Desmethylimipramine potentiates NMDA responses in a mouse cortical slice preparation

Desmethylimipramine (DMI) has been shown to interact with the N-methyl-D-aspartate (NMDA) receptor complex. Its probable action is through blockade of the cationic channel at the phencyclidine site and as a result it has potential anticonvulsant action. In this present study we have investigated the effects of DMI and ketamine on both NMDA-induced and spontaneous depolarizing shifts in cortical wedges prepared from genetically epilepsy-prone mice (DBA/2). Contrary to published reports, DMI potentiated the effects of NMDA and increased the frequency of spontaneous depolarizations. The actions of ketamine were inhibitory and these were reversed by DMI. Presynaptic mechanisms may be involved in the DMI-induced potentiation and this may explain the lowering of convulsive thresholds seen clinically with tricyclic antidepressants.

The effect of methamphetamine on the release of glutamate from striatal slices

One postulated role of dopamine in the striatum is to reduce neuronal activity in cortico-striatal glutamergic terminals. We investigated the effects of methamphetamine, which displaces dopamine, on glutamate release from rat striatal slices. Methamphetamine significantly reduced K(+)-stimulated (45 mM) glutamate release. In slices prepared from rats treated 8 days previously with methamphetamine there was enhanced (approximately 200%) release of glutamate. This study demonstrates that dopamine has a modulatory effect on glutamate release in the striatum.

Vasopressin and haemostatic responses to inguinal hernia repair under local anaesthesia

Major abdominal surgery is accompanied by intra-operative increases in factor VIII (FVIII), plasminogen activator activity (PAA) and fibrinopeptide A (FPA). Vasopressin (aVP) released during surgery mediates some of the effects but the mechanisms involved in this response are unclear. To investigate the role of the operative procedure, 20 subjects were studied during inguinal hernia operation under local anaesthesia. Venous blood samples were taken for FVIII coagulant activity (FVIII:C), euglobulin clot lysis time (ECLT), FPA, crosslinked FDPs (XL-FDP) and a VP. In six patients, aVP rose from (median) 0.5 to 38.3 pg/ml at bowel manipulation and fell to 4.1 pg/ml post-operatively. PAA rose from 33 units to 377 and 316 units (P less than 0.01), FVIII:C from 1.58 to 2.4 IU/ml (P less than 0.01) and FPA from 5.0 to 6.8 and 11.0 pmol/ml intra-operatively (P less than 0.002). XL-FDP rose from a median value of 34 ng/ml pre-operatively to 230 ng/ml post-operatively. In 14 patients plasma aVP levels remained constant and both FVIII:C and PAA remained unchanged. FPA rose from 2.6 pmol/ml to 5.9 pmol/ml intra-operatively (P less than 0.05) and XL-FDP fell from 110 to 60 ng/ml. Between groups, the changes were significantly different for FVIII:C (P less than 0.05) and PAA (P less than 0.03) with no differences in blood pressure, pulse or symptoms. These results support the hypothesis that aVP secretion during surgery mediates increases in FVIII and PAA. FPA tended to be higher in the aVP secreting group which indicates that aVP mediated activation of coagulation results in a hypercoagulable state.

The frequency of dental attendance of Scottish dentate adults between 1978 and 1988

The dental attendance of a sample of dentate adults (n = 702) within the National Health Service in Scotland was monitored longitudinally between 1978 and 1988. The attendance pattern of the sample appeared to be no different between 1983-88 than in the preceding 5 years, which suggests that the attendance behaviour of the sample has not changed significantly. National figures, available for the same period, show an increase in the number of courses of dental treatment provided. These figures were examined in detail, and the analysis suggested that only 40% of the increase in number of courses provided in 1988 compared with 1978 could be accounted for by an improvement in attendance patterns among Scottish adults as a whole. The remaining 60% could be attributed to a greater requirement for dental care to cater for the increased proportion of the Scottish population who retained their own teeth in 1988. Only 16% of the sample consistently attended for dental care within 2 years of a previous dental course (which is the criterion for remaining under continuing care in the new General Dental Service contract).

