Olli Korkala

Immunohistochemical demonstration of nociceptors in the ligamentous structures of the lumbar spine.

Substance P, a physiologically potent neuropeptide is known to participate in the sensory, and especially nociceptive, transmission of neural Impulses. On histologic grounds, the nerve terminals of the sinuvertebral nerve formerly have been suggested to be sensory in character and to mediate the low-back pain syndrome. Samples of paramedullary llgamentous structures were collected on disc operations. A positive Immunoreaction as an indicator of substance P was confirmed in some nerve terminals of the posterior longitudinal ligament. Neither the yellow ligament nor the intervertebral disc showed such nociceptive-type nerves.

Tranexamic acid reduces blood loss in cemented hip arthroplasty: A randomized, double-blind study of 39 patients with osteoarthritis

Background Tranexamic acid has been found to reduce blood loss and the need for blood transfusions in knee arthroplasty. In hip arthroplasty, the benefit of tranexamic acid is not as clear. Patients and methods In a randomized, double-blind study, 39 patients with primary cemented hip arthroplasty for osteoarthritis were divided into two groups; one receiving tranexamic acid and the other not receiving it. Tranexamic acid was given in a dose of 10 mg/kg before the operation and twice thereafter, at 8-hour intervals. Results and interpretation Total blood loss was smaller in the tranexamic acid group than in the control group. No thromboembolic complications were noticed. Tranexamic acid appears to be an effective and economic drug for reduction of blood loss in cemented primary hip arthroplasty for osteoarthritis.   ▪

Silver impregnation and immunohistochemical study of nerves in lumbar facet joint plical tissue

Impingement of plical synovial tissue in a facet joint could cause pain. Plical tissue was removed during surgery for recurrent disc herniation or spinal stenosis. The presence of nerves was studied with silver impregnation, immunofluorescence, and avidin-biotin-peroxidase complex (ABC) immunostaining. Heterologous antisera to protein gene product (PGP) 9.5, substance P, calcitonin gene-related peptide (CGRP), and galanin were used to stain nerves. After silver impregnation, nerve-like structures were observed perivascularly. Such nerves located close to blood vessels were also immunoreactive for PGP 9.5, a more general cytoplasmic neural marker, whereas only few perivascular small varicosities were seen with antisera to substance P and galanin and none with antiserum to CGRP. In addition, PGP-9.5-, substance-P-, and galanin-immunoreactive nerves were occasionally seen very near to fat globules. Very few peptide-immunoreactive nerve varicosities were seen with immunofluorescence, and none of the PGP-9.5-immunoreactive nerves that were observed with ABC immunostaining were immunoreactive for neuropeptides as well. One mechanism for pain production could be mechanical compression of fatty tissue, but it is considered more likely that nerves in this particular tissue are mainly involved in local vasoregulation and that they are not sensory nociceptive nerves.

Innervation of synovial membrane and meniscus

Substance P-immunofluorescent nerves, which are closely connected to pain transmission, were shown in human knee synovial membrane and menisci. Both tissues also contained enkephalin-immunofluorescent nerves, which are probably involved in the modulation of pain transmission. Previous suggestions on the presence of nociceptive receptors in these non-cartilaginous joint structures, made on a histological basis, are thus confirmed by a specific immunohistochemical method.

Fluorescence histochemical and electron-microscopical observations on the innervation of the atrial myocardium of the adult human heart

The existence of both adrenergic and cholinergic innervation of the atrial myocardium of the adult human heart was demonstrated by means of fluorescence induced by formaldehyde or glyoxylic acid and by electron microscopy. The adrenergic fluorescing axons (1) followed the course of blood vessels as typical perivascular nerve plexuses, and (2) formed a three-dimensional fairly dense nerve net obviously not related to the blood vessels. The varicosities frequently came into close apposition on myocardial cells. Several types of nerve terminals were differentiated at electron microscopy: (1) an “adrenergic” type containing small (diameter 450–700 Å) dense-cored vesicles and usually (in various proportions) small “empty” and/or large (900–1500 Å) dense-cored vesicles, (2) a “cholinergic” type containing small (ca. 500 Å) “empty” vesicles and occasionally also some large (mean diameter ca. 1200 Å) dense-cored vesicles, (3) a “pale” type containing only a few or no vesicles, (4) a “disintegrated” type containing degenerated mitochondria, autophagic vacuoles, and occasional normal-looking mitochondria, (5) nerve terminals containing a large number of mitochondria in addition to varying vesicle populations, and (6) a (possibly baroreceptive type of) nerve terminal containing myelinlike lamellated structures. The “disintegrated” and the “pale” types of nerve terminals possibly represent different stages of axonal degeneration, or may correspond to diminution in the transmitter substance concentration under certain pathophysiologic conditions, respectively. Nerve terminals crowded with mitochondria may be sensory and involved in mechano-or chemoreceptive functions. In preliminary experiments convincing evidence was obtained that the glyoxylic acid-induced fluorescence histochemical method will be suitable for comparative studies on (human) clinical specimens, e.g., for analyzing the degree of the functional activity of the intrinsic adrenergic innervation of the myocardium under various pathophysiologic conditions. The modification which appeared most appropriate for such studies is described in detail, and is proposed for use as a standard method in other similar or related studies on human clinical series. The essential criteria for analyzing the specimens at fluorescence microscopy are suggested as well.

