Patients as teachers: Evaluating the experiences of volunteer inpatients during medical student clinical skills training

PURPOSE

Early patient encounters in medical education are an important element of clinical skill development. This study explores the experiences of volunteer inpatients (VIPs) participating in clinical skills training with junior medical students (JMS) solely for educational purposes.

METHODS

Following first-year medical students practicing history taking and clinical examinations with VIPs at Toronto General Hospital (TGH) and Toronto Western Hospital (TWH), patients completed a questionnaire and a short audio-recorded interview. This study used a mixed methodological approach. A 5-point Likert-scaled survey queried satisfaction regarding the recruitment process, student and faculty interactions and patient demographics (e.g. age and educational background). A 10-minute follow-up interview investigated patient perspectives. Survey responses were correlated to patient demographics and descriptive thematic analysis summarized trends in patient perspectives.

RESULTS

Of 93 consenting VIPs, 66% were male and 58% participated at TGH. The mean overall experience was positive (4.76 and 4.93 at TGH and TWH, respectively). Three themes emerging through thematic analysis were Not "Just" a Medical Student, Patient as Teacher, and Promoting Best Practices. VIPs reported positive experiences when they were adequately informed of the VIP role during recruitment, and when students exhibited confidence, interest, and respect throughout the session.

CONCLUSION

Study results provide clarity about VIP experiences with JMS and lay a foundation for improved patient satisfaction and best practices within clinical skills curricula in the health professions.

Smooth pursuit and saccadic abnormalities in first-episode schizophrenia

BACKGROUND

Previous studies of oculomotor dysfunction in schizophrenia have tended to concentrate on abnormalities of smooth pursuit eye tracking in chronic medicated patients. We report the results of a study of smooth pursuit, reflexive and antisaccade performance in drug naive and antipsychotic treated first-episode schizophrenic patients.

METHODS

Smooth pursuit and saccadic eye movements were recorded in 36 first-episode schizophrenic patients and 36 controls matched for age and estimated IQ. The schizophrenic patients were divided into drug-naive (N = 17) and antipsychotic treated groups (N = 19).

RESULTS

Smooth pursuit velocity gain was significantly lower than controls only in the drug-naive patients. The treated patients did not differ significantly from either the controls or the untreated group. In an antisaccade paradigm both treated and drug-naive schizophrenic patients demonstrated an increased number of errors, but only drug-naive patients also demonstrated an increased latency in initiating correct antisaccades.

CONCLUSIONS

These impairments are unlikely to be due to a generalized deficit in oculomotor function in the schizophrenic groups, as there were no differences between the groups in saccadic metrics on a reflexive saccade task. The results show that both smooth pursuit and saccadic abnormalities are present at the onset of schizophrenia and are integral to the disorder.

Executive function in first-episode schizophrenia

BACKGROUND

We tested the hypothesis that schizophrenia is primarily a frontostriatal disorder by examining executive function in first-episode patients. Previous studies have shown either equal decrements in many cognitive domains or specific deficits in memory. Such studies have grouped test results or have used few executive measures, thus, possibly losing information. We, therefore, measured a range of executive ability with tests known to be sensitive to frontal lobe function.

METHODS

Thirty first-episode schizophrenic patients and 30 normal volunteers, matched for age and NART IQ, were tested on computerized test of planning, spatial working memory and attentional set shifting from the Cambridge Automated Neuropsychological Test Battery. Computerized and traditional tests of memory were also administered for comparison.

RESULTS

Patients were worse on all tests but the profile was non-uniform. A componential analysis indicated that the patients were characterized by a poor ability to think ahead and organize responses but an intact ability to switch attention and inhibit prepotent responses. Patients also demonstrated poor memory, especially for free recall of a story and associate learning of unrelated word pairs.

CONCLUSIONS

In contradistinction to previous studies, schizophrenic patients do have profound executive impairments at the beginning of the illness. However, these concern planning and strategy use rather than attentional set shifting, which is generally unimpaired. Previous findings in more chronic patients, of severe attentional set shifting impairment, suggest that executive cognitive deficits are progressive during the course of schizophrenia. The finding of severe mnemonic impairment at first episode suggests that cognitive deficits are not restricted to one cognitive domain.

Control of aromatase activity in breast tumours: the role of the immune system

Cytokines such as interleukin-6 (IL-6) and tumour necrosis factor alpha (TNF alpha), have been identified as important regulators of aromatase activity in fibroblasts derived from normal and malignant breast tissues, and may play an important role in controlling aromatase activity in breast tumours. The major source of such cytokines within breast tumours remains to be established but macrophages and lymphocytes, which can infiltrate tumours, have been identified as a potential source of aromatase stimulatory cytokines. To obtain further insight into the possible role played by the immune system in cancer development, and in particular its ability to regulate aromatase activity via cytokine production, we have obtained peripheral blood monocytes and lymphocytes from an immunosuppressed kidney transplant recipient, receiving cyclosporin A therapy, and a woman with breast cancer. Monocytes and lymphocytes were stimulated with lipopolysaccharide (LPS), and the conditioned medium (CM) collected from these cells was tested for its ability to stimulate aromatase activity in fibroblasts derived from normal breast tissue from a woman undergoing lumpectomy for the removal of a breast tumour. The white blood cell count was lower for the immunosuppressed patient, mainly because of the reduction in the number of monocytes and lymphocytes. The ability of CM from the monocytes and lymphocytes of the immunosuppressed patient to stimulate aromatase activity was significantly reduced (68% and 82% for monocytes and lymphocytes, respectively) compared with that of CM from the cells of the woman with breast cancer. It is possible, therefore, that immunosuppression, which has been found to be associated with a reduction in the incidence of de novo breast cancer in kidney transplant recipients, may exert its effect by inhibiting cytokine production by the cells of the immune system and thus oestrogen synthesis. In contrast to the stimulatory effects that TNF alpha has on aromatase activity in breast fibroblasts, in MCF-7 breast cancer cells, which possess low aromatase activity, it reduced activity. However, the extent of inhibition of aromatase activity in these epithelial cells was much lower than the marked stimulation which it can induce in breast fibroblasts.

