Iodine accumulation in sea urchin larvae is dependent on peroxide.

Iodine has many important biological functions and its concentrations vary with the environment. Recent research has provided novel insights into iodine uptake mechanisms in marine bacteria and kelp through hydrogen peroxide-dependent diffusion (PDD). This mechanism is distinct from sodium-dependent mechanisms known from vertebrates. In vertebrates, iodine accumulates in the thyroid gland by the action of the apical iodide transporter (AIT) and the sodium/iodide symporter (NIS). Neither of these proteins has, thus far, been identified outside of the chordates, and PDD (as an iodine uptake mechanism) has never been studied in animals. Using (125)I as a marker for total iodine influx, we tested iodine uptake via sodium-dependent transport versus PDD in embryos and larvae of the sea urchin Strongylocentrotus purpuratus. We found that iodine uptake in S. purpuratus is largely independent of NIS/AIT. Instead, we found that uptake is dependent on the presence and production of hydrogen peroxide, indicating that sea urchin larvae use PDD as a mechanism for iodine acquisition. Our data, for the first time, provide conclusive evidence for this mechanism in an animal. Furthermore, our data provide preliminary evidence that sodium-dependent iodine uptake via active transporter proteins is a synapomorphy of vertebrates.

Endocrine interactions between plants and animals: Implications of exogenous hormone sources for the evolution of hormone signaling.

Hormones are central to animal physiology, metabolism and development. Details on signal transduction systems and regulation of hormone synthesis, activation and release have only been studied for a small number of animal groups, notably arthropods and chordates. However, a significant body of literature suggests that hormonal signaling systems are not restricted to these phyla. For example, work on several echinoderm species shows that exogenous thyroid hormones (THs) affect larval development and metamorphosis and our new data provide strong evidence for endogenous synthesis of THs in sea urchin larvae. In addition to these endogenous sources, these larvae obtain THs when they consume phytoplankton. Another example of an exogenously acquired hormone or their precursors is in insect and arthropod signaling. Sterols from plants are essential for the synthesis of ecdysteroids, a crucial group of insect morphogenic steroids. The availability of a hormone or hormone precursor from food has implications for understanding hormone function and the evolution of hormonal signaling in animals. For hormone function, it creates an important link between the environment and the regulation of internal homeostatic systems. For the evolution of hormonal signaling it helps us to better understand how complex endocrine mechanisms may have evolved.

Gunshot wounds to the hand. The Martin Luther King, Jr, General Hospital experience.

This article is a retrospective review of patients who presented to Martin Luther King, Jr./Drew Medical Center with gunshot wounds and had either isolated or associated injuries to the hand. The following is an account of those injuries noting the location, soft-tissue or bony involvement, and interventional methods that were implemented in the treatment of these patients who resided primarily in South Central Los Angeles. Prompt evaluation and initiation of treatment is essential in the management of both high- and low-velocity gunshot wounds so as to decrease the potential morbidity that often follows. Society must also look at the prevalence of these injuries and address the underlying issues that often are the root of the acts of violence.

The pharmacokinetics of a single rectal dose of paracetamol (40 mg x kg(-1)) in children with liver disease.

BACKGROUND: The aim of our study was to measure the serum paracetamol concentrations achieved following a single rectal loading dose of 40 mg x kg(-1) in children with chronic liver disease. METHODS: We recruited 17 children (3-15 years, 10.6-75 kg) undergoing minor surgical procedures under general anesthesia. Paracetamol was administered at the end of surgery and blood samples were taken for analysis at 2, 3, 4, 6 and 8 h postdose. RESULTS: The mean Cmax of 11.4 mg x l(-1) [coefficient of variation (CV) 66%] was achieved at a Tmax of 2.7 h (CV 42%). The relative bioavailability (F) of the suppository formulation was not estimated, but clearance (Cl/F) estimates 0.73 l x kg(-1) x h(-1) (CV 87%) and time-concentration profiles for these children were similar to the normal pediatric population. CONCLUSIONS: There are currently no biologic markers available for monitoring possible hepatotoxicity in this cohort of patients with liver disease, but our data suggest that a single-dose suppository is a satisfactory analgesic alternative.

