643 Near-Peer Surgical Teaching for Junior Doctors: A 16-Month Retrospective Analysis

Introduction

Surgical departments across the UK are having to mitigate service demands, budget constraints and changes to work patterns with their statutory duty to provide high-quality training and education. Securing consultant-led teaching has also become increasingly difficult leading to the rise of near-peer teaching. We evaluate the long-term effectiveness of near-peer surgical teaching for junior doctors.

Method

We developed a rolling 12-week trainee-led didactic surgical education programme for Foundation doctors and Core Surgical Trainees. Junior doctors delivered teaching to peers with registrar input; session and supervision feedback was recorded using 5-point scales and free-text responses.

Results

42 junior doctors responded to our end-of-programme feedback surveys covering December 2018 to April 2020. The overall programme (8.83±1.08/10), relevance (4.62±0.58/5), presentation quality (4.60±0.50/5) and supervisor knowledge (4.81±0.40/5) were rated highly by respondents. Attendees also reported significant improvements in subject knowledge (3.72±0.92/5 to 4.50±0.56/5, P < 0.0001), clinical confidence, presentation and teaching skills.

Conclusions

Our near-peer teaching programme addressed the educational needs of junior doctors and developed their presentation and organisational skills. Supervision and input from registrars facilitated discussion and reinforced key concepts. The success of this programme highlights the role that trainees can play in designing, developing, and leading an effective surgical teaching programme.

Perioperative intravenous contrast administration and the incidence of acute kidney injury after major gastrointestinal surgery: prospective, multicentre cohort study

BACKGROUND

This study aimed to determine the impact of preoperative exposure to intravenous contrast for CT and the risk of developing postoperative acute kidney injury (AKI) in patients undergoing major gastrointestinal surgery.

METHODS

This prospective, multicentre cohort study included adults undergoing gastrointestinal resection, stoma reversal or liver resection. Both elective and emergency procedures were included. Preoperative exposure to intravenous contrast was defined as exposure to contrast administered for the purposes of CT up to 7 days before surgery. The primary endpoint was the rate of AKI within 7 days. Propensity score-matched models were adjusted for patient, disease and operative variables. In a sensitivity analysis, a propensity score-matched model explored the association between preoperative exposure to contrast and AKI in the first 48 h after surgery.

RESULTS

A total of 5378 patients were included across 173 centres. Overall, 1249 patients (23·2 per cent) received intravenous contrast. The overall rate of AKI within 7 days of surgery was 13·4 per cent (718 of 5378). In the propensity score-matched model, preoperative exposure to contrast was not associated with AKI within 7 days (odds ratio (OR) 0·95, 95 per cent c.i. 0·73 to 1·21; P = 0·669). The sensitivity analysis showed no association between preoperative contrast administration and AKI within 48 h after operation (OR 1·09, 0·84 to 1·41; P = 0·498).

CONCLUSION

There was no association between preoperative intravenous contrast administered for CT up to 7 days before surgery and postoperative AKI. Risk of contrast-induced nephropathy should not be used as a reason to avoid contrast-enhanced CT.

Modulation of angiogenic and inflammatory response in glioblastoma by hypoxia

Glioblastoma are rapidly proliferating brain tumors in which hypoxia is readily recognizable, as indicated by focal or extensive necrosis and vascular proliferation, two independent diagnostic criteria for glioblastoma. Gene expression profiling of glioblastoma revealed a gene expression signature associated with hypoxia-regulated genes. The correlated gene set emerging from unsupervised analysis comprised known hypoxia-inducible genes involved in angiogenesis and inflammation such as VEGF and BIRC3, respectively. The relationship between hypoxia-modulated angiogenic genes and inflammatory genes was associated with outcome in our cohort of glioblastoma patients treated within prospective clinical trials of combined chemoradiotherapy. The hypoxia regulation of several new genes comprised in this cluster including ZNF395, TNFAIP3, and TREM1 was experimentally confirmed in glioma cell lines and primary monocytes exposed to hypoxia in vitro. Interestingly, the cluster seems to characterize differential response of tumor cells, stromal cells and the macrophage/microglia compartment to hypoxic conditions. Most genes classically associated with the inflammatory compartment are part of the NF-kappaB signaling pathway including TNFAIP3 and BIRC3 that have been shown to be involved in resistance to chemotherapy.

Our results associate hypoxia-driven tumor response with inflammation in glioblastoma, hence underlining the importance of tumor-host interaction involving the inflammatory compartment.

Preferential migration of regulatory T cells mediated by glioma-secreted chemokines can be blocked with chemotherapy

Despite the immunogenicity of glioblastoma multiforme (GBM), immune-mediated eradication of these tumors remains deficient. Regulatory T cells (Tregs) in the blood and within the tumor microenvironment of GBM patients are known to contribute to their dismal immune responses. Here, we determined which chemokine secreted by gliomas can preferentially induce Treg recruitment and migration. In the malignant human glioma cell lines D-54, U-87, U-251, and LN-229, the chemokines CCL22 and CCL2 were detected by intracellular cytokine analysis. Furthermore, tumor cells from eight patients with GBM had a similar chemokine expression profile. However, only CCL2 was detected by enzyme-linked immunosorbent assay, indicating that CCL2 may be the principal chemokine for Treg migration in GBM patients. Interestingly, the Tregs from GBM patients had significantly higher expression levels of the CCL2 receptor CCR4 than did Tregs from healthy controls. Glioma supernatants and the recombinant human chemokines CCL2 and CCL22 induced Treg migration and were blocked by antibodies to the chemokine receptors. Production of CCL2 by glioma cells could also be mitigated by the chemotherapeutic agents temozolomide and carmustine [3-bis (2-chloroethyl)-1-nitrosourea]. Our results indicate that gliomas augment immunosuppression by selective chemokine-mediated recruitment of Tregs into the tumor microenvironment and that modulating this interaction with chemotherapy could facilitate the development of novel immunotherapeutics to malignant gliomas.

