Change in pulmonary venous admixture with varying inspired oxygen

Pulmonary venous admixture (Qsp/Qt) was analyzed as a function of fractional concentration of inspired O2 (FIO2) in 30 patients who required postoperative mechanical ventilation. Pulmonary and radial artery blood-gas tensions and pH were measured and Qsp/Qt was calculated with FIO2 ranging from 0.21 to 1. In all patients, Qsp/Qt decreased when FIO2 was increased from 0.21 to 0.4 and then stabilized to an FIO2 of approximately 0.6. As the FIO2 was increased to 1, Qsp/Qt increased. Since the inhalation of gas mixture with FIO2 greater than or equal to 0.6 increased right-to-left intrapulmonary shunting of blood, we recommend respiratory function be evaluated during inhalation of a clinically useful concentration of O2 rather than at an FIO2 of 1.     

Average length of spontaneous labor in Chinese primigravidas

The effect of long-term L-thyroxine (LT4) replacement therapy on bone mineral density and on biochemical markers of bone turnover were studied in children with congenital hypothyroidism (CH). Forty-four children and adolescents (mean age 8.5 +/- 3.5 years) with primary CH who began LT4 replacement therapy within the first month of life were studied. Bone mineral density (BMD) of the lumbar vertebrae and the upper femoral bone was measured by dual energy X-ray absorptiometry. Serum osteocalcin (OC) and bone alkaline phosphatase were measured as markers of bone formation and urinary deoxypyridinoline was taken as a marker of bone resorption. Bone mineral densities of CH children were not different from those in age-matched controls. The biochemical markers of bone turnover were normal except for the serum OC levels which were found to be higher than in controls and positively correlated with the free thyroid hormone levels (for FT4 r = 0.42, p = 0.02). Eight CH children demonstrated low BMD values (below -1 SDS) at -2 +/- 0.7 SDS for the lumbar spine and -1.6 +/- 0.5 SDS for the femoral site. These eight children showed lower mean weight (p < 0.05) and their dietary calcium intake tended to be less (p <0.06) than that seen in the normal BMD group. In conclusion, our results show that LT4 replacement therapy for 8 years is not detrimental to the skeletal mineralization of CH children. As in a healthy population, weight and current intake of calcium seem to be major determinants of bone density. Dietary recommendations, especially when calcium intake is below the recommended dietary allowance, may have to be reconsidered.     

Syndecan-4 proteoglycan cytoplasmic domain and phosphatidylinositol 4,5-bisphosphate coordinately regulate protein kinase C activity

Phosphatidylinositol 4,5-bisphosphate (PIP2) is involved in the organization of the actin cytoskeleton by regulating actin-associated proteins. The transmembrane heparan sulfate proteoglycan syndecan-4 also plays a critical role in protein kinase C (PKC) signaling in the formation of focal adhesions and actin stress fibers. The cytoplasmic domain of syndecan-4 core protein directly interacts with and potentiates PKCalpha activity, and it can directly interact with the phos- phoinositide PIP2. We, therefore, investigated whether the interaction of inositol phosphates and inositol phospholipids with syndecan-4 could regulate PKC activity. Data from in vitro kinase assays using purified PKCalpha beta gamma show that in the absence of phosphatidylserine and diolein, PIP2 increased the extent of autophosphorylation of PKCalpha beta gamma and partially activated it to phosphorylate both histone III-S and an epidermal growth factor receptor peptide. This activity was dose-dependent, and its calcium dependence varied with PKC isotype/source. Addition of the cytoplasmic syndecan-4 peptide, but not equivalent syndecan-1 or syndecan-2 peptides, potentiated the partial activation of PKCalpha beta gamma by PIP2, resulting in activity greater than that observed with phosphatidylserine, diolein, and calcium. This study indicates that syndecan-4 cytoplasmic domain may bind both PIP2 and PKCalpha, localize them to forming focal adhesions, and potentiate PKCalpha activity there.     

Morphometric video analysis of the engine-driven nickel-titanium Lightspeed instrument system

Two hundred and sixteen Lightspeed instruments were evaluated microscopically for the presence of corrosion, surface debris, and alloy defects. The instruments were assessed morphometrically for consistency of physical design and dimensions by measuring and analyzing eight parameters of the instrument pilot tips, heads, and shafts. Results from visual inspection showed that none of the instruments were corroded; 23 presented surface porosities, and 17 had sharp strips of alloy. Data obtained by morphometric analysis indicated the mean diameter of the head of only 7 of 18 sizes met the +/- 0.02 mm allowable tolerance set forth by the American Dental Association (ADA) Specification No. 28. Observation and video analysis indicated that instruments of the same size adhere to the same basic design, but that morphometric variations do exist. The visual and intersize analysis indicated that the Lightspeed is not an instrument of any one determined shape that changes only in diameter. Rather, it is a series of instruments that show gradual shifts in both size and shape as the instrument size increases. Lightspeed instruments are a new type of nickel-titanium endodontic instrument that cannot be evaluated using the standards proposed by the American National Standards Institute/ADA Specification No. 28 for files and reamers.     

