are in a strategic position to help couples adjust to the many changes that occur during the transition to parenthood. We review some of the issues for fathers at this time and suggest strategies for family physicians for including fathers and assisting couples to adjust to the changes in the interest of promoting healthy families.
OBJECTIVE: The purpose of this prospective investigation was to determine the utility of ultrasonographic measurement of the fetal nuchal skin in screening for chromosomal abnormalities. STUDY DESIGN: In 1510 patients undergoing genetic amniocentesis at 14 to 21 weeks' gestation, the fetal nuchal skin fold was measured. A measurement of > or = 6 mm was considered abnormal. RESULTS: In fetuses with normal karyotype the nuchal skin increased with advancing gestational age (r = 0.45, p < 0.001). Only 27 fetuses with normal karyotype (2.0%) had an abnormal nuchal skin thickness. Fifty-seven fetuses had abnormal karyotype. Eight of 14 fetuses with Down syndrome had abnormal ultrasonographic findings; four had increased nuchal skin as the only ultrasonographic abnormality. Increased nuchal skin alone, in the absence of other ultrasonographic dysmorphologic features, did not help to identify fetuses with other abnormal karyotypes. CONCLUSION: Nuchal skin thickness is a useful noninvasive measurement to screen for Down syndrome but does not help to identify fetuses with other chromosomal abnormalities.
Little data exist regarding the acute maternal and fetal cardiovascular effects of caffeine ingestion. The purpose of this study is assess the cardiovascular effects of caffeine ingestion in pregnant subjects and their fetuses. We examined seven caffeine-naive gravidas longitudinally at 25.7 (SE +/- 0.7) and 36.1 (+/- 0.7) weeks' gestation, before and after ingestion of a caffeine citrate solution (100 mg/m-2 body surface area). Maternal pulse, blood pressure, fetal heart rate, and fetal heart rate accelerations were determined before and after caffeine ingestion. Uterine artery, fetal aorta, and umbilical artery flow velocity waveforms were examined at similar intervals. Significant before and after caffeine differences, regardless of gestational age, were noted for maternal pulse (85.1 vs 74.2 beats/min), diastolic blood pressure (65.9 vs 73.8 torr), mean arterial blood pressure (81.5 vs 87.5 torr), uterine artery systolic-to-diastolic (S/D) ratio (1.9 vs 2.4), fetal heart rate (144.6 vs 135.4 beats/min), and fetal heart rate accelerations (1.6 vs 4.2 per 30 minutes). Differences for fetal aortic and umbilical artery S/D ratios were not significant with respect to caffeine administration. Fetal aortic peak velocities increased with caffeine (85.5 vs 130.2 cm/sec) and the increase was augmented with advancing gestational age. We conclude that maternal ingestion of modest amounts of caffeine citrate in caffeine-naive subjects significantly affects both the fetal and maternal cardiovascular systems.
Haemophilus influenzae produces surface structures called pili that promote adherence to human cells. Three genes encoding the major pilus structural component (pilin), chaperone, and usher proteins (designated hifA, -B, and -C, respectively) have been identified previously. In this study, transposon mutagenesis and DNA sequence analysis identified two open reading frames (ORFs) downstream of, and in the same orientation as, hifC. These genes have been designated hifD and hifE. Both genes have predicted C-terminal amino acid homology to HifA, and mutations in either gene resulted in the loss of morphologic and functional pili, indicating that hifD and hifE encode pilus structural components and are required for pilus expression. Another ORF, identified immediately downstream of hifE, has a predicted amino acid sequence that is 70% identical to an aminopeptidase of Escherichia coli called PepN, and a mutation within this ORF did not alter pilus expression. These data indicate that the pepN homolog is not required for pilus biogenesis and that one end of the pilus gene cluster has been defined.
Haemophilus influenzae type b (Hib) pili are complex filamentous surface structures consisting predominantly of pilin protein subunits. The gene encoding the major pilin protein subunit of Hib adherence pili has been cloned and its nucleotide sequence has been determined. In order to identify specific accessory genes involved in pilus expression and assembly, we constructed isogenic Hib mutants containing insertional chromosomal mutations in the DNA flanking the pilin structural gene. These mutants were screened for pilin production, pilus expression, and hemagglutination. Pili and pilin production were assessed by immunoassays with polyclonal antisera specific for pilin and pili of Hib strain Eagan. Hemagglutination was semiquantitatively evaluated in a microtiter plate assay. Six Hib mutants produced proteins immunoreactive with antipilin antiserum but no longer produced structures reactive with antipilus antiserum. In addition, the mutants were unable to agglutinate human erythrocytes. Nucleotide sequence analysis localized the insertion sites in the six mutants to 2.5-kb open reading frame upstream of the pilin structural gene and immediately downstream of an Hib pilin chaperone gene. The amino acid sequence encoded by this open reading frame has significant homology to members of the pilus assembly platform protein family, including FhaA of Bordetella pertussis, MrkC of Klebsiella pneumoniae, and the Escherichia coli assembly platform proteins FimD and PapC. This open reading frame, designated hifC, appears to represent a gene essential to Hib pilus biogenesis that has genetic and functional similarity to the pilus platform assembly genes of other gram-negative rods.
