The rotational component in the dynamics of the C2–3 spinal segment

Summary The technique of the PA axial projection of the arches of the upper cervical vertebrae into the occipital foramen and the normal findings, are described. The influence of maximum forced anteflexion at the craniocervical junction and rotation of the head on the relations of atlas and axis is demonstrated. It seems that in this position rotation at atlasaxis level is restricted and partly transmitted to the C_2–3 segment. Thus, selective clinical examination of the rotational component of the dynamics at C_2–3 can be achieved and the pathological restrictions of movement can be assessed.     

Release of vasoactive intestinal peptide in the central nervous system in man.

Recent work has shown that vasoactive intestinal peptide (VIP), one of the many candidate hormones of the gut, also occurs widely in neurones. To determine whether the neuronal peptide may have a neurotransmitter function, we studied changes in immunoreactive VIP in dog plasma and human cerebrospinal fluid after the infusion of choline esterase inhibitors (neostigmine and physostigmine, respectively). Immunoreactive VIP was released in both situations. The systemic changes (in VIP levels) were enhanced five weeks after portacaval shunting in dogs. Our results demonstrate that the immunoreactive VIP level increases as a result of choline esterase inhibitors. The plasma "release" may originate either from peripheral peptidinergic nerve terminals or from APUD cells of the gastroenteropancreatic system. The increase in immunoreactive cerebrospinal fluid VIP may very well originate from central neurons, since the peptide does not apparently cross the blood-brain barrier.     

Traumatic injuries of the abdominal aorta.

Despite immediate operation, patients with abdominal aortic injuries and profound hypovolemic shock do not respond to the usual methods of resuscitation and die soon after celiotomy, prior to control and repair of the aortic injury. The rate of aortic hemorrhage exceeds the ability to restore blood volume. Shock becomes "irreversible." In such patients tamponade of the aortic injury may be effected by the use of an external counterpressure device such as a G-suit or MAST suit. These devices, used in conjunction with transthoracic aortic occlusion, may raise blood pressure sufficiently to perfuse the sritical coronary and cerebral circulation, allowing time to correct acidosis and locate, control, and repair the aortic injury. Early aggressive therapy should result in increased survival.     

Study of preclinical changes in workers exposed to inorganic mercury in chloralkali plants

Summary The aim of the present work was to clarify the question of preclinical changes of Hg intoxication (micromercurialism) in man. The study to detect these disorders was performed on 39 chloralkali plant workers who had been exposed to mercury for more than 7 years. The ambient air, urine and blood values of the last few years were determined in extensive measurements by various methods and related to one another. The average ambient air concentrations were clearly below the currently applicable threshold limit value (German MAK) of 0.1 mg/m³. For the purpose of clarifying the mentioned question of preclinical changes of intoxication, the exposed persons were subjected to psychomotor-function examinations and compared with a group of nonexposed persons. The blood pressure and pulse frequency values of both groups were also determined and compared with one another. No significant differences between the two groups of persons examined were detectable.Presented at the 18th Congress of the Deutsche Gesellschaft für Arbeitsmedizin in Frankfurt, 24th May 1978     

Studies on metabolic actions of some xanthine derivatives of dopamine in the rat

Summary The lipolytic and hyperglycaemic actions of three xanthine derivatives of dopamine were studied in fed rats by determining the plasma levels of glycerol, free fatty acids and glucose. All three derivatives, 7-propyl-theophylline-dopamine, 7-(3-methyl)-propyl-theophylline-dopamine and 7-(2-methyl)-propyl-theophilline-dopamine, had a longer duration of action on lipolysis than had dopamine. These xanthine derivatives stimulated lipolysis at 10-to 100-times lower doses than dopamine and also had a greater maximal effect. Glycogenolysis was stimulated by 7-(3-methyl)- and 7-(2-methyl)-propyl-theophyllinedopamine at lower doses than by dopamine, the maximal effect, however, being smaller than that of dopamine. 7-propyl-theophylline-dopamine had practically no hyperglycaemic effect. Pretreatment with the -adrenoceptor blocking agents, phentolamine and dihydroergotamine, blocked the increase of the plasma level of glucose induced by dopamine, whereas the hyperglycaemic effect of 7-(3-methyl)-propyl-theophylline-dopamine was better antagonized by the -adrenoceptor blocking agent, propranolol. The -adrenoceptor antagonists had no clearcut effects on the lipolytic action of dopamine or its xanthine derivatives, which was, however, clearly antagonized by pretreatment with propranolol. Desipramine and reserpine, at doses which prevented the metabolic actions of tyramine, partially blocked the lipolytic and hyperglycaemic effect of dopamine, but not those of the xanthine derivatives. This suggests that the xanthine derivatives- in contrast to dopamine- do not have an indirect, tyramine-like component in their metabolic actions. Pretreatment with pargyline, an inhibitor of monoamine oxidase, strongly enhanced the metabolic effects of dopamine, but to a lesser extent the actions of its xanthine derivatives, indicating that these derivatives are more resistant to monoamine oxidase than is dopamine. The results indicate that the xanthine derivatives have metabolic effects similar to those of dopamine, but differ from dopamine in their activity and relative affinity with respect to metabolic - and -adrenoceptors and in their mechanism of action as well as in their metabolism.Deceased August 6, 1978     

Acute neurotoxicity of the Lathyrus sativus neurotoxin, L-3-oxalylamino-2-aminopropionic acid, in the squirrel monkey.

