Non-nociceptive capsaicin-sensitive nerve terminal stimulation allows for an original vasodilatory reflex in the human skin

A significant increase of cutaneous laser Doppler flowmetry was found before blood flow decreases with increasing pressure during a 5 mmHg min⁻¹ increase of pressure strain on the finger. Pre-treatment with a local anaesthetic or chronically applied capsaicin, resulted in the disappearance of the vasodilatory response. These results suggest an original vasodilatory axon reflex response to non-noxious pressure strain which is initiated by capsaicin-sensitive nerve terminals in the human skin.     

Impairment of bone turnover in elderly women with hip fracture

Summary Hip fracture is one of the most severe consequences of osteoporosis affecting aged women. However, abnormalities of bone turnover responsible for bone loss in this condition have not been clearly defined. To further evaluate the bone metabolic status of women sustaining hip fracture, we have prospectively measured serum osteocalcin as a marker of bone formation and urinary excretion of pyridinoline (Pyr) and deoxypyridinoline (D-pyr) cross-links as markers of bone collagen degradation in 174 independently living women (80 ± 8 years) within a few hours after a hip fracture. Comparison was made with 77 age-matched controls (80 ± 5 years) and 17 premenopausal women (39 ± 3 years). In addition 15 of the patients were followed with daily measurements during the first postoperative week. At the time of admission osteocalcin was 20% lower in the fractured women compared to the elderly controls (7.6 ± 3.8 vs. 9.5 ± 4.5 nglml,P = 0.001). Pyr and D-pyr were 36% and 40% higher, respectively (P = 0.0001), than in elderly controls and 85% and 76% higher than in premenopausal controls (P = 0.0001). Serum osteocalcin did not correlate with the cortisol level measured at the same time (r = 0.03, ns), nor with serum albumin and creatinine. Serum osteocalcin remained unchanged within 18 hours after fracture, whereafter it progressively decreased until the third postoperative day. No correlation was noted between the excretion of pyridinoline cross-links and the time elapsed from fracture.These data suggest that the abnormal levels of osteocalcin and pyridinolines are unrelated to traumatically induced acute changes, but reflect abnormalities of bone turnover existing prior to the fracture. Thus, hip-fracture patients have biochemical evidence of decreased bone formation and increased bone resorption when compared to age-matched controls. We suggest that these abnormalities may play a role in the decrease of the bone mass and the consequently increased bone fragility that characterize the osteoporotic hip fracture in the elderly.     

Iodomethylated fatty acid metabolism in mice and dogs

The myocardial uptake of fatty acids labeled with radioactive iodine and injected i.v. can only be evaluated with SPECT if their oxidation kinetics is slow enough. For this reason, we evaluated different iodomethylated fatty acids in mice and dogs to determine which of them shows the highest myocardial uptake and the slowest oxidation. The most suitable was found to be 16-iodo-3-methyl hexadecanoic acid (mono ) since its myocardial fixation was the same as that of the reference, i.e. 16-iodo-9-hexadecenoic acid (IHA), whereas it was degraded more slowly. Thirty min after injection of mono into dogs, the decrease in myocardial activity with respect to the maximum was two fold less than after IHA injection. The myocardial uptake of the two dimethylated fatty acids studied, i.e. 16-iodo-2,2-methyl hexadecanoic acid and 16-iodo-3,3-methyl hexadecanoic acid, was less than that of IHA in mice and dogs. In the latter, the myocardial uptake was so small that we were unable to study the time course of its activity. Consequently, these dimethylated fatty acids are not suitable for the study of the myocardial uptake of fatty acids in man.     

Aneurysm of the abdominal aorta in an eighteen-month-old child

We report the case of an infected aneurysm of the abdominal aorta in a 18 month-old child, discovered by routine palpation of the abdomen during hospitalization for pneumonia. Ultrasonography and arteriography showed a 6 cm aneurysm of the abdominal aorta beginning distal to the renal arteries which occluded the right common Iliac artery. The aneurysm was treated by interposing a 6 mm Gore-Tex graft between the infrarenal aorta and the aortic bifurcation. Pathologic examination of the aneurysmal wall demonstrated a leukocytic Infiltrate and the presence of encapsulated Gram positive organisms. Arterial aneurysms are exceedingly rare in children. Their etiology is varied: infection, connective tissue disease, trauma, inflammatory arterial disease or other rare diseases such as tuberous sclerosis, neurofibromatosis, or Beçhet’s disease.     

