Pitfalls of HbA1c in the Diagnosis of Diabetes

Many health care providers screen high-risk individuals exclusively with an HbA1c despite its insensitivity for detecting dysglycemia. The 2 cases presented describe the inherent caveats of interpreting HbA1c without performing an oral glucose tolerance test (OGTT). The first case reflects the risk of overdiagnosing type 2 diabetes (T2D) in an older African American male in whom HbA1c levels, although variable, were primarily in the mid-prediabetes range (5.7-6.4% [39-46 mmol/mol]) for many years although the initial OGTT demonstrated borderline impaired fasting glucose with a fasting plasma glucose of 102 mg/dL [5.7 mmol/L]) without evidence for impaired glucose tolerance (2-hour glucose ≥140-199 mg/dl ([7.8-11.1 mmol/L]). Because subsequent HbA1c levels were diagnostic of T2D (6.5%-6.6% [48-49 mmol/mol]), a second OGTT performed was normal. The second case illustrates the risk of underdiagnosing T2D in a male with HIV having normal HbA1c levels over many years who underwent an OGTT when mild prediabetes (HbA1c = 5.7% [39 mmol/mol]) developed that was diagnostic of T2D. To avoid inadvertent mistreatment, it is therefore essential to perform an OGTT, despite its limitations, in high-risk individuals, particularly when glucose or fructosamine and HbA1c values are discordant. Innate differences in the relationship between fructosamine or fasting glucose to HbA1c are demonstrated by the glycation gap or hemoglobin glycation index.

Review of methods for detecting glycemic disorders

Prediabetes (intermediate hyperglycemia) consists of two abnormalities, impaired fasting glucose (IFG) and impaired glucose tolerance (IGT) detected by a standardized 75-gram oral glucose tolerance test (OGTT). Individuals with isolated IGT or combined IFG and IGT have increased risk for developing type 2 diabetes (T2D) and cardiovascular disease (CVD). Diagnosing prediabetes early and accurately is critical in order to refer high-risk individuals for intensive lifestyle modification. However, there is currently no international consensus for diagnosing prediabetes with HbA1c or glucose measurements based upon American Diabetes Association (ADA) and the World Health Organization (WHO) criteria that identify different populations at risk for progressing to diabetes. Various caveats affecting the accuracy of interpreting the HbA1c including genetics complicate this further. This review describes established methods for detecting glucose disorders based upon glucose and HbA1c parameters as well as novel approaches including the 1-hour plasma glucose (1-h PG), glucose challenge test (GCT), shape of the glucose curve, genetics, continuous glucose monitoring (CGM), measures of insulin secretion and sensitivity, metabolomics, and ancillary tools such as fructosamine, glycated albumin (GA), 1,5- anhydroglucitol (1,5-AG). Of the approaches considered, the 1-h PG has considerable potential as a biomarker for detecting glucose disorders if confirmed by additional data including health economic analysis. Whether the 1-h OGTT is superior to genetics and omics in providing greater precision for individualized treatment requires further investigation. These methods will need to demonstrate substantially superiority to simpler tools for detecting glucose disorders to justify their cost and complexity.

Prevalence of obesity and its relationship to clinical lipodystrophy in HIV-infected adults on anti-retroviral therapy

BACKGROUND

Combination antiretroviral therapy (cART) is associated with lipodystrophy (lipoatrophy and lipoaccumulation) and several metabolic abnormalities that together can contribute to an increased cardiovascular risk. The aim of this study was to evaluate the prevalence of obesity in patients on cART according to the presence of clinical lipodystrophy (CL) and to analyze factors associated with obesity.

METHODS

We evaluated 368 HIV-infected adults on cART.

RESULTS

CL was present in 59.0%. Independently of gender, patients with CL were more frequently underweight [5.7% (21/368)] and of normal weight [47.3% (174/368)], and less frequently overweight [33.2% (122/368)] or obese [13.9% (51/368)]. Mean body mass index was higher in patients with abdominal prominence regardless of the presence of clinical lipoatrophy. Patients with CL had lower waist circumference, higher waist/hip and fat mass ratio and lower total and subcutaneous fat, without significant difference in visceral fat but with a higher visceral/subcutaneous fat ratio, as evaluated by CT at abdominal level. CL was significantly less frequent in overweight [odds ratio (OR)=0.21, 95% confidence interval (CI): 0.05-0.92] and obese (OR=0.05, 95%CI: 0.01-0.26) patients, when compared to underweight ones, independent of age, gender, duration of infection, cART regimen, virological suppression, and HIV-infection risk factor.

