Bilateral malignant carotid chemodectoma

A clinical case of carotid chemodectoma is reported. Unique character of this case consists in combination of rare manifestations of this disease in a patient (malignancy, bilateral location). Summarizing their own experience and analysis of literature data the authors give recommendations for diagnosis and management of such patients.     

Activation of phospholipase C and guanylyl cyclase by endothelins in human trabecular meshwork cells

PURPOSE: To characterize effects of endothelins on activities of phospholipase C (PLC) and nucleotide cyclases in human trabecular meshwork (TM) cells. METHODS: Cultured simian virus 40-transformed human TM (HTM-3) or non-transformed (HTM-16) cells were used. Changes in the PLC activity were determined by assaying the production of [3H] inositol phosphates. Accumulation of cyclic GMP or cyclic AMP in cell lysate was measured by radioimmunoassay. RESULTS: Endothelin-1 (ET-1; 1 microM) stimulated PLC in HTM-16 cells, but Sarafotoxin S6c (SRTX), an ET(B) receptor subtype-selective agonist (1 microM), did not. Similar results were obtained in HTM-3 cells: ET-1, but not ET-3 or SRTX, activated PLC in a dose-dependent manner, with a calculated EC50 of 646 pM. The peptide also stimulated the accumulation of cGMP in a concentration-dependent manner with an EC50 of 37.2 pM. ET-3 or SRTX was not effective except at much higher concentrations. Both the PLC and guanylyl cyclase stimulation induced by ET-1 (10 nM) were completely inhibited by pretreating the cells with BQ-123 (<10 microM), an ET(A) receptor selective antagonist, but not by BQ-788 (10 microM), an ET(B) receptor subtype-specific antagonist. Neither ET-1 nor ET-3 stimulated adenylyl cyclase activity in HTM-3 cells at concentration as high as 1 microM. CONCLUSION: ET-1 activates PLC and guanylyl cyclase in TM cells. Potency profiles of ET receptor agonists and antagonists suggest that the ET(A) receptor subtype is involved in both actions of ET-1. The effects of the ET peptides in TM cells are interesting and could be part of the mechanism of their IOP-lowering effect.     

CD5 expression is developmentally regulated by T cell receptor (TCR) signals and TCR avidity

Recent data indicate that the cell surface glycoprotein CD5 functions as a negative regulator of T cell receptor (TCR)-mediated signaling. In this study, we examined the regulation of CD5 surface expression during normal thymocyte ontogeny and in mice with developmental and/or signal transduction defects. The results demonstrate that low level expression of CD5 on CD4(-)CD8(-) (double negative, DN) thymocytes is independent of TCR gene rearrangement; however, induction of CD5 surface expression on DN thymocytes requires engagement of the pre-TCR and is dependent upon the activity of p56(lck). At the CD4(+)CD8(+) (double positive, DP) stage, intermediate CD5 levels are maintained by low affinity TCR-major histocompatibility complex (MHC) interactions, and CD5 surface expression is proportional to both the surface level and signaling capacity of the TCR. High-level expression of CD5 on DP and CD4(+) or CD8(+) (single positive, SP) thymocytes is induced by engagement of the alpha/beta-TCR by (positively or negatively) selecting ligands. Significantly, CD5 surface expression on mature SP thymocytes and T cells was found to directly parallel the avidity or signaling intensity of the positively selecting TCR-MHC-ligand interaction. Taken together, these observations suggest that the developmental regulation of CD5 in response to TCR signaling and TCR avidity represents a mechanism for fine tuning of the TCR signaling response.     

The 75 g oral glucose tolerance in pregnancy

The first case of the human immunodeficiency virus (HIV) infection was detected in Singapore in 1985 and the first case of the acquired immunodeficiency syndrome (AIDS) in 1986. Since then, the number of infections had increased. By the end of 1993, there were 222 residents with HIV infection, including 75 cases of AIDS. In view of the rapidly increasing magnitude of HIV infection, a microcomputer-based surveillance system was designed and developed in 1992 to better monitor epidemiological trends of HIV infection in Singapore. OBJECTIVE--The objective was to define a composite model of a successful HIV and AIDS registry that included: (a) patient data forms, (b) patient's contact data forms, (c) data analysis, and (d) report generation. METHODOLOGY--An IBM-compatible desk-top microcomputer was used for the project. The main software used for computer programming and data analysis were DBase IV (Version 1.5) and Epi Info (Version 5.0), respectively. Security features were incorporated into the programme to ensure confidentiality of information and that only authorized personnel could gain access to the programme. MAIN FINDINGS--The system functioned as the National HIV Notification Registry and was able to track notifications, analyse data and enabled prompt dissemination of information. The system was also linked to another database system for tuberculosis to enhance surveillance of both HIV infection and tuberculosis. CONCLUSION--The authors believe that this system would enhance surveillance and provide timely information for national AIDS control programmes. However, the effectiveness of this computer-based surveillance system is dependent on an established notification structure with notifications of sufficient completeness for both HIV infection and AIDS.     

