Double germline mutations in the RET Proto-oncogene in MEN 2A and MEN 2B kindreds.

Medullary thyroid carcinoma (MTC) is a rare form of thyroid cancer representing about 10% of all thyroid malignancies. It occurs mostly as a sporadic tumor or in association with autosomal dominant inherited cancer syndromes--multiple endocrine neoplasia (MEN) types 2A and 2B and familial MTC. Germline mutations in exons 8, 10, 11, 13, 14, 15 and 16 of the RET proto-oncogene are found in most of the familial cases. There are only a few published data reporting multiple germline mutations in the RET proto-oncogene. We have detected double germline mutations in 2 different exons on the same RET allele in two MEN 2 families. In the MEN 2A family, double germline mutation in exons 10 (Cys620Phe) and 13 (Tyr791Phe) was detected. In the MEN 2B family, beside the classical germline mutation in exon 16 (Met918Thr) a second germline mutation in exon 13 (Tyr791Phe) was found. This study revealed that MEN 2 syndromes can also be caused by double germline mutations in the RET proto-oncogene and these families can be added to small worldwide cohort of families with multiple germline mutations.     

Effect of short-term erythropoietin therapy in anemic premature infants.

OBJECTIVE: To determine the effectiveness of a 10-day subcutaneous erythropoietin (rHuEpo) course of 300 units per kg per dose plus oral iron compared to oral iron alone in anemic infants during their convalescent phase of illness. STUDY DESIGN: Prospective, randomized trial performed at a 40-bed, teaching, referral, level III, neonatal intensive care unit. Infants with a gestational age at birth of less than 32 weeks, hematocrit of less than or equal to 28% with a corrected reticulocyte count of less than or equal to 5%, postconceptual age of less than 48 weeks or 5 months chronological age, and a diagnosis of anemia of prematurity were considered for inclusion. Major outcome parameters included hematocrit, corrected reticulocyte count and red cell transfusion requirements. RESULTS: A total of 60 infants were enrolled (n=30 per group). Infants randomized to rHuEpo had a significantly higher post-treatment hematocrit and corrected reticulocyte count than infants in the iron only group (p<0.001). There was a trend towards fewer red cell requirements in the rHuEpo group. CONCLUSIONS: The rHuEpo regimen studied here was associated with an acute improvement in hematocrit and corrected reticulocyte counts. This study did not demonstrate a statistically significant decrease in transfusion therapy, in part related to increased subsequent use of rHuEpo in the control group. Taken together, these data demonstrate that this regimen can effectively treat anemia in convalescent premature infants.     

Identification of two genetic markers that distinguish pathogenic and nonpathogenic strains of Acanthamoeba spp.

Species-level identification of Acanthamoeba isolates is difficult and gives little or no indication of the isolate's pathogenicity. We identified two amplification-based genetic markers that were highly correlated with pathogenicity in Acanthamoeba spp. One marker, designed to amplify a 485-bp fragment of the small-subunit ribosomal RNA gene (ssrDNA), was preferentially amplified from the nonpathogenic strains; amplifications from the pathogenic strains yielded anomalous fragments of 650 and 900?bp. A second marker was developed on the basis of the anomalous 650-bp fragment. Primers to this sequence preferentially amplified a noncoding locus (called Ac6) only from the pathogenic strains. These two genetic markers may be useful for identification of pathogenic Acanthamoeba spp. strains.     

Effects of the anticholinesterase edrophonium on spectral analysis of heart rate and blood pressure variability in humans.

Edrophonium, an anticholinesterase, exerts a biphasic effect on cardiovascular autonomic drive in humans (lower doses enhance; higher doses reduce). Twenty-five anesthetized, mechanically respired (10 breaths. min(-1), constant tidal volume) patients were given either saline (n = 10) or edrophonium (0.01-1.0 mg. kg(-1), n = 15) following surgery. ECG, radial arterial pressure, and respiratory rate were sampled at 250 Hz to obtain time series for consecutive R-R intervals (RRIs), and systolic (SBP) and diastolic blood pressure (DBP). A Wigner distribution was used for time frequency mapping of spectral powers at high (HFP, 0.15-0.5 Hz) and low (LFP, 0.0-0.05 Hz) frequency. Edrophonium produced a dose-dependent decrease in heart rate [baseline 66.8 +/- 1.9 (S.E.M.) beats per minute; maximum decrease to 55.8 +/- 1.4 beats per minute with 1.0 mg. kg(-1), P < 0.01]. HFP of the RRI increased at low doses (0.2-0.4 mg. kg(-1); maximum increase to 111.0 +/- 58.2% baseline; P < 0.01) but decreased (-49.5 +/- 35.5% baseline; P < 0.01) at higher (1.0 mg. kg(-1)) doses. Edrophonium had no effect on SBP and DBP. HFP of SBP decreased with increasing doses (maximal decrease to -26.2 +/- 7.5% baseline, P < 0.01, 1.0 mg. kg(-1)). LFP of SBP was also decreased (-46.3 +/- 10.9% baseline, P < 0.01, 1.0 mg. kg(-1)). Edrophonium may enhance (lower dose) or reduce (higher dose) cardiovascular autonomic drive in humans, as evidenced by the significant changes it evokes in HFP of the RRI (parasympathetic drive), and in the HFP and LFP of SBP (sympathetic drive). These observations may account for the modest autonomic side effects of edrophonium when this drug is used clinically.     

