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RAPID DETECTION OF CHLAMYDIA TRACHOMATIS
109 CHARACTERISTICS AND PREGNANCY OUTCOME OF INSULIN-DEPENDENT DIABETICS WHO HAD THYROID DISEASE OR PERNICIOUS ANAEMIA
(CASES) AND THOSE
WHO DID NOT
Serial plasma theophylline values on days 1 and 3 (and single value on day 5) in patient given theophylline via infusion and enoxacin by mouth. were
taken.
Urine
was
collected
to
assess
renal clearance.
Theophylline concentrations in plasma and urine were determined by means of EMIT and HPLC (both methods gave identical theophylline concentrations). On day I the mean plasma theophylline level was 7 - 3 g/ml; on day 3 it was 14-33 /lg/ml; and on day 5 a further increase, to 25’44 /lg/ml, was found with the same theophylline dosage (figure). Plasma protein binding was 73 -1% on day 1 and 71 -3% on day 3. Renal theophylline clearance did not fall between day 1 and day 3. The plasma half-life of theophylline during enoxacin treatment was increased to about 20 h. We conclude that the serious complaints observed were due to high plasma theophylline levels in patients treated with both theophylline and enoxacin. In view of the unchanged plasma protein binding and renal clearance, the rise in plasma theophylline has to be explained by an altered metabolic clearance. Our preliminary clinical experience indicates that enoxacin may be of value in the treatment of P aeruginosa infections of the lower respiratory tract. However, if simultaneous administration of theophylline and enoxacin is necessary, theophylline will need monitoring if toxicity is to be avoided. Department of Pulmonary Diseases, Dekkerswald Medical
Centre,
University of Nijmegen, Nijmegen, Netherlands Department of Clinical Pharmacy, Sint Radboud Hospital, Nijmegen
W. J. A. WIJNANDS C. L. A.
VAN
HERWAARDEN
T. B. VREE
1 Chartrand S, Scribner R, Weber A, et al. In vitro activity of CI-919 (AT-2266), an oral antipseudomonal compound Antimicrob Ag Chemother 1983, 23: 658-63.
PREGNANCY OUTCOME IN INSULIN-DEPENDENT DIABETICS WITH THYROID DISEASE OR PERNICIOUS ANAEMIA
SIR,-We reported earlier (Jan 4, p 4) that the pregnancies of insulin-dependent diabetic women in whom thyroid disease or pernicious anaemia develop in later life are more likely to end in fetal or neonatal death than those of other diabetics. To determine whether these findings could be replicated, women attending the diabetic outpatient clinic at King’s College Hospital London were interviewed in 1983. All were taking insulin at the time of interview, had been diabetic for more than 5 years, were aged between 36 and 64 years, were white, and were or had been married. They were asked about their pregnancies, their diabetes, and whether or not they had had certain specified disorders. The information was checked against, and supplemented by, the clinic notes. 2 women were excluded because of major inconsistencies between the information reported at interview and that recorded in the notes. Of the 61 insulin-dependent diabetics, 12 had clinical evidence of thyroid disease, 1 had pernicious anaemia, 2 had rheumatoid arthritis, 2 had other conditions with possible autoimmune aetiology, and 44 had no evidence of other endocrine or autoimmune disorders. 11 (85%) of those with thyroid disease or pernicious anaemia and 37 (84%) of those with diabetes alone reported one or more pregnancies. In all but 1 of the cases with thyroid disease or pernicious anaemia the disease was diagnosed after the last reported pregnancy. The characteristics and pregnancy histories of these two groups are summarised in the table.
*Significant difference between
cases
and controls
(p<0
05, two-tailed).
52% of pregnancies women with thyroid disease or pernicious anaemia ended unfavourably, compared with 3107o in women with diabetes alone (p<0 05). No associations with pregnancy order or birthweight were found. These results support the main finding of in
our
previous study.
