INDEXING BIBLIOGRAPHIC DATA BASES

1458 DETENTION OF DR AL AGHA

SIR,-During a recent tour in Israel’s occupied territories we learned of the arrest of Dr Zakariya Al Agha, president of the Arab Medical Association in Gaza, an organisation founded in 1945. Last autumn, he was dismissed as head of the medical clinic at the Khan Younis Hospital. The only reason given was his presidency of the Arab Medical Association. On April 29, 1988, Dr Al Agha was put under "administrative detention" under a law that gives the authorities the right to put a person in prison for six months without a trial or formal accusation. His only "crimes" are discussions with foreign colleagues and journalists and participation in a Peace Now meeting. During the present unrest the need for medical care in the occupied territories is greater than ever and it is deplorable that Israeli authorities should arrest one of the key people in this humanitarian work.

evidence of toxicity; discovered elsewhere.

possibly

such

patients

Urinary opiates were not detected in a third of rectal heroin packers (which was the main mode of heroin packing). There were no data on the sensitivity of urinary heroin detection after day one. Also, the sensitivity of detecting urinary cocaine by day four was only 60%. Since transit time through the gut can be several days and smuggling occurs across international borders this level of sensitivity is poor. Also there was no evidence to suggest that urinary drug screening is any better in detection of smugglers than detection by custom officials or by use of radiological methods. Lancashire et all have commented on the use of radiological investigations. Moreover, it is likely that initial screening for further investigaton is done by custom officials or other law enforcing agencies. St Charles’ Hospital, London W10 6DZ

Department of Physiology, University of Lund, S- 223 62 Lund, Sweden

GERT ANDERSSON

Tisken Falun

LARS

Outpatients Clinic,

JERDÉN

INDEXING BIBLIOGRAPHIC DATA BASES

SIR,-Dr Pinatsis (April 23, p 942) comments on our March 5 letter on the indexing of bibliographic data bases. We are not alone in experiencing this problem.’ The computer search which we referred to was done by a head librarian (V. P.) who has ten years of experience with bibliographic data bases and who had been trained at two European MEDLARS centres (IMA-INSERM in Paris and BLAISE in London). She was assisted by two senior researchers skilled in perinatal questions. One of the major descriptors of perinatal asphyxia, the Apgar score, had not been taken into consideration by the MEDLINE indexers in 15% of our selected papers, even though the term Apgar score appeared in the title or abstract. Such findings suggest that the accuracy of this data base is limited, even though it is one of the best available. Your correspondent, comparing his "professional search" with our experience, questions the competence of our search, but he did not follow our premises exactly: his search was not restricted to the journals we selected and the term Apgar score was not used as a descriptor or as a free text term. The use of free text search merits a moment’s consideration. Everyone consulting on-line data bases daily is aware of the pros and cons of this choice, but surely it is not a measure of accuracy but merely a way to obtain more references when the use of descriptors fails. Whatever the approach selected, however, the need for a more accurate strategy in searching is of interest to everyone who uses and sets up bibliographic data bases. The means of access to such data bases are marketed for direct use, without the expert help of intermediaries. Laboratory of Clinical Pharmacology, Istituto di Ricerche Farmacologiche, Mario Negri, 20157 Milan, Italy

MARIA JESUS LARGAESPEADA VANNA PISTOTTI MAURIZIO BONATI

1. Lancashire

A. K. SHAH

MJR, Legg PK, Lowe M, Davidson SM, Ellis BW Surgical aspects of drug smuggling Br Med J 1988, 296: 1035-37.

international

ORONASAL

OBSTRUCTION, LUNG VOLUMES, AND ARTERIAL OXYGENATION

SIR,-We read with interest Dr Rodenstein and Dr Stanescu’s (April 16, p 889) on our paper (Jan 16, p 73). We must emphasise that we never claimed to be defining any relation between oronasal obstruction and airflow resistance. We merely attempted to account for the changes in lung volume observed in terms of some of the disparate facts about the resistance of the oral and nasal breathing routes. comments

Rodenstein and Stanescu cite the work of Cole

all

as

oronasal resistance in these circumstances. We did not suggest that, with interdental wiring, patients would be "unable to switch from nasal or oral breathing". Cole et al showed that when the teeth were fully occluded oral resistance was 50% higher than during spontaneous oronasal breathing, but the subjects could still breathe through the mouth. Rodenstein and Stanescu’s comments about an oronasal switching point at 35-45 1/min are valid for steady-state exercise, but exercise, exertion, and rates of air movement during everyday activity are rarely "steady state". There are also other circumstances in everyday life in which people at rest breathe out through the mouth-for example, when Rodenstein and Stanescu take issue with

versus

et

demonstrating that oral airflow resistance "only decreased when a mouthpiece was used". These workers did demonstrate, under well-controlled conditions of rest and graded steady-state exercise in a laboratory, that the resistance of the oral airway was "remarkably similar" to that of the nasal route. However, when the mouth was opened wide, oral airflow resistance was only 10% of nasal resistance; and even when the incisor teeth overlapped resistance was only 25% of that seen during spontaneous oronasal breathing. Our patients were free-living, continuing with their normal everyday activities, and we have no idea what happens to

talking. liver diseases from the MEDLARS searches. Controlled Clin Trials

1. Bernstein F. The retrieval of randomized clinical trials

medical literature. Manual 1988; 9: 23-90

may have been

in

DETECTION OF DRUGS IN URINE OF BODY-PACKERS

SIR,-Dr Gherardi and colleagues (May 14, p 1076) report on detection of drugs in the urine of body packers. However, their conclusion that "the measurement of drugs in the urine is a rapid, simple, and safe method that seems a reliable test for every type of body packer" needs consideration. They give no information on the method of selecting patients except that they were all examined at Hotel Dieu de Paris. The validity of the results may depend on the type of patient selected. For example, in their series there were no patients with clinical

our comment

that

changes in Pa02may be due to an effect of changes in the relationship between functional residual capacity (FRC) and closing volume. We made these comments only because this appears to be one of the explanations for the way that FRC affects

Pa02.2We do not know whether this is so or not; nor is it relevant to our argument. We know of no published data collected in circumstances similar to ours, but there does appear to be a positive relation between FRC and arterial oxygen saturation.3-6 Our results indicate such a relation in fit healthy people aged 18-20 years. We have no idea of the mechanism. Your correspondents argue that if partial nasal obstruction contributes to an improvement in Pa02"one would never recommend nasal surgery in patients with partial nasal obstruction". We found that partial nasal obstruction produced an increase in FRC while complete obstruction caused a decrease in FRC. There may be a point when nasal obstruction is so severe that, in terms of effects on lung volume, it is as if the obstruction were