Gi/o protein-coupled receptor inhibition of beta-cell electrical excitability and insulin secretion depends on Na+/K+ ATPase activation

Gi/o-coupled somatostatin or α2-adrenergic receptor activation stimulated β-cell NKA activity, resulting in islet Ca2+ fluctuations. Furthermore, intra-islet paracrine activation of β-cell Gi/o-GPCRs and NKAs by δ-cell somatostatin secretion slowed Ca2+ oscillations, which decreased insulin secretion. β-cell membrane potential hyperpolarization resulting from Gi/o-GPCR activation was dependent on NKA phosphorylation by Src tyrosine kinases. Whereas, β-cell NKA function was inhibited by cAMP-dependent PKA activity. These data reveal that NKA-mediated β-cell membrane potential hyperpolarization is the primary and conserved mechanism for Gi/o-GPCR control of electrical excitability, Ca2+ handling, and insulin secretion.

Pediatric asthma self-management: current concepts

The concept of asthma self-management began in asthma camps in the 1970s. Today all asthma camps are required to provide an educational asthma self-management program. The interaction between children and educators is brief, and if the children do not continue in an associated program after camp, the benefits may be lost. Open Airways, the first program developed specifically for minority children, has been the prototype for community asthma self-management. School-based intervention programs have incorporated asthma education into the health curriculum. Some asthma education programs include an emphasis on the environment. Another approach is to develop intervention projects with parents, as in the Head Start program. This program has been very effective in increasing early recognition of asthma and decreasing recidivism in a high-risk population. Another type of project addressed the reading ability and reading comprehension of asthmatic children. Improvement in reading skills resulted in a 47% decrease in asthma recidivism. After 18 months, there were only two hospitalizations among the enrolled participants. Asthma self-management programs that are most effective for inner-city children provide an interactive, culturally relevant form of asthma education and address issues such as literacy and continuity.

Coronary artery bypass on the beating heart with the Octopus: a North American experience

BACKGROUND

The practice of minimally invasive coronary artery bypass grafting remains controversial. This study outlines the results of single and multiple vessel bypass performed using the Medtronic Octopus Tissue Stabilization System and beating heart techniques. Results are compared with those of a standard cardiopulmonary bypass group.

METHODS

The group included 89 patients having operations performed during a 10-month period with average follow-up of 162.3 days. Complications, length of stay, and functional status were recorded. Postoperative stress testing and angiograms were performed selectively.

RESULTS

The average age was 62.3 years and the average ejection fraction was 0.65. Twenty-five percent of the patients underwent operations urgently or emergently, averaging 1.8 grafts/patient. In 83 of 89 patients operations were completed without cardiopulmonary bypass using the Octopus without mortality. Morbidities were statistically similar to a group of 369 cardiopulmonary bypass patients. Postoperative length of stay was shorter in the Octopus group (p = 0.005).

CONCLUSIONS

The Octopus provided predictable, reproducible immobilization with short-term results comparable with those obtained with standard cardiopulmonary bypass.

The effect of vancomycin on the corneal endothelium

Possible toxic effects of vancomycin on the corneal endothelium were assessed in rabbit eyes and subsequently in corneal transplant recipients. Fifteen New Zealand White rabbits were divided into five groups of three rabbits each. A paracentesis was performed on right eyes only. One hundred microliters of aqueous humor was removed followed by anterior chamber injection of 100 mu l of balanced salt solution (BSS) or varying concentrations of vancomycin (150, 750, 1,875, 7,500 mu g/ml). Left eyes served as untreated controls. Endothelial cell morphology and density were assessed by contact specular microscopy 48 h postinjection. There was no statistically significant difference in endothelial cell density between left (control) or right (treated) eyes receiving either BSS or varying concentrations of vancomycin. Transmission electron microscopy of rabbit corneal endothelium exposed to varying concentrations of vancomycin (150, 750, 1,875, 7,500 mu g/ml) showed no toxic effects. Six patients undergoing penetrating keratoplasty (PKP) received donor corneas stored in Optisol containing gentamicin to which vancomycin was added to make a final concentration of 150 mu g/ml. Eight patients undergoing PKP received corneas stored in Optisol alone. Specular microscopy was performed preoperatively and 3, 6, and 12 months postoperatively. No statistically significant difference in mean endothelial cell change was observed (Wilcoxon signed-rank test) at any time point postoperatively. Endothelial cell morphology and function are not adversely affected by therapeutic doses of vancomycin.

