Increased leaf area index and efficiency drive enhanced production under elevated atmospheric [CO2 ] in a pine-dominated stand showing no progressive nitrogen limitation

Enhancement of net primary production (NPP) in forests as atmospheric [CO2 ] increases is likely limited by the availability of other growth resources. The Duke Free Air CO2 Enrichment (FACE) experiment was located on a moderate-fertility site in the southeastern US, in a loblolly pine (Pinus taeda L.) plantation with broadleaved species growing mostly in mid-canopy and understory. Duke FACE ran from 1994 to 2010 and combined elevated [CO2 ] (eCO2 ) with nitrogen (N) additions. We assessed the spatial and temporal variation of NPP response using a dataset that includes previously unpublished data from 6 years of the replicated CO2  × N experiment and extends to 2 years beyond the termination of enrichment. Averaged over time (1997-2010), NPP of pine and broadleaved species were 38% and 52% higher under eCO2 compared to ambient conditions. Furthermore, there was no evidence of a decline in enhancement over time in any plot regardless of its native site quality. The relation between spatial variation in the response and native site quality was suggested but inconclusive. Nitrogen amendments under eCO2 , in turn, resulted in an additional 11% increase in pine NPP. For pine, the eCO2 -induced increase in NPP was similar above- and belowground and was driven by both increased leaf area index (L) and production efficiency (PE = NPP/L). For broadleaved species, coarse-root biomass production was more than 200% higher under eCO2 and accounted for the entire production response, driven by increased PE. Notably, the fraction of annual NPP retained in total living biomass was higher under eCO2 , reflecting a slight shift in allocation fraction to woody mass and a lower mortality rate. Our findings also imply that tree growth may not have been only N-limited, but perhaps constrained by the availability of other nutrients. The observed sustained NPP enhancement, even without N-additions, demonstrates no progressive N limitation.

A contemporary, population-based study of lymphedema risk factors in older women with breast cancer

BACKGROUND

We studied potential risk factors for lymphedema in a contemporary population of older breast cancer patients.

METHODS

Telephone surveys were conducted among women (65-89 years) identified from Medicare claims as having initial breast cancer surgery in 2003. Lymphedema was classified by self-report. Surgery and pathology information was obtained from Medicare claims and the state cancer registries.

RESULTS

Of 1,338 patients treated by 707 surgeons, 24% underwent sentinel lymph node biopsy (SLNB) and 57% axillary lymph node dissection (ALND). At a median of 48 months postoperatively, 193 (14.4%) had lymphedema. Lymphedema developed in 7% of the 319 patients who underwent SLNB and in 21% of the 759 patients who underwent ALND. When controlling for patient age, tumor size, type of breast cancer, type of breast and axillary surgery, receipt of radiation, chemotherapy, and hormonal therapy, and surgeon case volume, the independent predictors of lymphedema were removal of more than five lymph nodes [odds ratio (OR) 4.68-5.61, 95% confidence interval (CI) 1.36-19.74 for 6-15 nodes; OR 10.50, 95% CI 2.88-38.32 for >15 nodes] and presence of lymph node metastases (OR 1.98, 95% CI 1.21-3.24).

CONCLUSIONS

Four years postoperatively, 14% of a contemporary, population-based cohort of elderly breast cancer survivors had self-reported lymphedema. In this group of predominantly community-based surgeons, the number of lymph nodes removed is more predictive of lymphedema rather than whether SLNB or ALND was performed. As more women with breast cancer undergo only SLNB, it is essential that they still be counseled on their risk for lymphedema.

Effect of fuel and lube oil sulfur on the performance of a diesel exhaust gas continuously regenerating trap

The continuously regenerating trap (CRT) is a diesel exhaust emission control that removes nearly all diesel particulate matter on a mass basis, but under some circumstances oxidation of sulfur leads to the formation of nanoparticles. The objective of the four year study was to determine CRT performance under controlled, real-world, on-road conditions, and to develop quantitative relationships between fuel and lubrication oil sulfur concentration and particle number exhaust emissions. It was shown that nanoparticle emissions are minimized by the use of ultralow sulfur fuels and specially formulated low sulfur lubrication oil. Nanoparticle emissions increased with higher exhaust temperatures. Fuel and lubrication oil sulfur increased the particle concentration by, on average, 36 x 10(6) and 0.14 x 10(6) part/cm3 for each 1 ppm increase in sulfur. On the other hand there was a decrease in nanoparticle emissions by the CRT as the system aged.

