Interactions between extracellular Borrelia burgdorferi proteins and non-Borrelia-directed immunoglobulin M antibodies.

Previous work showed that outer surface protein A (OspA) and OspB of Borrelia burgdorferi may occur within an extracellular multiprotein complex, which was resolved by electrophoresis as an 83-kDa major extracellular protein band. To characterize the 83-kDa band, we sequenced the N terminus of the predominant peptide in the band and examined the interaction between the associated proteins. Peptide sequence and amino acid composition comparisons showed identity with the heavy chain of immunoglobulin M (IgM). Reduction sensitivity experiments and the recognition of the band by antibodies specific for rabbit mu chain indicated that the multiprotein complex contained pentameric IgM. Immunoelectron microscopy showed that anti-mu chain antibodies and monoclonal antibodies to OspA and OspB bound to extracellular amorphous material surrounding cells. Furthermore, the Osps coprecipitated with either nonspecific polyclonal rabbit IgM antibodies or with murine monoclonal anti-human serum albumin IgM antibodies, using insoluble anti-mu chain antibody conjugates. Although the apparent 83-kDa complex was stable under conditions of chelation and concentrated salts, it was disrupted by treatment with neuraminidase. These results indicate that extracellular B. burgdorferi proteins, including OspA and OspB, interact with IgM. The association is apparently not a classic antibody-antigen interaction but may result from other mechanisms.     

Neurodevelopmental outcome of hypoglycaemia in healthy, large for gestational age, term newborns

AIMS: To evaluate the effects of transient hypoglycaemia on the first day of life in 75 healthy term large for gestational age (LGA) infants, born to non-diabetic mothers, on their neurodevelopmental outcome at the age of 4 years. METHODS: Screening for hypoglycaemia was performed 1, 3, and 5 hours after birth, and continued if blood glucose levels were low. Treatment with intravenous glucose for hypoglycaemia was started if hypoglycaemia was severe or symptomatic. Patients' development and behaviour was examined at the age of 4 years by the Denver Developmental Scale, a non-verbal intelligence test, and the Child Behaviour Check List. RESULTS: There were no significant differences between children with neonatal normoglycaemia (n = 15) and hypoglycaemia (plasma glucose <2.2 mmol/l 1 hour after birth, or <2.5 mmol/l subsequently; n = 60) in Denver developmental scale scores and child behaviour checklist scores. Although total IQ did not differ between hypoglycaemic and normoglycaemic children, one subscale (reasoning) did (mean difference 9.3, 95% CI 1.3 to 17.2). The correlation between reasoning IQ and neonatal blood glucose levels was weak and not statistically significant. When other definitions for hypoglycaemia were applied, the difference in reasoning IQ was not found. There were no differences in any of the test scores between hypoglycaemic children who had and who had not been treated with intravenous glucose. CONCLUSION: Transient mild hypoglycaemia in healthy, term LGA newborns does not appear to be harmful to psychomotor development at the age of 4 years.     

Precise cannulation of the foramen ovale in trigeminal neuralgia complicating osteogenesis imperfecta with basilar invagination: technical case report

OBJECTIVE AND IMPORTANCE: Trigeminal neuralgia is a rare feature of basilar invagination, which is itself a complication of osteochondrodysplastic disorders. Microvascular decompression is an unattractive option in medically refractory cases. The conventional percutaneous approach to the trigeminal ganglion is anatomically impossible because the foramen ovale points inferiorly and posteromedially. We report a new technique for image-guided trigeminal injection in a patient with basilar invagination complicating osteogenesis imperfecta. CLINICAL PRESENTATION: A 26-year-old woman with osteogenesis imperfecta presented with a 3-year history of typical left maxillary division trigeminal neuralgia, which was poorly controlled by carbamazepine at the maximum tolerated dose. She had obvious cranial deformities, left optic atrophy, delayed left eye closure, tongue atrophy, but normal facial sensation and corneal reflexes. A computed tomographic scan and magnetic resonance imaging confirmed severe basilar invagination. TECHNIQUE: Frameless stereotactic glycerol injection of the left trigeminal ganglion was performed under general anesthesia using the infrared-based EasyGuide Neuro system (Philips Medical Systems, Best, The Netherlands) with magnetic resonance imaging and computed tomographic registration. The displaced and distorted left foramen ovale was cannulated via a true frameless stereotactic method with the trajectory determined by virtual pointer elongation. The needle placement was confirmed with injection of contrast medium into the trigeminal cistern. The path needed to enter the foramen traversed the right cheek, soft palate, and left tonsil. The patient went home pain-free with a preserved corneal reflex and no complications. CONCLUSION: Frameless stereotaxy allows customization to individual patient anatomy and may be adapted to a variety of percutaneous procedures used in areas where the anatomy is complex.     

