Double-blind randomized trial of tramadol for the treatment of the pain of diabetic neuropathy

OBJECTIVE

The objective of this study was to evaluate the efficacy and safety of tramadol in treating the pain of diabetic neuropathy.

BACKGROUND

The pain of diabetic neuropathy is a major cause of morbidity among these patients and treatment, as with other small-fiber neuropathies, is often unsatisfactory. Tramadol is a centrally acting analgesic for use in treating moderate to moderately severe pain.

METHODS

This multicenter, outpatient, randomized, double-blind, placebo-controlled, parallel-group study consisted of a washout/screening phase, during which all analgesics were discontinued, and a 42-day double-blind treatment phase. A total of 131 patients with painful diabetic neuropathy were treated with tramadol (n=65) or placebo (n=66) tramadol, which were administered as identical capsules in divided doses four times daily. The primary efficacy analysis compared the mean pain intensity scores in the tramadol and placebo groups obtained at day 42 of the study or at the time of discontinuation. Secondary efficacy assessments were the pain relief rating scores and a quality of life evaluation based on daily activities and sleep characteristics.

RESULTS

Tramadol, at an average dosage of 210 mg/day, was significantly (p < 0.001) more effective than placebo for treating the pain of diabetic neuropathy. Patients in the tramadol group scored significantly better in physical (p=0.02) and social functioning (p=0.04) ratings than patients in the placebo group. No statistically significant treatment effects on sleep were identified. The most frequently occurring adverse events with tramadol were nausea, constipation, headache, and somnolence.

CONCLUSIONS

The results of this placebo-controlled trial showed that tramadol was effective and safe in treating the pain of diabetic neuropathy.

Clinical Laboratory Practice Recommendations for the Use of Cardiac Troponin in Acute Coronary Syndrome: Expert Opinion from the Academy of the American Association for Clinical Chemistry and the Task Force on Clinical Applications of Cardiac Bio-Markers of the International Federation of Clinical Chemistry and Laboratory Medicine

This document is an essential companion to the third iteration of the National Academy of Clinical Biochemistry [NACB,8 now the American Association for Clinical Chemistry (AACC) Academy] Laboratory Medicine Practice Guidelines (LMPG) on cardiac markers. The expert consensus recommendations were drafted in collaboration with the International Federation of Clinical Chemistry and Laboratory Medicine Task Force on Clinical Applications of Bio-Markers (IFCC TF-CB). We determined that there is sufficient clinical guidance on the use of cardiac troponin (cTn) testing from clinical practice groups. Thus, in this expert consensus document, we focused on clinical laboratory practice recommendations for high-sensitivity (hs)-cTn assays. This document utilized the expert opinion class of evidence to focus on the following 10 topics: (a) quality control (QC) utilization, (b) validation of the lower reportable analytical limits, (c) units to be used in reporting measurable concentrations for patients and QC materials, (d) 99th percentile sex-specific upper reference limits to define the reference interval; (e) criteria required to define hs-cTn assays, (f) communication with clinicians and the laboratory's role in educating clinicians regarding the influence of preanalytic and analytic problems that can confound assay results, (g) studies on hs-cTn assays and how authors need to document preanalytical and analytical variables, (h) harmonizing and standardizing assay results and the role of commutable materials, (i) time to reporting of results from sample receipt and sample collection, and (j) changes in hs-cTn concentrations over time and the role of both analytical and biological variabilities in interpreting results of serial blood collections.

Isolated adrenal masses in nonsmall-cell bronchogenic carcinoma

Computed tomography has become an important diagnostic modality in the preoperative staging of patients with bronchogenic carcinoma. The adrenal glands represent one of the most frequent sites of metastasis. Therefore, an isolated adrenal mass discovered on preoperative thoracoabdominal CT poses a diagnostic problem. Three hundred thirty patients with histologically proved nonsmall-cell bronchogenic carcinoma were evaluated. Thirty-two had adrenal masses without further evidence of disease in the abdomen. Eight of these 32 masses were metastases, 17 were proved adenomas, and seven did not undergo biopsy. Thus, in the patients with nonsmall-cell bronchogenic carcinoma, an isolated adrenal mass is more likely benign than metastatic, and biopsy is advocated prior to withholding potentially curative surgery.