The Effect of Hypoxia on the Catecholamine Content of Human Fetal Abdominal Paraganglia and Adrenal Medulla

The responses of human fetal catecholamine storing tissues, the paraganglia and adrenal medulla to severe oxygen deficiency were tested by using perfusion techniques. The changes in catecholamine content of the target organs were registered by demonstrating the formaldehyde induced fluorescence exhibited by catecholamines. A definite decrease in the intensity of the catecholamine specific fluorescence was observed regularly in the paraganglia after 10–15 min hypoxia. Only very slight changes occurred occasionally in the corresponding adrenal medullae. The role of the target organs and the catecholamine release during oxygen deficiency are discussed.

Origin and development of the catecholamine-storing cells of the human fetal carotid body

SummaryThe carotid bifurcation areas of 25 human fetuses aged from 8 to 22 weeks were studied using the formaldehyde-induced fluorescence method. A long process from the sympathetic trunk reached the area at the age of 8 weeks contacting with the carotid body primordium. Brightly fluorescent cells can be seen both in the carotid body and in the ganglionic process. Migration of these cells from the sympathetic trunk to the carotid body is suggested. The connection from the sympathetic trunk to the carotid body totally disappeared after the tenth week, leaving no fluorescent elements between these two. Control electron microscopy and light microscopy were performed to identify the fluorescent and nonfluorescent components of the human fetal carotid body.

Articular cartilage after meniscectomy: Rabbit knees studied with the scanning electron microscope

Ten rabbits had a medial meniscectomy in both knees. The articular surface was studied with a scanning electron microscope 2, 4 or 12 weeks after the operation. Three sham operated and two unoperated rabbits served as controls. Progressive articular cartilage damage was observed on the weight-bearing areas of the medial condyles. The findings are compatible with clinical observations after meniscectomy; they confirm that meniscectomy is not a harmless operation.

Twenty-year results of the Evans operation for lateral instability of the ankle.

Twenty-four patients (25 ankles), operated on using the static modification of the Evans tenodesis for lateral instability, were evaluated 19 to 21 years after surgery. Twelve of the patients (12 ankles) had excellent results, seven patients (eight ankles) had good results, three patients (three ankles) had fair results, and two patients (two ankles) had poor results. The subjective results had no clear correlation to the stress radiographs, which showed minor or moderate anterior talar translation in 10 ankles. Moreover, the difference between the surgically treated and the contralateral ankle was not significant. Static modification of the Evans tenodesis is recommended if an anatomic reconstruction of the lateral ligaments is not feasible (general laxity of joints, reoperation).

Immunohistochemical demonstration of subclasses of inflammatory cells and active, collagen-producing fibroblasts in the synovial plicae of lumbar facet joints

Plical tissue removed perioperatively from lumbar facet joints was studied immunohistochemically with the avidin-biotin-peroxidase complex (ABC) method for a putative presence of various subclasses of inflammatory cells and active collagen-producing fibroblasts. These methods have previously been used successfully for demonstrating specific inflammatory cells in rheumatoid arthritic synovium and cervical ligament and for studying regeneration of connective tissue, respectively. An overt inflammatory cellular response could not be demonstrated, as B lymphocytes were totally absent and no lymphocyte activation markers, either interleukin-2 receptor or immune-response-associated la antigens were expressed. Most of the immunoreactive cells observed were CD11b monocytes, and even these were only scattered in the connective tissue. Occasional activated collagen-producing fibroblasts were seen, suggesting in these few cases a possible regenerative response of the collagenous tissue, maybe induced by an impingement phenomenon, as such cells are not normally seen in resting connective tissue