CONCLUSIONS

Being overweight or obese is highly prevalent in HIV-infected patients on cART. Patients with CL were more frequently under- or normal weight, and less frequently overweight or obese. Obesity is a condition that should be considered in HIV patients on cART.

Assessment of body fat composition disturbances by bioimpedance analysis in HIV-infected adults

HIV-lipodystrophy syndrome is characterized by different patterns of body fat distribution (BFD) which are identified by clinical and body composition (BC) assessment, including bioimpedance analysis (BIA). Our aim was to compare BC in HIV-infected patients on combination antiretroviral therapy (cART) according to 4 distinct phenotypes of BFD (G1-no lipodystrophy, G2-isolated central fat accumulation, G3-lipoatrophy, G4-mixed forms of lipodystrophy) and assessed factors associated with them. Anthropometry and BIA were performed in 344 HIV-1 patients. G2 and G4 phenotype patients had significantly higher fat mass (FM) but no differences were observed in fat-free mass (FFM) and total body water among the 4 phenotypes. Significant negative associations were found between the presence of lipoatrophy and female gender, body mass index (BMI), waist (WC), hip (HC) and thigh circumferences, and total body FM estimated by BIA. After adjustment for gender, cART duration and BMI, G3 had significant lower WC [odds ratio (OR)=0.84; 0.78- 0.90] and HC (OR=0.88; 0.81-0.96) mean. Independently of gender, cART duration and BMI, G2 remained significantly associated with higher WC (OR=1.11; 1.05-1.18) and HC (OR=1.15; 1.07-1.23) mean, and with FM estimated by BIA [FM as %, OR=1.17 (1.09-1.26); and FM as kg, OR=1.15 (1.06- 1.25)]. There was a significant positive association between G4 and female gender (OR=1.66; 1.01-2.75), BMI (OR=1.10; 1.04-1.17) and WC (OR=1.15; 1.09-1.21). The similar FFM along the BFD spectrum describes the actual BC of these patients without sarcopenia. In a clinical setting, BIA is an easy and useful tool to evaluate fat mass and FFM and gives us a picture of BC that was not possible with anthropometry.

A Randomized Trial Comparing Two Corticosteroid Regimens Combined With Mycophenolate Mofetil and Cyclosporine for Prevention of Acute Renal Allograft Rejection

INTRODUCTION

The launching of mycophenolate mofetil (MMF) has reduced the incidence of acute rejection episodes. We sought to evaluate the efficacy of decreasing the steroid dose.

MATERIALS AND METHODS

This was a quasiexperimental, randomized, prospective trial. We enrolled 150 patients who received de novo renal transplantations from living or cadaveric donors, fulfilling the screening criteria. Patients were randomized to one of the following two arms: (A) MMF at a 2 g/d dose, cyclosporine (CsA) at a dose necessary to achieve target levels, and corticosteroids at the usual doses; (B) MMF at a 2 g/d dose, CsA at a dose necessary to achieve target levels, and corticosteroids at doses 50% lower than those of group A.

RESULTS

Group A included 72 (48%) and group B, 78 patients (52%). There were no differences among the variables: leukopenia occurred in 11 patients in group A, and five patients in group B. Complications occurred in 67.4% (56) of group A, but only 32.6% (27) were related to infections. One case of urinary infection occurred in group B, while six occurred in group A. There was one case of acute rejection in group A, and none in group B. One graft loss occurred in group A. There were no differences in the remaining variables under study.

DISCUSSION

The results showed an increased complication rate related to receiving usual steroid doses. There was no increase in acute rejection episodes among patients receiving 50% of the usual steroid dose.