Human herpesvirus 8 LANA interacts with proteins of the mSin3 corepressor complex and negatively regulates Epstein-Barr virus gene expression in dually infected PEL cells

The human herpesvirus 8 (HHV-8) latency-associated nuclear antigen (LANA) is expressed in all latently HHV-8 infected cells and in HHV-8-associated tumors, including primary effusion lymphoma (PEL). To better understand the contribution of LANA to tumorigenesis and to the PEL phenotype, we performed a yeast two-hybrid screen which identified the corepressor protein SAP30 as a LANA binding protein. SAP30 is a constituent of a large multicomponent complex that brings histone deacetylases to the promoter. Glutathione S-transferase affinity assays confirmed interaction between LANA and SAP30 and also demonstrated interactions between LANA and two other members of the corepressor complex, mSin3A and CIR. The corepressors bound to the amino-terminal 340-amino-acid domain of LANA. In transient expression assays, this same domain of LANA mediated repression when targeted to a 5xGal4tk-CAT reporter as a GAL4-LANA fusion. PEL cells have the unusual feature that they are frequently dually infected with both HHV-8 and Epstein-Barr virus (EBV). We found that EBV EBNA-1 expression is downregulated in PEL cells at both the RNA and protein levels. In transient expression assays, LANA repressed activated expression from the EBV Qp and Cp latency promoters. Reduction of endogenous Qp activity could also be demonstrated in EBV-infected Rael cells transfected with a LANA expression plasmid. In contrast to the effect of LANA on EBV latency promoters, LANA activated expression from its own promoter. The data indicate that LANA can mediate transcriptional repression through recruitment of an mSin3 corepressor complex and further that LANA-mediated repression is likely to contribute to the low level of EBV latency gene expression seen in dually infected PEL cells.

Focal therapy in prostate cancer-report from a consensus panel

PURPOSE

To establish a consensus in relation to case selection, conduct of therapy, and outcomes that are associated with focal therapy for men with localized prostate cancer.

MATERIAL AND METHODS

Urologic surgeons, radiation oncologists, radiologists, and histopathologists from North America and Europe participated in a consensus workshop on focal therapy for prostate cancer. The consensus process was face to face within a structured meeting, in which pertinent clinical issues were raised, discussed, and agreement sought. Where no agreement was possible, this was acknowledged, and the nature of the disagreement noted.

RESULTS

Candidates for focal treatment should have unilateral low- to intermediate-risk disease with clinical stage <or=cT(2a). Prostate size and both tumor volume and tumor topography are important case selection criteria that depend on the ablative technology used. Currently, the best method to ascertain the key characteristics for men who are considering focal therapy is exposure to transperineal template mapping biopsies. MRI of the prostate using novel techniques such as dynamic contrast enhancement and diffusion weighed imaging are increasingly being used to diagnose and stage primary prostate cancer with excellent results. For general use, however, these new techniques require validation in prospective clinical trials. Until such are performed, MRI will, in most centers, continue to be an investigative tool in assessing eligibility of patients for focal therapy.

CONCLUSIONS

Consensus was derived for most of the key aspects of case selection, conduct of treatment, and outcome measures for men who are undergoing focal therapy for localized prostate cancer. The level of agreement achieved will pave the way for future collaborative trials.

Maintenance of the long-term effectiveness of tramadol in treatment of the pain of diabetic neuropathy

OBJECTIVE

The objective of this study was to evaluate the efficacy and safety of tramadol in a 6-month open extension following a 6-week double-blind randomized trial.

RESEARCH DESIGN AND METHODS

Patients with painful diabetic neuropathy who completed the double-blind study were eligible for enrollment in an open extension of up to 6 months. All patients received tramadol 50-400 mg/day. Self-administered pain intensity scores (scale 0-4; none to extreme pain) and pain relief scores (scale -1-4; worse to complete relief) were recorded the first day of the open extension (last day of the double-blind phase) and at 30, 90, and 180 days.