Skull metastases from follicular thyroid carcinoma

Distant metastatic disease from thyroid carcinoma is becoming a rare problem. Physicians and the public are increasingly aware of minimally invasive methods of early diagnosis of thyroid malignancy, such as fine-needle aspiration with cytologic examination. Total thyroidectomy itself has become less associated with morbidity than it once was. We describe three patients with follicular thyroid carcinoma metastatic to the skull who were seen recently. Two of these patients had masses neglected for 20 and 50 years, respectively. The management of this disease entity is discussed.

Head and neck malignancies in children: an age-incidence study

One hundred forty-seven (147) children under 18 years have been treated for head and neck malignancies at Texas Children's Hospital from 1970 to 1985 and form the data base for this study. In order of frequency, the most common tumors were lymphoma, Langerhans' histiocytosis (LH), rhabdomyosarcoma, neuroblastoma, and other soft-tissue sarcoma. Children under 2 were most likely to have LH; those from 3 to 5, LH or lymphoma; and those over 5, lymphoma.

Partial characterization of in vivo chemotactic activity: comparison to human C5a

Spontaneous eosinophil chemotactic activity (SECA) can mediate the directed movement of human eosinophils and neutrophils. Preliminary characterization of SECA has been carried out. SECA is nondialyzable and heat-stable (56 degrees C, 30 min). Chromatography on Sephadex G-75 demonstrated that SECA had elutional and functional properties similar to C5a (prepared from endotoxin-activated normal sera). Polyacrylamide gel electrophoresis (PAGE) with the use of 15% bisacrylamide gels of lyophilized, chemotactically active column fractions demonstrated a single protein band of identical electrophoretic mobility from either SECA or C5a preparations. Enzymatic hydrolysis with carboxypeptidase B, a known inhibitor of C5a activity, significantly decreased chemotactic activities of C5a and SECA. The addition of purified anti-C5 to either SECA or C5a significantly inhibited chemotactic activity. SECA is naturally occurring chemotactic activity identical to human C5a. Thus C5a may be an important source of in vivo chemotactic activity in various inflammatory disorders.

Allergy and infection

The majority of infectious asthma in children is of viral etiology. The respiratory syncytial and parainfluenza viruses are the etiologic agents in most young children, whereas rhinovirus primarily initiates asthmatic episodes in older children. Short-term or alternate day maintenance corticosteroid therapy probably does not significantly increase the asthmatic child's susceptibility to infection.

SECA, a new mediator of the human eosinophil response

Spontaneous eosinophilic chemotactic activity (SECA) present in human sera can mediate the directed movement of normal human eosinophils. Our data utilize normal peripheral blood eosinophils obtained from subjects with 500 eosinophils/m3 or less. SECA is defined as that chemotactic activity for eosinophils present in serum that has been heat-inactivated immediately after collection. It was demonstrated in patients with severe chronic eczema with eosinophilia (20 to 30%); mixed collagen vascular disease with vasculitis; clinical serum sickness; acute glomerulonephritis, and chronic membranoproliferative glomerulonephritis. Control sera were obtained from normal, healthy individuals. The data indicated: (1) that SECA in patient sera was significantly higher than in control sera; (2) when activated by endotoxin, no additional chemotactic activity was generated from patient sera over that spontaneously present--by contrast, addition of endotoxin to control sera did result in increased chemotactic activity; (3) sera from patients with extrinsic bronchial asthma had no SECA.