A two-centre experience of tonsil biopsies in the investigation of patients with tonsillar asymmetry

INTRODUCTION

We aim to evaluate our experience of tonsil biopsies in the investigation of patients presenting with asymmetrical tonsils.

METHODS

A two-centre retrospective analysis of all patients who underwent histology sampling of the palatine tonsils between 1 January 2013 and 31 December 2018 was completed. Data collected included patient demographics, method of obtaining tonsil tissue, histological diagnosis and need for repeat tissue sampling. A follow-up period of 36 months was allowed to establish whether any patients re-presented with missed diagnoses.

RESULTS

In total, 937 patients were included for analysis: 375 (40.0%) had a biopsy, of which 191 (50.9%) were performed in clinic. The mean duration from initial appointment with the ear, nose and throat clinic to tissue sample collection was 17.6 days (range 0-327 days) for all biopsies, reducing to 0.2 days (range 0-17 days) for biopsies performed in clinic. This was significantly shorter than for tonsillectomies (mean 38.9 days, range 0-444 days; p<0.05). Of the patients who underwent tonsil biopsy, six (1.6%) had malignancy that was not unequivocally diagnosed on initial biopsy. In all six patients, prior clinical suspicion was high, and repeat tissue sampling was undertaken on receipt of negative histology results.

CONCLUSIONS

Tonsil biopsy is a viable alternative to tonsillectomy for histology in the assessment of tonsil asymmetry. Tonsil biopsy in the outpatient setting has reduced surgical morbidity, significantly less delay in diagnosis, less inconvenience for patients and lower healthcare costs compared with formal tonsillectomy. Although tonsil biopsies should not be used in isolation, they can be useful in the investigation of patients presenting with tonsillar asymmetry.

Real-world accuracy of computed tomography in patients admitted with small bowel obstruction: a multicentre prospective cohort study

PURPOSE

Small bowel obstruction (SBO) is a common surgical emergency. Previous studies have shown the value computed tomography (CT) scanning in both confirming this diagnosis and identifying indications for urgent surgical intervention, such as strangulated bowel or closed loop obstructions. However, most of the literature is based on retrospective expert review of previous imaging and little data regarding the real-time accuracy of CT reporting is available. Here, we investigated the real-world accuracy of CT reporting in patients admitted with SBO.

METHODS

This was a multicentre prospective study including consecutive patients admitted with SBO. The primary outcomes were the sensitivity and specificity of CT scanning for bowel obstruction with ischaemia and closed loop obstruction. Data were retrieved from the original CT reports written by on-call radiologists and compared with operative findings.

RESULTS

One hundred seventy-six patients were included, all of whom underwent CT scanning with intravenous contrast followed by operative management of SBO. Bowel obstruction with ischaemia was noted in 20 patients, with a sensitivity and specificity of CT scanning of 40.0% and 85.5%, respectively. Closed loop obstructions were noted in 26 patients, with a sensitivity and specificity of CT scanning of 23.1% and 98.0%, respectively.

CONCLUSIONS

The real-world accuracy of CT scanning appears to be lower than previously reported in the literature. Strategies to address this could include the development of standardised reporting schemas and to increase the surgeon's own familiarity with relevant CT features in patients admitted with SBO.

Ultrasound guided L5-S1 placement of labor epidural does not improve dermatomal block in parturients

BACKGROUND

Based on their experience or training, anesthesiologists typically use the iliac crest as a landmark to choose the L3-4 or L2-3 interspace for labor epidural catheter placement. There is no evidence-based recommendation to guide the exact placement. We hypothesized that lower placement of the catheter would lead to a higher incidence of S2 dermatomal block and improved analgesia in late labor and at delivery.

METHODS

One-hundred parturients requesting epidural analgesia were randomly assigned to receive ultrasound-guided L5-S1 epidural catheter placement (experimental group) or non-ultrasound-guided higher lumbar interspace placement (control group). The primary outcome was the incidence of S2 block 30 minutes after administering 10 mL 0.125% bupivacaine. Secondary outcomes were average pain throughout labor and maximum pain during labor or during delivery.