RESULTS

A total of 117 patients (56 former tramadol and 61 former placebo) entered the study. On the first day of the study, patients formerly treated with placebo had a significantly higher mean pain intensity score (2. 2+/-1.02 vs. 1.4+/-0.93, P<0.001) and a lower pain relief score (0. 9+/-1.43 vs. 2.2+/-1.27, P<0.001) than former tramadol patients. By Day 90, both groups had mean pain intensity scores of 1.4, which were maintained throughout the study. Mean pain relief scores (2. 4+/-1.09 vs. 2.2+/-1.14) were similar after 30 days in the former placebo and former tramadol groups, respectively and were maintained for the duration of the study. Four patients discontinued therapy due to ineffective pain relief; 13 patients discontinued due to adverse events. The most common adverse events were constipation, nausea, and headache.

CONCLUSIONS

Tramadol provides long-term relief of the pain of diabetic neuropathy.

Directed evolution of RuBisCO hypermorphs through genetic selection in engineered E.coli

The Calvin Cycle is the primary conduit for the fixation of carbon dioxide into the biosphere; ribulose 1,5-bisphosphate carboxylase/oxygenase (RuBisCO) catalyzes the rate-limiting fixation step. Our goal is to direct the evolution of RuBisCO variants with improved kinetic and biophysical properties. The Calvin Cycle was partially reconstructed in Escherichia coli; the engineered strain requires the Synechococcus PCC6301 RuBisCO for growth in minimal media supplemented with a pentose. We randomly mutated the gene encoding the large subunit of RuBisCO (rbcL), co-expressed the resulting library with the small subunit (rbcS) and the Synechococcus PCC7492 phosphoribulokinase (prkA), and selected hypermorphic variants. The RuBisCO variants that evolved during three rounds of random mutagenesis and selection were over-expressed, and exhibited 5-fold improvement in specific activity relative to the wild-type enzyme. These results demonstrate a new strategy for the artificial selection of RuBisCO and other non-native metabolic enzymes.

Yeast killer toxin: site-directed mutations implicate the precursor protein as the immunity component

Yeast killer toxin and a component giving immunity to it are both encoded by a gene specifying a single 35 kd precursor polypeptide. This precursor is composed of a leader peptide, the alpha and beta subunits of the secreted toxin, and a glycosylated gamma peptide separating the latter. The toxin subunits are proteolytically processed from the precursor during toxin secretion. Using site-directed mutagenesis, we have identified a region of the precursor gene necessary for expression of the immunity phenotype. This immunity-coding region extends through the C-terminal half of the alpha subunit into the N-terminal part of the gamma glycopeptide. Mutations in other parts of the gene allow full immunity but produce precursors that fail to be processed. The precursor can therefore confer immunity, and we propose that it does so in the wild type by competing with mature toxin for binding to a membrane receptor.

Efficacy of octyl-2-cyanoacrylate tissue glue in blepharoplasty. A prospective controlled study of wound-healing characteristics

OBJECTIVE

To compare the surgical efficacy and wound-healing characteristics of the tissue adhesive octyl-2-cyanoacrylate (approved by the Food and Drug Administration) with traditional suture closure in upper blepharoplasty.

METHODS

Prospective, randomized, blinded study comparing cosmetic and functional outcome and time efficiency. Twenty subjects underwent upper eyelid blepharoplasty. Each patient had a control side and an experimental side determined randomly. One eyelid incision was closed with octyl-2-cyanoacrylate (Dermabond; Ethicon Inc, Somerville, NJ) tissue glue, and the other with 6.0 suture (polypropylene or fast-absorbing gut). Comparisons were performed for the time for closure by each method, wound healing, and patient satisfaction. Macrophotographs of the wounds at 1, 2, and 4 weeks after surgery were graded by 5 observers blinded to the closure method, using a 10-point scale and a modified Hollander wound evaluation scale.