Dr Cruickshanks and colleagues (March 17, p 629) reported that the pregnancy outcomes of 33 childhood-onset insulin-dependent diabetics with autoimmune disease were similar to those of 111 other childhood-onset diabetics who did not have these conditions. As they pointed out, this may be because women who become diabetic in childhood differ from those who acquire the disease in later life: the mean age at onset of diabetes being 8-77 years in their patients, 21-00 years in our first report, and 19-33 years for the present study. A further explanation for the discrepant findings could be that only 11 (33%) of Cruickshanks’ "autoimmune" group had thyroid disease or pernicious anaemia whereas 22 (67%) were described as having arthritis. It would have been interesting to know what type of arthritis these women had and whether their pregnancy outcome was similar to that of the diabetics with thyroid disease or pernicious anaemia. 2 diabetic women in our study, not included in the table, had rheumatoid arthritis in their late 30s; 1 had two live births followed by a neonatal death, and the other had two spontaneous abortions followed by a live birth. Division of Medical Statistics and Epidemiology, London School of Hygiene and Tropical Medicine, London WC1E 7HT
EVE ROMAN VALERIE BERAL
RAPID DETECTION OF CHLAMYDIA TRACHOMATIS
SIR,-Dr Ruijs and colleagues (April 28, p 960) have evaluated direct immunofluorescence microscopy with monoclonal antibodies (’Microtrak’; Syva) for diagnosing Chlamydia trachornatis infections in men, using urethral swabs and urine sediment. They obtained better results with culture than with the direct test on urethral swab only. We have studied 60 male patients with urethritis from a sexually transmitted disease (STD) clinic, using both methods. Urethral swabs were first rolled on the slide for direct immunofluorescent staining and then put in 2SP medium and transported to the laboratory. Samples were inoculated on cycloheximide-treated McCoy cells and Giemsa stained at least 24 h after collection. 9 specimens were positive by both culture and direct slide test. In 3 cases the direct test was positive and culture negative. No positive culture was negative by direct test. In contrast to Ruijs’ results, in our laboratory the fluorescent direct test was more sensitive than the culture method (20% against 15% by culture), despite our using urethral specimens only. The conditions for culture used by Ruijs et al are optimal but for us difficult to achieve. Many STD clinics do not do cultures and need to send specimens to a laboratory; the delay results in a loss of
viability of chlamydia. Although the direct test needs further evaluation, our experience suggests that it might have advantages over culture: (a) diagnosis
110 takes less than 1 h, while culture takes about 48 h; (b) the test costs no more than culture; and (c) the technology is easier and offers the possibility of diagnosing chlamydia infection in centres where tissue culture is not available. Bacteriology Service, Centro Nacional de Microbiologia, Mirología e Inmunología Sanitarias, Majadahonda, Madrid, Spain
SONSOLES BERRÓN
JULIO VAZQUEZ ASUNCIÓN FENOLL
PRE-SYNAPTIC AND POST-SYNAPTIC DOPAMINERGIC SYSTEM IN HUMAN BRAIN SIR,-Tracer techniques have lately been developed to investigate the dopaminergic system in the living human brain by means of positron emission tomography (PET). 1,2The ascending dopaminergic pathways from midbrain to striatum play a key role in normal striatal function and in several movement disorders, notably Parkinson’s disease.3However, we still do not know which specific components of the dopaminergic system are affected and how the lesions relate to the clinical signs and symptoms observed. For instance, why do some patients with Parkinson’s disease progress to the so-called "on-ofT’ stage-does this merely represent a continuing decline in the storage capacity for dopamine of the nerve terminals of the nigrostriatal pathways or have the post-synaptic dopaminergic receptors become disturbed? This question also applies to patients who no longer respond at all to levodopa. To answer it we need to be able to study, simultaneously, both dopamine storage capacity and dopamine receptor status in the human brain. Levodopa labelled with the 110 min half-life positron-emitting isotope F (L-18F-6-fluorodopa) can be used to measure the uptake of this dopamine precursor in brain. Methylspiperone, a dopamine D2 receptor ligand, when labelled with the positron emitter II C (half-life 20 min), is a suitable tracer for PET and its striatal uptake can be measured in man.Dopamine receptors have also been displayed in living human brain with 77Br-p-bromospiperone 4 using single photon emission tomography.4 We report here the first study in which both tracer techniques have been combined in an informed healthy volunteer. We used the single slice ECAT-11 tomograph at the MRC Cyclotron Unit, Hammersmith Hospital.5 5 II C-methylspiperone was produced by methylation of spiperone with llC-iodomethane, similar to the method used by Wagner et al2 (personal communication). 14 - 5 g of ligand containing 11 mCi of 11 C-methylspiperone was administered intravenously over 2 min. At the start of infusion, a series of consecutive scans was initiated and continued up to 80 minutes at a plane 4 - 5 cm above and parallel to the orbitomeatal line. Frequent blood samples were taken from an indwelling radial artery cannula and tracer concentrations were measured to establish.the arterial input function. At the end of the study, one scan was performed at the level of the cerebellum, 2’ 5 cm above the orbitomeatal line. Lastly transmission scans using a ring source of germanium-68 were done for both levels to permit accurate measured attenuation correction of the emission data. The measurement and visualisation of dopamine in the striatum was pioneered at the McMaster University Medical Centre, Hamilton, Canada.l°6 L-18F-fluorodopa is decarboxylated by the brain to L-18F-fluorodopamine, which is stored in the vesicles of the
pre-synaptic dopaminergic terminals.18F-labelled L-dopa was produced by a method8that yields 35% 2-, 5% 5-, and 60% 6-L-fluorodopa. 3 h after administration of llC-methylspiperone, L-18Ffluorodopa (±8 mg containing 2 - 9 mCi) was injected intravenously over 2 min. Again, the arterial input function of the tracer was measured. 40 min after the injection of L-18F-fluorodopa, scans were done serially for a further 40 min. The major accumulation of both tracers takes place in the showed striatum Consecutive scans that 1). (fig II C-methylspiperone was initially distributed over the brain in a pattern determined by blood flow. However, over time the striatum accumulated the tracer specifically while activity in the surrounding tissue gradually decreased. In the cerebellum there was appreciably less activity. At 80 min, the ratio between striatal and cerebellar activity was 3 3.