Immunological responses in a patient with glioblastoma multiforme treated with sequential courses of temozolomide and immunotherapy: case study

Cytotoxic chemotherapy that induces lymphopenia is predicted to ablate the benefits of active antitumor immunization. Temozolomide is an effective chemotherapeutic agent for patients with glioblastoma multiforme, but it induces significant lymphopenia. Although there is monthly fluctuation of the white blood cell count, specifically the CD4 and CD8 counts, there was no cumulative decline in the patient described in this case report. Depriving patients of this agent, in order to treat with immunotherapy, is controversial. Despite conventional dogma, we demonstrated that chemotherapy and immunotherapy can be delivered concurrently without negating the effects of immunotherapy. In fact, the temozolomide-induced lymphopenia may prove to be synergistic with a peptide vaccine secondary to inhibition of regulatory T cells or their delayed recovery.

A novel small molecule inhibitor of signal transducers and activators of transcription 3 reverses immune tolerance in malignant glioma patients

Overcoming the profound immunosuppression in patients with solid cancers has impeded efficacious immunotherapy. Signal transducers and activators of transcription 3 (STAT3) has recently emerged as a potential target for effective immunotherapy, and in this study, we describe a novel small molecule inhibitor of STAT3 that can penetrate the central nervous system (CNS) in mice and in physiologically relevant doses in vitro and reverse tolerance in immune cells isolated from glioblastoma multiforme (GBM) patients. Specifically, it induces the expression of costimulatory molecules on peripheral macrophages and tumor-infiltrating microglia, stimulates the production of the immune-stimulatory cytokines interleukin 2 (IL-2), IL-4, IL-12, and IL-15, and induces proliferation of effector T cells from GBM patients that are refractory to CD3 stimulation. We show that the functional enhancement of immune responses after STAT3 inhibition is accompanied by up-regulation of several key intracellular signaling molecules that critically regulate T-cell and monocyte activation. Specifically, the phosphorylation of Syk (Tyr352) in monocytes and ZAP-70 (Tyr319) in T cells are enhanced by the STAT-3 inhibitor in marked contrast to toll-like receptor and T-cell receptor agonists, respectively. This novel small molecule STAT3 inhibitor has tremendous potential for clinical applications with its penetration into the CNS, easy parental administration, direct tumor cytotoxicity, and potent immune adjuvant responses in immunosuppressed cancer patients.

Listeria-based vaccines can overcome tolerance by expanding low avidity CD8+ T cells capable of eradicating a solid tumor in a transgenic mouse model of cancer

We have created a transgenic mouse with tissue-specific expression of the human papilloma virus (HPV) 16 E6 and E7 oncoproteins in the thyroid as a model of HPV transformed cancer. The expression of the transgenes results in the formation of palpable thyroid tumors. E7 is not expressed in other tissues but is expressed in medullary thymic epithelial cells, which have been implicated in the control of negative selection. We show that Listeria-based vaccines against E7 can induce the regression of solid implanted tumors in the transgenic mice, although at a lower frequency than in wild type (WT) mice. E7-specific CD8+ T cells induced in transgenic mice are of both lower avidity and lower frequency when compared to the WT mice. In this model, Listeria-based vaccines against E7 appear to be overcoming central tolerance by expanding low avidity CD8+ T cells specific for E7 that are not deleted during thymopoesis and can eliminate solid tumors.

Clinical characteristics of pulmonary tuberculosis in adult Pakistani patients with co-existing diabetes mellitus

A review was made of the records of all patients with pulmonary tuberculosis and diabetes mellitus admitted over a 5-year period to a teaching hospital in Karachi, Pakistan. Among 42358 patients, the total number with both tuberculosis and diabetes was 173. The prevalence of tuberculosis in diabetic patients was 10-times higher than in non-diabetic patients and prevalence increased with duration of diabetes. The lower lung field was most frequently involved, followed by the upper and middle. Bilateral involvement was seen in half and an associated pleural effusion in one-third of the patients. Cavitating lesions were seen in 32% of men and 15% of women.

The role of human glioma-infiltrating microglia/macrophages in mediating antitumor immune responses

Little is known about the immune performance and interactions of CNS microglia/macrophages in glioma patients. We found that microglia/macrophages were the predominant immune cell infiltrating gliomas ( approximately 1% of total cells); others identified were myeloid dendritic cells (DCs), plasmacytoid DCs, and T cells. We isolated and analyzed the immune functions of CD11b/c+CD45+ glioma-infiltrating microglia/macrophages (GIMs) from postoperative tissue specimens of glioma patients. Although GIMs expressed substantial levels of Toll-like receptors (TLRs), they did not appear stimulated to produce pro-inflammatory cytokines (tumor necrosis factor alpha, interleukin 1, or interleukin 6), and in vitro, lipopolysaccharides could bind TLR-4 but could not induce GIM-mediated T-cell proliferation. Despite surface major histocompatibility complex class II expression, they lacked expression of the costimulatory molecules CD86, CD80, and CD40 critical for T-cell activation. Ex vivo, we demonstrate a corresponding lack of effector/activated T cells, as glioma-infiltrating CD8+ T cells were phenotypically CD8+CD25-. By contrast, there was a prominent population of regulatory CD4 T cells (CD4+CD25+FOXP3+) infiltrating the tumor. We conclude that while GIMs may have a few intact innate immune functions, their capacity to be stimulated via TLRs, secrete cytokines, upregulate costimulatory molecules, and in turn activate antitumor effector T cells is not sufficient to initiate immune responses. Furthermore, the presence of regulatory T cells may also contribute to the lack of effective immune activation against malignant human gliomas.