RESULTS

No statistically significant difference was found between the quality of octyl-2-cyanoacrylate closure and suture closure at 1 month. There were no differences in wound complications, duration of healing, inflammation, or final incision appearance. By 2 weeks, the sides were indistinguishable in 15 (75%) of the patients. Time for closure averaged 7 minutes with suture and 8 minutes with glue.

CONCLUSIONS

Octyl-2-cyanoacrylate glue is an excellent alternative to suture closure, producing equivalent quality of closure at all time points and no difference in appearance. This adhesive was sufficient to withstand the forces of closure in upper eyelid blepharoplasty without dehiscence in the absence of sutures.

Effects of the ACAT inhibitor CL 277,082 on cholesterol metabolism in humans

A common pharmacologic approach to lowering elevated serum cholesterol levels has been to interfere with intestinal sterol absorption. Inhibitors of acyl coenzyme A: cholesterol acyltransferase (ACAT) should produce this effect. In this study, we examined the effects of CL 277,082, N-(2,4-difluorophenyl)-N-(4-neopentylbenzyl)-N-(n-heptyl)urea, an ACAT inhibitor, on cholesterol metabolism in humans. Eight healthy male volunteers were given a placebo for 14 days, followed by 750 mg/day CL 277,082 for 20 days in a single-blind, crossover design. Subjects were studied in a hospital research unit and were fed strictly controlled diets. Cholesterol absorption was measured by the dual isotope method during the final week of both the placebo and the drug phases. Sterol balance was also assessed during these two periods by measuring cholesterol intake, and fecal neutral and acidic sterol excretion rates. Plasma lipids and lipoproteins were measured at the end of each period. The drug was well tolerated and produced no detectable clinical or laboratory side effects. Cholesterol absorption, sterol excretion rates, and plasma lipoprotein levels were all unaffected by treatment. We conclude that CL 277,082 may not interfere with ACAT activity or cholesterol absorption in humans at the doses given under the conditions tested in this study.

Therapeutic transcatheter arterial embolization in the management of intractable haemorrhage from pelvic urological malignancies: preliminary experience and long-term follow-up

OBJECTIVE

To evaluate the feasibility, efficacy and complications of internal iliac artery embolization as a palliative measure in the control of intractable haemorrhage from advanced pelvic urological malignancies.

PATIENTS AND METHODS

Six patients (mean age 80 years, range 76-87) with advanced pelvic malignancies (three each with bladder carcinoma and prostate carcinoma) underwent embolization between September 1997 and July 2001, using permanent coils in the anterior division of internal iliac artery bilaterally.

RESULTS

All patients had undergone conservative treatment before embolization for a mean of 2 days. The mean requirement for transfusion before embolization was 3.2 units. All patients except one were successfully embolized in a single setting with no complications. Bleeding was successfully controlled in one patient at the second attempt of embolization. There were minor complications, e.g. nausea, vomiting or fever, for a mean of 2 days, responding well to conservative treatment. At a mean follow-up of 22 months, no patient had a recurrence of bleeding.

CONCLUSION

Internal iliac artery embolization is a feasible, effective and minimally invasive option in managing advanced pelvic urological malignancies presenting with intractable bleeding; it should be bilateral and permanent.

Family dynamics, parental-fetal attachment and infant temperament

Family dynamics, parental-fetal attachment and infant temperament The purpose of this longitudinal study of families having their first or second baby was to explore relationships among family dynamics, paternal- and maternal-fetal attachment, and infant temperament. Data were collected from 156 women and 62 of their partners during the third trimester of pregnancy. One year later, when the infant was 8-9 months old, 75 of the women and 30 of their partners participated. In a hierarchical multiple regression analysis, after controlling for demographic variables, mutuality in the family was associated with greater maternal- and paternal-fetal attachment. Family dynamics were stable across the transition to parenthood except for an increase in role conflict reported by mothers. Sensitivity to specific family experiences by clinicians can provide assistance to families during these periods.

High-intensity focused ultrasound in the treatment of benign prostatic hyperplasia

OBJECTIVE

To assess the role of high-intensity focused ultrasound (HIFU) in the treatment of symptomatic benign prostatic hyperplasia (BPH).