RESULTS

Forty-nine subjects were enrolled in control group and 47 in the experimental group. The primary endpoint did not significantly differ between groups (control group 81% vs experimental group 91%, P=0.24). The secondary endpoints were not significantly different: pain relief after 30 minutes (mean pain score 1.4 in the control group vs 1.9 in the experimental group, P=0.2) and pain at delivery (mean score 4 in the control group vs 3.9 in the experimental group, P=0.6).

CONCLUSION

Placement of an epidural catheter at the L5-S1 interspace using ultrasound did not improve sacral sensory block coverage when compared with an epidural catheter placed at a higher lumbar interspace, without using ultrasound guidance.

Etiological factors for the persistence of endemic goiter in selected areas of Siddharthnagar district in Eastern Uttar Pradesh, India

AIM

To assess the prevalence of goiter, state of iodine nutrition of the population, consumption pattern of common goitrogenic food, and distribution of iodine through edible salt in selected CD Blocks of Siddharthnagar district in Eastern Uttar Pradesh.

METHODS

Goiter survey among 1,862 school children, aged 6-12 years, of both sexes, and analysis of iodine (I) and thiocyanate (SCN) in 240 urine samples, and iodine content in 210 edible salt samples collected from the selected study areas.

RESULTS

The prevalence of goiter was 26.3% (grade 1: 23.2%; grade 2: 3.1%). Median urinary iodine level was 6.0 microg/dl, and 42% had concentration < 5 microg/dl. Mean (SD) urinary SCN was 0.75 (0.4) mg/dl. Only17.1% of salt samples had iodine level > 15 ppm; 82.9% had < 15 ppm.

CONCLUSION

Consumption of inadequately iodized salt and cyanogenic plant foods containing goitrogenic/anti-thyroidal substances by the people of the studied region are possible reasons for the persistence of goiter during the post salt iodination phase.

Goiter prevalence and iodine nutritional status of school children in a sub-Himalayan Tarai region of eastern Uttar Pradesh

OBJECTIVES

The present work was undertaken to evaluate the prevalence of goiter, state of iodine nutrition of the population, distribution of iodine through edible salt, bioavailability of iodine, consumption of common goitrogenic food that generally interfere with iodine nutrition in Naugarh sub-division of Siddharthnagar district in Uttar Pradesh, India.

SETTING

Five areas were selected from 5 Community Development (CD) Blocks taking one from each by purposive sampling method. In each area, Primary and Junior high schools were selected by simple random sampling to get representative target population.

METHODS

Clinical goiter survey was conducted in 1663 school-aged children from both sexes (6-12 yrs), along with the biochemical analysis of iodine (I) and thiocyanate (SCN) in 200 urine samples, iodine content in 175 edible salt samples and 20 water samples collected from the selected study areas.

RESULTS

The studied region is severely affected by Iodine deficiency disorders (IDD) as goiter prevalence is 30.2% (grade 1: 27.1% grade 2:3.1%). Median urinary iodine level was 96 microg/L indicating biochemical iodine deficiency. The mean urinary thiocyanate was 0.810+/-0.490 mg/dL and mean of I/SCN ratios in all the studied areas were above the critical level of 7. However, 22% of the individual had I/SCN ratio <or=7 indicating their susceptibility for the development of goiter. Only 12.6% of the salt samples had adequate iodine i.e., >or=15 ppm while iodine content in drinking water varied between 7.5-10.7 microg/L.

CONCLUSION

Iodine deficiency is the primary cause, however the consumption of cyanogenic food may have important role for the persistence of IDD in the studied region during post salt iodization phase.

Nodular fasciitis of the head and neck

Nodular fasciitis is an unusual benign reactive process affecting superficial and deep fascia. Its rapid growth, rich cellularity, high mitotic activity and poorly circumscribed nature result in it being easily misdiagnosed as a sarcomatous lesion. Three cases of nodular fasciitis presenting as neck lumps are reported. They were successfully treated with local excision, with no signs of recurrence following two years of follow up. This paper describes the clinical presentation and microscopic features of this rare benign lesion and it emphasizes the need for accurate histopathology and clinical suspicion, if inappropriate aggressive management is to be avoided.