I-Brain PET scans of a cross-section, 4.5 cm above the orbitomeatal line, of a volunteer, imaging activity of tracers 11 C-methylspiperone and L-18F-fluorodopa.
Fig
Scans
taken from 50
60
and from 50
80 mm,
respectively.
Top of image is frontal, and left-hand side of image is left side of scale runs from dark red (highest uptake) to dark blue (lowest).
brain. Colour
were
to
mm
to
2 shows the arterial input and the tissue uptake data for the Rate constants for tracer uptake into tissue can be calculated from these data. The L-18F-fluorodopa is seen to accumulate in the striatum at the same location as the I C-methylspiperone. However, the pattern of distribution in the surrounding tissue is different for the two tracers. The total effective dose equivalent for the combined study was calculated to be about 5 mSv. The study of the balance between pre-synaptic dopamine storage capacity and its counterpart, dopamine receptor function, as
Fig
two tracers.
Fig 2-Measured activity of tracers L-’8F-fluorodopa and "Cmethylspiperone in arterial plasma (A), striatum (B), and cortex (C).
(CASES) AND THOSE
WHO DID NOT
Serial plasma theophylline values on days 1 and 3 (and single value on day 5) in patient given theophylline via infusion and enoxacin by mouth. were
taken.
Urine
was
collected
to
assess
renal clearance.
Theophylline concentrations in plasma and urine were determined by means of EMIT and HPLC (both methods gave identical theophylline concentrations). On day I the mean plasma theophylline level was 7 - 3 g/ml; on day 3 it was 14-33 /lg/ml; and on day 5 a further increase, to 25’44 /lg/ml, was found with the same theophylline dosage (figure). Plasma protein binding was 73 -1% on day 1 and 71 -3% on day 3. Renal theophylline clearance did not fall between day 1 and day 3. The plasma half-life of theophylline during enoxacin treatment was increased to about 20 h. We conclude that the serious complaints observed were due to high plasma theophylline levels in patients treated with both theophylline and enoxacin. In view of the unchanged plasma protein binding and renal clearance, the rise in plasma theophylline has to be explained by an altered metabolic clearance. Our preliminary clinical experience indicates that enoxacin may be of value in the treatment of P aeruginosa infections of the lower respiratory tract. However, if simultaneous administration of theophylline and enoxacin is necessary, theophylline will need monitoring if toxicity is to be avoided. Department of Pulmonary Diseases, Dekkerswald Medical
Centre,
University of Nijmegen, Nijmegen, Netherlands Department of Clinical Pharmacy, Sint Radboud Hospital, Nijmegen
W. J. A. WIJNANDS C. L. A.
VAN
HERWAARDEN
T. B. VREE
1 Chartrand S, Scribner R, Weber A, et al. In vitro activity of CI-919 (AT-2266), an oral antipseudomonal compound Antimicrob Ag Chemother 1983, 23: 658-63.