Innate immune functions of microglia isolated from human glioma patients

Background

Innate immunity is considered the first line of host defense and microglia presumably play a critical role in mediating potent innate immune responses to traumatic and infectious challenges in the human brain. Fundamental impairments of the adaptive immune system in glioma patients have been investigated; however, it is unknown whether microglia are capable of innate immunity and subsequent adaptive anti-tumor immune responses within the immunosuppressive tumor micro-environment of human glioma patients. We therefore undertook a novel characterization of the innate immune phenotype and function of freshly isolated human glioma-infiltrating microglia (GIM).

Methods

GIM were isolated by sequential Percoll purification from patient tumors immediately after surgical resection. Flow cytometry, phagocytosis and tumor cytotoxicity assays were used to analyze the phenotype and function of these cells.

Results

GIM expressed significant levels of Toll-like receptors (TLRs), however they do not secrete any of the cytokines (IL-1β, IL-6, TNF-α) critical in developing effective innate immune responses. Similar to innate macrophage functions, GIM can mediate phagocytosis and non-MHC restricted cytotoxicity. However, they were statistically less able to mediate tumor cytotoxicity compared to microglia isolated from normal brain. In addition, the expression of Fas ligand (FasL) was low to absent, indicating that apoptosis of the incoming lymphocyte population may not be a predominant mode of immunosuppression by microglia.

Conclusion

We show for the first time that despite the immunosuppressive environment of human gliomas, GIM are capable of innate immune responses such as phagocytosis, cytotoxicity and TLR expression but yet are not competent in secreting key cytokines. Further understanding of these innate immune functions could play a critical role in understanding and developing effective immunotherapies to malignant human gliomas.

Immunotherapy for human glioma: innovative approaches and recent results

The outcome for malignant glioma patients remains dismal despite treatment with surgical resection, radiation and chemotherapy. The goal of immunotherapy is to eradicate or suppress the residual infiltrative component of these tumors. Although there is clinical evidence for cell-mediated antiglioma activity, there are special considerations that need to be accounted for in the design of immunotherapeutics for CNS tumors, such as possible differences in antigen-presenting cells, trafficking of effector T-cells and immunosuppression. Previously characterized immunosuppression in glioma patients has included low peripheral blood lymphocyte counts, reduced delayed type hypersensitivity reactions to recall antigens, impaired mitogen-induced blastogenic responses by peripheral blood mononuclear cells, increased CD8+ suppressor T-cells, decreased CD4+ T-cell activity in vitro, diminished immunoglobulin synthesis by B-cells and impaired transmembrane signaling through the T-cell receptor/CD3 complex. Recent impairments that are being identified include anergy, failure of costimulation, lack of sufficient numbers of functional effector T-cells and the presence of T-suppressor cells within the tumor microenvironment. It is proposed that these inherent problems will need to be overcome in order for immunotherapies to realize their potential. Paradoxically, the efficacy of recent clinical immunotherapies for glioma patients appears equivalent to that seen in other cancer immunotherapeutic approaches. This review will provide an overview of the juxtaposition of the immune system and CNS, and will discuss the most recent and ongoing immunotherapeutic clinical trials that are demonstrating promising results.

Medical interns knowledge of TB in Pakistan

Of 460 interns from five Pakistani teaching hospitals surveyed, only 22% correctly identified the estimated number of new TB cases in Pakistan. The majority (96%) knew that droplet infection was the usual mode of transmission. Only 38% considered sputum smears for acid-fast bacilli as the best test for diagnosis of pulmonary TB and 43.5% for follow-up during TB treatment. The recommended four-drug anti-TB regimen was prescribed by 56.5% in the initiation phase and the recommended two-drug combination in the continuation phase by 52%. Most interns (82%) were unable to identify a single component of directly observed treatment short course (DOTS) strategy. Our study reflects poor awareness of and low compliance to the World Health Organization/National Tuberculosis Programme guidelines among interns. For effective control of TB, immediate action to improve undergraduate and continuing medical education is essential, with special emphasis on national guidelines.

Smoking prevalence, knowledge and attitudes among medical students in Karachi, Pakistan

A survey of smoking prevalence and attitudes was made among medical students randomly selected from classes at the Aga Khan University, Karachi, Pakistan. Of 271 respondents, 14.4% were current smokers (22.0% male and 3.8% females) and 3.3% ex-smokers. A majority of students recognized the dangers associated with active as well as passive smoking although only 55% of current smokers planned to quit in the near future. Most smokers (96%) believed that they as well as other health professionals needed training on smoking cessation and 95% of all students believed that doctors should play a role model in smoking cessation by not smoking themselves. Specific training and counselling should be a part of the required curriculum at medical schools.

Trends in hospital-based management of acute asthma from a teaching hospital in South Asia

The aim of this study is to evaluate the hospital-based management of acute asthma in south Asia and to compare practices over a 10-year period. Adult patients (n = 102) admitted at a teaching hospital with acute asthma were studied. Documentation of precipitating factors, family history and physical signs were inadequate in more than half of patients. Pulse oximetry was documented in 95 (93%) patients, but peak flow monitoring was performed only in 50 (49%) patients. Ten-year trend showed deterioration in history and physical examination skills, under use of peak flow readings, and poor pre-discharge instructions. Some aspects of improved care included frequent use of pulse oximeter, preference of inhaled over systemic bronchodilators and increased use of systemic steroids. Significant deficiencies were identified in hospital-based management of acute asthma. Most aspects of asthma care continued to fall short of asthma guidelines.