The role and proposed mechanism by which oestradiol 17 beta-hydroxysteroid dehydrogenase regulates breast tumour oestrogen concentrations

Synthesis of the biologically active oestrogen, oestradiol, within breast tumours makes an important contribution to the high concentrations of oestrogens which are present in malignant breast tissues. In breast tumours, oestrone is preferentially converted to oestradiol by the Type I oestradiol 17 beta-hydroxysteroid dehydrogenase (E2DH). Several growth factors, such as insulin-like growth factor Type I, and cytokines, such as Tumour Necrosis Factor alpha (TNF alpha), have been shown to stimulate E2DH activity in MCF-7 breast cancer cells. As little is known about the regulation of Type I E2DH expression and activity in other breast cancer cell lines, the expression and activity of this enzyme was examined in other oestrogen receptor positive and also oestrogen receptor negative breast cancer cell lines. As it is possible that E2DH activity may be limited by co-factor availability, the effects of exogenous co-factors on enzyme activity in these cell lines was also investigated. For T47D and BT20 breast cancer cells, the addition of exogenous co-factors was found to enhance enzyme activity. TNF alpha, in addition to stimulating E2DH activity in MCF-7 cells, also increased activity in T47D and MDA-MB-231 cells, although to a lesser extent than in MCF-7 cells. An investigation of signalling pathways involved in the regulation of E2DH activity revealed that stimulation of both the protein kinase C (PKC) and PKA pathways may be involved in regulation of E2DH activity. As several growth factors and cytokines have now been found to be involved in regulating E2DH activity, the role that macrophages and lymphocytes have in supplying these factors and the mechanism by which these factors may stimulate tumour growth, is also reviewed.

Predictors of recurrence for patients with small (one centimeter or less) localized breast cancer (T1a,b N0 M0)

BACKGROUND

The frequency of small (< or = 1 cm) axillary lymph node negative invasive breast cancers (T1a,b N0 M0) is increasing because of wider implementation of breast cancer screening. Identification of prognostic factors for these patients has been based largely on retrospective pathology review. The authors analyzed histologic factors recorded in the original pathology reports to determine predictors of recurrence for patients with T1a,b N0 M0 breast cancer.

METHODS

Two hundred eighteen patients were studied. Potential prognostic factors including measured millimeter tumor size in three dimensions, histologic grade, nuclear grade, and presence or absence of lymphatic vessel invasion were documented prospectively in routine surgical pathology reports of a large community (nonuniversity based) hospital. Follow-up was performed annually by the tumor registry.

RESULTS

With a median follow-up of 6.9 years (range, 3-15.8 years), overall recurrence free survival was 93%. Poor nuclear grade (hazard ratio, 5.8; 95% confidence interval, 1.70-19.82; P = 0.004) and lymphatic vessel invasion (hazard ratio, 4.6; 95% confidence interval, 1.34-15.61; P = 0.01) were independent predictors of recurrence. Only 10% of patients had cancers with both poor nuclear grade and lymphatic vessel invasion and their 67% 7-year recurrence free survival (RFS) rate was significantly lower than the 92% RFS rate observed for patients with one of these two factors (P = 0.007) and the 99% RFS for patients with neither poor risk factor (P = 0.0001).

CONCLUSIONS

The combination of poor nuclear grade and lymphatic vessel invasion identifies a very small subset (10%) of patients with T1a,b N0 M0 breast cancer with a significant relapse risk that warrants consideration of adjuvant systemic therapy. However, the majority of patients with T1a,b N0 M0 breast cancer have an exceptionally good prognosis.

IL-6sR: release from MCF-7 breast cancer cells and role in regulating peripheral oestrogen synthesis

The interleukin-6 soluble receptor (IL-6sR) may regulate the ability of IL-6 to stimulate oestrogen synthesis in breast cancer cells and breast tumours. Significant aromatase activity was detectable in IL-6 stimulated fibroblasts derived from subcutaneous adipose tissue, but the combination of IL-6sR plus IL-6 resulted in a marked 21-fold stimulation of aromatase activity. To examine the control of IL-6sR release, the effects of oestradiol, 4-hydroxytamoxifen (4-OHT), dexamethasone, TPA, TNF alpha or IL-6 on this process was examined using MCF-7 breast cancer cells. Oestradiol, TNF alpha and dexamethasone all markedly increased IL-6sR release. While 4-OHT had a small stimulatory effect on IL-6sR release, it blocked the ability of oestradiol to increase IL-6sR release. Significant concentrations of IL-6sR were also detected in conditioned medium collected from lymphocytes and macrophages and in cytosols prepared from normal and malignant breast tissues. These results indicate that IL-6sR may have an important role in potentiating the effect of IL-6 on oestrogen synthesis in breast cancer cells. The abilities of oestradiol or tamoxifen to potentiate or inhibit the IL-6 stimulation of oestrogen synthesis in breast cancer cells may result from their effects on IL-6sR release.

