Widely dispersed p53 mutation in respiratory epithelium. A novel mechanism for field carcinogenesis

Individuals with one aerodigestive tract malignancy have a high incidence of second primary aerodigestive tumors. The mechanism for this field effect has not been determined. We studied an individual with widespread dysplastic changes in the respiratory epithelium but no overt carcinoma. The entire tracheobronchial tree obtained at autopsy was embedded in paraffin, and bronchial epithelial cells were isolated by microdissection. DNA extracted from the microdissected cells was analyzed for point mutations in the p53 tumor suppressor gene. A single, identical point mutation consisting of a G:C to T:A transversion in codon 245 was identified in bronchial epithelium from 7 of 10 sites in both lungs. Epithelium at sites containing the p53 mutation was morphologically abnormal, exhibiting squamous metaplasia and mild to moderate atypia. No invasive tumor was found in the tracheobronchial tree or any other location. Cells from peripheral blood, kidney, liver, and lymph node exhibited no abnormality in the p53 gene. The widespread presence of a single somatic p53 point mutation in the bronchi of a smoker suggests that a single progenitor bronchial epithelial clone may expand to populate broad areas of the bronchial mucosa-a novel mechanism for field carcinogenesis in the respiratory epithelium that may be of importance in assessing individuals for risk of a second primary tumor as well as in devising effective strategies for chemoprevention of lung cancer.     

Structural and thermodynamic characteristics of the binding of the lambda N protein to a RNA hairpin

The specific binding of the lambda N protein to a 15 nucleotide RNA oligomer that forms a hairpin structure has been investigated by biophysical methods. Using fluorescence spectroscopy and equilibrium ultra-centrifugation, it was found that the N protein binds specifically to this RNA hairpin as a monomer. Circular dichroism experiments show that both the N protein and the RNA hairpin undergo structural change upon association of the complex.     

Immunochemical identification and differential phosphorylation of alternatively spliced forms of the alpha 1A subunit of brain calcium channels

Biochemical properties of the alpha 1 subunits of class A brain calcium channels (alpha 1A) were examined in adult rat brain membrane fractions using a site-directed anti-peptide antibody (anti-CNA3) specific for alpha 1A. Anti-CNA3 specifically immunoprecipitated high affinity receptor sites for omega-conotoxin MVIIC (Kd approximately 100 pM), but not receptor sites for the dihydropyridine isradipine or for omega-conotoxin GVIA. In immunoblotting and immunoprecipitation experiments, anti-CNA3 recognized at least two distinct immunoreactive alpha 1A polypeptides, a major form with an apparent molecular mass of 190 kDa and a minor, full-length form with an apparent molecular mass of 220 kDa. The 220- and 190-kDa alpha 1A polypeptides were also specifically recognized by both anti-BI-Nt and anti-BI-1-Ct antibodies, which are directed against the NH2- and COOH-terminal ends of alpha 1A predicted from cDNA sequence, respectively. These data indicate that the predicted NH2 and COOH termini are present in both size forms and therefore that these isoforms of alpha 1A are created by alternative RNA splicing rather than post-translational proteolytic processing of the NH2 or COOH termini. The 220-kDa form was phosphorylated preferentially by cAMP-dependent protein kinase, whereas protein kinase C and cGMP-dependent protein kinase preferentially phosphorylated the 190-kDa form. Our results identify at least two distinct alpha 1A subunits with different molecular mass, demonstrate that they may result from alternative mRNA splicing, and suggest that they may be differentially regulated by protein phosphorylation.     

Organ specificity of angiotensin II and Des-aspartyl angiotensin II in the conscious rat

Des-Asp angiotensin II (des-Asp AII) is a naturally occurring heptapeptide metabolite of angiotensin II (AII) which is formed by the enzymatic action of aminopeptidase A. Angiotensin II and des-Asp AII were infused into unanesthetized rats while direct mean arterial pressure, serum aldosterone and serum corticosterone were measured. Both AII and des-Asp AII caused a dose-related increase in serum aldosterone with a significant increase occurring with a dose as low as 1 ng/min. This effect was blocked by pretreatment with 1-Sar-8-Ala-angiotensin II, a competitive inhibitor of AII; however, the inhibitor was more effective in blocking the effects of AII (101%) than of des-Asp AII (82%). Both angiotensins induced a dose-related increase in serum corticosterone and mean arterial pressure. Des-Asp AII was however only 1/10 as potent as AII in elevating mean arterial pressure. 1-Sar-8-Ala-AII was also effective in inhibiting the pressor effects of AII and des-Asp AII. These data illustrate a high degree of organ specificity or selectivity for des-Asp AII and a low specificity for AII. Aminopeptidase A and leucine aminopeptidase were identified in the adrenal cortex and medulla in large amounts. Des-Asp AII may thus be formed from AII locally in the adrenal gland prior to exerting its action at that site.     