Coagulation and fibrinolytic activity in Behçet's disease

Coagulation and fibrinolytic activities were studied in 18 subjects with Behçet's disease and compared with results from 14 matched control patients suffering from sero-negative arthritis. Significantly higher plasma concentrations (median and range) were found in Behçet's patients for the following variables: fibrinogen 3.7 (1.7-6.9) vs 3.0 (2.0-5.1) g/l, p less than 0.05; von Willebrand factor antigen, 115 (72-344) vs 74 (60-119)%, p less than 0.002; plasminogen activator activity (10(6)/ECLT2) 219 (94-329) vs 137 (78-197) units, p less than 0.002; tissue plasminogen activator inhibitor (t-PA-I) activity, 9.1 (5.5-19.3) vs 5.1 (1.8-12.0) IU/ml, p less than 0.002; and PAI-1 antigen, 13.9 (4.5-20.9) vs 6.4 (2.4-11.1) ng/ml, p less than 0.002. Protein C antigen was significiantly lower: 97 (70-183) vs 126 (96-220)%, p less than 0.02. No differences were observed in antithrombin III activity or antigen, factor VIII coagulant activity, fibrinopeptides A and B beta 15-42, plasminogen, alpha-2-antiplasmin, functional and immunological tissue-plasminogen activator, thrombin-antithrombin complexes and D-dimer. Levels of tissue plasminogen activator inhibitor (activity and antigen) correlated with disease activity while fibrinogen and von Willebrand factor concentrations did not. Seven of the 18 subjects with Behçet's disease had suffered thrombotic events but it was not possible to distinguish these from the 11 patients without thrombosis using the assays performed. The results suggest the abnormal fibrinolytic activity in Behçet's disease is due to increased inhibition of tissue plasminogen activator. No abnormality of coagulation or fibrinolytic activity specific to Behçet's disease was detected.

Haemostatic responses and vasopressin release during colonoscopy in man

1. During major abdominal surgery there are increases in Factor VIII and plasminogen activator activity, associated with elevated plasma concentrations of vasopressin, of a magnitude shown to affect haemostasis. 2. To investigate the mechanisms involved in the haemostatic response to surgery, 12 patients undergoing fibre-optic colonoscopy were studied, of which six had a complete and six had an incomplete examination. 3. Venous blood samples were taken before, during and after the procedure for assay of plasma vasopressin, adrenaline and noradrenaline concentrations, Factor VIII coagulant activity, von Willebrand factor antigen level, euglobulin clot lysis time, tissue-type plasminogen activator activity and tissue-type plasminogen activator inhibition. 4. In the six patients who underwent a complete procedure the median plasma vasopressin concentration rose from 0.6 pg/ml to 153 pg/ml during colonoscopy. Factor VII coagulant activity rose from 0.9 to 2.4 i.u./ml and von Willebrand factor antigen level rose from 139 to 224%. Plasminogen activator activity increased from 20 to 144 units and tissue-type plasminogen activator activity rose from 107 to 1338 m-i.u./ml, whereas tissue-type plasminogen activator inhibition fell from 4.8 to 1.0 i.u./ml. 5. In the six patients in whom a limited procedure was performed, there were no changes in haemostatic function or in plasma vasopressin concentration. Plasma concentrations of adrenaline and noradrenaline did not change in either group. 6. The results indicate that vasopressin regulates the intrinsic coagulation pathway and fibrinolytic system in the absence of adrenaline release.

Treatment with atenolol prevents progression of microalbuminuria in type I diabetic patients

Nine patients with Type I diabetes mellitus, diastolic blood pressure of 90 to 100 mmHg and persistent microalbuminuria of greater than or equal to 30 micrograms/min were treated with 50 to 100 mg atenolol daily for 3 years in an uncontrolled pilot study to assess the effect of long-term reduction of blood pressure on microalbuminuria. Treatment with atenolol prevented progression of microalbuminuria with a median (range) urinary albumin excretion rate before treatment of 74 (33 to 196) micrograms/min and 50 (5 to 123) micrograms/min after 3 years of therapy (p less than 0.05). Blood pressure was significantly reduced from 156 (121 to 187) mmHg systolic and 95 (90 to 100) mmHg diastolic before treatment to 143 (112 to 168) mmHg systolic (p less than 0.04) and 82 (66 to 84) mmHg diastolic (p less than 0.0003) at 3 years. Measurements of renal function and diabetic control remained unchanged throughout the study period. These results suggest that early and prolonged use of antihypertensive therapy is beneficial in slowing down progression of microalbuminuria.

