G. Austin Gresham

Differential effects of angiostatic steroids and dexamethasone on angiogenesis and cytokine levels in rat sponge implants

1 . Subcutaneous implantation of sterile polyether sponges elicited a reproducible neovascular response in rats, as determined by blood flow measurement with a 133Xe clearance technique and confirmed histologically. This model was used to monitor the levels of two cytokines during angiogenesis and to compare the activities of angiostatic steroids and anti‐inflammatory steroids. 2 . Initial experiments followed the neovascular development over a 20‐day period. Daily local injection of hydrocortisone caused a dose‐dependent (0.5, 5 and 50 μg per sponge) inhibition of the basal sponge‐induced angiogenesis. However, daily systemic treatment of hydrocortisone (2, 10 and 50 mg kg−1, s.c.) was less effective at inhibiting angiogenesis, and this inhibition was not sustained by day 20 after sponge implantation. 3 . To investigate the involvement of cytokines during the course of angiogenesis, we measured the endogenous levels of tumour necrosis factor‐α (TNF‐α) and interleukin 6 (IL‐6) in sponge implants. Levels of IL‐6 and TNF‐α peaked at day 7 and day 11 after implantation, respectively. These cytokine levels subsided through the completion of angiogenesis by day 20. 4 . Subsequent experiments were carried out over a 14‐day period. Among the three angiostatic steroids tested, U‐24067 (6α‐fluoro‐17,21‐dihydroxy‐16α‐methylpregna‐4,9(11)‐diene‐3,20‐dione‐21‐acetate) showed a dose‐dependent inhibition (0.5, 5 and 50 μg per sponge per day) of sponge‐induced angiogenesis. Tetrahydro‐S was also effective at 5 μg doses, but medroxyprogesterone failed to affect the angiogenic response. None of these steroids caused atrophies of the spleen and thymus. 5 . Daily local injection of dexamethasone (0.5 μg per sponge) inhibited the basal sponge‐induced angiogenesis almost completely. Although higher doses of dexamethasone (5 and 50 μg per sponge) did not produce further inhibition of angiogenesis, they caused severe spleen and thymus weight losses, indicative of immunosuppression. 6 . At the daily dose of 5 μg per sponge, dexamethasone inhibited angiogenesis and produced a marked reduction in the levels of TNF‐α and IL‐6 at day 14. In contrast, hydrocortisone, U‐24067 and tetrahydro‐S did not influence the levels of TNF‐α and IL‐6. 7 . We concluded that the anti‐angiogenic activity of angiostatic steroids and anti‐inflammatory steroids in the rat sponge model is independent of their ability to reduce the production of TNF‐α and IL‐6. The differential effects of angiostatic and anti‐inflammatory steroids suggest that U‐24067 and its derivatives may have therapeutic potential in the management of angiogenic diseases such as rheumatoid arthritis.

Networks in the right side of the heart.

Delicate networks occur in the right side of the heart at three sites: at the entry of the inferior vena cava into the atrium, at the mouth of the coronary sinus, and between the endocardial surfaces of the right ventricle. The first clear account of the fenestrated valve of the inferior vena cava and coronary sinus was by Eustachi (1563, quoted by Franklin 1948). Franklin (1948) has reviewed the historical background of these valves and the theories concerned with their origin and function. Chiari (1879) described networks formed from the valves of the inferior vena cava, and in some cases of the coronary sinus, which showed attachments beyond the usual territories of these valves. These reticular formations are now called Chiari networks. Chiari himself considered them to act as a source of pulmonary emboli. Yater (1929) suggests that they may serve as a filter for emboli arriving at the right atrium from elsewhere in the venous system. This investigation is mainly concerned with the view that the network may act as a short circuit from sinu-atrial node to atrioventricular bundle. Hearts from 300 consecutive necropsies were examined for the presence of networks in the right atrium and in the right ventricle. Of these 260 were from adults, 23 of whom were below the age of fifty; 7 were from children in the first five years of life; and 33 were from stillbirths and neonates.

A case of ventricular fibrillation.

