A patient with right and left atrial membranes: the role of transesophageal echocardiography and magnetic resonance imaging in diagnosis

A patient who had right and left atrial membranes was examined. The diagnosis and the hemodynamic significance of both membranes were detailed by transesophageal echocardiography and were confirmed by magnetic resonance imaging. Transesophageal imaging was found to be superior to routine echocardiography in visualization of these atrial structures.     

Growth kinetics of microscopic hepatocellular neoplasms in carcinogen-resistant and carcinogen-responsive strains of mice.

The initiation and growth of microscopic hepatocellular neoplasms in C57BL/6 mice, considered relatively resistant to hepatocarcinogenesis, was compared with that of the more responsive C3H and B6C3F1 (C57BL/6 x C3H) strains. Tumors were induced by giving male mice injections of diethylnitrosamine when they were 15 days old. During the first 18 weeks postinjection, the growth rates of neoplasms in the three strains were almost identical (doubling time of 2.1 to 2.5 weeks). However, after that time, only the growth rates of the C57BL/6 neoplasms slowed; between 30 and 42 weeks the doubling time had increased to 13 weeks. In addition, at all sacrifice times the number of neoplasms in the C3H strain was at least 2.5 times higher than in the C57BL/6 and B6C3F1 strains. These results suggest that the genetic determinant(s) for inhibited tumor growth (expressed only in C57BL/6 mice) are recessive to those for unimpeded tumor growth (expressed in C3H and B6C3F1 mice), while the determinant(s) for large numbers of tumors (expressed only in C3H mice) are recessive to those for small numbers of tumors (expressed in C57BL/6 and B6C3F1 mice). In addition to the interstrain differences in tumor growth, two other types of tumor growth heterogeneity were identified. First, in each of the three strains, the largest tumors were found to grow faster than the smaller tumors. This suggests that the very broad range in tumor size that is seen in this model results from the long-term differences in the growth rates of individual neoplasms. Second, we found that in microscopic hepatic neoplasms in B6C3F1 mice, the thymidine labeling indices were 2.3 times greater in the outer 50-microns shell (2 cells thick) than in the next deeper 50-micron layer cells. This suggests that even in these minute neoplasms, gradients in blood-borne oxygen, nutrients, or growth factors are responsible for heterogeneous growth.     

Effects of coenzyme athletic performance system as an ergogenic aid on endurance performance to exhaustion.

This study examined the effects of the Coenzyme Athletic Performance System (CAPS) on endurance performance to exhaustion. CAPS contains 100 mg coenzyme Q10, 500 mg cytochrome C, 100 mg inosine, and 200 IU vitamin E. Eleven highly trained male triathletes were given three daily doses of either CAPS or placebo (dicalcium phosphate) for two 4-week periods using a double-blind crossover design. A 4-week washout period separated the two treatment periods. An exhaustive performance test, consisting of 90 minutes of running on a treadmill (70% VO2max) followed by cycling (70% VO2max) until exhaustion, was conducted after each treatment period. The mean (+/- SEM) time to exhaustion for the subjects using CAPS (223 +/- 17 min) was not significantly different (p = 0.57) from the placebo trial (215 +/- 9 min). Blood glucose, lactate, and free fatty acid concentrations at exhaustion did not differ between treatments (p < 0.05). CAPS had no apparent benefit on exercise to exhaustion.     

Nd:YAG laser laparoscopic coagulation of symptomatic myomas.

The Nd:YAG laser dispersion effect, 2-5 mm in diameter, is utilized in a new laparoscopic procedure to coagulate and reduce symptomatic serosal and intramural myomas of moderate size (less than or equal to 10 cm). Depot leuprolide pretreatment for 2-6 months resulted in 40-60% shrinkage. Seventy-five patients 35-50 years old with symptomatic myomas, pain and pressure then underwent Nd:YAG laser coagulation for thorough devascularization of uterine myomas. Postoperative transvaginal ultrasound one, three and six months later showed the myomas reduced an average of 50-70% beyond the effect attributable to leuprolide. In two groups of patients whose myomas measured 5-10 cm and 3-5 cm after leuprolide pretreatment, laser coagulation subsequently reduced the myomas an average of 50%. In patients with postleuprolide myomas of 2-3 cm, virtually no myomas were identified postoperatively. The patients were followed up to 14 months. This laparoscopic procedure can be used in patients approaching menopause who wish to avoid abdominal myomectomy or hysterectomy.     

Molecular cloning of a cDNA for rat diabetes-inducible cytochrome P450RLM6: hormonal regulation and similarity to the cytochrome P4502E1 gene.

1. A polyclonal, monospecific antibody to a constitutive, diabetes-inducible and insulin-reversible cytochrome P-450 isozyme (RLM6) was used to screen a male rat liver cDNA library in lambda gt 11. Six clones harbouring the RLM6 cDNA insert were isolated initially from the expression library and three of these were further plaque-purified and sub-cloned. A 1.1 Kb cDNA insert, representing approximately 65% of the expected full length cDNA was characterized by restriction endonuclease mapping and sequenced by the dideoxy chain-termination method. Comparison of the nucleotide sequence of RLM6 cDNA to that of ethanol-inducible P4502E1 rat cDNA showed the two cDNAs to be identical, the RLM6 cDNA corresponding to nucleotides 310-1402 of the P4502E1 sequence. 2. RLM6 cDNA probe was used in Northern blot and RNA dot blot hybridization analysis to demonstrate that both streptozotocin-induced diabetes and fasting significantly elevated the steady-state level of RLM6 mRNA in male rat liver. Increased RLM6 mRNA level in the diabetic rat resulted in increased RLM6 apoprotein synthesis when polysomal RNA was used in a cell-free, protein-synthesizing system, indicating that the elevated RLM6 level observed in diabetic rats was correlated directly with the increased RLM6 mRNA concentration. 3. Daily insulin treatment of diabetic rats reversed the diabetes-dependent increase in RLM6 mRNA in a time-dependent manner, returning to control values after approximately 2 weeks of continuous insulin treatment. This insulin-dependent decrease of the RLM6 mRNA level was paralleled by a similar time-dependent decrease in serum acetone concentration. 4. Treatment of the male diabetic rat with testosterone also resulted in a decrease in both RLM6 mRNA and in vitro translated apoprotein. 5. Modulation of RLM6 mRNA level in the diabetic rat by insulin and testosterone, and the nucleotide sequence similarity with that of P4502E1 confirms that diabetes-inducible P450RLM6 and ethanol-inducible P4502E1 are coded for by the same gene.     

Electrophysiologic studies of serotonin receptor activation. Answered and unanswered questions

Cellular electrophysiologic responses to serotonin and serotonin agonists in vertebrate neurons and cell cultures derived from neuronal or neuroblastoma x glioma hybrids are reviewed. Emphasis is on local rather than systemic drug administration, and on intracellular and patch clamp recording. Activation of serotonin receptors can open and close potassium channels, reduce voltage-dependent calcium currents and calcium-activated potassium currents, enhance hyperpolarization-activated cation currents, and open ligand-gated cation channels. The pharmacology of these responses is described and the assignment of serotonin receptor subtypes discussed. The review is selective rather than inclusive and was concluded in November 1989.