Growth cone inhibition--an important mechanism in neural development?

Since the growth cone was first described a century ago by Cajal, considerable effort has been directed towards understanding the mechanisms responsible for its guidance. Traditionally, attention has focussed on the role of adhesive molecules in determining neural development. Recently, it has become apparent that inhibitory interactions may play a crucial part in axonal navigation. A common feature of inhibition seen in three model systems (peripheral nerve segmentation, retinotectal mapping and CNS/PNS segregation) is a collapse of the motile structures of the growth cone. It is increasingly clear that the identification of molecular mechanisms of inhibition, as well as those of adhesion, will be of fundamental importance to understanding neural development.

Outcome of a second pregnancy after a previous elective caesarean section

At Queen Charlotte's Maternity Hospital from 1980 to 1987, 195 women had a trial of scar in their second ongoing pregnancy, having been delivered previously by elective caesarean section. Overall 154 (79%) achieved a vaginal delivery. Patients who went into spontaneous labour had a significantly better chance of being delivered vaginally than those who were induced. A past history of early pregnancy loss had no influence on the outcome, nor was outcome compromised in the group of patients whose elective caesarean section had taken place before 32 weeks gestation.

Lipid peroxidation and hepatic antioxidants in alcoholic liver disease

The generation of hepatic liver peroxidation by free radicals has been proposed as a mechanism for ethanol induced hepatotoxicity. To investigate this hypothesis, lipid extracts from hepatic needle biopsy specimens from alcoholic subjects were examined for evidence of lipid peroxidation by measuring total conjugated dienes by derivative spectroscopy and, after hydrolysis of hepatic lipid extract and reverse phase high performance liquid chromatography, the molar ratio between a diene-conjugated linoleic acid isomer (18:2 (9,11)) and the parent linoleic acid isomer (18:2(9,12)). Changes were related to hepatic histology, iron deposition, glutathione and vitamin E values. Derivative spectroscopy minima suggestive of diene conjugation were identified at 233 and 242 nm and correlated weakly, suggesting these two minima may represent different classes of lipid dienes. There was a weak relation with inflammatory histological changes in the biopsy specimen but no correlation with hepatic iron grade, glutathione, or vitamin E lipid ratio. The proportion of 18:2(9,11) linoleic acid in hepatic lipids correlated significantly with inflammatory histological features and inversely with hepatic glutathione. Furthermore, hepatic glutathione was lower in biopsy specimens with greater iron staining. The ratio of vitamin E to lipid was not related to histological group, inflammation, or iron grade. These findings suggest that excess alcohol consumption leads to hepatic inflammation and lipid peroxidation.

Variability of continuous-wave Doppler flow velocity waveform indices from the umbilical artery

Using continuous-wave Doppler ultrasound, the reproducibility of umbilical artery blood flow velocity waveforms, recorded by two operators, was evaluated in 20 high-risk antenatal inpatients. Inter-operator variability was not significant for any index. The intra-operator coefficients of variation for resistance index, pulsatility index, and systolic/diastolic ratio were 7 and 7%, 12 and 12%, and 15 and 11%, respectively, for each operator. The intra-class coefficient of reliability, calculated by analysis of variance, indicated that the contribution of inter-patient variability to total variance was four times that of intra-operator variability.

Potassium-stimulated release of nitric oxide from cerebellar slices

This study shows that nitric oxide release can be evoked from intact neuronal tissue. Stimulation of rat cerebellar slices for 4 min with 50 mM potassium significantly increased the release of nitric oxide and glutamate and was associated with a rise in the guanosine 3':5'-cyclic monophosphate (cyclic GMP) content of the tissue. Nitric oxide levels in the perfusate increased from 160 to 262 parts per billion. It is suggested that an increased release of endogenous glutamate in the slice, induced by exposure to potassium, may mediate the release of nitric oxide.

