Mosaics of ancient mitochondrial DNA: positive indicators of nonauthenticity

Research into ancient mitochondrial DNA is plagued by contamination, post mortem damage, and other artefacts. The stringent set of controls suggested by Cooper and Poinar a few years ago are, however, rarely followed in practice, and even when applied carefully, these criteria need not be sufficient to guarantee authenticity. The fairly relaxed prerequisites now common for ancient population studies have opened the door for all kinds of contamination and sequencing errors to enter ancient mtDNA data. To reject or question authenticity of particular sequencing results a posteriori, one can follow similar strategies of focused database comparisons that have proven to be effective and successful in the case of flawed modern mtDNA data.     

A novel infraclavicular brachial plexus block: the lateral and sagittal technique, developed by magnetic resonance imaging studies

A new infraclavicular brachial plexus block method has the patient supine with an adducted arm. The target is any of the three cords behind the pectoralis minor muscle. The point of needle insertion is the intersection between the clavicle and the coracoid process. The needle is advanced 0 degrees -30 degrees posterior, always strictly in the sagittal plane next to the coracoid process while abutting the antero-inferior edge of the clavicle. We tested the new method using magnetic resonance imaging (MRI) in 20 adult volunteers, without inserting a needle. Combining 2 simulated needle directions by 15 degrees posterior and 0 degrees in the images of the volunteers, at least one cord in 19 of 20 volunteers was contacted. This occurred within a needle depth of 6.5 cm. In the sagittal plane of the method the shortest depth to the pleura among all volunteers was 7.5 cm. The MRI study indicates that the new infraclavicular technique may be efficient in reaching a cord of the brachial plexus, often not demanding more than two needle directions. The risk of pneumothorax should be minimal because the needle is inserted no deeper than 6.5 cm. However, this needs to be confirmed by a clinical study. IMPLICATIONS: A new infraclavicular brachial plexus block method was investigated using magnetic resonance imaging without inserting needles in the volunteers. The study suggests two needle directions for performance of the block and that the risk of lung injury should be minimal. Expectations need to be confirmed by a clinical study.     

Salvage of a failed Keller resection arthroplasty

BACKGROUND: A number of typical complications have been associated with Keller resection arthroplasty. Recurrent valgus deformity, cock-up deformity, and a flail toe may be difficult problems for the treating surgeon because options for salvage are limited. In this study, we evaluated arthrodesis of the first metatarsophalangeal joint as a salvage technique following a failed Keller procedure. In addition, the outcomes of motion-preserving procedures were reviewed in a separate series. METHODS: Arthrodesis of the first metatarsophalangeal joint was performed in twenty-eight patients (twenty-nine feet, group A), and either a repeat Keller procedure or an isolated soft-tissue release was performed in eighteen patients (twenty-one feet, group B). The patients were evaluated at least twenty-four months postoperatively, with a personal interview and a clinical examination with use of a modification of the hallux metatarsal-interphalangeal scale. Radiographs were also made for the group treated with the arthrodesis. RESULTS: In group A, the average duration of follow-up was thirty-six months and fusion was achieved in twenty-six of the twenty-nine feet. Satisfaction was excellent or good in twenty-three cases, and the postoperative score according to the modified hallux metatarsal-interphalangeal scale averaged 76 points (maximum, 90 points). A repeat arthrodesis was necessary in five feet because of malposition or pseudarthrosis. In group B, the average duration of follow-up was seventy-four months. Satisfaction was excellent or good in only six cases, and the patient was dissatisfied in eleven cases. The score according to the modified hallux metatarsal-interphalangeal scale averaged 48 points. Valgus deviation and cock-up deformity had recurred in the majority of the feet at the time of follow-up. CONCLUSIONS: Although it is more technically demanding, we recommend arthrodesis for salvage following a failed Keller procedure since it may be associated with a higher rate of patient satisfaction and better clinical results.     