PATIENTS AND METHODS

Thirteen patients (mean age 65 years, range 58-74) were treated with HIFU as part of a phase-2 clinical trial and evaluated prospectively using the International Prostate Symptom Score, uroflowmetry, and transrectal and transabdominal ultrasonography to determine prostate size and post-void residual urine volume, respectively. The results and the patients' satisfaction were assessed at regular intervals for 2 years.

RESULTS

The new procedure was learned quickly and was easy to perform. Symptom scores decreased from a mean of 23 before treatment to 5 after 12 months and 7 after 2 years. There was an initial improvement in flow rates but they then declined. The size of the prostate and the post-void residual volume were both decreased after treatment.

CONCLUSIONS

The treatment is safe, easy to implement and was effective in substantially reducing symptom scores in these few patients. However, we would not encourage its use as an alternative to other well established treatment modalities until it has been assessed fully in a randomized trial.

Variability and Error in Cardiac Troponin Testing: An ACLPS Critical Review

OBJECTIVES

To provide a comprehensive overview of the complexities associated with cardiac troponin (cTn) testing. An emphasis is placed on the sources of error, organized into the preanalytical, analytical, and postanalytical phases of the testing pathway. Controversial areas are also explored.

METHODS

A case scenario and review of the relevant literature describing laboratory considerations involving cTn testing are described.

RESULTS

Advanced comprehension of the specific assay used in a given laboratory is necessary for optimal reporting, utilization, and quality monitoring of cTn.

CONCLUSIONS

cTn assays are reliable diagnostic tests for acute myocardial infarction, but understanding their limitations is required for appropriate result interpretation.

Acquisition of the L452R mutation in the ACE2-binding interface of Spike protein triggers recent massive expansion of SARS-Cov-2 variants

The recent rise in mutational variants of SARS-CoV-2, especially with changes in the Spike protein, is of significant concern due to the potential ability for these mutations to increase viral infectivity, virulence and/or ability to escape protective antibodies. Here, we investigated genetic variations in a 414-583 amino acid region of the Spike protein, partially encompassing the ACE2 receptor-binding domain (RBD), across a subset of 570 nasopharyngeal samples isolated between April 2020 and February 2021, from Washington, California, Arizona, Colorado, Minnesota and Illinois. We found that samples isolated since November have an increased number of amino acid mutations in the region, with L452R being the dominant mutation. This mutation is associated with a recently discovered CAL.20C viral variant from clade 20C, lineage B.1.429, that since November-December 2020 is associated with multiple outbreaks and is undergoing massive expansion across California. In some samples, however, we found a distinct L452R-carrying variant of the virus that, upon detailed analysis of the GISAID database genomes, is also circulating primarily in California, but emerged even more recently. The newly identified variant derives from the clade 20A (lineage B.1.232) and is named CAL.20A. We also found that the SARS-CoV-2 strain that caused the only recorded case of infection in an ape - gorillas in the San Diego Zoo, reported in January 2021 - is CAL.20A. In contrast to CAL.20C that carries two additional to L452R mutations in the Spike protein, L452R is the only mutation found in CAL.20A. According to the phylogenetic analysis, however, emergence of CAL.20C was also specifically triggered by acquisition of the L452R mutation. Further analysis of GISAID-deposited genomes revealed that several independent L452R-carrying lineages have recently emerged across the globe, with over 90% of the isolates reported between December 2020 - February 2021. Taken together, these results indicate that the L452R mutation alone is of significant adaptive value to SARS-CoV-2 and, apparently, the positive selection for this mutation became particularly strong only recently, possibly reflecting viral adaptation to the containment measures or increasing population immunity. While the functional impact of L452R has not yet been extensively evaluated, leucine-452 is positioned in the receptor-binding motif of RBD, in the interface of direct contact with the ACE2 receptor. Its replacement with arginine is predicted to result in both a much stronger binding to the receptor and escape from neutralizing antibodies. If true, this in turn might lead to significantly increased infectivity of the L452R variants, warranting their close surveillance and in-depth functional studies.

