Future dental public health programs: forging community and academic collaborations

In the past 5 years we have discovered 8 boys and 3 girls who suffer from fructose-1,6-bisphosphatase deficiency. Although they all showed the typical symptoms of the deficiency such as frequent vomiting, hypoglycemia, lactic acidosis, and hepatomegaly, the age at diagnosis varied from 2 months to 4 years. All the boys revealed the deficient enzyme activity in leukocytes but none of the girls. The liver biopsy was investigated in six patients to confirm the diagnosis. These results suggest the existence of tissue-specific isoenzymes for fructose-1,6-bisphosphatase possibly with a different gene origin.     

Glial development in the Drosophila CNS requires concomitant activation of glial and repression of neuronal differentiation genes

Two classes of glial cells are found in the embryonic Drosophila CNS, midline glial cells and lateral glial cells. Midline glial development is triggered by EGF-receptor signalling, whereas lateral glial development is controlled by the gcm gene. Subsequent glial cell differentiation depends partly on the pointed gene. Here we describe a novel component required for all CNS glia development. The tramtrack gene encodes two zinc-finger proteins, one of which, ttkp69, is expressed in all non-neuronal CNS cells. We show that ttkp69 is downstream of gcm and can repress neuronal differentiation. Double mutant analysis and coexpression experiments indicate that glial cell differentiation may depend on a dual process, requiring the activation of glial differentiation by pointed and the concomitant repression of neuronal development by tramtrack.     

Anti-D in a D-positive renal transplant patient

PURPOSE: We report a case of postoperative reparalysis in the recovery room, following nebulized epinephrine. The patient was pharmacologically reversed with edrophonium after paralysis with rocuronium. CLINICAL FINDINGS: A 12-yr-old girl developed postoperative reparalysis following the intraoperative administration of rocuronium. A total of 0.92 mg.kg-1 rocuronium was administered. After surgery, pharmacological reversal was achieved with 20 mg edrophonium with 0.15 mg atropine sulfate iv 35 min after the last administration of rocuronium. Muscular relaxation was monitored using an ulnar peripheral nerve stimulator (PNS). After reversal, a full train-of-four and sustained tetanus at 50 Hz were present. In the recovery room, following nebulized epinephrine, the patient became apneic. The patient was paralyzed and an ulnar PNS demonstrated only one faint twitch. The paralysis was reversed with 1.5 mg neostigmine with 0.3 mg glycopyrrolate. CONCLUSION: Postoperative reparalysis following rocuronium may be a cause of postoperative respiratory distress. The definitive diagnosis is made using PNS and observing the response to pharmacological reversal. Nebulized epinephrine may have a previously undescribed role in the development of postoperative reparalysis.     

The rationale for cementless total hip replacement

Current cementing techniques of distal plugging, pulsatile water cleaning of the canal, and retrograde filling with PMMA in a low-viscous state prepared using porosity reduction techniques and then pressurized have been shown to give excellent results at 10 or more years after operation. However, physical and aging characteristics of PMMA do not guarantee that those results will hold up in the 20- to 30-year time frame. Fifteen-year experience with bony ingrowth systems indicate the development of a durable interface without PMMA, although the interface does appear more vulnerable to attack by the biologic reaction to HMWPE debris. Bone remodeling appears more favorable around proximally fixed bone ingrowth prostheses than around distally fixed prostheses. Softening of the physical characteristics of the stem tip may reduce the incidence of thigh pain. Patients with high activity potential and a life expectancy of greater than 25 years should be strongly considered for a proximally fixed bone ingrowth or ongrowth prosthesis.     

The development of the temporomandibular joint: a review with regard to the lateral pterygoid muscle

This review sets out to explore the relationship between the lateral pterygoid muscle and the meniscus. It examines the embryological evidence to explain the controversy surrounding the apparent morphological discrepancy in the attachment of the lateral pterygoid muscle to the meniscus. It shows that the contribution of the lateral pterygoid muscle to the formation of the meniscus remains in dispute. Morphogenetic studies have not been able to support either one or other viewpoint and no direct conclusions can therefore be made on the embryology of the temporomandibular joint.     

Parameters affecting the use of the lac repressor system in eukaryotic cells and transgenic animals

Elements of the lactose operon were used to study parameters affecting gene expression in cultured cells and transgenic animals. A Lac repressor protein containing a nuclear transport signal was shown to inhibit expression of a reporter gene by interacting with lac operator sequences. In cultured cells, operator sequence, operator placement and induction parameters were all shown to be important for obtaining tight repression of a reporter gene followed by high level expression upon induction. Induction levels were also dependent on the reporter gene, with the luciferase gene yielding higher induction levels than the chloramphenicol acetyltransferase gene. In transgenic animals, the lacI mRNA was not detected in the C57BL/6 mouse strain until the animal was exposed to a demethylating agent. After 5-azacytidine treatment, expression of lacI mRNA was detected in the brain, heart, kidney, lung and ovary. In the FVB transgenic mouse strain, expression of lacI mRNA was detected without 5-azacytidine treatment in the kidney, liver, lung, and testes. Preliminary experiments with double transgenic animals containing both lacI and operator/luciferase transgenes showed a decrease in luciferase expression compared to the luciferase-only animals in both tissue extracts and transgenic fetal primary cultures, although IPTG induction was not achieved in these animals or primary cultures. The applicability and challenges of the system for regulation of gene expression are discussed.     

Effects ofSolanum glycoalkaloids on chemosensilla in the Colorado potato beetle

Steroidal glycoalkaloids, found in species of the Solanaceae, elicit bursting activity in galeal and tarsal chemosensilla of adult Colorado potato beetles. The effect has an average latency of 6–12 sec, depending on the sensillum/alkaloid combination. A 20-sec alkaloid treatment is often suffficient to render galeal sensilla unresponsive to gamma-aminobutyric acid, normally an effective stimulant. The alkaloids have similar effects on galeal sensilla of larval Colorado potato beetles and on labellar chemosensilla of the blowfly. It is concluded that these compounds act independently of any specialized chemoreceptor in the Colorado potato beetle, and that association of the Colorado potato beetle with solanaceous plants has not led to evolution of a specific receptor forSolanum glycoalkaloids.