The role of cytokines and sulphatase inhibitors in regulating oestrogen synthesis in breast tumours

Synthesis of oestrogens within breast tissues makes an important contribution to the high concentrations of oestradiol which are found in breast tumours. The activities of the enzymes involved in oestrogen synthesis, i.e. the aromatase, oestradiol dehydrogenase (E2DH) and oestrone sulphatase (E1-STS), can be stimulated by several growth factors and cytokines. As it is possible that some of these factors may be derived from cells of the immune system (macrophages and lymphocytes), the effects of basic fibroblast growth factor (bFGF) and interleukin-2 (IL-2), which are produced by these cells, on E2DH activity was examined in MCF-7 cells. Treatment of these cells with bFGF resulted in a dose-dependent increase in E2DH reductive activity whereas IL-2 was inactive at the concentration tested. To obtain further evidence that factors produced by macrophages and lymphocytes can modulate the activities of enzymes involved in oestrogen synthesis, conditioned medium was collected from these cells and found to stimulate both E1-STS and E2DH activities. In addition to understanding the control of oestrogen synthesis in breast tumours an inhibitor to block the synthesis of oestrone via the oestrone sulphatase pathway was developed. Oestrone-3-O-sulphamate (EMATE) is a potent, irreversible, inhibitor of E1-STS. A single dose of EMATE (10 mg/kg) inhibited tissue E1-STS activity in rats by more than 95% for up to 7 days, indicating that this compound may have considerable therapeutic potential for the treatment of breast cancer. Evidence is also reviewed that another steroid sulphatase, dehydroepiandrosterone sulphate sulphatase, may have a crucial role in regulating cytokine production and that this may indirectly control tumour oestrogen synthesis.

Stimulation of aromatase activity in breast fibroblasts by tumor necrosis factor alpha

The conversion of androstenedione to estrone, the reaction mediated by the aromatase enzyme complex, may make an important contribution to the synthesis of estrogens in breast tissues. In the present study, the effect of the cytokine. TNF alpha, on aromatase activity was examined in breast fibroblasts derived from normal and malignant breast tissue. TNF alpha (2.5-10.0 ng/ml), in the presence of stripped fetal calf serum and dexamethasone, significantly stimulated fibroblast aromatase activity in a dose-dependent manner. IL-1 and IL-6 also stimulated fibroblast aromatase activity, but no marked synergism between TNF alpha and IL-1 or IL-6 was detected. Using a specific radioimmunoassay, significant concentrations of TNF alpha were detected in samples of breast cyst fluid and breast tumor cytosol, which had previously been shown to stimulate aromatase activity, but not in conditioned medium from breast tumor-derived fibroblasts. As TNF alpha may be preferentially expressed and produced in the adipose tissue component of the breast, this cytokine may have an important role in regulating estrogen synthesis in normal and malignant breast tissues.

Regulation of estradiol 17 beta-hydroxysteroid dehydrogenase expression and activity by retinoic acid in T47D breast cancer cells

Estradiol 17 beta-hydroxysteroid dehydrogenase (17 beta HSD) mediates the interconversion of estrone and estradiol in endocrine-responsive tissues such as the breast. The control of 17 beta HSD expression by all-trans-retinoic acid (RA) in T47D breast cancer cells was examined using a specific 17 beta HSD complementary DNA probe. Two main 17 beta HSD messenger RNA (mRNA) transcripts of 2.2 and 1.3 kilobases (kb) were detected, of which only the 1.3-kb mRNA was regulated. RA increased expression of the 17 beta HSD 1.3-kb mRNA in a dose- and time-dependent manner, and the increased expression of this mRNA by RA was inhibited by a 10-fold excess of a RA antagonist Ro 41-5253. Insulin-like-growth factor-I, interleukin-1, and estradiol, previously shown to increase 17 beta HSD activity in breast cancer cells, had little effect on 17 beta HSD gene expression. To relate the effect of increased 17 beta HSD 1.3-kb mRNA expression to 17 beta HSD activity, the conversion of estrone to estradiol (reductive) and that of estradiol to estrone (oxidative) were measured in intact T47D cell monolayers. Whereas RA increased 17 beta HSD reductive activity, it had no effect on oxidative activity. The addition of excess NAD increased 17 beta HSD oxidative activity in control and RA-treated cells, but the addition of NADH had no effect on 17 beta HSD reductive activity. These results suggest that the increased expression of the 17 beta HSD 1.3-kb mRNA induced by RA is associated with an increase in 17 beta HSD reductive activity, but that endogenous cofactor levels may determine the direction in which this enzyme acts in T47D cells.