Dynamic changes in the distribution of the calcium-activated neutral protease in human red blood cells following cellular insult and altered Ca2+ homeostasis.

Mechanistic studies were conducted to examine the relationship between oxidative membrane protein damage, altered Ca2+ homeostasis, and changes in the levels of plasma membrane-bound Ca(2+)-activated neutral protease, microCANP. Alterations in the levels of plasma membrane-bound microCANP in erythrocytes and hemolysate following cumene hydroperoxide (CHP) insult were monitored using SDS-PAGE and immunoblot analyses. Free radical scavengers, antioxidant and EGTA effects on membrane-bound microCANP levels in CHP-treated cells and hemolysate were also examined. CHP (2 mM) addition to red cells caused a significant decrease/loss in intensity of numerous protein bands in the SDS-PAGE pattern, to include bands 1, 2, 2.1, 4.1, 4.2, and an approximately 60-kDa protein. N-acetylcysteine (20 mM), dithiothreitol (50 mM), and dimethylthiourea (50 mM) diminished CHP-mediated membrane protein damage; in contrast, dimethylfuran (50 mM) exacerbated CHP-mediated membrane protein damage. Dimethylsulfoxide (50 mM) was without significant effect. The free radical scavengers and antioxidants differentially affected membrane-bound microCANP levels largely in parallel with their ability to modulate membrane protein damage. Immunoblot analysis of 1 mM CHP-treated red cells revealed a time-dependent loss of membrane-bound microCANP, with a complete loss of microCANP monitored at 8 hr. Treatment of erythrocytes with CHP also resulted in concentration-dependent alterations in the level of membrane-bound microCANP: at 0.5 or 1.0 mM CHP a decreased level of membrane-bound microCANP was detected relative to control, whereas an increase in the level of bound enzyme was monitored from 2 to 4 mM CHP. CHP addition to hemolysate produced a decrease in membrane-bound microCANP levels comparable to that observed with erythrocytes; addition of the Ca2+ chelator EGTA or Calpain Inhibitor I (N-acetyl-leucyl-leucyl-leucyl-nor-leucinal) to hemolysate effectively inhibited this decrease. In contrast, treatment of erythrocytes with Ca2+ in the presence of the Ca2+ ionophore A23187 resulted in change in the SDS-PAGE protein bands and membrane-bound microCANP levels that were comparable to those produced by CHP. Inclusion of EGTA in this system prevented microCANP binding. These data provide evidence for membrane damage and concomitant dynamic alterations in membrane-bound microCANP levels in the red cell or hemolysate following oxidative insult, and show that this process can be modulated by free radical scavengers and antioxidant, simulated by treating cells with Ca2+ in the presence of ionophore, and inhibited by EGTA or Calpain Inhibitor I.     

Professional involvement in sexuality counseling for patients with spinal cord injuries

A national survey was conducted to determine how occupational therapists and rehabilitation nurses conduct sexuality counseling in practice settings with spinal cord-injured patients. A review of the literature and results from the survey demonstrated a high priority concern for sexuality counseling in the total rehabilitation of the spinal cord-injured patient; however, many of the professionals surveyed did not conduct sexuality counseling as part of their job. This study provides data comparing the sexuality counseling approach taken by these two disciplines and identifies ways to eliminate the incongruities between recommendations made in the literature and actual clinical practice.     

Reconstruction of lateral skull base defects after tumor ablation.

Neoplasms located in the lateral skull base region present a challenge for evaluation and management due to their difficult anatomic location and the complex reconstruction that is required following extensive tumor resection. Repair following tumor ablation requires a watertight dural seal, obliteration of the dead space, and coverage with vascularized soft tissue. Advances in radiologic imaging, diagnostic pathology, and surgical techniques and a multidisciplinary team for tumor ablation and reconstruction have significantly improved the treatment of these patients, minimized the occurrence of postoperative complications, and maximized patient outcome and quality of life. In this article, we present our experience in the reconstruction of extensive lateral skull base defects after tumor ablation.