Coagulation, fibrinolytic and platelet function in patients on long-term therapy with aspirin 300 mg or 1,200 mg daily compared with placebo

Aspirin has been shown to be beneficial in the prophylaxis of arterial thromboembolic disease. The rationale for its use as an antithrombotic drug lies in its inhibition of thromboxane A2-dependent platelet function. However, the effect of aspirin on coagulation and fibrinolysis during chronic therapy has not been studied. We have measured a range of haemostatic and platelet functions in 49 patients with transient ischaemic attacks randomly allocated to aspirin 300 mg a day, aspirin 1,200 mg a day or placebo. All had been taking their allocated treatment for between 9 months and 4 years prior to investigation. Bleeding time was prolonged, serum thromboxane diminished and platelet aggregation to arachidonic acid but not ADP was abolished by both 300 mg and 1,200 mg aspirin, in a non-dose dependent fashion. Serum salicylate increased with the dose of aspirin ingested. No effect was seen with either dose of aspirin on urinary thromboxane and 6-keto-PGF1 alpha excretion, or on coagulation. Patients taking 1,200 mg aspirin a day had a lower haemoglobin and packed cell volume, lower resting fibrinopeptide A concentration and lower basal plasminogen activator activity than those on placebo. Response to venous occlusion was normal in all groups. The results suggest 300 mg and 1,200 mg aspirin have an equivalent platelet inhibitory effect but 1,200 mg aspirin causes greater gastro-intestinal blood loss.

Molecular and cytogenetic analysis of the heterochromatin-euchromatin junction region of the Drosophila melanogaster X chromosome using cloned DNA sequences

We have used three cloned DNA sequences consisting of (1) part of the suppressor of forked transcription unit, (2) a cloned 359-bp satellite, and (3), a type I ribosomal insertion, to examine the structure of the base of the X chromosome of Drosophila melanogaster where different chromatin types are found in juxtaposition. A DNA probe from the suppressor of forked locus hybridizes exclusively to the very proximal polytenized part of division 20, which forms part of the beta-heterochromatin of the chromocenter. The cloned 359-bp satellite sequence, which derives from the proximal mitotic heterochromatin between the centromere and the ribosomal genes, hybridizes to the under replicated alpha-heterochromatin of the chromocenter. The type I insertion sequence, which has major locations in the ribosomal genes and in the distal mitotic heterochromatin of the X chromosome, hybridizes as expected to the nucleolus but does not hybridize to the beta-heterochromatic division 20 of the polytene X chromosome. Our molecular data reveal that the suppressor of forked locus, which on cytogenetic grounds is the most proximal ordinary gene on the X chromosome, is very close to the junction of the polytenized and non-polytenized region of the X chromosome. The data have implications for the structure of beta-heterochromatin-alpha-heterochromatin junction zones in both mitotic and polytene chromosomes, and are discussed with reference to models of chromosome structure.

The effect of modified electroconvulsive therapy on vasopressin release and haemostasis in man

Plasma concentrations of plasminogen activator activity (PAA) and factor VIII are partly controlled by circulating adrenaline and vasopressin. Acute rises in PAA and factor VIII occur during electroconvulsive therapy (ECT). To investigate the relationships between vasopressin (aVP), adrenaline and changes in PAA and factor VIII during ECT, 8 female and 2 male patients, median age 57 years (range 39-75) undergoing modified ECT had venous blood samples taken before and at 2 min, 15 min, 60 min and 24 h after cessation of seizure activity. AVP rose from 0.5 before ECT to 35.5 pg/ml at 2 min (P less than 0.005) and fell thereafter. PAA (10(6)/ECLT2) increased from 22 to 69 units (P less than 0.005) over the same time and fell to 13 units at 24 h (P less than 0.02). Tissue plasminogen activator activity (tPA) rose from 162 before to 1447 mIU/ml at 2 min. (P less than 0.005) and its inhibition activity fell from 8 to 3.75 IU/ml (P less than 0.005) over the same time and rose to 10.4 IU/ml after 24 h (P less than 0.02). There were no changes in adrenaline, noradrenaline, factor VIIIc, vWF or fibrinopeptides A and B beta 15-42. AVP correlated with tPA (rs = 0.64, P = 0.0022) and PAA (rs = 0.61, P = 0.004). These results support the hypothesis that aVP has a role in the regulation of fibrinolytic activity mediated by an increase in tPA. The absence of a factor VIII response may indicate that adrenaline is more important in the regulation of factor VIIIc and vWF.