The interaction of cytokines in regulating oestradiol 17 beta-hydroxysteroid dehydrogenase activity in MCF-7 cells

Oestradiol 17 beta-hydroxysteroid dehydrogenase (E2DH) has a pivotal role in the regulation of oestradiol (E2) concentrations in normal and malignant breast tissues. Previous studies have suggested that a number of cytokines can stimulate E2DH activity to increase the conversion of oestrone (E1) to E2. In this investigation we have examined the effect of TNF alpha, interleukin-1 beta (IL-1 beta) and IL-6 on E2DH activity in MCF-7 breast cancer cells. These cytokines may be produced by breast tumours and their presence in conditioned medium (CM) from tumour-derived fibroblasts was also measured to assess their possible contribution to its E2DH stimulatory activity. Treatment of MCF-7 cells with IL-1 beta and TNF alpha (5 ng/ml) significantly increased (P < 0.001) reductive E2DH (red-E2DH, the conversion of E1 to E2) activity. In contrast, IL-6 at a concentration of 100 ng/ml produced little, if any, stimulation of reductive activity. Combinations of all three cytokines acted synergistically to stimulate red-E2DH activity. No cytokine, either alone or in combination, affected oxidative (E2-->E1) activity. Significant concentrations of IL-6 and IL-1 beta were detected in CM, but the stimulation of red-E2DH activity was much greater than that which could be explained by their levels alone. It is concluded that these cytokines may play an important role in regulating E2DH activity in breast cancer cells and may act synergistically in vivo to enhance the formation of E2 in breast tumours.

Reversal of insulin resistance in type 1 diabetes following initiation of insulin treatment

The biological action and pharmacokinetics of insulin were assessed in nine type 1 (insulin-dependent) diabetic patients before and after 3 months conventional insulin treatment, and in seven age and weight-matched non-diabetic controls, by means of the euglycaemic insulin clamp technique. The mean (+/- S.E.) metabolic clearance rate of insulin, when infused at 1 mU/kg/min, was similar in untreated and treated diabetic patients and in controls (22.7 +/- 2.0, 19.3 +/- 3.8, and 22.9 +/- 3.3 ml/kg/min) but, when infused at 6 mU/kg/min, was greater (p less than 0.01 and less than 0.01) in untreated patients (18.0 +/- 2.5 ml/kg/min) than in treated patients (11.5 +/- 1.4 ml/kg/min) and controls (12.7 +/- 1.3 ml/kg/min). Insulin-mediated glucose disposal was reduced (p less than 0.01 and less than 0.01) at insulin infusion rates 1 and 6 mU/kg/min in untreated patients (18.5 +/- 1.9 and 33.8 +/- 4.5 mumol/kg/min) when compared with controls (35.8 +/- 3.4 and 62.0 +/- 4.7 mumol/kg/min) and was improved (p less than 0.01 and less than 0.01) following insulin treatment (36.1 +/- 4.6 and 64.8 +/- 4.2 mumol/kg/min). Daily insulin requirement fell by 33% following 3 months insulin treatment with improvement in mean HbA1 from 16.3 +/- 0.7 to 8.2 +/- 0.4%, but without significant increase in endogenous insulin secretion. The 'honeymoon phenomenon', which has traditionally been attributed exclusively to resurrection of endogenous insulin release, may also be related to normalization of insulin action following institution of insulin treatment.

Vitiligo in diabetes mellitus

We studied the association between vitiligo and diabetes mellitus, and found that vitiligo is associated with insulin-dependent diabetes but not with non-insulin-dependent diabetes. This gives further weight to the theory that vitiligo is an autoimmune disease.

Influence of insulin antibodies on pharmacokinetics and bioavailability of recombinant human and highly purified beef insulins in insulin dependent diabetics

Sixteen insulin dependent diabetics of long standing, with undetectable fasting plasma C peptide concentrations, and eight non-diabetic controls were each infused intravenously with biosynthetic human and highly purified beef insulin (1 mU/kg/min) while euglycaemia was maintained by a Biostator. No difference was observed between the two insulins in respect of insulin pharmacokinetics or biological action. The diabetics showed appreciable insulin resistance, manifested by a 40% reduction in the rate of insulin mediated glucose disposal, which was unrelated to the presence of insulin antibodies. Insulin binding antibodies, however, increased insulin's clearance rate and distribution space and prolonged its pharmacological and biological half lives. The rate at which insulin action was lost, after an intravenous infusion, was more rapid in diabetics without insulin antibody binding than in controls. In respect of their influence on insulin pharmacokinetics, moderate concentrations of insulin antibodies may be of positive advantage to all diabetics without endogenous insulin secretion and are not responsible for the insulin resistance of type 1 diabetes.

Insulin action and pharmacokinetics in insulin treated diabetics during the third trimester of pregnancy

Insulin action and pharmacokinetics were compared, using the euglycaemic insulin clamp technique, in seven insulin-treated diabetics during the third trimester of pregnancy and one to three weeks post-partum. At an insulin infusion rate of 1 mU/kg/min, insulin mediated glucose disposal was significantly greater (p less than 0.02) following delivery (1.194 +/- 0.138 mmol/m2/min) than in pregnancy (0.761 +/- 0.072 mmol/m2/min) and the rate of decline in insulin mediated glucose disposal, at the end of the insulin infusion, was significantly greater (p less than 0.02) following delivery (24.78 +/- 4.22 mumol/m2/min2) than in pregnancy (15.17 +/- 2.00 mumol/m2/min2). The metabolic clearance rate, distribution space and pharmacological half-life of insulin were not significantly altered by pregnancy. These findings show that the third trimester of pregnancy is associated with steady state insulin resistance accompanied by a reduced rate of insulin deactivation, but normal insulin pharmacokinetics.

