Renal sodium retention in cirrhosis: tubular site and relation to hepatic dysfunction

Renal sodium handling, assessed by the response to acute saline loading, was investigated in 14 well-compensated, nonascitic alcoholic cirrhotics and six normal controls. Urinary sodium excretion in cirrhotic patients (199 +/- 141 mumoles per min) was significantly lower than in controls (387 +/- 104 mumoles per min; p less than 0.01) at 3 hr postinfusion. In contrast to controls, renal plasma flow and glomerular filtration rate did not increase in the cirrhotics in response to acute saline loading. Proximal fractional reabsorption of sodium was estimated by clearance techniques in the presence of a hypotonic diuresis. Cirrhotic subjects with impaired functional liver cell mass as assessed by antipyrine clearance were unable to decrease proximal fractional reabsorption of sodium significantly in response to saline loading. Assessment in the cirrhotics included measurement of hepatic vein pressure gradient, indocyanine green extraction ratio, indocyanine green clearance, and antipyrine clearance as indices of portal pressure, intrahepatic shunting, hepatic blood flow and functional hepatocellular mass, respectively. Urinary sodium excretion in the cirrhotics correlated strongly with antipyrine clearance (r = 0.839, p less than 0.0001) and weakly with portal pressure (r = 0.562, p = 0.037). No correlation was seen with the other indices of hepatic blood flow and shunting. The findings of this study suggest that alcoholic cirrhosis is associated with a decline in hepatocellular function which results in either a decreased clearance of a salt-retaining hormone or decreased synthesis of a natriuretic hormone.(ABSTRACT TRUNCATED AT 250 WORDS)

Detection of haematoporphyrin derivative and haematoporphyrin excited states in cell environments

The photosensitiser currently used in the photodynamic therapy of cancer is haematoporphyrin derivative. Pulsed laser studies of this material and also of the "parent" molecule haematoporphyrin in polyoma-transformed fibroblast cells have now been studied. We report, for the first time, the observation of the triplet absorption of these sensitisers in cells. The corresponding triplet-triplet spectra are red shifted compared to aqueous buffer, lambda(max) 420 nm shifts to 460 nm. We also report our failure to observe singlet oxygen from the cells even though the triplet state can be seen to interact with the oxygen and even though singlet oxygen can be readily detected with the same sensitisers bound to serum albumin.

Improved assay for bismuth in biological samples by atomic absorption spectrophotometry with hydride generation

This simple, rapid, sensitive, reliable, and economical assay for bismuth in plasma, erythrocytes, and urine is based on atomic absorption spectrophotometry with hydride generation. Acid digestion eliminates the problem of foaming, which hitherto has complicated such assay of bismuth in plasma and erythrocytes. The detection limit of the assay has been improved to 0.1 micrograms/L, as compared with a previously documented limit of 2.5 micrograms/L. Average recovery exceeded 95% in all biological fluids. Economy of use derives from elimination of need for electrodeless discharge lamps and atomic absorption grade borohydride. Determination of basal concentrations of bismuth in clinical samples of body fluids gave reference intervals of 0.1-3.5 micrograms/L for plasma, 0.3-4.6 micrograms/L for urine.

Improved assay for bismuth in biological samples by atomic absorption spectrophotometry with hydride generation

This simple, rapid, sensitive, reliable, and economical assay for bismuth in plasma, erythrocytes, and urine is based on atomic absorption spectrophotometry with hydride generation. Acid digestion eliminates the problem of foaming, which hitherto has complicated such assay of bismuth in plasma and erythrocytes. The detection limit of the assay has been improved to 0.1 micrograms/L, as compared with a previously documented limit of 2.5 micrograms/L. Average recovery exceeded 95% in all biological fluids. Economy of use derives from elimination of need for electrodeless discharge lamps and atomic absorption grade borohydride. Determination of basal concentrations of bismuth in clinical samples of body fluids gave reference intervals of 0.1-3.5 micrograms/L for plasma, 0.3-4.6 micrograms/L for urine.

Helmet-induced skull base fracture in a motorcyclist

Observations after a fatal motorcycle accident suggested that the face bar of a full-face helmet may transmit an impacting force to the skull base via the chin strap and the mandibular rami and condyles, bypassing the energy-absorbing facial bones. If this mechanism is confirmed, the structural properties of these face bars will need to be reassessed.