A woman, aged 85, was admitted to Harrogate General Hospital under the care of Mr. Gordon Bailey on May 30, 1950 with vomiting and constipation that had been present for four days. Heart block had been diagnosed by her family doctor three weeks before. Her pulse was irregular, 32 a minute; the blood pressure was 230/90. She vomited repeatedly and gastric suction and intravenous saline were started to combat dehydration. On June 2 her vomiting had ceased; she was seen by Dr. Curtis Bain and a diagnosis of complete heart block with premature ventricular beats was made. The heart was not enlarged, but persistent crepitations were audible at the base of the left lung. On June 4 the patient developed attacks of unconsciousness lasting a few seconds, in which she became pulseless and cyanosed, with tonic and clonic movements of the limbs. The attacks became more frequent and she died on June 9. A cardiogram taken on June 6 showed complete heart block with an auricular rate of 100 and the Q-T time greatly prolonged, 0-72 sec. (Fig. 1). The ventricular rhythm was irregular due to multifocal ectopic beats, the rate being about 36. A short paroxysm of ventricular tachycardia is shown, preceded by an initial premature beat. The latter follows the preceding ventricular complex by an interval of 0t68 sec. and is directed downwards (Fig. 2).

Injury at Work

The severity and nature of industrial injuries vary with the type of job involved. In the steel industry where people are handling heavy, hot objects there is much danger and injury and strict codes of practice need to be provided and complied with if the hazards are to be avoided. The maintenance of a register of all injuries is essential but equally important is a register of incidents which do not involve personal injury but are still a potential hazard. Registers of this sort tend to reflect constant patterns of injury. For example, minor cuts are a steady feature of accident reports in histological laboratories. Accident and incident registers are the basis for improved patterns of work that should reduce injury at work.

PSORIASIS: A DISORDER OF NECROSIS.*

NECROSIS is an essential event in tlie normal maturation of squamous epithelium. Although the manufacture of keratin from the cytoplasmic constituents of squamous cells has mainly attracted cytochemical study, it is likely that the jjrime determinants in the formation of the horny layer are nuclear rather than cytoplasmic in origin. The synchronous karyolysis in the rete mucosum is indeed the most remarkable phenomenon of epidermal develo2)ment. Little in fact is known ahout this necrosis of the epidermal nuclei. Our ignorance is in a way paradoxical, since continuous death of the epidermal eells along with loss of their nuclei is a normal and uniform process extending over our entire integument. Only, however, when disorder arises in this process of death do we deem it worthy of serious attention. Psoriasis may be regarded as a disorder of necrosis. One of the most prominent features of the disease is the retention of lamellar nuclear remnants in psoriatic scales in the place of the synehi-onous nuclear dissolution of normal epidermis. These persistent band-like incarcerated nuclei are known to retain their desoxyribonucleic acid (DNA) whieh is stainable by the Feulgen method (Braim-Falco, 1958). This communication is concerned with nuclear changes in psoriasis as well as with the effects of these changes on epidermal eytoplasm. The cytoplasm of the rete mncosum is rich in tannophilic protein stainable by the oxidized tanninazo (OTA) method for protein (Dixon, 1959). During the formation of normal keratin this tannophihc protein almost completely disappears. Indeed the loss of tannophilic protein from the cytoplasm is a striking concomitant of the karyolysis in the epidermal cells. A study was therefore made of the distribution of tannophihc protein (detectable by the OTA method) both in

PREMATURE OBLITERATION OF THE FORAMEN OVALE

CASE HISTORY The patient was the second child of a mother (aet. 21) whose previous obstetric history was normal. Apart from two periods of rather rapid gain of weight for which no cause could be found, the pregnancy was uneventful. The child was eleven days postmature; labour was induced with an enema and lasted forty-five minutes. The infant cried lustily but was cyanosed: the heart was clinically normal. Abnormalities were present in all four limbs. The left radius and ulna were absent and rudimentary digits were present on the skin over the distal end of the limb. Terminal phalanges were absent in the fingers of the right hand, and four toes were present on each foot with a rudimentary fifth digit on the left foot. Cyanosis and dyspniea became more intense and the child died three hours after birth despite the use of oxygen.