A comparison of the biological actions and pharmacokinetics of intravenously infused highly purified beef and biosynthetic human insulins in normal man

By means of the euglycaemic insulin clamp technique the rate of insulin-mediated peripheral glucose disposal (GDR) was compared in response to intravenous infusions of highly purified beef insulin (BI) and biosynthetic human insulin (BHI), infused at 1 and 6 mU/kg/min, in healthy volunteers. The metabolic clearance rates of BI and BHI were similar at the lower insulin infusion rate and were both greater than those observed at the higher insulin infusion rate, which were also similar, implying the process of insulin clearance to be saturable. The GDRs were similar in response to infusions of BI and BHI at each insulin infusion rate. The rates of insulin deactivation were similar, having discontinued BI and BHI infusions at 1 mU/kg/min.

Diabetic lipohypertrophy delays insulin absorption

The effect of lipohypertrophy at injection sites on insulin absorption has been studied in 12 insulin-dependent diabetic patients. The clearance of 125I-insulin from sites with lipohypertrophy was significantly slower than from complementary nonhypertrophied sites (% clearance in 3 h, 43.8 +/- 3.5 +/- SEM) control; 35.3 +/- 3.9 lipohypertrophy, P less than 0.05). The degree of the effect was variable but sufficient in several patients to be of clinical importance. Injection-site lipohypertrophy is another factor that modifies the absorption of subcutaneously injected insulin.

Glycosylated haemoglobin and serum insulin antibodies in type I diabetes

Type 1 diabetics receiving once (Group 1, n = 72) and twice (Group 2, n = 48) daily subcutaneous injections of conventional beef insulin were compared, on a cross-sectional basis, in respect of insulin antibody binding by serum and total glycosylated haemoglobin (HbA1). Patients in Group 1 had higher insulin antibody binding (25.2 +/- 15.8% vs 17.0 +/- 13.9%; p less than 0.01) and higher HbA1 levels (12.5 +/- 2.0% vs 11.0 +/- 1.8%; p less than 0.001) than patients in Group 2. An inverse correlation (tau = -0.28, p less than 0.01) was observed between HbA1 and insulin antibody binding in C-peptide non-secretors of Group 1 but not in Group 1 C-peptide secretors, nor in C-peptide secretors and/or non-secretors of Group 2. It is suggested that in Type 1 diabetics who receive a single daily insulin injection and who have no endogenous insulin secretion, insulin antibodies may aid glycaemic control by prolonging insulin action.

Non-insulin-treated ICA positive and negative diabetics are equally insulin resistant

Insulin action was assessed in 5 cytoplasmic islet cell antibody (ICA) positive non-diabetics, 8 ICA positive (type I) non-insulin-treated diabetics, 7 ICA negative insulin-treated diabetics by measurement of steady state plasma glucose (SSPG) levels during a combined intravenous infusion of propranolol, adrenaline, glucose and insulin. SPPG values of ICA positive and negative non-diabetics were similar and their combined value (4.0 +/- 0.5 mmol/l) was significantly lower (p less than 0.01 and less than 0.01) than those (11.5 +/- 1.9 and 11.3 +/- 2.2 mmol/l) of ICA positive and negative diabetics, indicating that both groups of diabetics were similarly insulin resistant. Similar correlations were observed between SSPG and HbA1 levels when considering all ICA positive subjects (r = 0.89, p less than 0.001) and all ICA negative subjects (r = 0.73, p less than 0.01). Conventional insulin treatment (2.6 months) in 4 ICA positive diabetics improved insulin action in each case with a reduction in mean SSPG concentration from 14.0 +/- 2.3 to 8.5 +/- 3.4 mmol/l. Thus, ICA positive and negative diabetics, of equivalent degree of carbohydrate intolerance, are equally insulin resistant. Insulin treatment may improve, but appears not to normalise, insulin action in ICA positive (type I) diabetics.

Effect of dietary compliance on metabolic control in insulin-dependent diabetics

One hundred and seventy eight insulin dependent diabetics (IDDM) have been studied regarding their understanding of and compliance with a controlled carbohydrate diet. Forty per cent could not remember their dietary prescription, 35 per cent did not estimate carbohydrate and many scored badly in a 'quiz' on the carbohydrate content of common foods. Quiz scores were significantly associated with HbA1 levels (P less than 0.001). One hundred and thirty six patients completed a seven-day food record from which the pattern of eating was established. Of these 75 were injecting twice daily short and intermediate acting insulin; in this group there were significant relationships between HbA1 and both care with carbohydrate estimation and eating pattern (P less than 0.05). Thus, in IDDM, the understanding of a controlled carbohydrate diet and adherence to it are associated with better glycaemic control but adequate compliance is rare. Future dietary recommendations for insulin taking diabetics should be simple, easy to understand, acceptable in practice and of proven effectiveness if they are to appreciably influence the quality of diabetic control.

Carcinoma of the pancreas presenting as hyperglycemic, hyperosmolar non-ketotic coma

A patient presented with hyperglycemic, hyperosmolar non-ketotic coma and 3 months later was diagnosed as having carcinoma of the pancreas. There have been no previous reports of this temporal association.