Extent and pharmacokinetic mechanisms of oral atenolol-verapamil interaction in man

Chronic coadministration of oral verapamil with oral atenolol resulted in a variable increase in atenolol steady-state plasma concentrations in a group of 10 patients on chronic maintenance therapy. Individual subjects showed changes in area under the plasma atenolol concentration-time curve (AUC) of more than 100%, however group comparisons did not achieve statistical significance unless normalized for verapamil dose. Renal clearance of atenolol was shown to be decreased by more than 25% in 2 subjects studied using intravenous dosing of atenolol. This interaction is likely to contribute to the documented clinical intolerance of combinations of atenolol and verapamil.

The effect of demographic changes on road accident fatality rates: Japan 1970-1980

The effect of changes in the age distribution of the Japanese population from 1970 to 1980 was investigated to determine whether they played a role in the halving of the road accident death rate in Japan during that decade. This was done by applying the 1980 age-specific death rates to a population having the 1970 age distribution in percentage terms. Substantial changes in the percentage of the population in specific age groups during the 1970s resulted in major, but opposing, changes in the overall road accident death rate. When combined with the effect of an increase in the percentage of the elderly in the population, the overall effect of changes in the population distribution on the road accident death rate was negligible. In the absence of other changes, the ageing of the Japanese population is likely to lead to an increase of about 10% in the overall road accident death rate by the year 2000.

Relative effectiveness and costs of antiulcer medications as a basis for rational prescribing

To be maximally effective, antiulcer medications should relieve ulcer symptoms rapidly and promote rapid healing of an ulcer crater; after the cessation of a course of treatment the ulcer should not recur. A wide variety of agents is available. These are of similar efficiency in the control of ulcer symptoms and in the acceleration of the healing of the ulcer crater. However, evidence exists of differences in the rate of the recurrence of duodenal ulcers on the cessation of these drugs. Surface-active agents (bismuth complexes, sucralfate, prostaglandins and carbenoxolone) are consistently superior to H2-histamine receptor antagonist drugs (cimetidine and ranitidine). A high relapse rate produces more patients with active disease at any one time, hence more patients will be exposed to the complications of the disease, and will require active investigation and therapy. Because of the increased rate of relapse, the use of H2-receptor antagonist drugs as first-line intermittent healing therapy can be shown to be associated with an eight-fold (800%) increase in cost of pharmaceutical agents as compared with first-line treatment with bismuth salts; a four-fold increase compared with the cost of using antacid drugs; and a two-fold increase compared with the cost of using sucralfate. When maintenance therapy with H2-receptor antagonist agents is given instead of intermittent therapy with bismuth complexes, a 14-fold increase in pharmaceutical costs is incurred, with inferior results that have already been demonstrated under the conditions of a controlled clinical trial. These considerations of efficacy and cost suggest that H2-receptor antagonist drugs ought not to be first-line therapy for duodenal ulcers; rather, surface-active agents such as colloidal bismuth or sucralfate should be prescribed initially.

A double-blind comparison of the relative efficacy, side effects and cost of buprenorphine and morphine in patients after cardiac surgery

The analgesic efficacy, side effects and cost of administration of regimens of intravenous buprenorphine and intravenous morphine were compared in a randomized double-blind trial performed during the first 24 h after cardiac surgery. Seven patients received buprenorphine by intermittent intravenous injection and six received morphine by continuous infusion. Both these regimens provided good analgesia for the entire 24 h period, with only mild pain at rest and moderate pain on vigorous coughing. Both regimens also produced mild respiratory depression but this was not of clinical importance: the mean arterial PCO2 in both groups was less than 45 mmHg after extubation. The major difference between drugs in the clinical setting was the ease of administration. Buprenorphine had no narcotic code restriction and could be given by intermittent intravenous injection, whereas morphine required checking and handling as a restricted drug and administration by continuous intravenous infusion. When labour and material costs were computed, over the first 24 postoperative hours, it cost $19.76 per patient to administer morphine, but only $3.16 to administer buprenorphine. Thus the use of buprenorphine injections for the first 24 h after cardiac surgery produced pain relief and respiratory depression comparable to that produced by a morphine infusion, but with a significant cost saving in terms of labour and materials.