Remnants of necrotic grey matter

SummaryCerebral neurones, with their intricately branching processes, have the highest surface/volume ratio of all cells. When cerebral grey matter disintegrates, the uniquely extensive surface of these ramifying cells becomes disorganised. Hydrophobic lipid remnants derived from this vast expanse of lipoprotein membranes may thus account for the highly characteristic PAS-positive granules found in phagocytes present in zones of softening produced by ischaemic necrosis of the cerebral cortex.This view was supported by further observations on these granules in phagocytes of necrotic cerebral cortex and also by the presence of granules with the same cytochemical properties in similar phagocytes which were found in necrotic cerebellar cortex. In the latter tissue, in which the neurones also possess an exceptionally large surface area owing to the extent of their axo-dendritic arborisations, neuronal disintegration was also followed by the appearance of apparently identical intraphagocytic deposits.The granular material within phagocytes of necrotic grey matter of both cerebral and cerebellar cortex was intensely coloured by Sudan black B, PAS, and paraldehyde fuchsin after pre-treatment with KMnO4. The colouration by PAS was not inhibited by previous incubation with amylase nor by previous bromination, but was suppressed after acetylation. Although faint brown in colour the granules did not contain ferric iron.The granular histiocytes found in necrotic grey matter differed from the foamy histiocytes seen in disintegrating white matter during the destruction of myelin.The granular material in the phagocytes of softened grey matter may be a hydrophobic coacervate formed by disarray of orientated lipoproteins and gangliosides during the disintegration of the extensive surfaces of axo-dendridic arborisations.Cerebral neurones, with their intricately branching processes, have the highest surface/volume ratio of all cells. When cerebral grey matter disintegrates, the uniquely extensive surface of these ramifying cells becomes disorganised. Hydrophobic lipid remnants derived from this vast expanse of lipoprotein membranes may thus account for the highly characteristic PAS-positive granules found in phagocytes present in zones of softening produced by ischaemic necrosis of the cerebral cortex.

Are human spermatozoa separated on a Percoll* density gradient safe for therapeutic use?*Pharmacia Fine Chemicals (AB), Uppsala, Sweden.††Supported by a grant to P.R.B. from the Medical Research Council of Great Britain.

Motile morphologically normal human spermatozoa can be separated from semen by buoyant density centrifugation on Percoll (Pharmacia Fine Chemicals AB, Uppsala, Sweden) gradients. In this study, the authors have examined (1) the efficiency of washing procedures to remove contaminating Percoll particles from the separated spermatozoa, and (2) the potential of Percoll particles, which contain silica, to cause an inflammatory response when used for intrauterine insemination, or when introduced into the fallopian tube during gamete intrafallopian transfer (GIFT) procedures, as assessed by an intraperitoneal injection into mice. Although Percoll was phagocytosed at the injection site, and therefore cannot be presumed to be totally inert, no generalized inflammatory response was detected. A double spin and wash technique was found to remove most residual Percoll from the spermatozoa, as assessed by scanning electron microscopy. These results suggest that procedures involving the use of Percoll for the separation of human spermatozoa for in vitro fertilization, GIFT, or intrauterine insemination should include stringent washing protocols that will remove most, if not all, contaminating Percoll from the sample.

Accidental, Suicidal or Homicidal Injury

The study of wounds is mainly directed towards relating the tissue and organ changes to the mechanisms of injury and the time of their occurrence. In itself it is a fascinating aspect of biology but this study is also the key to the assessment of the mode of death. The position, form and grouping of wounds is often of great value in determining whether they were inflicted accidentally, suicidally or as the result of homicide.

Injury at Home

Serious accidents in the home are remarkably infrequent considering the wide range of hazards that exist in the average home. Many home injuries affect the young and the very old and are often due to lack of forethought and the proper maintenance of equipment. The home is also a closed sequestered environment within which all sorts of acts can be perpetrated. Abuse of children and others is an increasingly common activity that can go undetected. The abuse varies from obvious physical violence to more subtle psychological injury that is often difficult to verify.