Humoral immunity in type 1 diabetes mellitus: a prospective study

Cytoplasmic islet cell antibodies, as detected by anti-IgG (ICAb), and circulating immune complexes (AgAb), detected by the solid phase C1q test (C1qSP), were evaluated in 153 insulin dependent diabetics (IDD) at diagnosis and subsequently in 88 of these patients who were studied prospectively at regular intervals for up to 3 yr. AgAb detected by the conglutinin (KgBt) and Raji cell (RAJI) techniques were also studied at diagnosis in 34 and 50 diabetics respectively. Normal controls were included in the AgAb studies. Complement fixing islet cell antibodies (CF-ICAb) were evaluated in 30 randomly selected diabetics both at diagnosis and after 6 months. Viral antibodies (VAb) were measured in 30 IDD at diagnosis and in 30 matched controls. Insulin antibodies (IBC) were measured 9 months after diagnosis in 35 diabetics and HLA studies (B8 and B15) performed in 115 patients. In the prospective study the ICAb positivity declined from 50% at diagnosis to 45, 38, 36, 31, 26, 19 and 17% at 1, 3, 6, 9, 12, 24 and 36 months after diagnosis respectively. CF-ICAb were found in 30% of the diabetics at diagnosis and in 23% at 6 months. All patients with CF-ICAb at diagnosis were ICAb positive whilst only 47% of patients with ICAb also had CF-ICAb in the serum. AgAb were found at diagnosis in 35% of patients by C1qSP (p less than 0.001 vs. normals), in 35% by KgBt (p less than 0.001) and in 54% by RAJI (p less than 0.002). Eighty-four patients were studied at diagnosis by more than one AgAb method and of these 57% had at least one positive AgAb result. AgAb by C1qSP declined to less than 20% within 6 months of diagnosis. AgAb, as measured by C1qSP and RAJI techniques, correlated with ICAb at diagnosis whereas there was no correlation with VAb levels, IBC values, nor with the HLA antigens. There was no correlation between AgAb (C1q) and CF-ICAb. HLA B15 positive patients tended to form higher IBC levels than B15 negative patients. Thus, AgAb presence seems to parallel that of ICAb in the early stages of diabetes and both phenomena may be primarily or secondarily involved in the development of the disease.

Prediction of diabetic retinopathy from clinical variables and color vision data

Predictions about the onset of retinopathy in 295 diabetic patients, all originally having no evidence of retinopathy, have been made in a longitudinal study over 7 yr. Out of many color vision tests and clinical variables, the best individual predictor was a measure of yellow-blue discrimination, using an anomaloscope. The other predictors of significance were the degree of blood glucose control and the duration of diabetes. Although the predictions from a linear logistic model were significant in classifying the diabetic subjects into those whose fundus will remain normal and those in whom it will develop retinopathy, the number of misclassifications was substantial. An examination of the goodness of fit between the data and the model suggested a criterion value (P) of around P = 0.3 for the probability that a patient develops retinopathy. At this value, the probability of being normal for an individual classed as normal was 0.82, and the probability of developing retinopathy for an individual classed as having retinopathy was 0.54.

Alpha 2-macroglobulin and proliferative retinopathy in type 1 diabetes

Serum alpha 2-macroglobulin (alpha 2m) and total glycosylated haemoglobin (HbA1) concentrations were measured in 110 insulin dependent Type 1 diabetics with minimal or no fundoscopic retinopathy, referred to as non-retinopaths, and in 52 proliferative retinopaths. Proteinuria was recorded in 8 (7%) non-retinopaths and 29 (56%) retinopaths and was accompanied by elevated alpha 2m concentrations in both groups of diabetics but only significantly so in the non-retinopaths. Diabetics without proteinuria showed a significant correlation between alpha 2m concentration and duration of diabetes, HbA1 and age (being higher at extremes of age). Alpha 2m concentrations were significantly higher in retinopaths than in non-retinopaths without proteinuria when allowance was made for the influence of age and duration of diabetes on alpha 2m. This difference may be attributed to the higher HbA, levels found in retinopaths than in non-retinopaths and was no longer evident when account was taken of the prevailing HbA1 concentration in individual patients.

HLA antigens and other risk factors in the development of retinopathy in type 1 diabetes

Factors possibly influencing the development of diabetic retinopathy were studied in 112 randomly selected type 1 diabetics having no or minimal retinopathy (group A) and in 82 type 1 diabetics with known severe diabetic retinopathy. The latter comprised those with severe background retinopathy (group B, n = 17) and those having proliferative retinopathy without (group C, n = 38) and with group D, n = 27) diabetic nephropathy. Nonretinopaths (group A) were of similar sex ratio, body weight, and age at diagnosis of diabetes but had been diabetic longer (p less than 0.001) and were thus older (p less than 0.001) than retinopaths (groups B-D). The distribution of HLA antigens of the A, B, and C loci was similar in nonretinopaths and retinopaths with the exception that HLA B7 showed a reduced (p less than 0.05) prevalence in the retinopaths (6% versus 17%) and was singularly underrepresented in group D, where no patients had this antigen. Mean postprandial plasma glucose and HbA1 concentrations were higher (p less than 0.01 and p less than 0.001) and cigarette smoking was more prevalent (p less than 0.01) in the retinopathy groups B-D than in group A. Systolic and diastolic blood pressures were similar in groups A-C, with higher (p less than 0.001) values only in group D. There was no association between insulin antibody binding in the serum or measurable plasma C-peptide immunoreactivity and retinopathy status. The risk of development of diabetic retinopathy in type 1 diabetes may be related to HLA-associated genetic factors and to cigarette smoking.