What is needed for effective antitumor immunotherapy? Lessons learned using Listeria monocytogenes as a live vector for HPV-associated tumors

As a vaccine vector, Listeria monocytogenes targets the innate immune system, resulting in a cytokine response that enhances antigen-presenting cell function as well as inducing a Th1 profile. It also enhances cell-mediated immunity by targeting antigen delivery in antigen-presenting cells to both the MHC class I pathway of exogenous presentation that activates CD8 T cells and the MHC class II pathway that processes antigen endogenously and presents it to CD4 T cells. In this review, we describe the development of vaccine constructs that target the human papillomavirus 16 (HPV-16) E7 antigen, and we characterize their effects on tumor regression as well as various immune parameters both innate and adaptive. In particular, we describe the effect on tumor angiogenesis, induction of antitumor suppressor factors like CD4+CD25+ T cells and regulatory cytokines TGF-beta and IL-10, homing and infiltration of antigen-specific CD8+ T cells to the tumor, and also effects of the vaccines on antigen-presenting cells, especially focusing on dendritic cell maturation and ability to influence tumor regression. We believe that the identification of several immune parameters that correlate with antitumor efficacy, and of some that have a negative correlation, may have wider application for other cancer immunotherapeutic approaches.

CD4+CD25+ regulatory T cells that secrete TGFbeta and IL-10 are preferentially induced by a vaccine vector

CD4CD25 T cells generated in a vaccine scenario can play a critical role in limiting antitumor therapy, thus having widespread implications for the immunotherapy-based treatment of cancer. The authors previously used Listeria monocytogenes to develop two vaccine constructs that express HPV-16 E7 protein and induce strong cellular immunity to HPV-E7-expressing tumors. Immunization of mice bearing established E7-expressing tumors with Lm-LLO-E7 induced regression of the tumors, whereas Lm-E7 showed little or no tumor regression. To investigate the possibility that regulatory CD4CD25 T-cell populations may be responsible for the differences in tumor regression, the authors characterized the role of these cells generated by the two vaccine systems. The authors compared the prevalence of CD4CD25 T cells in tumor-bearing vaccinated mice and demonstrate that Lm-E7-vaccinated mice have significantly increased numbers of CD4CD25 T cells in both the spleen and tumor-infiltrating lymphocytes compared with Lm-LLO-E7-vaccinated mice. The authors confirm that these increased numbers of CD4CD25 T cells are indeed suppressor in function by in vitro suppression assays and that the mechanism of action of the tumor-infiltrating cells involves the production of suppressor cytokines interleukin-10 and transforming growth factor beta. These results show that it is possible for a tumor vaccine system to generate tumor-infiltrating CD4CD25 regulatory T cells that critically affect tumor regression and the overall success of vaccine therapy.

Massive pleural effusion and marked increase of CA-125

The tumour associated CA-125 antigen is widely used in monitoring ovarian carcinoma. In women with a massive pleural effusion and ascites, markedly increased CA-125 levels may lead to an erroneous diagnosis of ovarian cancer. Very high levels of tumour markers may be present in patients with benign pleural effusion, ascites, and chronic liver disease. Raised levels of tumour markers in serum or pleural fluid, in the absence of positive cytology, should be interpreted with caution.

The Ability of TwoListeria monocytogenesVaccines Targeting Human Papillomavirus-16 E7 to Induce an Antitumor Response Correlates with Myeloid Dendritic Cell Function

Previous work from our laboratory has shown that Lm-LLO-E7 induces complete regression of approximately 75% of established TC-1 tumors, whereas Lm-E7 only slows the growth of such tumors. In this study, we examine the effects of Lm-LLO-E7 vs Lm-E7 on APCs. We hypothesize that the difference in antitumor efficacy of the two vaccines is due to the ability of each of these vectors to render immature dendritic cells (DCs) effective APCs in terms of MHC class II or costimulatory molecule expression. We also examine the ability of these vectors to stimulate cytokine production by DCs. Both vectors induced IL-12 and TNF-alpha, but only Lm-LLO-E7 induced IL-2 production by DCs. Lm-LLO-E7 also induced significantly higher levels of MHC class II molecules, CD40, and B7 costimulatory molecules (CD86, B7-H1, and B7-DC) on DCs than Lm-E7. Interestingly, a shift of CD11c(+) cells from CD86(low) to CD86(high) is observed post-Lm-LLO-E7 infection. A similar shift is also observed for B7-H1 and B7-DC molecules. Moreover, Lm-LLO-E7, but not Lm-E7-pulsed DCs, stimulate naive T cell proliferation. These results indicate that Lm-LLO-E7 is more effective than Lm-E7 at inducing DC maturation. This effect is independent of the E7 Ag, because Lm-LLO-NP, and a mixture of Lm-LLO-NP and Lm-E7 induce the same changes in DC phenotype as Lm-LLO-E7. Taken together, the changes in DC expression correlate well with the differences in antitumor efficacy between these two vaccines.

Asthma management by general practitioners in Pakistan

SETTING

Teaching university hospital in Karachi, Pakistan.

OBJECTIVES

Asthma management guidelines have been developed to assist practising physicians in treating asthma patients. The objective of this study was to evaluate if the prescribing habits of practitioners in Karachi were consistent with the published asthma guidelines.

DESIGN

A questionnaire survey was conducted among practitioners attending a pulmonary continuing medical education (CME) programme. Three case scenarios of asthma were given, and the doctors were asked to write a prescription for each case. Doctors were asked about their views on inhaler therapy and dietary restrictions in asthma.