Pulmonary nodules: detection using magnetic resonance and computed tomography

Detection of pulmonary nodules using spin-echo magnetic resonance (MR) imaging was compared with detection using computed tomography (CT). Of the 25 patients studied independently by two radiologists, no lung nodules were detected in 11 (CT or MR), ten had a single nodule, and four had multiple nodules. The lesions not seen using CT or MR were less than 1.3 cm in diameter. The greater spatial resolution of CT enabled better detection of nodules close to the diaphragm, the pleura, or to each other, whereas the better contrast resolution of MR enabled the detection of several nodules close to blood vessels. With MR, nodules were best seen on images with long repetition times (2.0 sec). Most pulmonary nodules are seen using both CT and MR. CT generally enables the detection of more small nodules than MR does, and some low-density nodules near blood vessels are better displayed using MR.     

Usage of antimicrobial agents in a private primary healthcare setting in South Africa

Objective The aim of this study was to investigate the prescribing of antimicrobials in a private primary healthcare setting in South Africa. Setting A group of private primary healthcare clinics in South Africa. Method A retrospective, drug utilisation study was conducted on nine clinics that were randomly selected from 33 clinics situated in different geographical areas of South Africa, and whose data were electronically available. Data were obtained from the central database of the private primary healthcare provider and extracted for the period January 1, to December 31, 2001. Key findings The study population consisted of the total patient population (n = 83 655) who visited the clinics during this one‐year period. The total number of medicine items prescribed was 515 976 at a total cost of R1 716 319 ($17 163). Of these, antimicrobials represented 18.69% (n = 96 421) of all medicine items prescribed at a cost of R1 045 108 ($10 451) (60.89%). Antimicrobials were prescribed during 72.72% of consultations at the nine clinics during the one‐year period. The antimicrobials most frequently prescribed were penicillins (38.17%) followed by sulphonamides (22.49%), antiprotozoals (9.88%) and tetracyclines (9.34%). The most common diagnoses for which antimicrobials were prescribed were viral influenza, upper respiratory tract infections, hypertension, acute bronchitis, and common cold. Conclusions The high percentage of antimicrobial prescribing obtained in this study could indicate excessive use of antimicrobials in the private primary healthcare setting. The prescribing of antimicrobials in respiratory tract infections could indicate overuse and inappropriate use of these agents. This could have an effect on the health of the patients needing care, and the general budget for healthcare services. It is recommended that further investigations on the prescribing protocols of antimicrobial usage be done.     

Response characteristics of muscle afferents in the domestic duck

1. Response patterns of 116 muscle stretch receptor units isolated from the sciatic nerve of the duck have been studied, and the units classified as muscle spindles and tendon organs.2. Units classified as spindles had low threshold tensions for maintained discharge. From conduction-velocity measurements, the calculated fibrediameter spectrum appears to be unimodal, ranging from 5 to 11-12 mum.3. Spindle units showed essentially ;in parallel' behaviour, though increase in initial tension often led to the appearance of ;in series' responses. Although apparent ;alpha-excitation' during maximal tetanic contractions was a common occurrence, no direct evidence of alpha-innervation of spindles was obtained.4. Evidence has been obtained for motor innervation of spindles by fibres distinct from those constituting the alpha supply to extrafusal muscle fibres. Afferent response attributable to this fusimotor innervation is influenced by initial tension and stimulus-frequency. Electrical thresholds for fusimotor responses ranged from 1.1 to 4.03 times alpha maximum.5. Tendon organ units consistently showed ;in series' response patterns during muscle contractions. They were not influenced by stimulation of the high-threshold efferent nerve supply to the muscles.6. Threshold tensions required for maintained discharge in tendon organ units from m. gastrocnemius pars lateralis were characteristically high; however, many units from m. flexor perforans et perforatus d. 3 had unexpectedly low mechanical thresholds. The calculated fibre-diameter spectrum for tendon organ units is unimodal, ranging from 4-7 to 10-11 mum. As in mammals, they contribute to the coarse-fibre component in the muscle nerve and include the fastest fibres present.