Endolymphatic sac tumours

Endolymphatic sac tumours (ELST) are rare tumours of the petrous temporal bone. They may arise sporadically or be associated with von Hippel-Lindau disease. Their differential diagnosis is discussed. We present the clinical and histopathological features of two new patients with ELST and outline the management of their condition. In addition, we review a third case previously reported as a choroid plexus papilloma in which the histology has been re-assessed and the diagnosis changed to ELST. The controversy regarding the cellular origins of adenomatous tumours of the temporal bone is highlighted.

Attitudes, practices, and preferences of pediatricians regarding initiation of hepatitis B immunization at birth

OBJECTIVES

To explore practices and attitudes of pediatricians toward administration of the first dose of hepatitis B vaccine to infants, and to identify factors influencing the decision of pediatricians to initiate immunization at birth versus at 1 to 2 months of age.

METHODS

A random sample of 600 pediatricians obtained from the American Academy of Pediatrics membership database was surveyed by mail.

RESULTS

Three hundred eighty (68%) of the 563 pediatricians who were located responded to the survey. Of these 380 pediatricians, 279 provided routine immunizations to children. Of the 270 pediatricians who vaccinated children with hepatitis B vaccine and indicated their practice regarding the birth dose, 50% offered the first dose of hepatitis B vaccine at birth to all infants; the rest either offered the vaccine at birth only to infants of hepatitis B surface antigen-positive mothers and mothers whose serostatus is unknown, or did not offer the birth dose to any infants at all. Practicing in the inner city, working for a medical school or government hospital, and living in a state with universal immunization supply policies were associated with the respondent giving the birth dose. The strongest perceived barriers to giving the birth dose in the hospital were the difficulty tracking these vaccines (39%), the increased cost (27%), and the lack of reimbursement from insurance companies (26%). If a combination vaccine that includes hepatitis B; diphtheria, tetanus, pertussis (diphtheria and tetanus toxoids and acellular pertussis vaccine); and polio (inactivated poliovirus vaccine) antigens become available in the near future, then 38% of physicians who currently give the birth dose to all infants would prefer to wait until 2 months of age to initiate hepatitis B immunization.

CONCLUSIONS

Efforts to achieve high implementation of hepatitis B birth dose administration may falter once a hepatitis B-containing pentavalent combination vaccine becomes available. Programmatic efforts should ensure prevention of perinatal hepatitis B virus transmission through universal prenatal hepatitis B surface antigen screening and immunoprophylaxis of high-risk newborn infants.

Hepatitis B vaccination practices in hospital newborn nurseries before and after changes in vaccination recommendations

BACKGROUND

Routine use of hepatitis B vaccine for low-risk newborns was suspended on July 7, 1999, because of concern about the potential risk of thimerosal, a mercury-containing vaccine preservative. Reinstatement of the birth dose was recommended when a thimerosal-free vaccine became available.

OBJECTIVE

To explore changes in hepatitis B vaccination practices for newborns related to the revised recommendations for low-risk infants (in this study, the terms newborn and infant are used interchangeably).

DESIGN

A telephone survey of a random sample of 1000 US hospitals.

PARTICIPANTS

Nurse managers, nursery directors, and staff nurses of the newborn nurseries.

MAIN OUTCOME MEASURES

Nursery vaccination practices before and after July 7, 1999, and the availability and use of thimerosal-free vaccine.

RESULTS

Interviews were conducted with 773 (87%) of 886 eligible hospitals. Before July 7, 1999, 78% of the hospitals reported vaccination practices that were consistent with recommendations at that time, although only 47% vaccinated all low-risk infants at birth. After July 7, 1999, almost all hospitals discontinued vaccination of low-risk infants, in accordance with the recommendation change; however, there was a 6-fold increase in the number of hospitals that were not vaccinating all high-risk infants. After the introduction of thimerosal-free vaccine, only 39% of the hospitals reported vaccinating all low-risk infants.