RESULTS

Of 120 doctors, 100 (83%) responded. Thirty different regimens of short acting beta2-agonist and 16 regimens of steroid therapy were prescribed by the practitioners. Only 35% of the doctors prescribed corticosteroids for persistent asthma symptoms. The great majority of doctors were not aware of treatment options for persistent symptoms despite the use of preventive therapy (8% prescribed long-acting beta2-agonists, 6% high-dose inhaled corticosteroids and 13% theophyllines). Misconceptions about inhaler therapy and diet were found in 20 and 50 doctors, respectively.

CONCLUSION

General practitioners in Pakistan did not follow asthma management guidelines. There was serious lack of knowledge about asthma medications coupled with misconceptions about inhaler therapy and dietary factors.

Clinical characteristics of 110 miliary tuberculosis patients from a low HIV prevalence country

SETTING

A university teaching hospital in Karachi, Pakistan.

OBJECTIVE

To define the clinical characteristics and outcome of miliary tuberculosis (TB) patients from a low human immunodeficiency virus (HIV) prevalence country.

DESIGN

Review of adult miliary TB patients admitted between 1994 and 2001. Clinical characteristics of those dying from miliary TB were compared with those of the survivors.

RESULTS

Most of the 110 cases reviewed were middle aged or elderly, with a female preponderance. An underlying medical condition was present in 47%. Presenting symptoms were of several weeks' duration, and mostly constitutional (fever and weight loss). Common laboratory findings included anaemia (62%), lymphopaenia (71%), hyponatraemia (74%), elevated serum alkaline phosphatase (57%) and hypoalbuminaemia (92%). Typical miliary pattern was observed in 77% of radiographs. Sputum smear and culture were positive in respectively 36% and 52% of those tested. Biopsy was performed in selected patients. Mean hospital stay was 8.8 days, and mortality was 30%. Those who died were significantly older than survivors and had a more fulminant course. Presence of altered mental status, lung crackles, leucocytosis, thrombocytopaenia and the need for ventilation were associated with increased mortality.

CONCLUSION

Miliary TB carries a high mortality. It should be considered in patients who present with prolonged systemic symptoms. A positive TB culture or biopsy is needed to establish a diagnosis.

Tuberculosis diagnosis and treatment practices of private physicians in Karachi, Pakistan

In a densely populated urban area of Karachi, Pakistan, a questionnaire survey was made of the knowledge and practices of 120 private general practitioners about the diagnosis and treatment of tuberculosis (TB). The majority knew that cough, fever and weight loss were the main symptoms of TB, but less than half knew that blood in sputum, poor appetite and chest pain were associated with the disease. Only 58.3% of physicians used sputum microscopy for diagnosing TB and 35.0% used it as a follow-up test. Only 41.7% treated TB patients themselves, the remaining referring their patients to specialists. Around 73.3% of the doctors were aware of the 4 first-line anti-TB drugs. Efforts to improve the knowledge of private practitioners, and strategies to enhance public-private collaboration forTB control in urban areas are urgently required.

Overnight home oximetry: can it identify patients with obstructive sleep apnea-hypopnea who have minimal daytime sleepiness?

BACKGROUND

Overnight home oximetry is being widely used as a case selection technique for patients with suspected obstructive sleep apnea-hypopnea (OSAH). In the absence of excessive daytime sleepiness (EDS), patients with snoring and/or witnessed apnea are considered to have low probability of OSAH.

METHODS

Patients suspected to have OSAH, who denied EDS, and had a normal overnight home oximetry were studied by polysomnography for presence of significant OSAH (apnea/hypopnea index (AHI) > 15/h).

RESULTS

Twelve (40%) of the 30 patients studied had significant OSAH. All had a 2% oxygen desaturation index of less than 10/h. The sensitivity of oximetry increased at lower desaturation indices butthis was associated with decreased specificity. Review of oximetry waveform pattern, by experienced physicians, did not improve the diagnostic accuracy. Combining oximetry with a clinical prediction rule would have reduced the need for polysomnography by 30%.

CONCLUSION

Many patients, who present with snoring and/or witnessed apnea and are referred to a sleep disorder clinic for suspected OSAH, may have significant OSAH even if they deny EDS. Overnight home oximetry did not help discriminate between those patients with or without OSAH.

Is there a value of mantoux test and erythrocyte sedimentation rate in pre-employment screening of health care workers for tuberculosis in a high prevalence country?

SETTING

Pre-employment screening of health care workers (HCWs) is practiced widely. Research needs to be carried out to evaluate the screening procedure in developing countries.

OBJECTIVE

To evaluate the efficacy of Mantoux test and erythrocyte sedimentation rate (ESR) for the diagnosis of active tuberculosis (TB), in pre-employment screening of HCWs, in a high prevalence country.

DESIGN

Pre-employment screening of all new employees was reviewed from June to September 2000. The screening consisted of history, physical examination, blood and urine tests, Mantoux test and a chest radiograph. Patients with clinical, laboratory or radiological features suggestive of active TB were referred to a specialist.

RESULTS

Out of 207 employees, a Mantoux reaction of > or = 10 mm and ESR of > or = 25 mm/first hour was noted in 90 (43.5%) and 21 (10.1%), respectively. One person had symptoms suggestive of TB and was already on anti-tuberculosis therapy at the time of screening. All other employees were asymptomatic. Based on radiographic findings, four (2%) cases were referred and one was given anti-tuberculosis therapy. An additional 48 (23.1%) employees were referred on the basis of positive Mantoux or elevated ESR; none were found to have active TB.