Anaesthesia for porphyria.

Porphyrias arise due to enzyme defects in the haem synthetic pathway. They are of concern to the anaesthetist as acute crises may be precipitated by anaesthetic drugs. Anaesthesia must be carefully managed in patients with porphyria in order to achieve a successful outcome.

The choice of inhalation anaesthetic for major abdominal surgery in children with liver disease.

Many children with liver disease undergo major abdominal surgery. Maintenance of anaesthesia is thus an important consideration in this surgical population. Despite a comprehensive and painstaking review of the literature, a sound evidence base, on which a choice of inhalation anaesthetic may be made, is lacking due to limited research in these patients. Differences between the more recent agents such as isoflurane, sevoflurane and desflurane are minor. Sevoflurane is favoured in paediatric practice for gaseous induction, but desflurane or isoflurane are marginally the preferred agents for maintenance of anaesthesia in children with liver disease undergoing major abdominal surgery. However, on the evidence that exists, much of it admittedly in animals and in adults, all three are preferable to halothane in this group of patients. More work is needed in this area before sound conclusions can be drawn and one agent proved to be definitely superior to the others.

Accuracy of the preoperative examination in Zone 5 wrist lacerations.

Fifty patients were studied to determine the accuracy of the preoperative physical examination in flexor tendon Zone 5 wrist lacerations. Initially, a retrospective review of the charts of 33 patients who were examined by a second- or third-year postgraduate physician was done. An average of three errors per examination was found. Then a prospective study of 17 patients was performed to see if an examiner's level of training in hand surgery influenced the accuracy of the examination. Error rates improved slightly with experience. Ninety-seven examinations were performed in the combined prospective and retrospective studies, and only 13 were completely correct. Nearly 1/2 of all examinations had three or more errors. If a structure had been lacerated, the injury was not detected 33% of the time on the preoperative examination. The size and mechanism of injury of the skin laceration did not correlate with the number of structures that were cut.

A comparison of the vasodilatation produced by two topical anaesthetics.

The vasoactive properties of EMLA (eutectic mixture of local anaesthetic) and amethocaine were compared using Doppler colour ultrasound to measure vein diameter in 20 male volunteers. EMLA or amethocaine cream were applied over veins on the dorsum of the hand and vein diameter was measured prior to application of the preparations and at 1, 1.5 and 2 h after removal. Visual analogue scores for skin colour and vasodilatation were performed at 1 h. The results showed no significant difference in vein diameter between the EMLA and amethocaine groups. However, the amethocaine-treated hands were significantly more erythematous at 1 h (p < 0.00002).

Swanson metacarpophalangeal joint arthroplasty in patients with rheumatoid arthritis.

Between 1981 and 1991, 348 Swanson metacarpophalangeal replacements were implanted in patients with rheumatoid arthritis. There were 64 female and seven male patients. Both hands were reconstructed in 18 patients. Clinically, 170 implants were available for an average of 5.2 years (range, 2-10 years) followup. Severe synovitis was seen in 7% of metacarpophalangeal joints, moderate synovitis in 25%, slight synovitis in 17%, and synovitis was not present in 51%. Pain was found to be severe in 4% of the joints, moderate in 3%, slight in 39%, and not present in 54% of the joints. The average preoperative active arc of motion was 38 degrees, and the average postoperative arc of motion was 27 degrees. Eleven of 12 fractures found were revised. There were no infections. Functionally, of 58 patients assessed, 58 (100%) reported the ability to feed themselves, 55 (94%) to button clothes, and 54 (93%) to write. Quality radiographs were available in 144 joints. Eighty-four percent of implants showed sclerosis of bone and 8% showed resorption adjacent to the implant. Survivorship analysis revealed a 94% success rate at 5 years, 93% at 7 years, and 90% at 10 years using the end point of revision surgery.