Air-transfer production method for large-area picosecond photodetectors.

We have designed and prototyped the process steps for the batch production of large-area micro-channel-plate photomultipliers (MCP-PMT) using the "air-transfer" assembly process developed with single LAPPDTM modules. Results are presented addressing the challenges of designing a robust package that can transmit large numbers of electrical signals for pad or strip readout from inside the vacuum tube and of hermetically sealing the large-perimeter window-body interface. We have also synthesized a photocathode in a large-area low-aspect-ratio volume and have shown that the micro-channel plates recover their functionality after cathode synthesis. These steps inform a design for a multi-module batch facility employing dual nested low-vacuum and ultra-high-vacuum systems in a small-footprint. The facility design provides full access to multiple MCP-PMT modules prior to hermetic pinch-off for leak-checking and real-time photocathode optimization.

Apparent heparin resistance from elevated factor VIII during pregnancy.

BACKGROUND: Heparin resistance is the need for more than 35,000 units of heparin per 24 hours to achieve therapeutic activated partial thromboplastin time (APTT) values. Elevated factor VIII can cause apparent heparin resistance by suppressing the APTT result without inhibiting the antithrombotic effect of heparin. CASE: A 41-year-old gravida 2 para 0 presented at 25 weeks of a twin gestation with a deep venous thrombosis that required unusually high doses of heparin, resulting in hematuria. Apparent heparin resistance caused by elevated factor VIII was diagnosed, and the heparin dose was appropriately decreased with anti-Xa heparin monitoring. The deep venous thrombosis and hematuria resolved. CONCLUSION: Factor VIII rises significantly during pregnancy, and can cause apparent heparin resistance. When this occurs, anti-Xa heparin levels are superior to APTT for monitoring heparin therapy.

Air transport of obstetric critical care patients to tertiary centers.

OBJECTIVE: To evaluate critical care diagnoses and their frequency in an air transport situation. STUDY DESIGN: A retrospective review was done of all obstetric air transports performed by Samaritan AirEvac to tertiary hospitals in Phoenix, Arizona, from January 1, 1990, to August 31, 1991. RESULTS: In the 20-month study period, 1,541 maternal transports were performed. Critical care diagnoses were found in 360 (23.4%) of the patient. The following categories were used: hypertensive crisis, 188/360 (52%); hemorrhage, 131/360 (36%); trauma, 21/360 (6%); and respiratory compromise, 11/360 (3%). CONCLUSION: Critical care diagnoses represented about 25% of all obstetric air transports in this study. Our transport team is made up of an obstetric flight nurse and another team member (adult trauma nurse, neonatal flight nurse, flight respiratory therapist of flight paramedic). Skill in both obstetric diagnosis and management and in critical care necessary in these situations.

In utero fetal cardiac resuscitation: a case report.

A patient presented at 21 weeks gestation with nonimmune hydrops of her singleton fetus. A cordocentesis confirmed fetal anemia. During the course of the procedure, fetal cardiac arrest occurred. The fetus was resuscitated with intracardiac epinephrine and fetal transfusion was performed. The resuscitation was initially successful, however the fetus died 12 h later.

Effect of prolonged oral terbutaline therapy on glucose tolerance in pregnancy.

OBJECTIVE: Our objective was to elucidate the pathophysiologic effects and potential reversibility of terbutaline-induced changes in carbohydrate metabolism. STUDY DESIGN: We prospectively evaluated serum glucose, insulin, glucagon, C-peptide, and pancreatic polypeptide levels in response to a 100 gm glucose challenge (oral 3-hour glucose tolerance test) in 17 obstetric patients without complications who were given terbutaline (5 mg orally every 4 hours) for 5 consecutive days between 24 and 32 weeks' gestation. Each patient served as her own control, with day 1 representing pretreatment, day 7 the treatment phase, and day 14 the posttreatment evaluation. Body mass index and posttreatment serum terbutaline levels were also measured. RESULTS: A significant initial treatment effect (day 1 versus 7) was observed for glucose (elevated), insulin (elevated), insulin/glucose ratio (elevated), and pancreatic polypeptide (elevated). A significant delayed treatment effect (day 1 versus 14) was also observed for insulin (elevated), insulin/glucose ratio (elevated), and pancreatic polypeptide (elevated). Body mass index directly correlated with postchallenge measures of insulin, insulin/glucose ratio, pancreatic polypeptide, and C-peptide. Posttreatment serum terbutaline levels directly correlated with pancreatic polypeptide, but not with other parameters. CONCLUSIONS: Our data support a dose-independent, terbutaline-induced glucose intolerance mediated by glucagon and caused by diminished insulin sensitivity.

Development and initial experience with a manually controlled spring wire device ("Cordostat") to aid in difficult funipuncture.

Funipuncture has evolved as a useful tool in prenatal diagnosis and treatment. The ease with which it can be performed depends on placental implantation site, amniotic fluid volume, fetal presentation and activity, gestational age, and operator experience. Under select circumstances, such as hydramnios, oligohydramnios/anhydramnios, a back-up fetus/posterior placenta, or gestation of fewer than 20 weeks, funipuncture can be difficult or impossible. We have developed a new instrument, the "Cordostat," which can help the operator perform difficult funipuncture by providing stabilization and allowing intrauterine manipulation of the umbilical cord. The instrument consists of a deflecting wire guide threaded through a 19.5-guage trochar needle, which can be manually controlled to coil around and stabilize a free loop of cord. Conventional funipuncture can then be performed through a second uterine puncture. We describe use of this instrument in 12 patients undergoing second-trimester induced abortion.

Spontaneous regression of a large intrathoracic fetal lesion before birth.

All fetal intrapulmonary lesions diagnosed antenatally reported in the literature to date have persisted as an ultrasound finding for the remainder of the pregnancy, although spontaneous improvement in utero has been reported recently. We describe a case of a large intrathoracic lesion diagnosed at 24 weeks' gestation by ultrasound that became indistinguishable from the rest of the lungs as the pregnancy approached term. Although the frequency with which this process occurs cannot yet be assessed, the possibility of significant spontaneous regression must now be considered when counseling the parents on an affected fetus.

Antenatal diagnosis of sacral agenesis syndrome in a pregnancy complicated by diabetes mellitus.

The sacral agenesis syndrome is a severe congenital abnormality consisting of agenesis of the lumbar spine, sacrum, and coccyx, as well as hypoplasia of the lower extremities. It is considered the most characteristic of all congenital anomalies associated with maternal diabetes mellitus. We describe the sonographic and radiologic findings of agenesis of the lumbosacrococcygeal spine with lower limb and genital hypoplasia in the offspring of a woman with both diabetic retinopathy and nephropathy. The diagnosis was established at 25 weeks' gestation and was confirmed by radiologic evaluation of the neonate.

Spontaneous rupture of uteroovarian veins in pregnancy: two case reports.

Two cases of acute spontaneous rupture of uterine ovarian veins during the third trimester of pregnancy are reported. This condition has an obscure etiology and a relatively infrequent incidence and has been associated in the past with very high maternal and fetal mortality. The clinician is faced with both a puzzling diagnostic dilemma and a perplexing management scheme.