CONCLUSIONS

Most hospital nurseries altered their newborn hepatitis B vaccination practices consistent with changes in national recommendations. However, unintended consequences included the failure of some hospitals to continue vaccinating all high-risk infants and the delay in reintroducing vaccination for low-risk newborns after the introduction of a thimerosal-free vaccine. Assessments of the appropriateness of this country's response to the threat of thimerosal in vaccines should consider these findings.

Combined 'trache-stent': a useful option in the treatment of a complex case of subglottic stenosis

The authors describe the adaptation of a Montgomery T-tube laryngo-tracheal stent to incorporate an uncuffed fenestrated Shiley tracheostomy tube in the management of a complex case of subglottic stenosis. The combined 'trache-stent' provided a secure, unobstructed airway and optimal phonation. The presence of a removable inner tube facilitated cleaning and reduced patient anxiety regarding the perceived risks of stent obstruction with dried secretions. The combined 'trache-stent' was upsized at four weeks with minimal evidence of local granulation formation. The device was removed entirely six weeks later after direct laryngoscopy reconfirmed the above findings. Almost two years later the patient retains a good voice and airway using a simple fenestrated tracheostomy tube and speaking valve. The subglottic area is stable and the patient has returned to full-time employment.

Hypoglycaemic action of the flavonoid fraction of Cuminum nigrum seeds

The seeds of Cuminum nigrum were screened phytochemically and were found to contain 8% flavonoids and 0.01% alkaloids. When studied for their effect on blood glucose levels, oral administration of the flavonoid contents of the plant caused a hypoglycaemic effect at a dose range of 0.5 to 1.5 g/kg, both in normal and alloxan-diabetic rabbits. The hypoglycaemic effect started 2 h after drug administration, reaching a maximum within 4-8 h and the blood glucose levels returned close to normal within 24 h of drug administration. The glibenclamide (5 mg/kg), produced a hypoglycaemic effect in the normal rabbits, whereas it had no effect on the blood glucose levels of alloxan-diabetic rabbits. The alkaloids isolated from C. nigrum seeds, however, failed to exert any significant hypoglycaemic effect in either the normal or diabetic rabbits. A 7 day acute toxicity study in rabbits did not produce any apparent adverse effect at doses as high as 5 g/kg orally. These data indicate that the total flavonoid contents of C. nigrum seeds exhibited considerable hypoglycaemic activity in rabbits and may therefore be responsible for the previously reported antidiabetic activity of the seeds. Furthermore, it is conceivable that the C. nigrum flavonoids possess insulin triggering and/or insulin-like properties.

Unsafe injections and the transmission of hepatitis B and C in a periurban community in Pakistan

Following reports of frequent deaths associated with jaundice and chronic liver disease among adults in a periurban community of Karachi, Pakistan, an investigation was conducted to evaluate the relationship between injections and viral hepatitis infections, to identify the reasons why patients received frequent injections, and to observe the injection practices employed in clinics. Two hundred and three adult patients were interviewed as they left each of the 18 area clinics. Practitioners were interviewed and three consecutive injections were observed at each clinic. Eighty-one per cent of patients received an injection on the day of the interview. Of the 135 patients who provided a serum sample, 59 (44%) had antibodies against hepatitis C virus and 26 (19%) had antibodies against hepatitis B virus. Patients who received more injections were more likely to be infected with hepatitis C. If oral and injected medications were equally effective, 44% of patients preferred injected medication. None of the practitioners knew that hepatitis C could be transmitted by injections. Non-sterile syringes and needles that had been used earlier in the day on other patients were used for 94% of the observed injections. Interventions to limit injections to those which are safe and clinically indicated are needed to prevent injection-associated infections in Pakistan and other low-income countries.