When Gender Identity Doesn't Equal Sex Recorded at Birth: The Role of the Laboratory in Providing Effective Healthcare to the Transgender Community

BACKGROUND

Transgender is an umbrella term used to describe individuals who identify with a gender incongruent to or variant from their sex recorded at birth. Affirming gender identity through a variety of social, medical, and surgical interventions is critical to the mental health of transgender individuals. In recent years, awareness surrounding transgender identities has increased, which has highlighted the health disparities that parallel this demographic. These disparities are reflected in the experience of transgender patients and their providers when seeking clinical laboratory services.

CONTENT

Little is known about the effect of gender-affirming hormone therapy and surgery on optimal laboratory test interpretation. Efforts to diminish health disparities encountered by transgender individuals and their providers can be accomplished by increasing social and clinical awareness regarding sex/gender incongruence and gaining insight into the physiological manifestations and laboratory interpretations of gender-affirming strategies. This review summarizes knowledge required to understand transgender healthcare including current clinical interventions for gender dysphoria. Particular attention is paid to the subsequent impact of these interventions on laboratory test utilization and interpretation. Common nomenclature and system barriers are also discussed.

SUMMARY

Understanding gender incongruence, the clinical changes associated with gender transition, and systemic barriers that maintain a gender/sex binary are key to providing adequate healthcare to transgender community. Transgender appropriate reference interval studies are virtually absent within the medical literature and should be explored. The laboratory has an important role in improving the physiological understanding, electronic medical system recognition, and overall social awareness of the transgender community.

Hematology reference intervals for transgender adults on stable hormone therapy

BACKGROUND

The complete blood count (CBC) is a cornerstone of patient care. Several of the normal values for the components of the CBC differ by sex and, therefore, male-specific and female-specific reference intervals are required to interpret these laboratory results. Transgender individuals are often prescribed hormone therapy to affirm their gender, with resulting serum hormone concentrations similar to those of cisgender individuals. Gender-specific reference intervals for transgender men and women have not been established for any laboratory measurements, including hematology. We established clinically relevant hematological reference intervals for transgender individuals receiving stable hormone therapy.

METHODS

Healthy transgender individuals prescribed testosterone (n = 79) or estrogen (n = 93) for ≥12 months were recruited from internal medicine and primary care clinics that specialize in transgender medical care. Concentrations for hemoglobin, hematocrit, MCV, MCHC, and RDWCV, as well as counts for red cells, white cells, and platelets, were evaluated. Results were interpreted in reference to the overall distribution of values and relative to serum estradiol and total testosterone concentrations. Calculated reference intervals were compared to established cisgender reference intervals.

RESULTS

Regardless of serum hormone concentration, individuals prescribed testosterone or estrogen had hematology parameters that were not clinically different from cisgender males and females, respectively.

CONCLUSION

The hematology parameters for transgender men and women receiving stable hormone therapy should be evaluated against the cisgender male and cisgender female reference ranges, respectively and does not require concurrent sex hormone analysis. Care providers can utilize this observation to aid in interpretation of hematology laboratory values for transgender people.

Peyronie's disease with erectile dysfunction: penile modeling over inflatable penile prostheses

OBJECTIVES

To evaluate, retrospectively, the impact of penile correction by modeling of the penis over an inflatable penile prosthesis and the subsequent improvement in erectile function. Advanced Peyronie's disease with severe penile curvature and poor quality erections presents a challenge to the urologist.

METHODS

In our series, 46 patients with advanced Peyronie's disease and associated erectile dysfunction underwent insertion of an inflatable penile prosthesis between 1998 and 2003. Of the 46 patients, 28 (61%) underwent a standard modeling procedure; the other 18 patients (39%) did not need additional modeling, because their curvature was corrected by inflation of the prosthesis alone. Patients were evaluated postoperatively in the clinic, as well as by a postal questionnaire.