Relationship of glycosylated haemoglobin to C-peptide secretory status and antibody binding of insulin in insulin-dependent diabetes

Diabetic control, assessed by measuring the concentration in venous blood of total glycosylated haemoglobin (HbA1), endogenous insulin secretion, as estimated by the C-peptide response (delta C-P) to intravenous glucagon, and serum beef insulin antibody binding were measured in 50 juvenile onset insulin dependent diabetics (IDDM) receiving a single daily injection of soluble and protamine zinc insulin. The delta C-P correlated inversely with duration of diabetes (tau = -0.27, p less than 0.01) and daily insulin requirement (tau = -0.22, p less than 0.05) in the 50 IDDM studied of whom 28 exhibited a measurable delta C-P. In C-peptide nonresponders, but not in the C-peptide responders, and inverse regression (t = 2.19, p less than 0.05) was observed between beef insulin antibody and HbA1. In the 25 IDDM having the lowest insulin antibody binding, and inverse correlation (tau = 0.36, p less than 0.02) was observed between delta CP and HbA1, which was not found (tau = 0.05) in the remaining 25 IDDM who had the highest insulin antibody binding. These findings suggest that, in the absence of endogenous insulin secretion, diabetic control in IDDM receiving a single daily injection of conventional beef insulin is better in patients with high beef insulin antibody binding. Conversely, in patients with low beef insulin antibody binding, diabetic control appears to be better in those with persisting endogenous insulin secretion.

Diabetic control in patients treated with once or twice-daily insulin injections, including a comparison of conventional beef and highly purified pork insulins

Twenty patients were changed from a single daily injection of beef insulin (a mixture of soluble and protamine zinc insulin) to two daily injections (mixtures of soluble and isophane insulins). This was associated with a reduction, one month later, in the concentration of glycosylated haemoglobin (HbA1) and in the degree of late evening glycosuria. A reduction was shown 6 months later in antibody binding of beef and pork insulin by serum. Subsequent conversion to a twice daily regime of highly purified pork insulin was not associated with further improvement in diabetic control, but was associated after 1 month with a reduction in daily insulin dose, and after 5 months with a further reduction in antibody binding of beef and pork insulin by serum. Patients failing to show a C-peptide response to intravenous glucagon had a fall in HbA1 after conversion from a once to a twice daily insulin regime, which correlated inversely with insulin antibody binding estimated at the beginning of the study.

Contraception for the insulin-dependent diabetic woman: the view from one clinic

Experience in a large diabetic clinic has confirmed the suspicion that insulin-dependent diabetic women are at considerably increased risk of thromboembolic disease if they take combined estrogen/progestogen oral contraceptive preparations. The most obvious alternative, an intrauterine device, is associated with an unexpectedly high failure rate, probably because of an unusual metabolic interaction with the diabetic endometrium. In a small group of diabetic women the progestogen-only pill was found to be a successful form of contraception not associated with any side effects except for menstrual irregularities. For most diabetic women the choice of contraceptive should therefore be between a progestogen-only pill and a mechanical method. Female sterilization and injectable progesterone each have their place in particular circumstances. Careful counseling of each patient is essential to ensure the best choice of contraceptive and correct application of the chosen method.

Driving and insulin-dependent diabetes

A survey of 250 patients with insulin-dependent diabetes (IDD) holding a full motor vehicle driving licence revealed that 107 (42.8%) had not declared IDD on their application for a driving licence. 70 of these (28% of entire group) claimed that they were unaware of the statutory requirements. There was no difference in the declaration-rate between men and women. 159 patients (66%) declared IDD for their motor insurance. 86 patients (34.4%) had had severe or frequent hypoglycaemia in the preceding six months, during which they had been driving regularly. 34 patients (13.6%) admitted involvement in a driving accident since commencing treatment with insulin, and 13 of these patients were aware that hypoglycaemia had been an important causal factor. The prevalence of diabetic retinopathy and cataracts was considerable, but few patients (2.4%) had severe impairment of vision in both eyes.

Fatal coma in diabetes

Analysis of causes of death in a population of 3,113 diabetics was carried out for a period of eight years and those patients dying of some form of diabetic coma identified. Of 1,274 deaths, only 22 (1.73%) were primarily due to coma; 7 hypoglycaemia, 8 ketoacidosis, 3 hyperosmolar coma and 4 lactic acidosis. Three of the ketoacidosis patients may have died from other causes. Most deaths occurred in patients with long-standing diabetes. In the hypoglycaemic group all were on insulin and several had been difficult to control for many years. Infection was an important precipitating factor for ketoacidosis and hyperosmolar coma. Phenformin was the cause of all cases of fatal lactic acidosis. It is reassuring that death from coma is a comparatively rare event in known treated diabetic patients.

Glucose and insulin responses to oral glucose in overt non-insulin-dependent diabetics with and without the islet cell antibody

Plasma insulin, glucose, and insulin/glucose responses to a 50-g oral glucose tolerance test (OGTT) were compared in 14 islet cell antibody (ICAb) positive non-insulin-dependent diabetics (NIDDM), 14 matched ICAb negative NIDDM, and 14 ICAb negative nondiabetic controls. Both groups of NIDDM exhibited marked carbohydrate intolerance with insulinopenia. Despite having significantly higher plasma glucose concentrations during the study, the ICAb positive NIDDM had significantly lower insulin levels, and thus lower insulin/glucose ratios, than the ICAb negative NIDDM both in the fasting state and in response to the OGTT. Similarily, ICAb positive NIDDM had higher integrated glucose responses (delta G), lower integrated insulin responses (delta I), and lower delta I/delta G values than ICAb negative NIDDM. Three ICAb negative and seven ICAb positive NIDDM subsequently required insulin treatment. These findings show that ICAb positive NIDDM suffer from a greater disturbance of B-cell function than do matched ICAb negative NIDDM.

