Investigating associations between biting time in the malaria vector Anopheles arabiensis Patton and single nucleotide polymorphisms in circadian clock genes: support for sub-structure among An. arabiensis in the Kilombero valley of Tanzania.

BACKGROUND: There is growing evidence that the widespread use of Long-Lasting Insecticidal Nets (LLINs) is prompting malaria vectors to shift their biting towards times and places where people are not protected, such as earlier in the evening and/or outdoors. It is uncertain whether these behavioural shifts are due to phenotypic plasticity and/or ecological changes within vector communities that favour more exophilic species, or involve genetic factors within vector species to limit their contact with LLINs. Possibly variation in the time and location of mosquito biting has a genetic basis, but as yet this phenomenon has received little investigation. Here we used a candidate gene approach to investigate whether polymorphisms in selected circadian clock genes could explain variation in the time and location of feeding (indoors versus outside) within a natural population of the major African malaria vector Anopheles arabiensis. METHODS: Host-seeking An. arabiensis were collected from two villages (Lupiro and Sagamaganga) in Tanzania by Human Landing Catch (HLC) technique. Mosquitoes were classified into phenotypes of "early" (7 pm-10 pm) or "late" biting (4 am -7 am), and host-seeking indoors or outdoors. In these samples we genotyped 34 coding SNPs in 8 clock genes (PER, TIM, CLK, CYC, PDP1, VRI, CRY1, and CRY2), and tested for associations between these SNPs and biting phenotypes. SNPs in 8 mitochondrial genes (ATP6, ATP8, COX1, COX2, COX3, ND3, ND5 and CYTB) were also genotyped to test population subdivision within An. arabiensis. RESULTS: The candidate clock genes exhibited polymorphism within An. arabiensis, but it was unrelated to variation in the timing and location of their biting activity. However, there was evidence of strong genetic structure within An. arabiensis populations in association with the TIM, which was unrelated to geographic distance. Substructure within An. arabiensis was also detected using mitochondrial markers. CONCLUSIONS: The variable timing and location of biting in An. arabiensis could not be linked to candidate clock genes that are known to influence behaviour in other Diptera. This finding does not rule out the possibility of a genetic basis to biting behaviour in this malaria vector, but suggests these are complex phenotypes that require more intensive ecological, neuronal and genomic analyses to understand.

Using comparative genomics to develop a molecular diagnostic for the identification of an emerging pest Drosophila suzukii.

Drosophila suzukii (Spotted Wing Drosophila) has recently become a serious invasive pest of fruit crops in the USA, Canada, and Europe, leading to substantial economic losses. D. suzukii is a direct pest, ovipositing directly into ripe or ripening fruits; in contrast, other Drosophilids utilize decaying or blemished fruits and are nuisance pests at worst. Immature stages of D. suzukii are difficult to differentiate from other Drosophilids, posing problems for research and for meeting quarantine restrictions designed to prevent the spread of this pest in fruit exports. Here we used a combined phylogenetic and bioinformatic approach to discover genetic markers suitable for a species diagnostic protocol of this agricultural pest. We describe a molecular diagnostic for rapid identification of single D. suzukii larva using multiplex polymerase chain reaction. Our molecular diagnostic was validated using nine different species of Drosophila for specificity and 19 populations of D. suzukii from different geographical regions to ensure utility within species.

Involvement of nervous system in maternally inherited diabetes and deafness (MIDD) with the A3243G mutation of mitochondrial DNA.

OBJECTIVES: The A3243G mutation of mitochondrial DNA (mtDNA) has been associated with maternally inherited diabetes and deafness (MIDD) in a number of reports; however, the involvement of the nervous system has rarely been mentioned, prompting this exploration of the manifestation of neurological disorders in MIDD cases. MATERIAL AND METHODS: We investigated four generations of a large Taiwanese family in which MIDD is manifest. We conducted a series of clinical examinations, including computed tomography (CT) and magnetic resonance imaging (MRI) of the head, brain 99mTc-HMPAO single photon emission computed tomography (SPECT), cognitive function tests, and nerve conduction velocity (NCV) studies. Blood levels of creatine kinase (CK) and lactate, pathology of muscle biopsy samples and proportions of mutant mtDNA in blood cells, hair follicles, muscle and skin were also analyzed. Mean follow-up period was 4 years. RESULTS: The patients exhibited the clinical features of diabetes mellitus including sensorineural hearing loss, short stature, and/or histories of spontaneous abortion. No stroke-like episodes were reported. Analysis for mtDNA revealed that the A3243G mutation existed in 11 members (6 symptomatic and 5 asymptomatic members) of this MIDD-prone family, with the proportion of mutant mtDNA ranging from 21% to 47% in leukocytes. Head CT revealed diffuse brain atrophy for all 6 (100%) patients examined and bilateral basal ganglia calcification in 4 of 6 (67%) patients. Brain 99mTc-HMPAO SPECT revealed diminished uptake in the bilateral parieto-occipital or occipital regions for all 6 tested patients, cognitive function for these patients was normal. Results of head CT and SPECT were normal in one asymptomatic member of the family. One muscle biopsy revealed abundant ragged-red fibers with modified Gomori-trichrome stain. Muscle-enzyme activity and serum-lactate levels were normal. CONCLUSION: We have demonstrated that a wide spectrum of sub clinical pathologies of the central nervous system and muscle are present for this MIDD-prone family, none of whom developed typical MELAS during the 4-year period of follow-up study.