Urinary excretion and clearance of insulin in diabetic and normal children and adolescents

Seventy-two diabetic (38 males) and 86 normal (41 males) children provided timed overnight urine collections. Fourteen of the diabetic and 33 of the normal children had concurrent overnight plasma insulin profiles. Urinary insulin clearance in the diabetic subjects was compared with excretion of albumin, growth hormone, retinol-binding protein, and N-acetyl-beta-D-glucosaminidase. In the normal subjects, urinary insulin excretion correlated with mean overnight plasma levels in the boys (r = 0.82, p < 0.001) but not in the girls (r = 0.32), and varied with puberty stage in the boys. Insulin clearance was greater in boys than girls during puberty, and fell in both sexes with advancing puberty. Insulin excretion was greater in diabetic than normal children in both sexes at all puberty stages. Insulin clearance was also greater in diabetic than normal subjects (1.05 +/- 0.1 ml min-1 1.73 m-2 vs 0.48 +/- 0.05 ml min-1 1.73 m-2, p < 0.001). Insulin excretion as a percentage of the filtered load was also greater in diabetic than normal subjects (1.9 +/- 0.27% vs 0.85 +/- 0.09%, p < 0.01). In the diabetic children, there was a correlation between urinary insulin and growth hormone excretion (r = 0.52, p < 0.02), and retinol-binding protein in those (n = 10) with higher retinol binding protein excretion (r = 0.76, p = 0.01). The value of urinary insulin excretion as a measure of free plasma insulin levels in normal and diabetic children may be limited by sex differences in renal insulin clearance, and by proximal renal tubular dysfunction in children with diabetes.     

Kinetics of release of serotonin from isolated secretory granules. I. Amperometric detection of serotonin from electroporated granules

In the CD4+ T cell lineage, two well-defined differentiated populations are the Th1 and Th2 cells, which stem from a common naive T helper precursor (Thp). In this study, we begin to dissect the signaling pathways selectively used by Th1 or Th2 cells as they mature from a common naive precursor in vitro. We show that the maturing Th1 cells mount a vigorous and specific Ca2+ transient upon contact with immunogenic ligand, which is enhanced over that of the naive progenitor cells. As the cells differentiate toward a Th2 phenotype, they quickly lose the ability to engage this pathway, indicating a developmental segregation of intracellular signaling utilization. Moreover, altered peptide ligand stimulation of the Th1 line stimulates a similar Ca2+ transient as native ligand stimulation of the naive precursors, consistent with a quantitative difference in intracellular signaling by these two peptides. These data provide a direct and sequential assessment of a signaling pathway utilization in peripheral T cells as they differentiate to their final functional states.     

Effect of prosthetic superstructure accuracy on the osteointegrated implant bone interface

OBJECTIVE: To compare the behavior of macrosomic newborns who were vaginally delivered of healthy mothers without diabetes with that of non-macrosomic, appropriate-for-gestational-age (AGA) newborns. DESIGN/SETTING: Newborns were recruited conveniently from a tertiary hospital. Newborns were examined at 12-24 and 36-48 hours of age, using the Brazelton Neonatal Behavioral Assessment Scale (NBAS). PARTICIPANTS: Thirty macrosomic newborns who were delivered vaginally were matched with AGA newborns for ethnicity, maternal education, parity, and obstetric medications. MAIN OUTCOME MEASURES: Dimensions scores derived from the individual NBAS items measured reflex functioning, response decrement, orientation, motor processes, range of state, autonomic stability, and regulation of state. RESULTS: Macrosomic newborns performed weaker than AGA newborns on the reflex and motor dimensions. Both groups displayed improved motor scores on Day 2, but regulation of state scores were weaker. For orientation, AGA newborns scored higher on Day 1, and macrosomic newborns scored higher on Day 2. CONCLUSIONS: Increased head, limb, and body mass of macrosomic newborns, compared with adjacent and overall muscle strength, might have interfered with the execution of coordinated movements. Nurses can inform mothers of changes they can expect in their newborns' behavior.