PREGNANCY OUTCOME IN INSULIN-DEPENDENT DIABETICS WITH THYROID DISEASE OR PERNICIOUS ANAEMIA
SIR,-We reported earlier (Jan 4, p 4) that the pregnancies of insulin-dependent diabetic women in whom thyroid disease or pernicious anaemia develop in later life are more likely to end in fetal or neonatal death than those of other diabetics. To determine whether these findings could be replicated, women attending the diabetic outpatient clinic at King’s College Hospital London were interviewed in 1983. All were taking insulin at the time of interview, had been diabetic for more than 5 years, were aged between 36 and 64 years, were white, and were or had been married. They were asked about their pregnancies, their diabetes, and whether or not they had had certain specified disorders. The information was checked against, and supplemented by, the clinic notes. 2 women were excluded because of major inconsistencies between the information reported at interview and that recorded in the notes. Of the 61 insulin-dependent diabetics, 12 had clinical evidence of thyroid disease, 1 had pernicious anaemia, 2 had rheumatoid arthritis, 2 had other conditions with possible autoimmune aetiology, and 44 had no evidence of other endocrine or autoimmune disorders. 11 (85%) of those with thyroid disease or pernicious anaemia and 37 (84%) of those with diabetes alone reported one or more pregnancies. In all but 1 of the cases with thyroid disease or pernicious anaemia the disease was diagnosed after the last reported pregnancy. The characteristics and pregnancy histories of these two groups are summarised in the table.
*Significant difference between
cases
and controls
(p<0
05, two-tailed).
52% of pregnancies women with thyroid disease or pernicious anaemia ended unfavourably, compared with 3107o in women with diabetes alone (p<0 05). No associations with pregnancy order or birthweight were found. These results support the main finding of in
our
previous study.
Dr Cruickshanks and colleagues (March 17, p 629) reported that the pregnancy outcomes of 33 childhood-onset insulin-dependent diabetics with autoimmune disease were similar to those of 111 other childhood-onset diabetics who did not have these conditions. As they pointed out, this may be because women who become diabetic in childhood differ from those who acquire the disease in later life: the mean age at onset of diabetes being 8-77 years in their patients, 21-00 years in our first report, and 19-33 years for the present study. A further explanation for the discrepant findings could be that only 11 (33%) of Cruickshanks’ "autoimmune" group had thyroid disease or pernicious anaemia whereas 22 (67%) were described as having arthritis. It would have been interesting to know what type of arthritis these women had and whether their pregnancy outcome was similar to that of the diabetics with thyroid disease or pernicious anaemia. 2 diabetic women in our study, not included in the table, had rheumatoid arthritis in their late 30s; 1 had two live births followed by a neonatal death, and the other had two spontaneous abortions followed by a live birth. Division of Medical Statistics and Epidemiology, London School of Hygiene and Tropical Medicine, London WC1E 7HT
EVE ROMAN VALERIE BERAL
RAPID DETECTION OF CHLAMYDIA TRACHOMATIS
SIR,-Dr Ruijs and colleagues (April 28, p 960) have evaluated direct immunofluorescence microscopy with monoclonal antibodies (’Microtrak’; Syva) for diagnosing Chlamydia trachornatis infections in men, using urethral swabs and urine sediment. They obtained better results with culture than with the direct test on urethral swab only. We have studied 60 male patients with urethritis from a sexually transmitted disease (STD) clinic, using both methods. Urethral swabs were first rolled on the slide for direct immunofluorescent staining and then put in 2SP medium and transported to the laboratory. Samples were inoculated on cycloheximide-treated McCoy cells and Giemsa stained at least 24 h after collection. 9 specimens were positive by both culture and direct slide test. In 3 cases the direct test was positive and culture negative. No positive culture was negative by direct test. In contrast to Ruijs’ results, in our laboratory the fluorescent direct test was more sensitive than the culture method (20% against 15% by culture), despite our using urethral specimens only. The conditions for culture used by Ruijs et al are optimal but for us difficult to achieve. Many STD clinics do not do cultures and need to send specimens to a laboratory; the delay results in a loss of
viability of chlamydia. Although the direct test needs further evaluation, our experience suggests that it might have advantages over culture: (a) diagnosis
110 takes less than 1 h, while culture takes about 48 h; (b) the test costs no more than culture; and (c) the technology is easier and offers the possibility of diagnosing chlamydia infection in centres where tissue culture is not available. Bacteriology Service, Centro Nacional de Microbiologia, Mirología e Inmunología Sanitarias, Majadahonda, Madrid, Spain
