Three-dimensional temperature control of palladium-nickel thermoseeds: a computer aided and experimental evaluation

The capability of self-regulating thermoseeds to compensate for nonuniform cooling along their longitudinal axis has been investigated in this study. For this purpose a quasi three-dimensional computer model has been developed. Calculations of the temperature profile in tissue with nonuniform heat loss demonstrated a clear improvement in the longitudinal temperature control of PdNi seeds compared to constant power seeds. Further, two strategies for improved control of nonuniform cooling along the longitudinal axis of ferromagnetic seeds have been investigated: (1) application of a 'normal' undivided seed; and (2) division of a long seed in smaller segments of which each segment is able to respond more directly to local variations in the temperature distribution. Calculations with the quasi three-dimensional model showed that the loose segments do respond more directly to their close proximity. However, the equilibrium temperature of a segment in an area with high local blood flow will be relatively low due the limited heat production of PdNi thermoseeds. In the undivided seeds the high thermal conductivity of PdNi causes some levelling of the longitudinal temperature gradient in the seed. In addition, calorimetric experiments have shown that the heat production of a segmented seed is less effective because of a demagnetizing field. Also, the absence of PdNi between the segments reduces the heat production of the seed.     

Antenatal hormone therapy for fetal lung maturation

In summary, several agents have been studied, but only CS and thyroid hormones have been found to accelerate fetal lung maturation in animal studies. Thirty years of research has documented the beneficial effect of antenatal CS on fetal lung maturation, and antenatal steroid in combination with postnatal surfactant remains the mainstay of prevention and therapy for RDS in preterm infants. The efficacy and safety of postnatal steroids have yet to be demonstrated. Unfortunately, the addition of antenatal TRH to this regimen has not provided further benefit to the neonatal outcome of preterm infants as evidenced by the recently completed multicenter trials. In addition, the optimal number of courses of antenatal CS for lung maturation remains unclear.     

Age-dependent and lobe-specific spontaneous hyperplasia in the brown Norway rat prostate

PURPOSE: Response of quiescent (Q) and total tumor cells in solid tumors to neutron irradiation with three different cadmium (Cd) ratios was examined. The role of Q cells in tumor control was also discussed. METHODS AND MATERIALS: C3H/He mice bearing SCC VII tumors received continuous administration of 5-bromo-2'-deoxyuridine (BrdU) for 5 days using implanted mini-osmotic pumps to label all proliferating (P) cells. Thirty minutes after intraperitoneal injection of sodium borocaptate-10B (BSH), or 3 h after oral administration of dl-p-boronophenylalanine-10B (BPA), the tumors were irradiated with neutrons, or those without 10B-compounds were irradiated with gamma rays. This neutron irradiation was performed using neutrons with three different cadmium (Cd) ratios. The tumors were then excised, minced, and trypsinized. The tumor cell suspensions were incubated with cytochalasin-B (a cytokinesis-blocker), and the micronucleus (MN) frequency in cells without BrdU labeling (Q cells) was determined using immunofluorescence staining for BrdU. The MN frequency in total (P + Q) tumor cells was determined from tumors that were not pretreated with BrdU. The sensitivity to neutrons was evaluated in terms of the frequency of induced micronuclei in binuclear tumor cells (MN frequency). RESULTS: Without 10B-compounds, the MN frequency in Q cells was lower than that in the total cell population. The sensitivity difference between total and Q cells was reduced by neutron irradiation. Relative biological effectiveness (RBE) of neutrons compared with gamma rays was larger in Q cells than in total cells, and the RBE values for low-Cd-ratio neutrons tended to be larger than those for high-Cd-ratio neutrons. With 10B-compounds, MN frequency for each cell population was increased, especially for total cells. This increase in MN frequency was marked when high-Cd-ratio neutrons were used. BPA increased the MN frequency for total tumor cells more than BSH. Nevertheless, the sensitivity of Q cells treated with BPA was lower than that in BSH-treated Q cells. This tendency was clearly observed in high-Cd-ratio neutrons. CONCLUSION: From the viewpoint of enhancing the Q-cell sensitivity, tumors should be irradiated with high-Cd-ratio neutrons after BSH administration. However, normal tissue reaction remains to be examined because of its low tumor-to-normal tissue and tumor-to-blood biodistribution ratios.     

Effect of amniotic fluid volume on neonatal outcome in diamniotic twin pregnancies

PROBLEM: We assessed neonatal outcome of normal diamniotic twin pregnancies with known amniotic fluid (AF) volume. METHOD: The AF volume was empirically determined in 39 diamniotic twin gestations. The neonates were stratified by AF volume and evaluated for clinical outcome, gestational age, lecithin-sphingomyelin (L/S) ratio, and birth weight. RESULTS: Neonatal complications did not significantly differ among infants delivered from pregnancies with low (155 to 404 mL), moderate (405 to 807 mL), or high (808 to 5,430 mL) volumes of AF. Relatively constant volumes of AF were maintained throughout the 27 to 38 week range of gestational age, with no apparent correlation between AF volume and gestational age. Variations in the L/S ratio and newborn birth weights were also independent of AF volume. Gestational age was the only significant determinant of the frequency of neonatal complications. CONCLUSION: Amniotic fluid volume does not greatly affect neonatal outcome in normal diamniotic twin pregnancies.     

Rates of flu-like infection in patients with affective illness

Studies of immunologic profiles of depressed patients are suggestive of chronic viral infection and several investigators have found specific viral protein in some depressed patients. Moreover, several psychotropic drugs have anti-viral activity and can inhibit viral replication. In this preliminary report, we retrospectively examined the rate of reported flu-like episodes before and during psychotropic drug treatment in 236 affectively ill patients: 177 receiving lithium prophylaxis and 59 receiving chronic antidepressant medication. We observed a small but significant reduction in the mean rate of reported flu-like illness during lithium therapy (P < 0.001), with a greater reduction in men vs. women (P < 0.05). We also found a modest reduction in reported flu-like illness during chronic treatment with antidepressants (P = 0.08). Although these observations are preliminary in nature, they complement earlier reports that some psychotropic drugs may have anti-viral activity.