CONCLUSION

In high prevalence countries use of Mantoux test and ESR in pre-employment screening of HCWs is not recommended for detection of active TB.

A hospital based preliminary report on sleep disordered breathing in Pakistani population

BACKGROUND

Sleep Disordered Breathing is an important medical condition leading to significant morbidity and mortality. Western studies have shown its prevalence in middle age to be 9% in women and 24% in men. The aim of this study was to have a preliminary assessment on the frequency of Sleep Disordered Breathing in Pakistani subjects.

METHOD

Patients attending a medical clinic were surveyed. A sleep questionnaire elicited information about snoring, witnessed apnea, nocturnal choking and excessive daytime sleepiness. Data were recorded for age, height, collar size and weight. Epworth Sleepiness Scale was used to assess excessive daytime sleepiness. Statistical analysis was by chi square test, t-test and Fisher's exact test. A p-value less than 0.05 was considered significant.

RESULTS

A total of 123 subjects (M:F = 2:1) were included in the study. The frequency of snoring was found to be 46%. Snoring with apnoea was reported in 7% and snoring with apnoea and excessive daytime sleepiness in 3%. Snorers were more obese (p < 0.001), older (p < 0.003), with higher body mass index (p < 0.001) and larger collar size (p < 0.006) than non-snorers. Hypertension was more common in patients with sleep disordered breathing (35%) as compared to those without (16%).

CONCLUSIONS

This is the first preliminary data on sleep disordered breathing from Pakistan that reflects that the prevalence is similar to that seen in the West. The risk factors and association with hypertension are also comparable.

Differential SLP-76 expression and TCR-mediated signaling in effector and memory CD4 T cells

We present in this study novel findings on TCR-mediated signaling in naive, effector, and memory CD4 T cells that identify critical biochemical markers to distinguish these subsets. We demonstrate that relative to naive CD4 T cells, memory CD4 T cells exhibit a profound decrease in expression of the linker/adapter molecule SLP-76, while effector T cells express normal to elevated levels of SLP-76. The reduced level of SLP-76 is memory CD4 T cells is coincident with reduced phosphorylation overall, yet the residual SLP-76 couples to a subset of TCR-associated linker molecules, leading to downstream mitogen-activated protein (MAP) kinase activation. By contrast, effector CD4 T cells strongly phosphorylate SLP-76, linker for activation of T cells, and additional Grb2-coupled proteins, exhibit increased associations of SLP-76 to phosphorylated linkers, and hyperphosphorylate downstream Erk1/2 MAP kinases. Our results suggest distinct coupling of signaling intermediates to the TCR in naive, effector, and memory CD4 T cells. Whereas effector CD4 T cells amplify existing TCR signaling events accounting for rapid effector responses, memory T cells engage fewer signaling intermediates to efficiently link TCR triggering directly to downstream MAP kinase activation.

Heterogeneity of the memory CD4 T cell response: persisting effectors and resting memory T cells

Defining the cellular composition of the memory T cell pool has been complicated by an inability to distinguish effector and memory T cells. We present here an activation profile assay, using anti-CD3 and antigenic stimuli, that clearly distinguishes effector and memory CD4 T cells and defines subsets of long-lived memory CD4 T cells based on CD62 ligand (CD62L) expression. The CD62L(low) memory subset functionally resembles effector cells, exhibiting hyper-responsiveness to antigenic and anti-CD3 mediated stimuli, high proliferative capacity, and rapid activation kinetics. The CD62L(high) memory subset functionally resembles resting memory cells, exhibiting hyporesponsiveness to anti-CD3 stimuli, lower proliferative capacity, and slower activation kinetics. Our results indicate that the memory CD4 T cell pool is heterogeneous, consisting of persisting effectors and resting memory T cells.

[Atypical endometrial hyperplasia. Prognosis and course]

The treatment of patients with the diagnosis atypical endometrial hyperplasia has been disputed during the last decades. The aim of the study was to evaluate the treatment of these patients and analyse the progression rate to invasive carcinoma of the endometrium. Fifty-seven patients with atypical hyperplasia were examined and treated from 1976 through 1991. The medical records were examined retrospectively and the pathology slides were revised by one pathologist in accordance with the 1975 WHO recommendations. Thirty-one (54%) patients were on oestrogen treatment as monotherapy at the time of diagnosis. Forty-two patients had a hysterectomy performed within five months, and five patients had a hysterectomy performed 10 to 61 months after diagnosis. A total of 18 out of 57 patients (31.6%) had or developed endometrial carcinoma all with myometrial invasion: 14 stage I with < or = 50% myometrial invasion, three stage I with > 50% myometrial invasion, and one stage IV. There was no significant difference in age, body mass index, parity or hormone replacement treatment between the group with endometrial carcinoma and the group without endometrial carcinoma. We conclude that unopposed oestrogen treatment and nulliparity are the main risk factors for atypical hyperplasia and that hysterectomy is the appropriate treatment for patients with atypical hyperplasia of the endometrium.

Pneumothorax: a review of 146 adult cases admitted at a university teaching hospital in Pakistan

OBJECTIVE

There is a lack of data on the etiology and outcome of pneumothorax among the Pakistani population. Our aim was to review the etiology, clinical course, management and outcome of patients presenting with pneumothorax.

PATIENTS AND METHODS

All adult cases with pneumothorax admitted to a University Teaching Hospital in Karachi, between January 1992 and June 1996, were reviewed and analyzed.