Genotype-phenotype relationships in Berardinelli-Seip congenital lipodystrophy

Generalised lipodystrophy of the Berardinelli-Seip type (BSCL) is a rare autosomal recessive human disorder with severe adverse metabolic consequences. A gene on chromosome 9 (BSCL1) has recently been identified, predominantly in African-American families. More recently, mutations in a previously undescribed gene of unknown function (BSCL2) on chromosome 11, termed seipin, have been found to be responsible for this disorder in a number of European and Middle Eastern families. We have studied the genotype/phenotype relationships in 70 affected subjects from 44 apparently unrelated pedigrees of diverse ethnic origin. In all subjects, hepatic dysfunction, hyperlipidaemia, diabetes mellitus, and hypertrophic cardiomyopathy were significant contributors to morbidity with no clear differences in their prevalence between subjects with BSCL1 or BSCL2 and those with evidence against cosegregation with either chromosome 9 or 11 (designated BSCLX). BSCL2 appears to be a more severe disorder than BSCL1 with a higher incidence of premature death and a lower prevalence of partial and/or delayed onset of lipodystrophy. Notably, subjects with BSCL2 had a significantly higher prevalence of intellectual impairment than those with BSCL1 or BSCLX (p<0.0001, OR 17.0, CI 3.6 to 79.0). The higher prevalence of intellectual impairment and the increased risk of premature death in BSCL2 compared to BSCL1 emphasise the importance of molecular diagnosis of this syndrome and have clear implications for genetic counselling.

[Craniopharyngiomas. Clinicopathological aspects in different age groups]

Craniopharyngiomas are rare brain tumors of the hypothalamo-pituitary region, developing from embryonic remnants of Rathke's pouch and sac. Their overall incidence is 0.13 per 100,000 person years. Most frequently, they are suprasellar, start growing in childhood and originate neurological and hormonal symptoms. We retrospectively studied patients treated in our institution for craniopharyngioma in the last 10 years, in order to evaluate their clinical, imaging and pathological characteristics. Of the 32 patients analysed, 18 were females and 14 males with ages ranging between 6 and 81 years (early onset group--EOG aged 5-14 years: 7 patients; middle age onset group--MAOG aged 15-49 years: 15 patients; late age onset group--LOG aged > or = 50 years: 10 patients). Visual impairment was the most frequent presenting clinical feature in EOG (71.4%) and MAOG (86.6%), while in the LOG personality and cognitive changes including memory loss predominated (60%). Headaches were very frequent in all groups (EOG 42.8%, MAOG 60%, LOG 40%). Meningitis and seizures were presenting features, each in one patient. Regarding endocrine symptoms and signs, growth failure was present in 57.2% of the EOG. Amenorrhea was present in 5 of 10 female patients of the MAOG. Preoperatively, TSH was deficient in 25%, ACTH in 15.6% and gonadotropin in 25% of the patients. There were no cases of diabetes insipidus. Preoperative CT and MR revealed a calcified mass in 12 (37.5%), a partially cystic mass in 20 (62.5%) and a lesion involving or extending into the third ventricle in 7 (21.9%) patients. Twenty seven (84.4%) patients were treated primarily by surgery. In 4 (12.5%) cases the tumour was considered inoperable and 1 (3.1%) patient refused surgery; all were in the LOG. Surgical approach was transsphenoidal in 2/27 (7.4%) (all of them in the LAOG) and by craniotomy in the others. The tumour removable was considered complete in 10 (37%--EOG 2/7, MAOG 6/15, LOG 2/5) and subtotal in 17 (62.9%) patients. Eight (29.6%) patients were reoperated for recurrent tumour. Postoperative radiotherapy was administered in 12 cases with residual tumor, and 3 inoperable tumors were treated primarily by conventional external radiotherapy. Pathological study revealed the adamantinomatous type in 25 (92.6%) and the papillary type in 2 (7.4%--all men in the MAOG) tumors. The average follow-up was longer in the EOG (82.6 +/- 40.7 months) than in MAOG (57.2 +/- 48.5 months) and in LOG (48 +/- 92 months). Four (12.5%) patients died, 1 during the follow-up period due to a radiation-induced astrocytoma and 3 in the postoperative period because of cerebral hemorrhage and hydrocephalus (1 in the EOG and 2 in the LOG). In summary, we found the clinical presentation to be different in the 3 age groups, with a large number of patients in the MAOG. In this group were the only examples of the papillary form. Better prognosis was associated with a total resection at initial surgery.

Prevalence and risk factors of clinical diabetic polyneuropathy in a Portuguese primary health care population

OBJECTIVE

Distal symmetrical polyneuropathy in diabetics (DPN) has a variable prevalence around 30% and increases the risk for foot ulcers and amputations. We aimed at evaluating the prevalence of clinical DPN and associated risk factors in patients followed in primary care centers.