Psychomotor slowing in hepatitis C and HIV infection

BACKGROUND: Both HIV and hepatitis C virus (HCV) may enter the central nervous system and cause cognitive and/or motor dysfunction. There are limited data on cognition and no data on motor performance in HIV/HCV-coinfected patients. OBJECTIVE: To provide data on cognition and motor performance in HIV/HCV infected patients. METHODS: We compared 43 HIV-seropositive but HCV-seronegative patients, 43 HIV/HCV-coinfected patients, and 44 HIV-negative but HCV-positive patients, all of whom went through neuropsychologic testing and electrophysiologic assessment of basal ganglia-mediated motor function. RESULTS: No significant differences could be found among the groups with regard to premorbid verbal and actual nonverbal intelligence, attention, and memory; the HIV dementia scale; and all somatic and most psychiatric complaints. Affective disorders were less frequent in HIV-negative but HCV-positive patients. This group also scored lower for depression. For all 3 groups, significant pathologic slowing of most rapid alternating movements (right hand) compared with those of HIV/HCV-negative controls as well as significantly prolonged contraction times (both hands) could be diagnosed. Simple reaction times were significantly prolonged only in HIV/HCV-coinfected patients. CONCLUSIONS: Although clinically asymptomatic, both HIV-positive and HCV-positive patients may show affective disturbances and significant psychomotor slowing. A potential predictive value for the further course of infection, which is well established in HIV-positive patients, remains to be investigated in HCV-positive or HIV/HCV-coinfected patients.     

Validity of intra-operative neuromonitoring signals in thyroid surgery

Background Although intra-operative neuromonitoring (IONM) is widely used in thyroid surgery, the validity of the received IONM signals are still unknown.Method Prospective collection of data forms in 29 hospitals from 8,534 patients with 15,403 nerves at risk, who underwent surgery for benign and malignant goitre disorders between August 1999 and January 2001. IONM was performed by indirect stimulation via the vagal nerve and by direct recurrent laryngeal nerve (RLN) stimulation in 12,486 cases. IONM signals were compared with early (<14 days) and late (6 months) postoperative vocal cord function findings.Results The transient and permanent RLN palsy rate was 2.8% and 0.7%, respectively. Monitoring of the RLN function was significantly more reliable via the indirect IONM stimulation route than via the direct IONM stimulation route (specificity P<0.05). IONM by indirect stimulation via the vagal nerve reliably excluded postoperative, permanent, vocal cord palsy (specificity 97.6%, negative predictive value 99.6%). However, a changed IONM was insufficient to predict permanent RLN palsy (sensitivity 45.9%, positive predictive value 11.6%). IONM was not associated with increased general morbidity.Conclusions For intra-operative neuromonitoring, indirect stimulation of the RLN is superior to direct stimulation. An intact acoustic IONM signal is highly predictive of intact postoperative RLN function. When the IONM signal is abnormal or absent, a one-stage extensive thyroid resection should be performed only if the surgeon is absolutely convinced that the first RLN is not harmed or a total thyroidectomy is mandatory.     

Targets of antidementive therapy: drugs with a specific pharmacological mechanism of action

Diagnosis and therapy of dementia have made considerable progress in recent years. Drugs have been developed which improve cognitive performance, delay the loss of abilities of daily living and prevent early nursing home placement in a considerable number of patients. With the various pharmacological and non-pharmacological approaches, effective treatment options of AD are available at present and the therapeutic potential will even increase in future. Thus, the treatment of dementia should more focused and explicit in its goals for the doctor, the patient and the relatives. Therapeutic targets must be defined on the basis of the individual needs and deficits and with regard to different levels of the disease process. Ideally, treatment should always aim at an etiological and/or a pathophysiological level. At present, however, aiming at the neurotransmitter level, the core syndrome of cognitive deficits can be approached by treatment options. Further therapeutic targets can be defined on the level of activities of daily living, following a resource focused approach, as well as on the level of behavioral disturbances. Additional therapeutic targets should be seen under a humanitarian or palliative perspective. And finally, family members are also targets for therapy in dementia, even if such therapy is not directed towards the demented patient. All these treatment targets have to be evaluated and adapted under the perspective of time because prominent symptoms in AD change considerably with disease progression. Selection and adaptation of medication becomes easier if such targets are considered and if therapeutic effects are monitored target-specifically.