Intragenic suppression of trans-dominant lethal substitutions in the conserved GEME motif of the beta subunit of RNA polymerase: evidence for functional cooperativity within the C-terminus

BACKGROUND

The ubiquitous multimeric RNA polymerases contain two large, conserved subunits, of which the beta subunit has been implicated in all three stages of transcription. We have previously described a genetic system involving random, PCR-mediated mutagenesis of the region of rpoB encoding the C-terminal 116 amino acids of the beta subunit of Escherichia coli RNA polymerase and the characterization of dominant-negative mutations. This study identified the invariant motif GEME (residues 1271-->1274; Cromie et al. 1999). Starting with three of these GEME-motif lethal mutations (G1271E, G1271V, M1273V), we have selected for intragenic suppressors, located within the same 3'-region, that prevent expression of the trans-dominant phenotype.

RESULTS

We isolated a total of 24 missense mutants and a further 14 frameshift alleles (the latter generating a nested set of C-terminal deletions of the beta subunit) and studied the effect of the missense suppressors in vivo and in vitro. The majority of the second-site substitutions pinpoint highly conserved residues and were allele-specific. In contrast, one particular missense substitution (S1332P) acted on all three primary site mutations whilst not appreciably affecting assembly proficiency, suggesting motif-specific suppression. Two missense substitutions were found to perturb assembly of the beta subunit (M1232T and L1233P) and define a small conserved region (1228-->1233) adjacent to one of the active-site residues identified by affinity-labelling, H1237. The majority of primary mutations were located in three main clusters within the 116 amino acid region.

CONCLUSIONS

The importance and functional co-operativity of the three main clusters pinpointed is supported by the present isolation of suppressors of three different GEME primary mutations in the same three regions (whereas the suppressors of G1271V and M1273V are located in all three clusters, those for G1271E are all C-terminal of this residue). Moreover, the location of the suppressors suggests that the GEME and HLVDDK regions are present as alpha-helices in holoenzyme, and that functional co-operativity is through one particular face of each helix.

The dynamics of glomerular filtration after Caesarean section

The objective of this study was to determine whether the glomerular hyperfiltration of pregnancy is maintained even after Caesarean section and, if so, to define the responsible hemodynamics. The dynamics of glomerular filtration were evaluated in 12 healthy women who had just completed an uncomplicated pregnancy and were delivered by Caesarean section. Age-matched but non-gravid female volunteers (n = 22) served as control subjects. GFR in postpartum women was elevated above control values by 41%; 149+/-10 versus 106+/-3 ml/min per 1.73 m2, respectively (P < 0.001). In contrast, corresponding renal plasma flow was the same in the two groups, such that the postpartum filtration fraction was significantly elevated by 20%. Computation of glomerular intracapillary oncotic pressure (piGC) from knowledge of plasma oncotic pressure and the filtration fraction revealed this quantity to be significantly reduced in postpartum women, 20.6+/-1.7 versus 26.1+/-2.0 mmHg in control subjects (P < 0.001). A theoretical analysis of glomerular ultrafiltration suggests that depression of piGC, the force opposing the formation of filtrate, is predominantly or uniquely responsible for the observed postpartum hyperfiltration.

Trans-dominant mutations in the 3'-terminal region of the rpoB gene define highly conserved, essential residues in the beta subunit of RNA polymerase: the GEME motif

BACKGROUND

The multimeric DNA-dependent RNA polymerases are widespread throughout nature. The RNA polymerase of Escherichia coli, which is the most well characterized, consists of a holoenzyme with subunit stoichiometry of alpha2betabeta'sigma. The beta subunit is conserved and has been implicated in all stages of transcription. The extreme C-terminus of the beta subunit, which includes two well-conserved sequence segments, contributes to the active centre and has been proposed to act in transcriptional termination. We describe a genetic system for further characterizing the role of the extreme C-terminus of the beta subunit of E. coli RNA polymerase. This involves random, PCR (Polymerase Chain Reaction)-mediated mutagenesis of the 3' region of rpoB encoding the C-terminal 116 amino acids of beta, followed by the isolation and characterization of trans-dominant-negative mutations.