Use of endometrial measurement as an exclusion criterion for in vitro fertilization using clomiphene citrate

OBJECTIVE: Previous reports have indicated an association between endometrial development and pregnancy outcome for patients treated with clomiphene citrate (CC) in conjunction with intrauterine insemination or intercourse. We expanded the use of CC for ovulation induction in association with in vitro fertilization (IVF). This study was designed to determine if endometrial thickness should be used as an inclusion or exclusion criterion for CC-IVF. STUDY DESIGN: One hundred twenty-eight patients were enrolled in an ovulation-induction regimen using CC for expected IVF-ET between January 1992 and December 1992. A total of 81 patients met inclusion criteria for CC-IVF and had endometrial measurement performed prior to human chorionic gonadotropin administration. Patients were categorized on the basis of endometrial measurement as follows: (A) > 4 - < 7 mm, (B) > or = 7 - < or = 10 mm, and (C) > 10 mm. Standard IVF was performed, and pregnancy rates for each category were evaluated. RESULTS: A total of 23 pregnancies (28% per retrieval) were established. Pregnancy rates were not different by category (P > .10, Fisher's Exact Test): (A) 3/15 (20%), (B) 13/41 (32%), and (C) 7/25 (28%). CONCLUSION: These data suggest that for CC-IVF. endometrial measurement should not be used as an exclusion criterion since pregnancies occurred at comparable frequencies in all the groups.     

The role of stomach pathology as a risk factor in ulcer formation at different times of chronic dialysis treatment

Two groups of patients with chronic renal failure (CRF) underwent chronic hemodialysis within 1976-1990. Acute ulcerogenic situation in them arose during month 1-3 of the treatment. Formation of ulcers was closely related to the acid-peptic factor. Hemodialysis procedure was found to contribute to ulcerogenesis, chronic hemodialysis being somewhat an iatrogenic risk factor in such patients. Modern policy of managing duodenal ulcers in hemodialysis patients is discussed.     

Amination of tyrosine in liver cytosol protein of male F344 rats treated with 2-nitropropane, 2-nitrobutane, 3-nitropentane, or acetoxime

Previously, the secondary nitroalkane 2-nitropropane, a strong hepatocarcinogen in rats, had been shown to induce the formation of 8-aminoguanine in both DNA and RNA of rat liver through a sulfotransferase-mediated pathway. This pathway was postulated to convert the carcinogen into an aminating species [Sodum, R. S., et al. (1994) Chem. Res. Toxicol. 7, 344-351]. To submit this postulate to further test, we examined liver proteins of rats treated with 2-nitropropane, other carcinogenic secondary nitroalkanes, or the related rat liver tumorigen acetoxime for the presence of 3-aminotyrosine, the expected product of tyrosine amination. Using ion-pair and/or cation-exchange high-performance liquid chromatography with electrochemical detection, we found that the liver cytosolic proteins of these animals contained 0.1-1.5 mol of 3-aminotyrosine/10(3) mol of tyrosine. Treatment with the noncarcinogenic primary nitroalkane 1-nitropropane or with other primary nitroalkanes did not produce an analogous increase in the aminated amino acid (level of detection estimated at approximately 0.01 mol/10(3) mol of tyrosine). To our knowledge, this is the first report of the modification of protein tyrosine in vivo by a carcinogen. In vitro studies with acetoxime-O-sulfonate and hydroxylamine-O-sulfonate showed that these proposed intermediates in the activation pathway of 2-nitropropane react with guanosine to give 8-aminoguanosine, N1-aminoguanosine, and 8-oxoguanosine and also react with tyrosine to give 3-aminotyrosine and 3-hydroxytyrosine. The in vitro amination and oxidation of guanosine at C8 were also produced by acetophenoxime-O-sulfonate and 2-heptanoxime-O-sulfonate. These results provide additional evidence for the production of a reactive species capable of aminating nucleic acids and proteins from 2-nitropropane and other carcinogenic secondary nitroalkanes by a pathway involving oxime- and hydroxylamine-O-sulfonates as intermediates.     

Esophageal squamous carcinoma

Squamous cell carcinoma of the esophagus is a tumor with poor prognosis; it is usually in an advanced state when first diagnosed. Because a multimodal treatment approach is currently used, proper tumor staging is essential to determine whether therapy should be directed toward cure or palliation. Important prognostic features of squamous cell carcinoma include the depth of tumor infiltration into or through the esophageal wall and the presence of distant metastases. Imaging strategies should not be limited to visualization of the tumor but also should be directed toward accurate pretreatment staging. In this article, the authors review the use of barium swallow, CT scans, and endoscopic ultrasonography both alone and in combination to visualize and stage esophageal carcinoma. The strengths and limitations of each modality are also discussed.     

Prediction of major depression and dysthymia from CES-D scores among ethnic minority adolescents

Two tumour cell clones, 6D1 and 4C2 cells, which are defective both in the major histocompatibility gene complex (MHC) class I expression and in the endogenous antigen presentation, are recovered with interferon (IFN)-gamma treatment. The present study describes the ultrastructure of these cells by using scanning and transmission electron microscopy in relation to the effect of IFN-gamma treatment. The general morphology of these cells was found to be similar to each other and comparable to that of a tumour cell clone, 4A1 cells, of the same origin, normal in MHC class I expression; they exhibited a fibroblast-like appearance and had many blebs on all the cell surfaces, with desmosome-like junctions between cells. On IFN-gamma treatment, surface fine blebs appeared less, and mitochondria became more densely stained. Expression of MHC class I molecules on the cell surface was much higher in the IFN-gamma treated 6D1 and 4C2 cells than in untreated cells, when estimated by immunoelectron microscopy. The addition of an epitope peptide to these cells did not enhance the class I expression, which differed from other antigen presentation-defective cells such as RMA-S cells, nor change the cell surface morphology.