MATERIAL AND METHODS

101 type 2 diabetics were evaluated and 8 were excluded due to the presence of other causes of neuropathy. The remaining 93 had a mean age of 65.4 +/- 10.1 years and a mean diabetes duration of 10.1 +/- 11.1 years, 60.2% were women and 39.8% men. DPN was defined as the presence of both altered sensitivities and reflexes, regardless of symptoms.

RESULTS

Seventy-two (80%) patients had symptoms of polyneuropathy, but DPN was present only in 29 (32.2%). Calluses (37.8%) and trophic skin (74.4%) and nail (75.6%) changes were found in both feet. There was a significant positive association of DPN with age (69.0 +/- 9.1 vs 63.3 +/- 9.9 years, p=0.01), disease duration (15.7 +/- 13.5 vs 7.2 +/- 8.8 years, p=0.001), feet skin changes (38.8 vs 13.0%, p=0.04) and myocardial infarction/ischemia (14.8 vs 1.7%, p=0.03).

CONCLUSIONS

This sample of diabetic patients cared by family doctors presented a high prevalence of DPN. Aging, disease duration, the presence of feet skin changes and myocardial infarction/ischemia are factors that increase the prevalence of the disease. Primary care doctors awareness of the problem might help to decrease the associated morbidity.

Identification of the gene altered in Berardinelli-Seip congenital lipodystrophy on chromosome 11q13

Congenital generalized lipodystrophy, or Berardinelli-Seip syndrome (BSCL), is a rare autosomal recessive disease characterized by a near-absence of adipose tissue from birth or early infancy and severe insulin resistance. Other clinical and biological features include acanthosis nigricans, hyperandrogenism, muscular hypertrophy, hepatomegaly, altered glucose tolerance or diabetes mellitus, and hypertriglyceridemia. A locus (BSCL1) has been mapped to 9q34 with evidence of heterogeneity. Here, we report a genome screen of nine BSCL families from two geographical clusters (in Lebanon and Norway). We identified a new disease locus, designated BSCL2, within the 2.5-Mb interval flanked by markers D11S4076 and D11S480 on chromosome 11q13. Analysis of 20 additional families of various ethnic origins led to the identification of 11 families in which the disease cosegregates with the 11q13 locus; the remaining families provide confirmation of linkage to 9q34. Sequence analysis of genes located in the 11q13 interval disclosed mutations in a gene homologous to the murine guanine nucleotide-binding protein (G protein), gamma3-linked gene (Gng3lg) in all BSCL2-linked families. BSCL2 is most highly expressed in brain and testis and encodes a protein (which we have called seipin) of unknown function. Most of the variants are null mutations and probably result in a severe disruption of the protein. These findings are of general importance for understanding the molecular mechanisms underlying regulation of body fat distribution and insulin resistance.

[Quality of health care]

Quality assurance is a relatively recent concern but already plays a major role in health care management and provision. Quality involves the definition of a comprehensive programme tailored by realistic and effective objectives and norms that include the structured review of procedures (namely clinical audits) and the use of up-to-date protocols. The involvement and motivation of health professionals, together with an adequate internal and external communication strategy, play a key role in the planning and application of these programmes. The use of programmed assessment, based on a solid knowledge of current practice, should have practical implications, optimising procedures in order to improve the quality of care. This commitment towards quality in health care should go far beyond governmental policy and should have clear support from health professionals.

The value of transesophageal echography in the clinical staging of lung cancer

The noninvasive preoperative assessment of lung cancer is currently based on CT scan. This technique is used to find out the local extension of the tumor and to identify the presence of mediastinal adenopathies by distinguishing as accurate as possible between benign and metastatic adenopathies according to their size. When CT scan suggests the presence of suspected mediastinal lymph nodes, invasive diagnostic methods are indicated to confirm whether the lymph nodes are affected (transbronchial needle aspiration, mediastinoscopy, mediastinotomy and thoracoscopy). Transesophageal echography (TEE) was first used in the 80's as a diagnostic guide in the clinical classification of gastrointestinal tumors and may be of help in the mediastinal evaluation of lung cancer as well. Several studies have demonstrated the value of TEE in detecting mediastinal adenopathies and mediastinal structures involvement (great vessels and mediastinal organs) by assessing the direct growth of the primary tumor which is crucial in the surgical decision. To distinguish benign from metastatic nodes TEE, unlike CT scan, does not consider their size only but other issues as shape, definition of edges and echographic structure. Generally speaking, TEE detects more adenopathies than CT scan but not in all mediastinal stations since it is limited by the presence of air; thus, adenopathies located in the upper mediastinum, mainly on the right side, are usually missed by TEE. The areas more clearly visualized are the subcarinal, paraesophageal, tracheobronchial and hilar ones and mainly those located in the aortopulmonary window. Currently, TEE can be used also to guide a thin needle toward the lymph nodes and to perform its aspiration biopsy. In conclusion, transesophageal and/or endobronchial echography are developing promising diagnostic methods which provide additional information that can influence the clinical decision making process and the prognosis. They are well tolerated by the patients but time is needed to find out their role. Lastly, their usefulness will depend also on their feasibility since an expensive equipment and specifically well trained staff are needed.