RESULTS

Of the 46 patients, 44 were satisfied with the penile correction and 2 (4.4%) underwent removal of their prosthesis because of infection. These 2 patients underwent revision surgery; subsequently both prostheses had to be removed, one for severe pain and the other for urethral erosion. None of the patients underwent reoperation for additional straightening. Of the 44 patients with intact prostheses, erectile function significantly improved in 41 (93%).

CONCLUSIONS

The results of our study have indicated that patients with severe Peyronie's disease and erectile dysfunction should be offered the choice of penile modeling over an inflatable penile implant to correct the curvature, as well as improve erectile function.

Epidemiology of facial injury in blunt assault. Determinants of incidence and outcome in 802 patients

BACKGROUND

Facial assault trauma has reached epidemic proportions. While the biomechanics of injury, methods of repair, and general demography of blunt facial trauma are well known, statistical associations between epidemiological factors, incidence, and outcome are poorly understood.

OBJECTIVES

To provide a comprehensive epidemiological survey of this patient population. To assess factors determining outcome and pattern of injury.

DESIGN

Retrospective review of 802 patients admitted with blunt assault facial trauma. Statistical analysis of associations between epidemiological factors, incidence, and outcome with chi 2 test, 2-tailed t test, and Fisher exact test.

SETTING

Urban university and county hospital.

RESULTS

Statistically significant associations are demonstrated between gender and the context of assault, incidence of armed assault, presence of fracture, and rate of intoxication at injury. Poor prognostic indicators for outcome include use of tobacco and presence of a mandible fracture. Open reduction and internal fixation were found to bear a higher complication rate only in mandible fractures.

CONCLUSIONS

While choice of treatment carries a statistically significant association with outcome, social variables, including gender, tobacco use, intoxication, and low socioeconomic status, produce dramatic worsening of both injury incidence and outcome.

Dose levels outside radiotherapy beams

The specification of a radiotherapy generator calls for the leakage radiation through the housing of the source to be 0.1% (the ICRP has recently (1982) changed this figure to 0.2% of the dose rate inside the useful beam). When a patient is irradiated, the dose level outside the useful beam is not only determined by this leakage radiation, but also by scattered radiation from the beam-defining system and from the treatment volume of the patient. Measurements have been made on a 300 kV X-ray unit, and on two different 4 MV and one 8 MV linear accelerators to determine the levels of leakage radiation and scattered radiation in air, and in a phantom comparable in size to the trunk of the patient. Similar measurements have also been made for a 15 MeV neutron generator. It is shown that for all these generators the dose delivered outside the radiation beam is determined mainly by the two scattering processes mentioned, and it is argued that for linear accelerators it would be feasible to increase the permitted level of leakage radiation by a factor of 2 or 3 without a significant increase in the stray radiation delivered to the patient.

Tumor necrosis factor-alpha polymorphism, bone strength phenotypes, and the risk of fracture in older women

TNFalpha is a proinflammatory cytokine that promotes osteoclastic bone resorption. We evaluated the association between a G-308A polymorphism (rs1800629) at the TNFA locus and osteoporosis phenotypes in 4306 older women participating in the Study of Osteoporotic Fractures. Femoral neck bone mineral density (BMD) and structural geometry were measured using dual-energy x-ray absorptiometry and hip structural analysis. Incident fractures were confirmed by physician adjudication of radiology reports. Despite similar femoral neck BMD, women with the A/A genotype had greater subperiosteal width (P = 0.01) and endocortical diameter (P = 0.03) than those with the G/G genotype. The net result of these structural differences was that there was a greater distribution of bone mass away from the neutral axis of the femoral neck in women with the A/A genotype, resulting in greater indices of bone bending strength (cross-sectional moment of inertia: P = 0.004; section modulus: P = 0.003). Among 376 incident hip fractures during 12.1 yr of follow-up, a 22% decrease in the risk of hip fracture was seen per copy of the A allele (relative risk 0.78; 95% confidence interval 0.63, 0.96), which was not influenced by adjustments for potential confounding factors, BMD, or bone strength indices. The G-308A polymorphism was not associated with a reduced risk of other fractures. These results suggest a potential role of genetic variation in TNFalpha in the etiology of osteoporosis.