We describe a new exonuclease-based method for joining and/or constructing two or more DNA molecules. DNA fragments containing ends complementary to those of a vector or another independent molecules were generated by the polymerase chain reaction. The 3' ends of these molecules as well as the vector DNA were then recessed by exonuclease activity and annealed in an orientation-determined manner via their complementary single-stranded regions. This recombinant DNA can be transformed directly into bacteria without a further ligase-dependent reaction. Using this approach, we have constructed recombinant DNA molecules rapidly, efficiently and directionally. This method can effectively replace conventional protocols for PCR cloning, PCR SOEing, DNA subcloning and site-directed mutagenesis.
Presented is a case of nonimmune hydrops caused by Noonan syndrome. This autosomal dominant disorder, with an incidence of 1 in 1000 births, is manifested by trunk and limb edema, lymphatic abnormalities, webbed neck, short stature, and cardiac and genital anomalies. In this case the initial presentation was polyhydramnios at 31 weeks' gestation, followed in 1 week by pleural effusions and a week later by skin edema. An 18-week ultrasound had been normal. Because of variable expressivity, only the most severe cases of the disease are usually diagnosed. Thus, the incidence may be higher than 1 in 1000, and Noonan syndrome may be underdiagnosed as a cause of nonimmune hydrops. Since lymphedema in this syndrome may regress spontaneously, conservative obstetric management is preferable unless the fetus develops distress.
Measurements of the fetal mandible were made on 204 women with uncomplicated pregnancies and reliable gestational dates. The measurements were made in the sonographic plane, which included the fetal mandible and the hypopharynx. The antero-posterior and transverse jaw measurements increased with gestational age (p < 0.0001), and correlated well with both the biparietal diameter and femur length (p < 0.0001). Measurements were technically more difficult to obtain during the late third trimester. These standards for fetal jaw measurement may be useful in the sonographic identification of micrognathia.
The clinical course and pregnancy outcome of all patients undergoing extensive nonobstetric operation during pregnancy during a ten-year period was reviewed. During this time, there were 49,567 births and 78 women had nonobstetric operation; an incidence of one in 635. The most common indications for surgical treatment were appendicitis, adnexal mass and cholecystitis. The perinatal mortality rate was not increased in women undergoing nonobstetric operation, provided that fetal viability was established preoperatively. In this series, there was no measurable benefit from the use of perioperative prophylactic tocolytic agents. However, nonobstetric operation was associated with an increased risk of preterm labor. Postoperatively, patients should be monitored for contractions and treated with tocolytic agents when appropriate.
Non-immune hydrops fetalis is a rare pregnancy complication, which can be caused by a myriad of conditions. Etiologies include metabolic or chromosomal disorders, fetal structural anomalies, and fetal infections. We present a case of non-immune hydrops caused by an intra-uterine infection with Type 1 Herpes Simplex Virus. Evaluation of the fetus with non-immune hydrops should include an amniocentesis for viral culture of the amniotic fluid.
Adnexal masses complicate approximately 1/2,000 pregnancies. Teratomas are the most common ovarian neoplasms found in pregnancy, representing up to 36% of adnexal masses. However, almost all these dermoids are less than 10 cm in diameter. We present a case of a massive benign cystic teratoma complicating pregnancy. The patient initially presented with what appeared to be ascites. Imaging evaluation included ultrasound, magnetic resonance and angiography. These studies demonstrated a large teratoma. The tumor was resected without complications. Important aspects of perioperative care are discussed.
Orf virus infection is endemic among sheep and goats, and can occur in humans who handle these animals. Orf virus infection in humans causes a characteristic skin lesion, and systemic symptoms can occur. Very little is known about Orf virus infection in human pregnancy. A case of Orf virus infection, with onset at 33 weeks gestation, is presented. There were no pathological findings in the infant born at term, or in the placenta.