Organization of Host Afferents to Cerebellar Grafts Implanted into Kainate Lesioned Cerebellum in Adult Rats

This paper examines the organization of host afferents within cerebellar grafts implanted into kainic acid lesioned cerebellum. Our selection of a cerebellum, a prime example of a 'point-to-point' system, permits precise determination of the degree and the specificity of host-graft interactions. One month after a cerebellar injection of kainic acid, the lesion produced can be divided into two concentric regions: (i) a central necrotic zone, totally depleted of neurons (zone 1), and (ii) a peripheral zone which lacks all Purkinje cells but preserves its cortical lamination (zone 2). Two months after the implantation of solid pieces of embryonic cerebellum, the graft has evolved into a minicerebellar structure, occupying most of zone 1. The grafted minicerebellum consists of a highly convoluted trilaminated cortex with a core containing deep nuclear neurons. Purkinje cells are positioned between the molecular and granular layer with their short and irregular dendrites branching within the former. Donor foetal Purkinje cells migrate into the contiguous portion of the molecular layer of the host zone 2. These embryonic neurons set up within the upper three-quarters of the host molecular layer, and develop monoplanar dendritic trees that span the whole width of the layer. The organization of host-graft interactions was studied by autoradiography of anterogradely transported tritiated leucine, injected in the host bulbar region containing the caudal half of the inferior olivary complex (origin of all vermal climbing fibres) and the dorsally adjacent paramedian reticular nucleus (origin of a few mossy fibres). Numerous labelled fibres cross the host-graft interface from the white matter of the host cerebellum, and provide innervation to the minicerebellar structure. The vast majority of these labelled axons terminate in the molecular layer, forming axonal arborizations that follow the shape of the Purkinje cell dendrites. The labelled climbing fibres are organized into uneven sagittally aligned strips, which mimic that of olivocerebellar projections in control rats. Only a small proportion of host labelled fibres end in the donor granular layer, forming typical mossy fibre rosettes. The latter are present in the region of the graft close to the host-graft interface. In addition, labelled axons are observed climbing over the dendritic trees of grafted Purkinje cells that have invaded a portion of the host molecular layer of zone 2. In all regions containing grafted Purkinje cells and labelled climbing fibres, the density of the innervation is close to normal with practically all Purkinje cells receiving a climbing fibre. The extensive integration of the grafted cells into the deficient neuronal networks of the host clearly illustrates the positive neurotropic effect exerted by immature cerebellar neurons on adult extracerebellar afferent fibres. The hodological integration, allowing a possible restoration of the impaired cerebellar circuitry, takes place respecting the specificity and topographic distribution which characterize the 'point-to-point' arrangement of normal cerebellar circuitry.     

Respiratory hazards in hard metal workers: a cross sectional study

A cross sectional study was conducted on 513 employees at three hard metal plants: 425 exposed workers (351 men, 74 women) and 88 controls (69 men, 19 women). Cough and sputum were more frequent in workers engaged in "soft powder" and presintering workshops compared with controls (12.5% and 16.5% v 3.5%). Spirometric abnormalities were more frequent among women in sintering and finishing workshops compared with control women (56.8% v 23.8%) and abnormalities of carbon monoxide test were more frequent in exposed groups than in controls; this difference was more pronounced in women (31.4% v 5.6%) than in men (18.5% v 13%). No significant correlation was observed between duration of exposure and age adjusted lung function tests. Slight abnormalities of chest radiographs (0/1, 1/1 according to ILO classification) were more frequent in exposed men than controls (12.8% v 1.9%) and mostly in soft powder workers. In subjects with abnormal chest radiographs FVC, FEV1 and carbon monoxide indices (fractional uptake of CO or CO transfer index or both) were lower compared with those with normal chest radiographs. Although relatively mild, the clinical, radiological, and functional abnormalities uncovered call for a regular supervision of workers exposed to hard metal dust.     

The diagnostic use of the second oscillatory potential in clinical electroretinography

Of all the electroretinogram (ERG) components (a-wave, b-wave, and oscillatory potentials) only one oscillatory potential, OP₂, was found to be significantly correlated with the absolute intensity of the flash stimulus (i.e., the intensity of the stimulus irrespective of the state of retinal adaptation). Our finding was further confirmed in single cell recordings of lateral geniculate unit activity in rabbits in which peak time of OP₂ was found to correlate better with the geniculate activity. For these reasons we have identified OP₂ as the intensity coding oscillatory potential of the ERG. In order to investigate if this new feature could have some clinical significance, we examined photopic ERGs recorded from patients affected with various retinopathies. In most instances the peak time of OP₂ paralleled that of the b-wave, that is, in the ERG with delayed b-wave the peak time of OP₂ was also delayed, while in ERGs with normal b-wave peak time the peak time of OP₂ was also normal. However, in some conditions (especially in cone-rod diseases) a delayed OP₂ was found in ERGs with normal b-wave peak times.