Serum alpha 2-macroglobulin levels in diabetes

Serum alpha 2-macroglobulin levels have been determined in diabetic patients by quantitative radial immunodiffusion and compared with those observed in age- and sex-matched controls. In addition, the results in diabetics have been analysed with respect to such variables as the age and sex of the patient, the duration of disease, treatment, control, and the occurrence of retinopathy or nephropathy. The alpha 2-macroglobulin levels in diabetic patients were found to be significantly higher than in age- and sex-matched controls, thus confirming previous observations. However, these differences were most apparent in the more extreme age groups. Multiple regression analysis also revealed that the only variables contributing significantly to the regression apart from age and sex were control and retinopathy.

Seasonal onset of insulin dependent diabetes in relation to sex and age at onset

All newly diagnosed insulin dependent diabetics presenting consecutively to the Diabetic Department of the Royal Infirmary from the City of Edinburgh or its environs, between the years 1964 and 1977, were analysed for sex (297 males, 205 females), age at diagnosis (range 10--75 years), month of diagnosis, duration of symptoms and month of symptomatic onset. Males aged 10--19 years showed a significant seasonal variation in diagnosis (p less than 0.025) with an increase in autumn and winter months which was not seen in females aged 10--19 years nor in patients of either sex aged more than 19 years at diagnosis. The duration of diabetic symptoms increased with increasing age at diagnosis in both males and females and was consistently greater in females than in males for each age group at diagnosis. When the month of symptomatic onset was considered in relation to sex and age at diagnosis, having excluded patients with duration of symptoms of more than three months, only males aged 10--19 years at diagnosis showed a significant seasonal variation in incidence (p less than 0.005).

Diabetic mortality in Edinburgh

A prospective study of mortality in 3,113 diabetics was carried out in Edinburgh over a period of eight years; 1,272 patients (41 %) died. Death rates for females equalled those for males and, in relation to the general population, there was a considerable excess mortality which was greater for females. Statistical analysis indicated that the important mortality risk-factors are age, duration of diabetes of greater than ten years and treatment. The risk of oral therapy or insulin were approximately equally greater than that of diet therapy and probably reflected severity of disease. Using international coding for diagnosis, 27 % of deaths were classified as directly due to diabetes and 49 % to vascular disease. Reclassifying the terminal cause of death left only 26 patients (2 %) recorded with diabetes as the direct cause of death. Three hundred and thirty five males (66 %) and 561 females (73 %) died of vascular disease. There was a predominance of myocardial infarction in males and cerebrovascular disease in females. These percentages were a little lower when post-mortem information was available. These results provide additional evidence that diabetes reduces life expectancy by inducing premature vascular disease and that the effect is greater in women than in men.

Glycosylated haemoglobin concentrations in newly diagnosed diabetics before and during treatment

Concentrations of total glycosylated haemoglobins (Hb A1) were measured in 40 diabetics at diagnosis and at monthly intervals after treatment with chlorpropamide, insulin, or diet alone was begun. The mean Hb A1 concentration at presentation in 16 patients treated with chlorpropamide was significantly higher than that in 12 patients treated with insulin, and the duration of glycaemic symptoms was much longer in the chlorpropamide-treated group. In contrast, the mean plasma glucose concentration was similar in both groups. The mean concentrations of Hb A1 and plasma glucose at diagnosis in the 12 patients treated by diet alone were lower than those in the other two groups, and most of these patients were free of symptoms. Treatment quickly relieved symptoms and lowered plasma glucose in all patients. The Hb A1 concentration fell significantly with treatment such that after two months there was no significant difference between the three groups, although results remained above the normal range. These findings support the theory that the Hb A1 concentration reflects the blood glucose control over the previous one to two months and suggest that the duration of hyperglycaemia may be important in determining the Hb A1 concentration as well as the absolute blood glucose concentration.

The value of islet cell antibody in predicting secondary failure of oral hypoglycaemic agent therapy in Diabetes mellitus

The sera of 160 diabetics who were well controlled by oral hypoglycaemic agents (OHA) for at least three months after diagnosis were tested for pancreatic islet cell antibodies (ICAb) either at diagnosis or within two years after diagnosis. 129 were non-obese at diagnosis and of these ICAb was detected in the sera in 20 (16%). 31 were obese at diagnosis and of these ICAb was detected in the sera in three (10%). All of the 160 diabetics were insulin independent at the time of testing the serum for ICAb. The presence of ICAb was associated with a high probability of becoming insulin dependent, calculated from actuarial statistics. 86% of ICAb positive patients initially controlled on OHA may be expected to be insulin dependent at five years from diagnosis as compared to 18% of ICAb negative patients. Obesity at diagnosis did not significantly affect the probability of becoming insulin dependent. ICAb positive diabetes controlled by OHA can be regarded as a less severe form of insulin-dependent (Type I) diabetes.