RESULTS

A total of 146 patients were reviewed. Their mean age was 46.3 years (SD +/- 17.8 years) with a male to female ratio of 3.7:1. Secondary pneumothorax was the commonest type seen (45%), followed by traumatic (21%), iatrogenic (18%) and primary (16%). Tuberculosis (47%) and COPD (45%) were most common lung diseases associated with secondary pneumothorax. Pneumothorax secondary to TB presented at an earlier age than that with COPD (49.6 vs. 60.1 years). Similarly, patients with primary pneumothorax were significantly younger than patients with secondary pneumothorax (42.3 vs. 51.7 years). Rib fracture was the most common cause of traumatic pneumothorax. Coronary artery bypass grafting, transthoracic fine needle aspiration and neck vein cannulations were the leading iatrogenic causes. The commonest symptoms of pneumothorax were dyspnea (68%) and chest pain (40%). Most cases (81%) were successfully managed by intercostal tube drainage.

CONCLUSION

In our study population, secondary pneumothorax was the commonest variety seen. TB was the commonest cause of secondary pneumothorax, closely followed by COPD. Nearly 40% of pneumothorax were either traumatic or iatrogenic. Intercostal tube drainage remains the treatment of choice for pneumothorax.

Effector CD4 T Cells Are Biochemically Distinct from the Memory Subset: Evidence for Long-Term Persistence of Effectors In Vivo

Memory T cell responses are believed to be mediated by long-lived memory T cells that arise directly from a subset of short-lived, activated effector T cells that have reverted to the resting state. Although widely accepted, definitive proof that memory T cells arise from effectors is lacking because of the inability to reliably distinguish these subsets based on known phenotypic or functional parameters. We have used a biochemical approach to distinguish effector and memory CD4 T cell subsets and follow the differentiative fate of effector cells in vivo. When examined biochemically, effector and memory CD4 T cells are strikingly distinct and exhibit qualitative and quantitative differences in tyrosine phosphorylation. These effector-specific patterns were identical in effectors derived either from naive CD4 T cells (primary effectors) or memory CD4 T cells (memory effectors). To monitor the fate of effector cells in vivo, Ag-activated CD4+ TCR-transgenic T cells were transferred into irradiated BALB/c mice. These TCR-transgenic CD4 T cells persisted in adoptive hosts for several months, gave a recall response to Ag, yet exhibited effector-specific biochemical profiles. These results suggest that a subset of effector CD4 T cells can persist in vivo and contribute to long-term immunity by mediating secondary immune responses.

Effector CD4 T cells are biochemically distinct from the memory subset: evidence for long-term persistence of effectors in vivo

Memory T cell responses are believed to be mediated by long-lived memory T cells that arise directly from a subset of short-lived, activated effector T cells that have reverted to the resting state. Although widely accepted, definitive proof that memory T cells arise from effectors is lacking because of the inability to reliably distinguish these subsets based on known phenotypic or functional parameters. We have used a biochemical approach to distinguish effector and memory CD4 T cell subsets and follow the differentiative fate of effector cells in vivo. When examined biochemically, effector and memory CD4 T cells are strikingly distinct and exhibit qualitative and quantitative differences in tyrosine phosphorylation. These effector-specific patterns were identical in effectors derived either from naive CD4 T cells (primary effectors) or memory CD4 T cells (memory effectors). To monitor the fate of effector cells in vivo, Ag-activated CD4+ TCR-transgenic T cells were transferred into irradiated BALB/c mice. These TCR-transgenic CD4 T cells persisted in adoptive hosts for several months, gave a recall response to Ag, yet exhibited effector-specific biochemical profiles. These results suggest that a subset of effector CD4 T cells can persist in vivo and contribute to long-term immunity by mediating secondary immune responses.

Prevalence of pulmonary tuberculosis on the roof of the world

SETTING

The Shimshal Valley, a remote village in Northern Pakistan, is one of the seven Pamirs of Central Asia, widely known as the roof of the world.

OBJECTIVE

To investigate the prevalence of pulmonary tuberculosis (TB) in the Shimshal Valley.

DESIGN

The Rapid Village Survey Method (RVS) was used to investigate the prevalence of pulmonary tuberculosis. The selection criteria were chronic cough, hemoptysis, past history of TB and close contact with a tuberculous patient. After clinical examination, a chest radiograph was done and a single spot sputum sample was obtained for smear examination.

RESULTS

The total population of the village was 1077, of whom 231 cases were studied. Overcrowding affected 75% of the study population. The prevalence of smear positive pulmonary TB in the village studied was 554 per 100000 population, and the prevalence of active smear-negative TB was estimated at 1949/100 000. The prevalence of active pulmonary TB increased with age and the only risk factor for active TB was age over 45 years. Of the 21 cases with a past history of pulmonary TB, only 38% had completed a full course of chemotherapy.

CONCLUSION

Pulmonary TB is a very serious health issue in the rural community (Shimshal Valley) of Pakistan. This study highlights the lack of efficacy of national tuberculosis control programs in the country.

Role of fibreoptic bronchoscopy in the management of immunocompromised patients with pulmonary infiltrates

Immunocompromised patients are prone to develop various pulmonary complications. The range of diagnostic possibilities is wide, infection being the commonest cause. Non-invasive diagnostic tests are often unrewarding. In this study, we have evaluated the diagnostic efficacy and safety of fibreoptic bronchoscopy in immunocompromised patients with pulmonary infiltrates. Patients tolerated the procedure well. This technique identified the etiology in up tp 75% of cases. After treatment based on the result of bronchoscopy, 63% patients improved and were discharged.

Attitudes of Asian medical students towards smoking

BACKGROUND

There have been numerous studies on smoking habits among young adults in developed countries. Similar data from developing countries are scanty.