Teaching an illiterate transplant patient

RSR is now several years posttransplant. He has a serum creatinine of 2.1 mg/dl and his hypertension remains borderline with additional medication. He is seen regularly by his local nephrologist and once a year at the transplant center. In RSR's case, collaboration with physicians, nurses, and home health helped this patient achieve the goal of self-care. Illiteracy was no barrier to achieving this goal when assessing the patient's skills, developing a plan that uses those skills, and working together as a team to implement the plan.     

Supracondylar humerus fractures in children

Supracondylar fractures of the humerus are the most common fractures in children that require surgery. A significant advancement in the field of pediatric orthopedics has been closed reduction and percutaneous pinning of these fractures. This technique, using high quality fluoroscopic imaging, allows for a near anatomical reduction of fractures without the need for an open surgical procedure or prolonged traction. Supracondylar fractures in children are often associated with neurologic and vascular damage that must be recognized before fracture reduction. Nursing staff members' skill with pediatric patients can greatly aid the surgeon in the timely and safe treatment of these fractures.     

In vivo electrochemical studies of dopamine overflow and clearance in the striatum of normal and MPTP-treated rhesus monkeys

Translational recruitment of maternal mRNAs is an essential process in early metazoan development. To identify genes required for this regulatory pathway, we have examined a collection of Drosophila female-sterile mutants for defects in translation of maternal mRNAs. This strategy has revealed that maternal-effect mutations in the cortex and grauzone genes impair translational activation and cytoplasmic polyadenylation of bicoid and Toll mRNAs. Cortex embryos contain a bicoid mRNA indistinguishable in amount, localization, and structure from that in wild-type embryos. However, the bicoid mRNA in cortex embryos contains a shorter than normal polyadenosine (poly(A)) tail. Injection of polyadenylated bicoid mRNA into cortex embryos allows translation demonstrating that insufficient polyadenylation prevents endogenous bicoid mRNA translation. In contrast nanos mRNA, which is activated by a poly(A)-independent mechanism, is translated in cortex embryos, indicating that the block in maternal mRNA activation is specific to a class of mRNAs. Cortex embryos are fertilized, but arrest at the onset of embryogenesis. Characterization of grauzone mutations indicates that the phenotype of these embryos is similar to cortex. These results identify a fundamental pathway that serves a vital role in the initiation of development.     

Transcutaneous electrical nerve stimulation and temporary S3 neuromodulation in idiopathic detrusor instability

PURPOSE: We studied the effects of electrical stimulation on idiopathic detrusor instability. MATERIALS AND METHODS: Between January 1993 and December 1994, 30 men and 41 women (mean age plus or minus standard deviation 48 +/- 16 years) underwent transcutaneous electrical nerve stimulation (TENS) of the S2-S3 dermatomes, and 13 men and 22 women (mean age 48 +/- 12 years) underwent S3 neuromodulation. Subjective assessment was performed using a diary and symptom score of 0 to 14. Objective outcome was analyzed with urodynamic studies. RESULTS: Mean duration of TENS was 3 +/- 1 weeks (range 2 to 4). Although there were no major complications 31% of the patients reported local skin irritation. The overall urinary symptom scores improved from 10 +/- 2 (range 5 to 14) before the study to 7 +/- 3 (range 1 to 14) during stimulation. Urodynamic analysis revealed significant (p < 0.05) improvements in total bladder capacity and voided volume, and decreases in the number and frequency of unstable contractions. Mean duration of S3 neuromodulation was 6 +/- 1 days (range 4 to 8 days). Four procedures failed due to electrode displacement in 3 cases and procedure intolerance in 1. Hemorrhage from the puncture site occurred in 1 patient. Overall urinary symptom scores were 10 +/- 3 (range 5 to 14) before the study and 5 +/- 2 (range 2 to 10) during stimulation. Although symptomatic relief was more pronounced with S3 neuromodulation, no statistically significant differences were found regarding urinary symptoms compared to TENS. CONCLUSIONS: In patients with severe detrusor instability refractory to conservative treatments the use of TENS and S3 neuromodulation produced significant changes in urodynamic parameters and presenting symptoms. Our results appear to justify evaluation with neuromodulatory techniques before definitive surgical intervention in these patients.