Deaths of heroin users in a general practice population

Recent evidence suggests that heroin users in the UK are 16 times more likely to die than otherwise expected, although causes of death are varied. The present investigation examines deaths of heroin users at a large Scottish general practice over a four-year period prior to 1 July 1985. A mortality rate of 9.72 per 1000 heroin-user patients per year was observed, roughly half that previously reported, although this difference did not prove to be statistically significant. A higher proportion of the observed deaths were attributed to heroin, and fewer to the misuse of other drugs, and it is speculated that this may reflect the practice's policy of not prescribing opiates to heroin users. Factors associated with heroin-user deaths are examined and areas identified where general practitioners may help to avert some of these deaths.     

Clonal analysis and virulence of Australian isolates of Streptococcus suis type 2.

Multilocus enzyme electrophoresis was used to divide 124 Australian isolates of Streptococcus suis type 2 into 17 electrophoretic types (ETs). Isolates in ET 1 were the most frequent cause of disease amongst Western Australian pigs, but isolates of ET 8 were more commonly associated with disease in other Australian states. Multiple isolates from 10 of 19 farms all belonged to the same ET, whilst isolates from the other farms belonged to between 2 and 4 different ETs. Some isolates could be differentiated further by DNA restriction endonuclease analysis, whilst others with the same restriction pattern were located in different, but closely-related ETs. Fourteen isolates were tested for their virulence in mice. Most caused disease if given in high numbers, but isolates in ET 1 were virulent at lower dose rates. This virulent clone also was distinguished by the fact that 80% of isolates produced extracellular factor (EF).     

Central administration of a specific angiotensin II receptor antagonist on baroreflex function in spontaneously hypertensive rats.

To determine whether the increase in baroreflex sensitivity previously reported in lifetime captopril-treated spontaneously hypertensive rats (SHR) was due to an inhibition of brain angiotensin II mechanisms, we tested the effect of intracerebroventricular administration of an angiotensin II receptor antagonist on baroreflex control of heart rate in lifetime captopril-treated and untreated male and female SHR. Baroreceptor reflex control of heart rate was assessed by the slope of the relationship between changes in mean arterial pressure (delta MAP, mmHg) and changes in pulse interval (delta PI, ms). MAP was raised and lowered with infusions of phenylephrine and nitroprusside, respectively. Following basal assessment of baroreflex control of heart rate, rats received an intracerebroventricular injection (100 pmol) of Sar1Thr8 angiotensin II (sarthran) and reflex control of heart rate was reassessed. Adequacy of blockade was tested with central and peripheral administration of angiotensin II. Captopril-treated male (130 +/- 7 mmHg) and female (123 +/- 4 mmHg) rats had significantly lower MAP than untreated rats (174 +/- 4 and 173 +/- 8 mmHg, respectively) and enhanced bradycardia in response to increases in MAP. Intracerebroventricular administration of sarthran had no effect on basal blood pressure or heart rate but enhanced the bradycardia in response to increases in MAP in both untreated and captopril-treated rats. The increase in the slope of the line relating delta MAP to delta PT was greater for untreated than captopril-treated SHR (male untreated 2.7-fold versus captopril-treated 1.5-fold; female untreated 1.6-fold versus captopril-treated 1.5-fold).(ABSTRACT TRUNCATED AT 250 WORDS)     

Survival of corneal endothelium in McCarey-Kaufman (M-K) medium subjected to agitation

Studies were made comparing the corneal endothelium of bisected human corneas; one half of each was mechanically agitated in McCarey-Kaufman (M-K) medium, while the other half remained static in M-K medium for an equal period of time. Scanning electron microscopic (SEM) analysis of the corneal endothelium suggested that the endothelium of the corneas undergoing agitation does not show deterioration in morphology when compared with the non-agitated group. This finding is significant as donor corneas are now being transported in greater numbers.     

The effects of hypo- and hyperthyroidism on fibre composition and mitochondrial enzyme activities in rat skeletal muscle.

Hypo- and hyperthyroidism have been associated with changes in the activities of mitochondrial enzymes in homogenates of skeletal muscles, but it is unclear whether such changes were due to changes in single fibre enzyme activities or to previously documented changes in relative numbers of fibres. In this study the activities of the mitochondrial enzymes alpha-glycerol phosphate dehydrogenase (m-alpha GPDH) and succinate dehydrogenase (SDH) were measured in single fibres of the soleus and gastrocnemius muscles of the rat by cytochemical assays. In the soleus muscles of hypothyroid animals there was a decrease in the mean percentage (+/- S.D.) of type II fibres from 8.0 +/- 6.0 to 0.8 +/- 1.9% (P less than 0.05) and decreases in SDH activities in all fibre types (P less than 0.005). In the gastrocnemius muscles of these animals there were no changes in fibre composition but type IIB fibres had reduced (P less than 0.05) m-alpha GPDH activities. In the hyperthyroid animals, in which body weight had increased relative to the euthyroid animals, there were increases in the percentages of type IC and type II fibres in the soleus from 4.3 +/- 1.7 to 13.1 +/- 9.0% (P less than 0.05) and from 9.6 +/- 7.2 to 33.4 +/- 9.6% (P less than 0.005) respectively and an increase in the percentage of type IIA fibres in the gastrocnemius from 92.9 +/- 2.3 to 97.0 +/- 2.9% (P less than 0.05). However, there were no increases in single fibre mitochondrial enzyme activities.(ABSTRACT TRUNCATED AT 250 WORDS)     

Value of endoscopic surveillance in the detection of neoplastic change in Barrett's oesophagus

Fifty-six patients with Barrett's oesophagus diagnosed between 1977 and 1986 were prospectively studied by 6-monthly endoscopic surveillance and biopsy. During follow-up to-date, four patients have developed high-grade dysplasia and three have adenocarcinoma of the oesophagus. Two of the adenocarcinomas were preceded by progressively severe dysplastic changes but in the third no dysplasia had been previously detected. The incidence of adenocarcinoma was 1 per 56 patient-years of follow-up. Changes in symptomatology or gross endoscopic appearances were usually absent, even after adenocarcinoma had developed, indicating that biopsy is essential for early diagnosis. The high risk of malignant change makes endoscopic surveillance advisable in all patients with Barrett's oesophagus.     

Design and fabrication of cementless hip stems

Theoretical and experimental studies before and after stem insertion demonstrated that stresses and strains were closer to normal for uncemented stems than for cemented stems. The values were affected by relative tightness of fit in the proximal and distal regions and by the presence or absence of a collar. For designing an optimal fit-stem, the average femoral geometry was first determined. The stem was used in a photoelastic coating study that showed a continuous strain field over the bone surface. The average proximomedial bone strains for intact, press-fit, loose press-fit with collar, and proximally cemented (to simulate ingrowth) designs were 100%, 65%, 101%, and 54%, respectively. Localized patches of high strain were seen on the proximal bone surface and beneath a collar, indicative of localized stem-bone contact points.