Deletion and insertion mutations in early region 1a of type 5 adenovirus that produce cold-sensitive or defective phenotypes for transformation

On the basis of earlier findings showing that H5hr1 (hr1) is cold sensitive for transformation, a series of mutants were constructed so that they contained deletions or insertions in different sites of early region 1a (E1a) to ascertain: (i) whether the cold-sensitive phenotype of hr1 was the result of the identified single-base pair deletion of nucleotide 1,055 or due to a missense mutation at another site and (ii) what region and how much of the E1a 51-kilodalton protein is actually required to produce cell transformation. A mutant, H5dl101 (dl101), was constructed to contain a 5-base pair deletion of nucleotides 1,008 to 1,012, which produced a frameshift and a subsequent stop codon at nucleotide 1,241. This mutant, which should encode a truncated 33-kilodalton protein in place of the wild-type 51-kilodalton protein, had a cold-sensitive phenotype for transformation essentially identical to hr1. Consonant with this finding, a mutant (H5in106) engineered to contain a 16-base pair insertion initiated after nucleotide 1,009, with a stop codon beginning at the newly inserted nucleotide 1,013, also had a cold-sensitive phenotype like hr1 and dl101. It is striking, however, that a mutant (H5dl105) with a 69-base pair deletion beginning at nucleotide 1,003, and having a stop codon at nucleotide 1,544, was totally defective for transformation at any temperature. Transfection studies with plasmids containing the E1a or E1a and E1b genes of sub309, hr1, and dl101 further revealed that the cold-sensitive transformation phenotype observed could be exhibited in the absence of viral E1b gene expression.     

Dermatoscopy and High Frequency Sonography: Two Useful Non-Invasive Methods to Increase Preoperative Diagnostic Accuracy in Pigmented Skin Lesions

Dermatoscopy and high frequency sonography have recently been combined to increase diagnostic preoperative accuracy in the treatment of pigmented skin lesions. In this monocentric study 80 patients with pigmented skin lesions were evaluated clinically, by dermatoscopy, and 20 MHz-sonography followed by dermatohistopathological evaluation; 39 malignant melanomas, 37 common nevi, 3 dysplastic nevi, and 1 nevus Spitz were diagnosed histologically. In 72 of the 80 cases (91.3%) dermatoscopical diagnoses were confirmed by histopathology, compared to only 79% correct clinical diagnoses. For the mere clinical diagnosis of melanoma sensitivity was 79%, specificity was 78% and diagnostic accuracy was 65%. All diagnostic values increased by dermatoscopy: sensitivity reached 90%, specificity was 93%, and diagnostic accuracy was 83%. In order to determine tumor thickness preoperatively tumor thickness was measured by 20 MHz sonography. The correlation of tumor thickness between histometric and sonographic results was determined for nevi (r = 0.93) and melanoma (r = 0.95); 74.3% of melanomas were diagnosed correctly within an 0.2 mm range. Regarding the clinical important limit of 1 mm tumor thickness, 87.2% were diagnosed in accordance with histometric evaluation. An increase of 18% in diagnostic accuracy by dermatoscopy and 87.2% of correctly diagnosed cases of tumor thickness of malignant melanoma by high frequency sonography clearly demonstrate that these methods should be considered standard procedures in the diagnosis of pigmented skin lesions and will facilitate the decision on necessary surgical treatment.     

The effect of lactation on the length of the post partum anovulatory period: an application of a bivariate stochastic model

A model of the effects of lactation on the post partum anovulatory period is presented. Parameters are estimated and the model is seen to fit the data of Perez et al. (1971) very well. Models of this type can be used to study other situations in which individuals change randomly over time in characteristics which affect a dependent behavioral process. It is hypothesized that the relative effects of nursing on post partum sterility are constant across societies, although the absolute effects vary from society to society. The hypothesis is shown to be in agreement with a variety of apparently inconsistent studies in the literature.     

Chenodeoxycholic acid normalizes elevated lipoprotein secretion and catabolism in cerebrotendinous xanthomatosis

Cerebrotendinous xanthomatosis (CTX) is a rare inherited lipid storage disease caused by a defect in bile acid synthesis in which cholesterol and its product cholestanol are deposited in neurological and vascular tissue. Therapy with chenodeoxycholic acid but not with the 7 beta-epimeric ursodeoxycholic acid is usually successful. In an untreated patient, total and low density lipoprotein (LDL) cholesterol were found to be low (134 +/- 11 and 78 +/- 8 mg/dl, respectively). The production rate (PR) and fractional catabolic rate (FCR) of very low density (VLDL) apolipoprotein B (apoB) were, however, both markedly increased (34.7 mg/kg per day and 13.7 pools/day, respectively vs. 15.1 +/- 5.0 mg/kg per day and 6.2 +/- 3.8 pools/day in controls) while the PR and FCR of LDL apoB were moderately elevated (16.3 mg/kg per day and 0.65 pools/day, respectively vs. 12.9 +/- 1.2 mg/kg per day and 0.52 +/- 0.10 pools/day in controls). After 1 month of 750 mg/day of chenodeoxycholic acid, the FCR and PR of both VLDL and LDL apoB became normal while total plasma cholesterol increased significantly to 145 +/- 18 mg/dl. In a second patient who had been receiving 750 mg/day of chenodeoxycholic acid for 6 months lipoprotein kinetics were normal. These parameters did not change when the subject was switched to 750 mg/day ursodeoxycholic acid. We postulate that cholesterol biosynthesis in CTX is derepressed by a diminished hepatic pool of chenodeoxycholic acid and that the elevated secretion of apoB is a response to the increased rate of cholesterol production.     

New synthesis of a platelet-specific protein: platelet factor 4 synthesis in a megakaryocyte-enriched rabbit bone marrow culture system

The site of synthesis of platelet-specific proteins remains to be established. With the use of short-term megakaryocyte-enriched cultures, direct evidence was obtained to show that megakaryocytes synthesize the platelet-specific protein, platelet factor 4. A megakaryocyte-enriched fraction of rabbit bone marrow for culture was obtained by centrifugal elutriation and cultured with [3H]leucine. Newly synthesized 3H-platelet factor 4 was sought by copurification with added carrier rabbit platelet factor 4, using heparin agarose affinity chromatography and immunoprecipitation with specific goat anti- rabbit platelet factor 4 antisera. SDS PAGE of the washed immunoprecipitates demonstrated a [3H]leucine-containing peak which migrated identically with purified homogeneous rabbit platelet factor 4. A second, slightly larger molecular-weight protein was identified in the gels also, suggesting that rabbit platelet factor 4 may be synthesized as a larger molecular-weight precursor in rabbit megakaryocytes. These results provide direct evidence that the platelet- specific protein, platelet factor 4, is synthesized in rabbit megakaryocytes before it is packaged into alpha-granules for release in circulating platelets.