This paper provides the first evidence that the Lathyrus sativus neurotoxin, l-3-oxalylamino-2-aminopropionic Acid (OAP), is toxic when administered intraperitoneally to a primate with a mature bloodbrain barrier. Drowsiness, vomiting, muscle tremors, twitching, convulsions, and death occurred in young male squirrel monkeys (Saimiri sciureus) following injection of 4.26 and 11.4 μmol (0.750 and 2.00 mg) OAP/g body wt. Electroencephalographic changes characteristic of each stage of intoxication were observed. Unchanged OAP was recovered from brain of intoxicated animals. These observations support a possible role for OAP in the etiology of human neurolathyrism, a paralytic disease prevalent among adults in Central India who have consumed large quantities of L. sativus seeds for several months.     

Different behavioural patterns induced by apomorphine: evidence that the method of administration determines the behavioural response to the drug

The behavioural effects of s.c. injected apomorphine was studied on habituated rats in a test-box designed to measure 8 different components of behaviour. Apomorphine, 1 mg/kg, induced two different behaviours: The "G-type" of behaviour characterized by compulsive gnawing and the "LS-type" of behaviour characterized by increased locomotion, sniffing and repetitive head and limb movements. G-type behaviour was induced when apomorphine, dissolved by heating, was injected s.c. into the flank of the animal. LS-type behaviour was induced both when apomorphine, dissolved by heating, was injected s.c. into the neck and when it was dissolved by heating together with a high concentration of ascorbic acid (1 mg/ml) and injected s.c. into the flank. G-type behaviour could not be elicited by changing the dose which induced LS-type behaviour or vice versa. We therefore conclude that these different behavioural effects of apomorphine were not dose--response effects but were elicited by at least two different synaptic mechanisms in the brain. Experimentally induced changes from one of these apomorphine-induced behaviours to another can therefore not merely be interpreted as a change in the intensity of the behavioural response as is done in e.g. commonly used stereotypy rating scales.     

Prosthetic arteriovenous fistula for vascular access in hemodialysis.

Vascular access through subcutaneous prosthetic arteriovenous fistulas was studied in eighteen dogs. Dacron velour and woven Dacron grafts (6 mm diameter) were constructed across the lower abdomen between the common femoral artery and the opposite common femoral vein. In heparinized animals 197 percutaneous punctures were made with a "14 guage hemodialysis cannula at weekly intervals. Over a period of one and a half years there was no instance of infection. One of the fourteen Dacron velous and all four woven Dacron fistulas thrombosed. These data suggested the feasibility of achieving repetitive blood access through Dacron velour vascular prostheses. Nineteen Dacron velour fistula bypasses between the brachial artery and median basilic vein were performed in fifteen selected patients for a total dialysis period of ninety-six months. Failed standard subcutaneous fistulas or absence of suitable vessels in the upper extremity were indications for the primary procedure. Of three looped forearm fistulas, two thrombosed at twenty-two and two months. Complications among sixteen straight bypasses in the arm included two graft infections and one cannula tract infection. There were no instances of thrombosis in this group. The advantages of single needle dialysis in these high risk patients have been emphasized. Eleven grafts are presently functioning two to nine months postoperatively. Our preliminary results suggest that a Dacron velour fistula merits consideration as an alternative for vascular access in maintenance hemodialysis.     

Effect of short-term administration of lead to pregnant rats.

Lead was administred to adult female rats in drinking water (0;0.1:1 and 10 ppm) for 3 weeks before mating, during pregnancy and during 3 weeks after delivery. On day 21 after delivery the mothers and their newborns were sacrified and various parameters of blood -- lead concentration on (Pb-B), hematocrit (Htc), hemoglobin (Hb), free erythrocyte porphyrins (FEP), delta0aminolevulinate dehydratase (ALAD) -- and tissue -- ALAD, free tissue porphyrins (FTP), lead concentration (Pb-T) -- were determined. In mothers a significant increase in Pb-B and Pb concentration in kidney was found in the 10 ppm group, but this increase in lead concentration was not associated with any statistically significant modification of the biochemical parameters. In newborns, lead concentration in blood and in kidney was also significantly increased in the 10 ppm group and this lead exposure was associated with a decrease of the ALAD activity in blood and an increase of FTP in kidney. On the basis of the biochemical parameters investigated one can therefore conclude that the developing organism is more susceptible to the biological action of lead than the organism of adult animals and that the "no-effect" level of lead administered during pregnancy and in the neonatal period is around 1 ppm.     

Clonidine antinociceptive activity: Effects of drugs influencing central monoaminergic and cholinergic mechanisms in the rat

Summary Clonidine is able to increase the threshold for vocalisation during stimulation and the threshold for vocalisation after withdrawal of stimulus (vocalisation afterdischarge). These effects of clonidine were investigated after treatment of rats with drugs influencing central monoaminergic and cholinergic mechanisms.Chlorpromazine, atropine and p-chlorophenyl-alanine increased the activity of clonidine at both thresholds while phenoxybenzamine and reserpine pretreatment increased the activity at the threshold for vocalisation only.Yohimbine decreased clonidine activity at both thresholds while 5-HTP and -methyl-p-tyrosine decreased the effects at the threshold for vocalisation afterdischarge. Naloxone did not change the activity of clonidine at either pain response studied.It is concluded from the present findings that influence from several neuronal systems modulate the antinociceptive action of clonidine.The inhibition of the medullary nociceptive response after clonidine might be connected to a decreased activity of noradrenergic neurons. Endogenous noradrenaline seems to be of minor importance in mediating this effect. It is moreover shown that decreased cholinergic receptor activity enhances clonidine antinociceptive action on both medullary and diencephalic-rhinencephalic pain responses. The possible involvement of serotonin in these functional responses after clonidine is also discussed.Data from this investigation was presented at the International Narcotic Research Club Conference, Airlie, Va. 1975.