RESULTS

Substitutions of conserved residues in this region were obtained that exhibited different degrees of growth inhibition in a host expressing the chromosomal-encoded wild-type form of the beta subunit. A number of different substitutions were isolated within the highly conserved sequence motif GEME (residues 1271-->1274 of the E. coli beta subunit). In addition, substitutions were obtained in the extreme C-terminal (surface-exposed) region of beta and at two residues previously proposed to be in the active site (H1237, K1242). The properties of the purified mutant holoenzymes, assessed by transcription assays in vitro, suggested a promoter blockading action.

CONCLUSIONS

We have identified an important, highly conserved motif in the beta subunit, GEME (residues 1271-->1274). The nature and effect of the amino acid substitutions at the Gly residue in GEME emphasize the importance of a small, uncharged residue at this position. The in vitro properties of the most extreme trans dominant-negative mutants altered in the GEME motif (and the mutant characteristics in vivo) were similar to those of certain previously identified active-site mutants, suggesting that the altered RNA polymerases were capable of promoter binding and RNA chain initiation but were deficient in the subsequent transcriptional stage.

Teaching clinician-patient communication in the treatment of breast diseases

In 1998, some 179,000 women in the United States were newly diagnosed with breast cancer, and 48,500 women died from it. Early detection by mammography, physical examination, and breast self-examination improves survival rates and can decrease mortality. The clinician's level of comfort with discussing education and prevention with patients can influence patients' adherence to preventive measures. Improved clinician-patient interpersonal communication has a demonstrated positive impact on adherence and health outcomes. We developed and pilot tested a core curriculum on breast health aimed at primary care community physicians and resident house staff. The goal was to improve interpersonal communication between clinician and patient. Two groups of participants attended either a week-long or a 2-week-long training program consisting of four components: a brief demonstration of an interview and breast examination, interviews and breast examinations with a standardized patient, and two separate workshops of varying length. This pilot program had a significant impact on clinician behavior and knowledge. We recommend further investigation of this area with larger sample sizes.

Nature of glomerular dysfunction in pre-eclampsia

BACKGROUND

Pre-eclampsia is characterized by hypertension, proteinuria and edema. Simultaneous studies of kidney function and structure have not been reported. We wished to explore the degree and nature of glomerular dysfunction in pre-eclampsia.

METHODS

Physiologic techniques were used to estimate glomerular filtration rate (GFR), renal plasma flow and afferent oncotic pressure immediately after delivery in consecutive patients with pre-eclampsia (PET; N = 13). Healthy mothers completing an uncomplicated pregnancy served as functional controls (N = 12). A morphometric analysis of glomeruli obtained by biopsy and mathematical modeling were used to estimate the glomerular ultrafiltration coefficient (Kf). Glomeruli from healthy female kidney transplant donors served as structural controls (N = 8).

RESULTS

The GFR in PET was depressed below the control level, 91 +/- 23 versus 149 +/- 34 ml/min/1.73 m2, respectively (P < 0.0001). In contrast, renal plasma flow and oncotic pressure were similar in the two groups (P = NS). A reduction in the density and size of endothelial fenestrae and subendothelial accumulation of fibrinoid deposits lowered glomerular hydraulic permeability in PET compared to controls, 1.81 versus 2.58 x 10(-9) m/sec/PA. Mesangial cell interposition also curtailed effective filtration surface area. Together, these changes lowered the computed single nephron Kf in PET below control, 4.26 versus 6.78 nl/min x mm Hg, respectively.

CONCLUSION

The proportionate (approximately 40%) depression of Kf for single nephrons and GFR suggests that hypofiltration in PET does not have a hemodynamic basis, but is a consequence of structural changes that lead to impairment of intrinsic glomerular ultrafiltration capacity.