The Spanish data base for the staging of lung cancer. Experience of the Bronchogenic Carcinoma Cooperative Group of the Spanish Society of Pneumology and Thoracic Surgery (GCCB-S)

The Bronchogenic Carcinoma Cooperative Group of the Spanish Society of Pneumology and Thoracic Surgery (GCCB-S) has been enrolled in a prospective data collection project from patients with bronchogenic carcinoma who underwent thoracotomy in 20 Spanish hospitals from October 1993 to September 1997. In this 4-year period, 2995 patients were registered and demographic, clinical, biological, diagnostic, surgical, pathological and follow-up information collected in a homogeneous way. The main objectives of the Group are to describe the population with lung cancer at the time of diagnosis in Spain; to analyse operative morbi-mortality; and to identify multiple prognostic factors. So far, some preliminary results have already been published concerning the description of the population, the methodology of the Group, the assessment of morbi-mortality, and the validation of the 1997 TNM classification.

Inefficiency of the anticoagulant therapy in the regression of the radiation-induced optic neuropathy in Cushing's disease

Radiation-induced optic neuropathy is a rare complication (prevalence less than 1%) following radiotherapy of the sellar region. However, the vasculopathy in Cushing's disease predisposes to radiation-induced injury. We report the case of a 24-year-old man with Cushing's disease since he was 16. The hormonal study including bilateral inferior petrosal sinus catheterization diagnosed a pituitary right lesion, but imagiology was always negative. He underwent a transsphenoidal microadenomectomy and the pathological study showed the presence of corticotrophic hyperplasia but no adenoma. Secondary hypothyroidism and hypogonadism as well as permanent diabetes insipidus were diagnosed and because the patient was not cured he underwent a second transsphenoidal total hypophysectomy. After that and because he was still hypercortisolemic, pituitary external irradiation was given in a total dose of 6000 rad. Six months later he developed progressive bilateral visual loss. Cerebral MR revealed focal enhancement of the enlarged optic nerves and chiasm, associated with demyelination areas of the posterior visual pathways. Treatment was tried first with high doses of corticosteroids and later with anticoagulants-heparin EV. 1000 U/h during 7 days followed by warfarin, but unsuccessfully, probably because the patient was already amaurotic at the beginning of the last treatment.

Prevention of peritonitis with disconnect systems in CAPD: a randomized controlled trial. The Mexican Nephrology Collaborative Study Group

BACKGROUND

Recently, disconnect systems for CAPD that are associated with a reduced frequency of peritonitis have been introduced. Our objective was to compare the incidence of peritonitis using three current CAPD systems in a high-risk population with low educational and socioeconomic levels, and high prevalence of malnutrition.

METHODS

In a prospective controlled trial, 147 patients commencing CAPD were randomly assigned to one of three groups: 29 to the conventional, 57 to the Y-set, and 61 to the twin bag systems. The number of peritonitis episodes was registered, and patients were followed up for an average of 11.3 months.

RESULTS

The average peritonitis-free interval for the conventional group was 6.1 months, for the Y system was 12.0 months, and for the twin bag was 24.8 months (P < 0.001). By multivariate analysis, the only factor associated with peritonitis was the CAPD system. Peritonitis-related hospitalization was 5.3 +/- 2.0, 2.7 +/- 1.0, and 1.5 +/- 0.9 days/patient/year in the conventional, Y system, and twin bag groups, respectively. The cost per bag was similar for the conventional and Y system, but higher for the twin bag. However, the total costs of treatment (pesos/patient/year) were lower for twin bag (62,159 for the conventional, 70,275 for the Y system, and 54,387 for the twin bag), due to the lower peritonitis incidence and associated hospitalizations.