SONSOLES BERRÓN
JULIO VAZQUEZ ASUNCIÓN FENOLL
PRE-SYNAPTIC AND POST-SYNAPTIC DOPAMINERGIC SYSTEM IN HUMAN BRAIN SIR,-Tracer techniques have lately been developed to investigate the dopaminergic system in the living human brain by means of positron emission tomography (PET). 1,2The ascending dopaminergic pathways from midbrain to striatum play a key role in normal striatal function and in several movement disorders, notably Parkinson’s disease.3However, we still do not know which specific components of the dopaminergic system are affected and how the lesions relate to the clinical signs and symptoms observed. For instance, why do some patients with Parkinson’s disease progress to the so-called "on-ofT’ stage-does this merely represent a continuing decline in the storage capacity for dopamine of the nerve terminals of the nigrostriatal pathways or have the post-synaptic dopaminergic receptors become disturbed? This question also applies to patients who no longer respond at all to levodopa. To answer it we need to be able to study, simultaneously, both dopamine storage capacity and dopamine receptor status in the human brain. Levodopa labelled with the 110 min half-life positron-emitting isotope F (L-18F-6-fluorodopa) can be used to measure the uptake of this dopamine precursor in brain. Methylspiperone, a dopamine D2 receptor ligand, when labelled with the positron emitter II C (half-life 20 min), is a suitable tracer for PET and its striatal uptake can be measured in man.Dopamine receptors have also been displayed in living human brain with 77Br-p-bromospiperone 4 using single photon emission tomography.4 We report here the first study in which both tracer techniques have been combined in an informed healthy volunteer. We used the single slice ECAT-11 tomograph at the MRC Cyclotron Unit, Hammersmith Hospital.5 5 II C-methylspiperone was produced by methylation of spiperone with llC-iodomethane, similar to the method used by Wagner et al2 (personal communication). 14 - 5 g of ligand containing 11 mCi of 11 C-methylspiperone was administered intravenously over 2 min. At the start of infusion, a series of consecutive scans was initiated and continued up to 80 minutes at a plane 4 - 5 cm above and parallel to the orbitomeatal line. Frequent blood samples were taken from an indwelling radial artery cannula and tracer concentrations were measured to establish.the arterial input function. At the end of the study, one scan was performed at the level of the cerebellum, 2’ 5 cm above the orbitomeatal line. Lastly transmission scans using a ring source of germanium-68 were done for both levels to permit accurate measured attenuation correction of the emission data. The measurement and visualisation of dopamine in the striatum was pioneered at the McMaster University Medical Centre, Hamilton, Canada.l°6 L-18F-fluorodopa is decarboxylated by the brain to L-18F-fluorodopamine, which is stored in the vesicles of the
pre-synaptic dopaminergic terminals.18F-labelled L-dopa was produced by a method8that yields 35% 2-, 5% 5-, and 60% 6-L-fluorodopa. 3 h after administration of llC-methylspiperone, L-18Ffluorodopa (±8 mg containing 2 - 9 mCi) was injected intravenously over 2 min. Again, the arterial input function of the tracer was measured. 40 min after the injection of L-18F-fluorodopa, scans were done serially for a further 40 min. The major accumulation of both tracers takes place in the showed striatum Consecutive scans that 1). (fig II C-methylspiperone was initially distributed over the brain in a pattern determined by blood flow. However, over time the striatum accumulated the tracer specifically while activity in the surrounding tissue gradually decreased. In the cerebellum there was appreciably less activity. At 80 min, the ratio between striatal and cerebellar activity was 3 3.
I-Brain PET scans of a cross-section, 4.5 cm above the orbitomeatal line, of a volunteer, imaging activity of tracers 11 C-methylspiperone and L-18F-fluorodopa.
Fig
Scans
taken from 50
60
and from 50
80 mm,
respectively.
Top of image is frontal, and left-hand side of image is left side of scale runs from dark red (highest uptake) to dark blue (lowest).
brain. Colour
were
to
mm
to
2 shows the arterial input and the tissue uptake data for the Rate constants for tracer uptake into tissue can be calculated from these data. The L-18F-fluorodopa is seen to accumulate in the striatum at the same location as the I C-methylspiperone. However, the pattern of distribution in the surrounding tissue is different for the two tracers. The total effective dose equivalent for the combined study was calculated to be about 5 mSv. The study of the balance between pre-synaptic dopamine storage capacity and its counterpart, dopamine receptor function, as
Fig
two tracers.
Fig 2-Measured activity of tracers L-’8F-fluorodopa and "Cmethylspiperone in arterial plasma (A), striatum (B), and cortex (C).