Microproteinuria in type 2 diabetes mellitus from diagnosis

Glomerular and tubular microproteinuria precede the development of overt nephropathy in Type 1 diabetes mellitus. However, in Type 2 diabetes urinary protein excretion and its relationship to diabetic nephropathy has not been clearly characterized. Twenty consecutive, newly diagnosed patients with Type 2 diabetes, whose urine was Albustix-negative and sterile on culture, were studied. Two timed overnight urine samples were collected at diagnosis, and after 2 months and 2 years, and excretion rates of albumin, alpha-1-microglobulin and N-acetyl-beta-D-glucosaminidase were calculated. HbA1c fell from 12.1 +/- 2.4% at diagnosis to 9.5 +/- 1.5% at 2 months and 9.6 +/- 2.2% at 2 years. Albumin excretion rate fell marginally from 6.5 (2.1-242.5) micrograms min-1 at diagnosis to 5.5 (1.7-274.0) micrograms min-1 at 2 months (p less than 0.05) rising again to 6.1 (1.9-201.7) micrograms min-1 at 2 years. alpha-1-Microglobulin excretion rate fell from 13.5 (3.6-59.9) micrograms min-1 at diagnosis to 8.4 (2.9-16.1) micrograms min-1 at 2 months and 8.8 (1.8-54.1) micrograms min-1 at 2 years (both p less than 0.05). Albumin excretion rate was found to correlate significantly with creatinine clearance at diagnosis (rs = 0.61, p less than 0.005), though not subsequently. In contrast, excretion rates of alpha-1-microglobulin and N-acetyl-beta-D-glucosaminidase correlated with HbA1c (rs = 0.68 and 0.66, respectively, p less than 0.005 at diagnosis and rs = 0.57 and 0.53, p less than 0.05 subsequently in both cases).(ABSTRACT TRUNCATED AT 250 WORDS)

Contribution of a general practitioner hospital: a further study

OBJECTIVE

To audit the workload of a general practitioner hospital and to compare the results with an earlier study.

DESIGN

Prospective recording of discharges from the general practitioner hospital plus outpatient and casualty attendances and of all outpatient referrals and discharges from other hospitals of patients from Brecon Medical Group Practice during one year (1 June 1986-31 May 1987).

SETTING

A large rural general group practice which staffs a general practitioner hospital in Brecon, mid-Wales.

PATIENTS

20,000 Patients living in the Brecon area.

RESULTS

1540 Patients were discharged from the general practitioner hospital during the study period. The hospital accounted for 78% (1242 out of 1594) of all hospital admissions of patients of the practice. There were 5835 new attendances at the casualty department and 1896 new outpatient attendances at consultant clinics at the hospital. Of all new outpatient attendances by patients of the practice, 71% (1358 out of 1896) were at clinics held at the general practitioner hospital. Since the previous study in 1971 discharges from the hospital have increased 37% (from 1125 to 1540) and new attendances at consultant clinics 30% (from 1450 to 1896). The average cost per inpatient day is lower at this hospital than at the local district general hospital (pounds 71.07 v pounds 88.06 respectively).

CONCLUSIONS

The general practitioner hospital deals with a considerably larger proportion of admissions and outpatient attendances of patients in the practice than in 1971 and eases the burden on the local district general hospital at a reasonable cost.

IMPLICATIONS

General practitioner hospitals should have a future role in the NHS.