Percutaneous microdecompressive endoscopic cervical discectomy with laser thermodiskoplasty.

OBJECTIVE: To study the surgical outcome of outpatient percutaneous microdecompressive endoscopic cervical discectomy with lower energy laser for shrinkage of disc material (thermodiskoplasty). METHOD: Since 1994, 200 patients with herniated cervical discs have presented at the authors' clinic, with unilateral radicular pain. The diagnosis was confirmed by MRI or CT, and EMG. RESULTS: At an average follow-up of 25 months, 94.5% of the cases had good-to-excellent results. Eleven patients (5.5%) remained symptomatic, with persistent neck and upper extremity pain associated with paresthesias. There were no significant postoperative complications. Average time before returning to work was 10 days. CONCLUSIONS: Percutaneous microdecompressive endoscopic cervical discectomy with laser thermodiskoplasty has proven to be a safe and efficacious minimally invasive procedure.

Microdecompressive percutaneous endoscopy: spinal discectomy with new laser thermodiskoplasty for non-extruded herniated nucleosus pulposus.

Open spinal discectomy, at times with spinal fusion, is associated with significant local morbidity and long-term convalescence, requires general anesthesia, and involves dissection of muscle, removal of bone, ligament and disc, which are all at greater financial cost. Therefore, the search for a less traumatic spinal discectomy began, including micro-discectomy, and percutaneous techniques and endoscopic discectomy. Lyman Smith reported intradiscal injection of chymopapain in 1964. Onik et al. developed the automated percutaneous discectomy device for continuous aspiration/irrigation of disc tissue in 1985. Hijikata et al also described nucleotomy independently in 1985. In 1986, Ascher and Choy first reported laser discectomy to decrease intradiscal pressure.

Percutaneous (endoscopic) decompression discectomy for non-extruded cervical herniated nucleus pulposus.

In 1838, Key described the pathological findings of two cases of cord compression by "intervertebral substance." In the 1800s and early 1900s many cases of chondromas of the cervical spine were reported. In 1928 Stookey, described the clinical symptoms and anatomic location of cervical disk herniation. In 1934, Mixter and Barr documented four cervical disc protrusions. Before 1950, the standard approach to discs in this region was posteriorly with laminectomy. In the 1950s Bailey, Badgley, Cloward, Smith and Robinson popularized the anterior approach with interbody fusion. Hirsch in 1960, then Robertson in 1973, recommended cervical discectomy without fusion. Similar results were noted.

Clinical assessment and arteriography for patients with penetrating extremity injuries: a review of 500 cases with the Veterans Affairs West Side Medical Center.

For patients suspected of having arterial injuries form penetrating trauma to the extremities, the decision to perform arteriography should be based on clinical criteria rather than "proximity" alone. In order to demonstrate the increased yield of arteriography resulting from appropriate patient selection, we reviewed the results of 500 arteriograms performed at the West Side Veterans Affairs Medical Center to exclude arterial injuries in symptomatic patients following penetrating trauma to their extremities. According to their clinical presentation, the patients were grouped into three different screening categories A, B, and C, which correspond respectively to "mild," "soft," and "hard" clinical signs and symptoms suggestive of arterial injury. All symptomatic patients injured by shotgun were included in category C due to the weapon's destructive power. The majority (318/500, 63.6%) of the 500 arteriograms were positive, and 102 of the positive studies identified major injuries that required surgical intervention. The remaining 216 identified injuries were minor or self-limiting. Increasing incidence of major injuries was found when comparing patients with mild (1.22%), soft (27.8%), and hard (60.0%) clinical signs and symptoms of arterial injury. These result suggest that arteriography, when combined with appropriate patient selection based on clinical examination, would be most effective in finding significant arterial injuries.

Morphological studies on the erector spinae muscle in sixty consecutive scoliotic patients.

Paraspinal muscle biopsy was done on the erector spinae muscles in sixty consecutive scoliotic patients. Together with the clinical and muscle biopsy findings, these sixty patients were classified into thirty-two patients with idiopathic scoliosis, eleven patients with myopathic scoliosis, nine patients with neuropathic scoliosis, and eight patients with miscellaneous scoliosis. Of the thirty-two patients with idiopathic scoliosis, nineteen cases displayed neurogenic changes in the grouping of the Type 1 fibers and target fiber formation more common on the convex side back muscles. The myopathies consisted of central core disease, nemalin myopathy, congenital fiber type disproportion, mitochondrial myopathy, congenital muscular dystrophy, and myositis. Patients with neuropathic scoliosis all showed loss of the normal mosaic pattern and grouping of both Type 1 and 2 fibers in their muscle biopsies. This result indicates that there is a variety of neuromuscular diseases in scoliotic patients. The neurogenic changes observed more commonly on the convex side muscle of idiopathic scoliotic patients deserve further investigation.