Primary non-Hodgkin's lymphoma of the larynx in an AIDS patient

A case of primary non-Hodgkin's lymphoma of the larynx in an AIDS patient is presented with a review of the literature. Non-Hodgkin's lymphomas in AIDS patients are common but the primary laryngeal presentation is very rare. The symptoms usually include dysphonia and progressive airway obstruction requiring tracheostomy. As with laryngeal non-Hodgkin's laryngeal lymphomas in non-HIV positive patients the majority are of B cell lineage and respond well to radiotherapy. Our patient had a high grade lymphoma of B cell lineage which showed a good response to radiotherapy. The role of chemotherapy and surgery is not yet established. We suggest that the diagnosis of AIDS should not influence the management of these patients unless the individual is in the terminal disease stage.

Cholera in a developing megacity; Karachi, Pakistan

Despite rapid urbanization and increasing affluence in Karachi, cases of cholera are frequent. We analysed computerized isolation data from the AKUH Clinical Microbiology Laboratory, Karachi, from 1990-6 to examine microbiological, temporal and demographic trends in Vibrio cholerae infections. During this period 888 strains of V. cholerae (566 V. cholerae serogroup O1, and 204 V. cholerae serogroup O139) were isolated from specimens from 886 patients; 214/464 were adult inpatients, and 250/464 paediatric inpatients, the remaining 422 outpatients. Isolations peaked between June and August. Overlapping epidemics occurred in 1993 and 1994 of serogroup O1 (May to August), and serogroup O139 (August to October). All ages and social and economic strata were affected. Forty-four percent of all isolates were from children under the age of 5 years. The mean age of all patients with serogroup O1 infections was 19.6 years (+/-0.9) compared with 367 (+/-1.7) for serogroup O139 infections (P < 0.0001, t test). More than a quarter (27%) of all serogroup O1 isolates were from babies under 2 years of age. One patient had a serogroup O1 infection followed by a serogroup O139 infection 1 year later. Another patient was infected with serogroup O1 strains 5 years apart. Emergence of resistant strains was observed, but by 1996 serogroup O139 had disappeared. An aquatic organism, cholera nevertheless continues to take its toll in this city of 11 million situated in a desert.

The purB gene of Escherichia coli K-12 is located in an operon

The structural gene (purB) for succinyl-AMP (S-AMP) lyase and three additional ORFs are on the same DNA strand of the chromosome of Escherichia coli. Cassette mutagenesis and primer extension mapping demonstrated that purB is co-transcribed with an upstream gene (ORF23, or ycfC) encoding a 22.9 kDa membrane-associated protein of non-essential, but unknown, function unrelated to purine biosynthesis. The purB operon lies between phoP and an ORF expressing an essential function which may correspond to asuE (trmU). S-AMP lyase was purified to near homogeneity. The purified enzyme is a homotetramer of 50 kDa subunits, has a K(m) for S-AMP of 3.7 microM and a pH optimum of 7.4-7.6.

Medical students' contribution to the development of a smoke-free hospital policy in a university medical centre: a relevant learning experience

In a research methodology course, second-year medical students conducted a survey on 'Enforcing a Smoking Ban in the Soroka Medical Center: a Survey of Hospital Employees on Facilitating Factors and Obstacles'. They defined the study objectives and design, developed the study instrument, carried out the survey, coded and entered the data into mainframe computers, analysed the computer output, and prepared oral and written reports. The aims of the project were twofold: to survey employees' attitudes to a hospital smoking ban and to train medical students in the planning and conduct of a research project on public health or preventive medicine. Twelve students conducted a cross-sectional survey of 208 hospital employees (10% of the hospital staff). Employees were surveyed regarding smoking status, interest in quitting smoking, knowledge of the law banning smoking in public places, knowledge of the health effects of passive smoking, attitudes towards a hospital smoking ban and potential obstacles to its implementation. The students rated the course as excellent. They gained important research skills, as well as practical medical and public health experience through active participation in the design and execution of a study project with public health implications. At the first meeting of the hospital committee appointed to enforce a smoke-free hospital, the students' findings were reported in full, and their recommendations have guided policy decisions.

Violence against physicians

OBJECTIVE

To ascertain the incidence of violence against internists.

SETTING

A county-operated tertiary care center in Nassau County, New York.