CONCLUSIONS

Y system and twin bag use was associated with a reduction of 50 and 75% peritonitis incidence, respectively, in patients on CAPD. The cost of the twin bag was actually lower, because of savings from a decreased usage of antibiotics and fewer hospitalizations.

[Medical aspects of urinary tract lithiasis]

The authors review some etiological, clinical and diagnostic aspects of nephrolithiasis, describing briefly the approach that should be taken to study this disease. Some of the practical aspects of its treatment are also discussed.

[Building up nursing knowledge by means of reflexive practice]

After analyzing the prior questions which determine the nursing field contents, the authors propose "reflective practice" as the methodological and pedagogical philosophy of choice in the formation of nurses. According to the authors, the professor is responsible for developing the curriculum. As such, the professor makes decisions regarding course design, methodology, content development, and student evaluation in terms of aptitute, attitude and knowledge acquisition. Research studies seem to demonstrate that the knowledge which, in the end, aids in comprehending the context taught and which determines the decisions a professor takes, is that knowledge based on a reflective practice, a product of the professor's experiences, background, knowledge and active relationship with nursing practice. The contents in this article were presented as a conference in the Third Seminar of Professors of Nursing for General Practice and Surgery.

Laminin alpha 5, a major transcript of normal and malignant rat liver epithelial cells, is differentially expressed in developing and adult liver

The laminin family of extracellular matrix glycoproteins plays a major role in cell migration and differentiation and in tumor cell invasion. As previously shown, the laminin deposited by normal and malignant rat liver epithelial cells in their extracellular matrix (ECM) and into their ECM migration tracks does not contain a typical (EHS-like) alpha 1 heavy chain. By RT-PCR screening we have now identified two alpha chains among a total of five additional laminin chains produced by these cells. Three of the newly identified chains were not previously known for the rat. Their sequences have been deposited in the EMBL nucleotide sequence data bank. The alpha 5 chain now identified is expressed at comparably high levels by both the normal and the malignant liver epithelial cells. The chain is also expressed in fetal liver together with the alpha 2 and beta 2 chains, but it is only vestigially expressed in the mature organ as shown by RT-PCR. These results suggest for alpha 5 a role in development and production of the chain by only a small subset of cells in adult liver. At the level of detection used, no changes were observed in regenerating liver after partial hepatectomy. In addition to the alpha 5 chain, the cultured cells express the beta 1 and beta 2 light chains, indicating the expression of more than one laminin isoform by the same cell line. The expression of the alpha 5 chain and of the other new non-EHS isoform chains was also analyzed in various tissues. The malignant liver epithelial cells, but not their nontumorigenic parental cells, also express, in addition to the alpha 5 chain the alpha 2 chain, which is expressed at high level by the NBT II bladder carcinoma cell line, suggesting a relationship with malignancy.

Imaging of post-transplant spindle cell tumors

Spindle/smooth muscle cell proliferation is an additional neoplastic process related to immunosuppression and EBV infection. We describe four post transplant children with this diagnosis. Multiple organ systems may be involved, particularly the liver, gastrointestinal tract, and lungs. Lesions are radiographically, clinically, and endoscopically indistinguishable from those of post-transplant lymphoproliferative disease (PTLD).

Imaging systems evaluation: effect of subtle cases on the design and analysis of receiver operating characteristic studies

OBJECTIVE

Large-scale receiver operating characteristic (ROC) studies are expensive and time-consuming. If most of the difference in diagnostic accuracy occurs in a subset of subtle cases, considerable effort could be saved by restricting comparisons to this subset. We investigate the effect of subtle cases on diagnostic accuracy, the magnitude of error that can occur because of an imbalance of subtle cases in two groups, and the potential for sample size reductions if only subtle cases are used.

METHODS

Data from a previous study of posteroanterior chest radiographs were reanalyzed separately for subsets of typical cases and subsets of subtle cases. Actually positive and actually negative cases were classified as subtle or typical and as difficult or easy for diagnosis of the specific abnormality. The area under the ROC curve (Az) was used as the measure of diagnostic accuracy. Pairwise comparisons were done among three techniques and for the detection of nodules and interstitial disease.

RESULTS

The performance index (Az) was significantly (> or = 25%) lower for the subset of subtle cases as compared with the subset of typical cases. The difference in observer performance between two techniques was more often greater in the subset of subtle cases than in the subset of typical cases.