Influence of hydralazine on the pharmacokinetics of orally administered d-propranolol and lidocaine in conscious dogs

A study was conducted on the influence of oral coadministration of hydralazine (H) on the pharmacokinetics of d-propranolol (P) and lidocaine (L) in 6 conscious dogs. They were given an oral solution containing P (2 mg/kg) and L (15 mg/kg) alone or together with 25 mg H. Plasma concentrations of P and L and the metabolites monoethylglycinexylidide (MEGX) and glycinexylidide (GX) were measured by specific HPLC methods. Concomitant administration of H caused a significant (p less than 0.05) increase in P peak concentrations (Cmax, 34 +/- 5: 73 +/- 10 ng/ml) and the area under plasma concentration time curve (AUC, 142 +/- 18: 254 +/- 56 ng/ml X hr) of P with significant (p less than 0.05) 24% reduction of the apparent oral clearance. The time to reach peak concentrations (Tmax) and the terminal half life (t1/2 beta) were not altered. In contrast to the pattern seen with P the disposition of L was not affected by H. The change in presystemic clearance of P by H cannot be explained by a general underlying mechanism such as an alteration in liver blood flow alone or portal-systemic shunting, since then the pharmacokinetics of L should parallel those of P. It is speculated that other mechanisms, most likely alteration of P metabolism, are primarily responsible for the observed interaction between P and H.

Severity of injuries in road crashes. A comparison of injured occupants of forward control vehicles and conventional passenger cars

Light vans are being used increasingly as substitutes for conventional passenger cars in Australia. These "forward control" vans are not required to meet the same safety standards as passenger cars. A study group of 258 injured occupants of light vans was identified from the records of the Motor Accidents Board of Victoria. A comparison group of 3468 injured occupants of conventional cars was also identified. Both groups had been injured in accidents occurring in Victoria between 1980 and 1983. The injuries received by the van occupants were compared with those received by the car occupants. Van occupants injured in frontal crashes were more likely to have sustained leg injury, and were more likely to have sustained serious injury than were car occupants who were injured in frontal crashes. Forward control vans were found to lack protection for occupants in frontal crashes.

Interaction between oral hydralazine and propranolol. II. Assessment of altered splanchnic blood flow as the determinant of altered presystemic extraction

Coadministration of p.o. hydralazine and d-propranolol or dl-propranolol in six conscious dogs caused a significant increase in peak plasma concentration and area under the p.o. plasma concentration-time curve of propranolol (P less than .01, P less than .01, peak plasma concentration; P less than .01 and P less than .05, area under the plasma concentration-time curve; d-propranolol and dl-propranolol, respectively). Coadministration of p.o. hydralazine with p.o. dl-propranolol resulted in a small trend toward an increase in systemic clearance of i.v. dl-[3H]propranolol; however, this did not reach statistical significance (P less than .2, P less than .1, d-propranolol and dl-propranolol, respectively). When a mixture of d-propranolol and 14C-labeled dl-propranolol was administered into the jejunum of seven anesthetised dogs, the absorption into portal vein of the 14C-labeled dl-propranolol paralleled closely that of d-propranolol both in terms of time to peak and absorption as measured by a percentage of total area under the plasma concentration-time curve at an arbitrary time (10 min) postdose. Assessment of hepatic extraction (E) showed similar close parallels (d-propranolol, E = 0.85 +/- 0.02; dl-[14C]propranolol, E = 0.86 +/- 0.03: mean +/- S.E.M., n = 5, P less than .70). Hepatic extraction of propranolol and blood flow in mesenteric artery and hepatic artery were measured in 23 anesthetised dogs given a constant infusion of d-propranolol into portal vein (11 micrograms/kg/min), made up to 6 control and 17 hydralazine-treated dogs.(ABSTRACT TRUNCATED AT 250 WORDS)

Polypharmacy in an Australian teaching hospital. Preliminary analysis of prevalence, types of drugs and associations