Effect of warfarin on plasma concentrations of vitamin K dependent coagulation factors in patients with stable control and monitored compliance

There is a discrepancy in the results of reported studies of levels of vitamin K dependent coagulation factors in patients on warfarin therapy. This may have arisen partly because of the problem of assuring compliance with therapy in outpatients. The plasma concentrations of the vitamin K dependent clotting factors II, VII, IX and X were studied in 23 outpatients whose adherence to prescribed warfarin therapy was determined using a pharmacological indicator of compliance. In these patients, who were shown to have consistently good compliance and stable anticoagulant control over a period of 3-6 months, the activities in plasma of the four coagulation factors were not equally suppressed. Factor IX levels were significantly greater than those of factor VII (P less than 0.0001) which in turn were significantly greater than the levels of factor II (P less than 0.0001) or factor X (P less than 0.0001). There was no significant difference between the levels of factors II and X which were depressed to a similar extent. The proportion of variability of the International Normalized Ratio (INR) explained by linear regression was 51-77% and a model was derived to predict the INR from the mean of the levels of the four clotting factors. The concentrations of the coagulation factors II, VII, IX and X are likely to be highly dependent on the degree of compliance with warfarin therapy which should be taken into account when investigating the behaviour of these factors.

Isolation from chick somites of a glycoprotein fraction that causes collapse of dorsal root ganglion growth cones

The segmented pattern of peripheral spinal nerves in higher vertebrates is generated by interactions between nerve cells and somites. Neural crest cells, motor axons, and sensory axons grow exclusively through anterior-half sclerotome. In chick embryos, posterior cells bind the lectins peanut agglutinin (PNA) and Jacalin. When liposomes containing somite extracts are applied to cultures of chick sensory neurons, growth cones collapse abruptly, recovering within 4 hr of liposome removal. Collapse activity is eliminated by immobilized PNA, and SDS-PAGE demonstrates two major components (48K and 55K), which are absent from anterior-half sclerotome. Rabbit polyclonal antibodies against these components recognize only posterior cells and may also be used to eliminate collapse activity. We suggest that spinal nerve segmentation is produced by inhibitory interactions between these components and growth cones.

Thrombin stimulated platelet accumulation on protein coated glass capillaries: role of adhesive platelet alpha-granule proteins

The generation of trace amounts of thrombin at artificial surfaces in contact with blood is likely to be a contributing factor in thrombosis on biomaterials. Using an in vitro capillary perfusion system, platelet accumulation on glass surfaces, uncoated or precoated with purified bovine collagen or human plasma proteins, was determined in the presence or absence of preadsorbed purified human thrombin. Static adsorption for 15 min at 22 degrees C from solutions of thrombin 100 NIH units (33 micrograms)/ml gave surface concentrations in the range 0.019-0.101 micrograms/cm2. Protein coated capillaries, thrombin treated or untreated, were perfused for 2 min at 37 degrees C with suspensions of washed 111In-labeled human platelets in Tyrode's-albumin buffer containing 40% washed red blood cells, under conditions of controlled, non pulsatile laminar flow (50 s-1 or 2,000 s-1). Platelet accumulation was increased in the presence of surface adsorbed thrombin on uncoated and albumin or fibrinogen coated glass but little affected on fibronectin or collagen coated glass. On von Willebrand factor (vWF) coated glass, thrombin enhancement was observed only at high shear forces. In experiments using antibodies against human platelet alpha-granule proteins, thrombin stimulated platelet deposition in uncoated glass capillaries was inhibited at 2,000 s-1 by anti-vWF and to a lesser extent by anti-fibrinogen but not by anti-thrombospondin antibodies.

The stability of the nitrosated products of indole, indole-3-acetonitrile, indole-3-carbinol and 4-chloroindole