CONCLUSION

The difference in diagnostic accuracy between the subset of typical cases and the subset of subtle cases is large enough that a difference in the proportion of subtle cases in two samples could result in clinically significant false differences in observer performance. Furthermore, the generally larger difference observed in the group of subtle cases suggests that sample sizes for some experiments could be reduced by 45-90% if the experiment were restricted to subtle cases.

Characterization and distribution of cholinesterase activity in mouse uterine horns: changes in estrous cycle

1. Both butyrylcholinesterase (BChE) and acetylcholinesterase (AChE) are present in the mouse uterus, BChE being more abundant. 2. Their molecular forms were sequentially solubilized by different extraction media obtaining three ChE fractions whose specific activity was different, depending on the stage of the estrous cycle: hydrosoluble (estrous: 75.5 +/- 6.6 and diestrous: 47.9 +/- 8.7 mU/mg prot); detergent-soluble or amphiphilic (estrous 26.6 +/- 2.4 and diestrous 14.7 +/- 3.3 mU/mg prot.), and high ionic strength-soluble (estrous: 18.7 +/- 4.2 and diestrous 12.8 +/- 1.2 mU/mg prot.). 3. Histochemical procedures demonstrated a different distribution for both ChE activities. AChE was found in nerves next to smooth muscle cells of the circular layer and blood vessels, while BChE was concentrated in the longitudinal stratum surrounding the smooth muscle cells. Under the predominance of progesterone, BChE was also found in the endometrial glands. 4. Maximal contractions evoked by the addition of ACh to the isolated organ bath were concentration dependent and greater in estrous than in diestrous. Nevertheless the difference at the two stages of the estrous cycle disappeared when contractions were normalized to smooth muscle cross-sectional area. 5. BChE but not AChE inhibition augmented maximal contractions elicited by ACh in longitudinal but not in circular smooth muscle. 6. The effect of BChE inhibition on the contractile force developed was greater at lower concentrations of ACh and did not depend on the stage of the estrous cycle.

Nicotine stimulates adrenergic terminals and inhibits contractions of mouse uterine horns

1. Nicotine (1-100 microM) stimulated both basal and electrically evoked release of 3H-norepinephrine and also caused a transient inhibition of contractions in an in vitro preparation of mouse uterine horns. 2. The inhibitory effect of nicotine on electrically evoked contractions was potentiated by aminophylline (89 micrograms/ml), and overcome by both propranolol (1 microM) and by omitting magnesium from the physiological solution. Acetylcholine (10 microM), in the presence of atropine (10 microM) was able to reproduce the inhibitory effect of nicotine. 3. These pharmacological findings suggest that the inhibitory action of nicotine on electrically evoked contractions in mouse uterus could be indirect, i.e. mediated through the action of this compound on presynaptic nicotine receptors located on adrenergic terminals.

Efficacy of an individualized outpatient program in the treatment of chronic post-traumatic headache

Twenty patients disabled for work because of chronic post-traumatic headaches were treated: 13 men, and seven women. Their ages ranged between 26 and 69 years (mean = 40.3). Their accidents occurred three months to eight years prior to the initial visit (mean = 1.5 yrs). Thirteen patients had concurrent spinal injuries. They were assigned to an individualized program with emphasis on doctor-patient relationship. All patients received medications, biofeedback, and educational sessions. Thirteen patients with concurrent spinal injuries received additionally therapeutic exercises and transcutaneous nerve stimulation. Five patients needed neuromuscular re-education, and three, stress management. All sessions were individualized. Patients attended the Center one to three times a week for three to 12 weeks (average = 9 weeks). The number of treatment days ranged from six to 37 (average = 18.8 days). The average cost of the program for patients with headache alone was $3849.00; and for those with additional spinal injuries, $7030.00. All patients improved: markedly, 14; moderately, four; and slightly, two patients. The improvement occurred within seven to 150 days (average = 48.7 days). Seventeen out of the 20 patients, (85%) returned to work within 21-224 days (average = 111 days). An individualized outpatient program is very successful in the treatment of post-traumatic headache.

Organic headaches mimicking chronic paroxysmal hemicrania

The article describes two women who had headaches that mimicked chronic paroxysmal hemicrania (CPH). The first patient had a collagen vascular disorder; and the second one, a large malignant tumor in the right frontal lobe. The similarity of the headaches of the first patient to CPH included an absolute response to indomethacin. The existence of these cases may lead to a better understanding of the pathophysiology of CPH. At the same time, their existence also calls for caution in the diagnosis of CPH.