DESIGN AND PARTICIPANTS

Questionnaires were distributed to 100 internal medicine residents and attending physicians. They were asked to report: whether they had ever been assaulted or battered either by patients or by relatives of patients; the point in their medical training at which such episodes had occurred; the nature and severity of the violent episodes; and the circumstances surrounding such episodes.

RESULTS

Questionnaires were returned by 63 physicians (response rate, 63%). Ten physicians (16% of the respondents) reported that they had been battered, three (5%) on multiple occasions. Twenty-six physicians (41%) reported that they had been assaulted, 15 (24%) on multiple occasions. The majority (54%) of violent episodes had been instigated either by intoxicated patients or by patients with psychiatric histories. In this small sample, no injury was reported.

CONCLUSIONS

Violence against medical residents and attending physicians exists and is most commonly associated with patients who are intoxicated or who have psychiatric histories.

Strain and cultivar specificity in the Agrobacterium-chickpea interaction

The susceptibility of four genotypes of chickpea to four wild strains of Agrobacterium tumefaciens was evaluated. Successful transformation was dependent on specific bacterial strain-plant cultivar interactions. Agropine strain A281 was the most effective for tumor induction. Tumors displayed hormone autonomous growth, were opine positive and contained DNA that was homologous to the T-DNA of the inciting strain.

Ca(2+)- and ATP-dependent reversible inactivation of pancreatic islet phosphoinositide-specific phospholipase C activity

Phosphoinositide-specific phospholipase C (PI-PLC) activity in whole homogenates of mouse pancreatic islets decreased 60-85% when the homogenates were incubated at 37 degrees C for 1 h in the presence of down to micromolar concentrations of Ca2+. Ca(2+)-induced inactivation was augmented by calmodulin, the phorbol ester 12-O-tetradecanoylphorbol 13-acetate in the presence of ATP-Mg, and by Mg2+. Inactivation was inhibited when ATP was removed and completely abolished by trifluoperazine and EGTA. Inactivation was not affected by the non-phosphorylating ATP analogue, AMP-PCP, GMP-PNP, glucose, Zn2+ or a series of protease inhibitors. These observations suggest that PI-PLC in broken cell preparations of pancreatic islets may be inactivated via phosphorylation by Ca(2+)-calmodulin-stimulated protein kinase and/or protein kinase C. Inactivation of PI-PLC was reversible. Reactivation started after approx. 2 h incubation, when the concentration of ATP in the homogenate was below 0.15 x 10(-6) M. PI-PLC activity returned to values approx. 25% higher than the initial values. PI-PLC inactivation via phosphorylation by the mentioned protein kinases may constitute a feedback control on the phosphoinositide response, attenuating subsequent diacylglycerol formation and/or Ca2+ mobilization by inositol trisphosphate.

Characteristics of phosphoinositide-specific phospholipase C activity from mouse pancreatic islets

In pancreatic islets the bulk of phosphoinositide-specific phospholipase C (PI-PLC) activity was cytosolic. The soluble enzyme was activated by submicromolar concentrations of Ca2+, independent of calmodulin. It was unaffected by glucose and a series of glycolytic intermediates, including glyceraldehyde 3-phosphate. These observations lend support to the hypothesis that glucose-stimulated inositol triphosphate production in islets may be secondary to and provoked by glucose-mediated Ca2+ influx. All four pyridine nucleotides stimulated PI-PLC. Phosphatidylinositol hydrolysis was also stimulated by dioleine and arachidonic acid, and by the polyamines, putrescine and spermine. Phosphatidylinositol hydrolysis was inhibited by chlorpromazine, tetracaine, ATP, 5'-AMP, inorganic pyrophosphate and by phosphatidylinositol 4,5-bisphosphate, phosphatidylcholine and phosphatidylserine--but not affected by phosphatidylethanolamine. The cyclic nucleotides, cAMP and cGMP had no effect on the enzyme, and GTP-gamma-S did not activate the enzyme event at very low Ca2+ concentrations. The diglyceride lipase inhibitor, RHC 80267, and the cyclooxygenase inhibitor, indomethacin, had no effect on PI-PLC activity.