A computer-based prescription retrieval system was used to study 21,521 prescriptions that had been provided to hospital patients who were receiving predominantly outpatient care. Over a three-month period 338 patients were found to be receiving 10 or more different drugs concomitantly. A further 338 patients were drawn at random from the same outpatient population for comparison. Age was linked significantly to polypharmacy (polypharmacy group: mean age, 63.7 years, SEM = 1.09; comparison group: mean age, 53.8 years, SEM = 1.00, P less than 0.05; chi 2 = 62.8, P less than 0.001). The relative risk of polypharmacy was related linearly to age. Admission to hospital was associated with increased prescribing rates in the polypharmacy sample (P less than 0.05), as was attendance at multiple clinics and multiple attendance at outpatient clinics (P less than 0.05 and P less than 0.05, respectively). Benzodiazepine agents were included in 63.7% of prescriptions in the polypharmacy group and in 37.3% of prescriptions in the comparison group. Non-prescription drugs were noted in 97.2% of prescriptions in the polypharmacy group and 58.0% of prescriptions in the comparison group, representing 34.7% and 27.3% of all items, respectively. In patients of less than 30 years of age agents for allergy/asthma/atopy contributed most to polypharmacy; agents that were associated with renal failure most in patients aged 31-50 years; and agents for cardiovascular disease contributed most in patients aged over 50 years. Our results suggest that a reduction in the use of non-prescription and psychotropic agents, heightened awareness of the dangers of polypharmacy and coordination and integration of over-all care and prescribing habits should reduce polypharmacy materially.

Rapid and simultaneous extraction of propranolol, its neutral and basic metabolites from plasma and assay by high-performance liquid chromatography

A high-performance liquid chromatographic method is described for the determination of propranolol, its neutral and basic metabolites from a single plasma sample. These analytes were extracted simply and efficiently by a solid-phase extraction column based on C18 modified silica (C18 Bond-Elut). Propranolol, the 4-hydroxy and N-desisopropyl metabolites were separated on a mu Bondapak C18 column with a mobile phase of acetonitrile--0.1% phosphoric acid. Propranolol glycol was selectively eluted from the C18 Bond-Elut column with acetonitrile and chromatographed separately with a mobile phase of acetonitrile--water. The recoveries of propranolol and all metabolites were greater than 78% with an intra-assay coefficient of variation between 4.9 and 7.3% at a concentration of 5-50 ng/ml. The minimum detectable levels in 1 ml of plasma were 1.0 ng/ml propranolol, 6.0 ng/ml 4-hydroxypropranolol, 1.0 ng/ml N-desisopropylpropranolol and 2.5 ng/ml propranolol glycol. Enzyme hydrolysis, Bond-Elut extraction and high-performance liquid chromatography revealed that propranolol, the neutral and basic metabolites were extensively conjugated in dog plasma (propranolol 67%, 4-hydroxypropranolol 98%, N-desisopropylpropranolol 55% and propranolol glycol 80%). With the use of pure enzymes and a selective inhibitor the nature of this conjugation appeared to involve both glucuronidation and sulfation. The conjugation of propranolol involved mainly glucuronidation (58-62%) compared to sulfation (7-12%), whilst that of 4-hydroxypropranolol mainly involved sulfation (55-65%) compared to glucuronidation (32-38%). The values for N-desisopropylpropranolol and propranolol glycol were 26-31% and 12% sulfation, 16-29% and 68-85% glucuronidation, respectively.

The choice of ulcer healing agent influences duodenal ulcer relapse rate and long-term clinical outcome

The mode of pharmacological healing influences subsequent ulcer relapse. Duodenal ulcer relapse following healing and withdrawal of active therapy has been studied in 18 prospectively randomised comparative studies involving cimetidine and alternative healing agents. Most studies (eleven of the 18) showed comparative agents with a lower (greater than 10%) incidence of relapse than cimetidine while a minority (seven of the 18) showed equal (+/- 10%) relapse. The probability of this distribution occurring by chance is less than 1:1000 (p = 0.0005, sign test). In three of the 11 published comparative studies the relapse rate was significantly higher in those who had previously received cimetidine (p less than 0.05, two-sided significance test). This was despite the fact that most of the individual studies were small and required a substantial difference in results for the 5% significance level to be reached. Paired comparative incidences of relapse at six months were converted to relapse rates (percentage of healed population relapsing monthly), average rates for comparative agents were 8.05 +/- 2.7% while those for cimetidine were 16.9 +/- 4.4% (means +/- SEM, n = 5); cimetidine relapse rates derived from non-comparative trials were 17.0 +/- 1.9% (means +/- SEM, n = 7). Higher relapse rates translate into larger numbers of patients at risk and in need of active therapy. These results are of biological and clinical significance. Differences in relapse must reflect beneficial effects of one group of agents on the ulcer diathesis or adverse effects of the comparator, cimetidine. Each alternative reflects negatively on cimetidine as an antiulcer medication; however, confirmation of adverse effects would force radical review of most current therapy of ulcer disease. Research into ulcer therapeutics must emphasise both the relapse and the healing potential of pharmacologic agents.