Pediatric chest trauma

Blunt and penetrating chest trauma in children results from many causes but the major cause is motor vehicle accidents. The trauma induces a variety of injuries to the bony thorax, the pulmonary parenchyma, and mediastinal structures. In recent years, a disturbing increase in iatrogenic chest trauma has occurred in patients, particularly small infants, receiving intensive hospital care. Radiologic evaluation plays an important role in documenting and diagnosing these traumatic and iatrogenic injuries. The various radiologic manifestations of these injuries are described and discussed.

Cluster headache variant. Spectrum of a new headache syndrome

The syndrome of cluster headache variant is characterized by the occurrence of three combined symptoms: atypical cluster headaches, multiple jabs, and background vascular headaches. Atypical cluster headaches are localized headaches that occur several times daily, usually without any headache-free periods. They differ from the typical chronic cluster headache in their location, duration, frequent shifting, and frequency. Multiple jabs are short-lasting, sharp pains of variable severity and location. Background vascular headache is a chronic, continuous often unilateral headache of variable severity that throbs at rest or begins to throb during exertion. We have studied 54 patients between the ages of 14 and 78 years (average age, 40.5 years). Forty-five (83%) patients responded to indomethacin. Complete control was achieved in 50% of the patients. The nine patients who did not respond to indomethacin were depressed. These nine patients responded well to tricyclic antidepressants.

Cyclical migraine

We have observed 27 migraineurs whose headaches occurred in groups separated by headache-free periods. Twenty-one of the patients were women. The headaches occurred on either side in most patients. The headaches were severe lasting for an average of 25.5 hours, often preceded by scintillating scotomas, and often associated with nausea, vomiting, and photophobia. The attacks occurred in cycles that lasted an average of six weeks. The cycles recurred an average of five times per year; during the cycles, severe migraine occurred several times per week. In many patients, the cycles were often accompanied by a constant, low-grade headaches and depression. Twenty-two patients were treated with lithium carbonate. Complete or partial control of the headaches was achieved in 19 patients.

Lithium carbonate therapy for cluster headache. Changes in number of platelets, and serotonin and histamine levels

Three groups of patients were studied: Group A consisted of 12 patients with cluster headache that was treated with lithium carbonate. Group B consisted of six patients with cluster headache that was managed with other drugs. Group C consisted of five patients with muscle contraction headache who received lithium. Serum lithium levels, platelet count, platelet serotonin levels, and platelet-rich plasma histamine levels were determined before and during therapy. The frequency of the headache and levels of serotonin and histamine tended to follow a parallel course in groups A and B: as the headache frequency dropped, serotonin and histamine levels fell. The stable period was characterized by little change in serotonin and histamine levels. Recurrences of headaches were accompanied by a return of serotonin and histamine to pretreatment levels. The course of cluster headache is related to changes in serotonin and histamine levels. Lithium, by modifying the headache course, changes serotonin and histamine levels.

Syndrome of agitated delirium and visual impairment: a manifestation of medial temporo-occipital infarction

Three patients presented with sudden visual impairment followed by agitated delirium one to three days later. Examination revealed marked agitation, dementia, and loss of vision. Computerised axial tomography demonstrated temporo-occipital infarctions. All recovered from the agitated state in four days to two months, but their visual impairment and dementia persisted one to four years later.

The clinical link between migraine and cluster headaches

We describe seven patients with vascular headaches. Five of them had cluster headaches, which were preceded by migrainous scotamata (two patients), weakness contralateral to the pain (one), accompanied by ipsilateral photopsias (one), or by contralateral paresthesias (one). The other two patients had "clusters" of daily common migraine headaches separated by long free intervals. The symptoms of these patients suggest a common root for cluster and migraine headaches.

Localized myokymia caused by peripheral nerve injury

One year after a gunshot wound in the popliteal fossa, a 30-year-old man began to experience cramps and myokymia in the left gastrocnemius muscle. Myokymia was characterized by vermicular fibrillary movements localized to the gastrocnemius muscle and accompanied by plantarflexion and dorsiflexion of the toes. Neurologic examination, nerve conduction velocities, electromyograms, and muscle biopsy findings showed affection of left common peroneal and posterior tibial nerves. The myokymia disappeared during sleep, spinal anesthesia, and treatment with carbamazepine.