METHODS

A survey of medical students from one of the medical colleges in Pakistan assessed their smoking habits and attitudes towards smoking. In June 1993 a coded survey questionnaire was sent to each medical student at The Aga Khan Medical University in Karachi requesting data on their smoking habits, their attitudes towards smoking in various areas of the hospital, and their views about passive smoking and tobacco publicity.

RESULTS

Of 324 medical students, 89% responded of whom 11% were current smokers. The incidence of smoking was greater among male students than females (17% versus 4%). The average age of initiation of smoking was 17 years and the major influence was friends. There was an increased awareness of harmful effects of smoking among medical students. Almost all felt that passive smoking was injurious to health.

CONCLUSION

The prevalence of current smokers among Asian medical students was found to be 11%. Females smoked less than their male counterparts. There has been an increased awareness of the hazards of passive smoking among the medical students and most were in favour of legislative actions to discourage tobacco advertising.

Hot flushes in men with pituitary adenoma

BACKGROUND

Hot flushes are common in menopausal women and also in men made acutely hypogonadal after orchiectomy or testicular injury. It is, however, an unusual symptom in patients with hypogonadism secondary to pituitary tumors.

METHODS

In evaluating the histories of men with hypogonadal state associated with nonfunctioning pituitary macroadenoma we were struck by the presence of hot flushes in four of them.

RESULTS

All four of the patients were hypogonadal with sexual dysfunction preoperatively. All had low gonadotropins and low testosterone levels with varying degrees of panhypopituitarism. All had successful transsphenoidal removal of tumors. None had endocrine improvement following surgery. All patients had improvement in sexual function and the hot flushes with administration of testosterone postoperatively.

CONCLUSIONS

Hot flushes are an uncommon presentation in men with pituitary adenoma. Perhaps the symptom will become more prominent if it is specifically questioned. We postulate that the cause of the flushing is related to nonsuppressed pulsatile secretion of gonadotropin-releasing hormone (GnRH) from the hypothalamus.

Attitudes to smoking and smoking habits among hospital staff

BACKGROUND

Health professionals should take an active role against smoking, so it is relevant to have information on their smoking habits and their attitudes towards smoking, especially with a view to identifying and offering help to those smokers who wish to stop. Staff in Llandough Hospital were surveyed to determine their smoking habits and attitudes, and the findings were compared with those of a similar survey at Llandough in 1987.

METHODS

In October 1991 a questionnaire was sent to each member of staff employed half time or more requesting data on age, sex, department, smoking habit, attitudes to smoking in various areas of the hospital, and attitudes to access to smoking rest rooms for patients, staff, and visitors. Smokers were asked whether they would like to join a "quit smoking" group. Non-responders were sent a reminder four weeks later and all replies returned by 31 December 1991 were analysed.

RESULTS

The response rate was 82%; of the respondents, 65% were non-smokers, 15% ex-smokers, and 20% current smokers. The prevalence of current smokers was 5% among doctors, 20% among nurses, 18% among administrative and clerical staff, and 40-42% among domestics, catering, and portering staff. Thirty eight per cent of responders wished smoking to be completely forbidden in all areas of the hospital and 90% in certain areas such as wards, offices, cafeteria, and laboratories. Nearly half wanted smoking to be allowed in rest rooms and over 60% wanted a 24 hour facility for smoking for staff, 56% for patients, and 44% for visitors. Only 39% of smokers wished to join a "quit smoking" support group. In comparison with the 1987 survey, the response rate in this study was higher (82% v 70%), the proportion of non-smokers had increased (65% v 59%), and more smokers wanted help (39% v 26%). Fewer wanted 24 hour access to smoking areas for staff and for visitors.

CONCLUSION

This hospital should capitalise on these changes of attitude among staff and proceed more rapidly with the implementation of policies to further reduce smoking among staff, visitors, and patients. As a first step a smoking cessation counsellor has been appointed.

Tuberculosis contact tracing: are the British Thoracic Society guidelines still appropriate?

The value of contact tracing in South Glamorgan for the period May 1987 to December 1989 was assessed. Tuberculosis was diagnosed in six (3.5%) of 170 close contacts. All were young and were detected in the initial screening. Tuberculosis was not found among 441 casual contacts. The value of follow up of contacts after the initial screening and of screening casual contacts in districts with a low prevalence of tuberculosis is questioned.

Audit of a tuberculosis contact tracing clinic

OBJECTIVE

To determine the efficiency of tuberculosis contact tracing in South Glamorgan 1987-9.

DESIGN

Review of records of contact tracing clinic and of data from the Mycobacterium Reference Unit. The clinic's practice was compared with 1983 British Thoracic Society's recommendations.

SETTING

Health authority tuberculosis control programme.

MAIN OUTCOME MEASURES

Proportion of contacts screened, follow up attendance rates, number of secondary cases detected, and quality of record keeping.

RESULTS

101 index patients and 611 contacts were identified. 596 (97.5%) contacts were screened, of whom 139 should not have been. Of 356 contacts requiring a Heaf test, 237 were tested, seven refused the test, and 112 had chest radiography without a Heaf test. 95 contacts were unnecessarily tested. 87 contacts had chest radiography unnecessarily and seven should have had radiography but did not. 34 contacts were given follow up appointments inappropriately and seven were overlooked for follow up. Tuberculosis was diagnosed in five asymptomatic contacts, all at initial screening and all close contacts of index patients with pulmonary disease.

CONCLUSION

Inadequacy of data, non-adherence to contact tracing guidelines, and failure to define the term highly infectious index case resulted in many contacts being unnecessarily screened or followed up.

IMPLICATIONS

The efficiency of tracing contacts would be improved by specifying smear results and ethnic origin of the index case on the notification form, clearly classifying contacts as close or causal, and clearly defining the term highly infectious.