The nitrosation rates of indole-3-acetonitrile, indole-3-carbinol, indole and 4-chloroindole and the stability of their nitrosated products were investigated. Each of the nitrosated indole compounds was directly mutagenic to Salmonella typhimurium TA100 in the following order of potency: 4-chloroindole much greater than indole-3-carbinol greater than or equal to indole greater than indole-3-acetonitrile. Total N-nitroso determinations, carried out according to a modified method of Walters et al. (Analyst, Lond. 1978, 103, 1127), and Ames test results revealed that each of the indole compounds immediately formed mutagenic N-nitroso products upon nitrite treatment under acidic conditions. However, the nitrosation rates of indole and 4-chloroindole were higher than those of indole-3-acetonitrile and indole-3-carbinol. For indole-3-carbinol, indole-3-acetonitrile and indole, no change in the amount of nitrosated products was observed at increasing incubation times from about 15 up to 60 min. For 4-chloroindole the amount of nitrosated products decreased with increasing incubation times. In all cases the responses in the Ames test paralleled the amounts of nitrosated products. The stabilities of the nitrosated products of the indole compounds were investigated at pH 2 and 8. Both mutagenicity data and measurements by high-performance liquid chromatography using a photohydrolysis detector indicated that the nitrosation products of indole-3-acetonitrile, indole-3-carbinol and indole were more stable at pH 8 than at pH 2. Conversely, nitrosated 4-chloroindole was stable at pH 2 but not at pH 8. The pH 8 chromatograms showed a large nitrite peak. From this we hypothesized that the presence of free nitrite might be responsible for the stability of nitrosated indole-3-acetonitrile, indole-3-carbinol and indole at pH 8. Experiments confirmed the existence of an equilibrium between the nitrosated indole compound and the free indole compound plus nitrite.

Intravenous regional analgesia with prilocaine for foot surgery. The effect of slow injections and high tourniquet inflation pressures

Intravenous regional analgesia for foot surgery with an ankle tourniquet was used for 48 cases. Prilocaine 0.5% 3 mg/kg body weight was injected either quickly over about 2 minutes or slowly over about 5 minutes. The tourniquet was inflated either to occlusion pressure plus 100 mmHg or to occlusion pressure plus 200 mmHg. Plasma prilocaine levels were measured while the tourniquet remained inflated and after release of the tourniquet. All four techniques resulted in a low incidence and magnitude of prilocaine leak and low prilocaine plasma levels after tourniquet release. The data suggest that slow injection with the high tourniquet inflation pressure is better, although the differences in leakage with an intact tourniquet were not statistically significant. Excellent analgesia was achieved in over 90% of patients and there were no complete failures. No dangerously high prilocaine plasma levels were produced and no serious side effects observed.

Poor compliance is a major factor in unstable outpatient control of anticoagulant therapy

Control of oral anticoagulant therapy in outpatients is often unsatisfactory. The contribution of poor compliance with prescribed warfarin to unstable anticoagulant control was investigated prospectively using low-dose phenobarbitone as an indicator of compliance in 30 out-patients, 15 with stable and 15 with unstable control. Following entry to the study, there was no significant change in anticoagulation (p = 0.36) in the group with stable control. In the group who previously had unstable control, there was a significant change in INR (p = 0.0045) and anticoagulant control greatly improved. It appears that the considerable fluctuation in INR seen in many of the latter patients before the study was due to poor compliance and that entering them into the study modified their behavior. Two patients in this group who continued to have unstable anticoagulant control were shown to be poorly compliant using the phenobarbitone indicator. The results suggest that, in outpatients, poor compliance is the major cause of unstable anticoagulation with warfarin.

Anti-hypertensive drugs non-specifically reduce "spontaneous" activation of blood platelets

Abnormal activation of blood platelets may be a contributory factor in the accelerated vascular disease which occurs in hypertension. We investigated the effects of lowering blood pressure in 12 patients with mild hypertension on several aspects of platelet function, initially in a placebo-controlled, double-blind, cross-over study with nisoldipine, and subsequently in the same patients comparing nisoldipine with the patients' usual anti-hypertensive therapy. Values were compared with those from an age, sex-matched control population. Seven hypertensive patients with renal failure were also studied. Administration of nisoldipine reduced ex vivo "spontaneous" aggregation of blood platelets significantly, and a similar significant effect was seen when blood pressure was lowered by the patients usual anti-hypertensive therapy. "Spontaneous" aggregation occurring in the control population was similar to that in the treated hypertensives. Blood platelet count, and aggregation in response to ADP and adrenalin were unaffected by treatment. Median plasma beta thromboglobulin levels were significantly higher in the untreated hypertensive patients (43 ng ml-1) than in the controls (30 ng ml-1), and there was a trend to reduced values for beta thromboglobulin on treatment of the hypertension. These results indicate that blood platelet activity is enhanced in hypertension and that function returns towards normal when blood pressure is lowered by treatment.