Initial screening transferrin saturation values, serum ferritin concentrations, and HFE genotypes in Native Americans and whites in the Hemochromatosis and Iron Overload Screening Study

We compared initial screening transferrin saturation (TfSat) and serum ferritin (SF) phenotypes and HFE C282Y and H63D genotypes of 645 Native American and 43,453 white Hemochromatosis and Iron Overload Screening Study participants who did not report a previous diagnosis of hemochromatosis or iron overload. Elevated measurements were defined as TfSat >50% in men and >45% in women and SF >300 ng/ml in men and >200 ng/ml in women. Mean TfSat was 31% in Native American men and 32% in white men (p = 0.0337) and 25% in Native American women and 27% in white women (p < 0.0001). Mean SF was 153 microg/l in Native American and 151 microg/l in white men (p = 0.8256); mean SF was 55 microg/l in Native American women and 63 microg/l in white women (p = 0.0015). The C282Y allele frequency was 0.0340 in Native Americans and 0.0683 in whites (p < 0.0001). The H63D allele frequency was 0.1150 in Native Americans and 0.1532 in whites (p = 0.0001). We conclude that the screening TfSat and SF phenotypes of Native Americans are similar to those of whites. The allele frequencies of HFE C282Y and H63D are significantly lower in Native Americans than in whites.

Sentinel node biopsy after neoadjuvant chemotherapy in breast cancer: results from National Surgical Adjuvant Breast and Bowel Project Protocol B-27

PURPOSE

Experience with sentinel node biopsy (SNB) after neoadjuvant chemotherapy is limited. We examined the feasibility and accuracy of this procedure within a randomized trial in patients treated with neoadjuvant chemotherapy.

PATIENTS AND METHODS

During the conduct of National Surgical Adjuvant Breast and Bowel Project trial B-27, several participating surgeons attempted SNB before the required axillary dissection in 428 patients. All underwent lymphatic mapping and an attempt to identify and remove a sentinel node. Lymphatic mapping was performed with radioactive colloid (14.7%), with lymphazurin blue dye alone (29.9%), or with both (54.7%).

RESULTS

Success rate for the identification and removal of a sentinel node was 84.8%. Success rate increased significantly with the use of radioisotope (87.6% to 88.9%) versus with the use of lymphazurin alone (78.1%, P = .03). There were no significant differences in success rate according to clinical tumor size, clinical nodal status, age, or calendar year of random assignment. Of 343 patients who had SNB and axillary dissection, the sentinel nodes were positive in 125 patients and were the only positive nodes in 70 patients (56.0%). Of the 218 patients with negative sentinel nodes, nonsentinel nodes were positive in 15 (false-negative rate, 10.7%; 15 of 140 patients). There were no significant differences in false-negative rate according to clinical patient and tumor characteristics, method of lymphatic mapping, or breast tumor response to chemotherapy.

CONCLUSION

These results are comparable to those obtained from multicenter studies evaluating SNB before systemic therapy and suggest that the sentinel node concept is applicable following neoadjuvant chemotherapy.

Sequelae of cryotherapy in breast tissue

Cryotherapy is a novel treatment for benign and malignant breast lesions that is under evaluation. We assessed the acute and subacute outcomes of breast cryotherapy in normal goat teats using physical, microscopic, and imaging modalities. Eight goats were subjected to two freeze-thaw cycles of breast tissue producing a 2cm iceball and sacrificed either 2 or 7 weeks later. Acute skin changes were minimal unless obvious tissue injury occurred during cryotherapy; however, depigmentation developed over several weeks in dark-skinned goats despite the presence of melanocytes. By histology, breast epithelial elements could not be identified at cryotherapy sites. There was no cystic degeneration, which is common at surgical excision sites. Neither calcifications nor prominent scarring could be attributed to cryotherapy on imaging studies after 2 or 7 weeks. When compared to standard breast surgery, the sequelae of cryotherapy using histologic, radiographic, and sonographic criteria were decreased. Our study suggests that cryotherapy, with technical modifications, is feasible within breast tissue and warrants further study.

Characteristics of four types of patient assaults: six year analysis of the Assaulted Staff Action Program (ASAP)

Although psychiatric patient assaults may include physical and sexual assaults, nonverbal intimidation, and verbal threats, most studies of assaultive psychiatric patients to date have grouped all assaults together in one category. This study explored differences in patient assailant variables and staff victim variables in each of the four categories of patient assault during a six-year period. These differential analyses of assault types yielded at least three important findings: the presence of significant numbers of females as both assailants and victims in several categories of assaults, the importance of psychological fright in staff victims, and the serious psychological disruptions found in staff victims of physical, sexual, and verbal assaults. The findings are discussed and the implications for health care safety and emergency mental health are noted.

A primer for predicting risk of disease in HFE-linked hemochromatosis

Since the discovery of the hemochromatosis gene (HFE) in 1996, there has been increasing interest in diagnostic testing for the C282Y and H63D mutations. The high frequency of these two alleles and their incomplete penetrance in homozygotes and compound heterozygotes make genetic counseling for hemochromatosis different from some other autosomal recessive conditions in that parents and children may also be at risk for iron overload, while homozygotes may remain asymptomatic. We provide a guideline for genetic counseling in HFE-linked hemochromatosis based on the genetic probability of inheriting HFE mutations and known information about expression of iron overload in various HFE genotypes. Genetic probabilities were based on allele frequencies derived from large population studies and Hardy-Weinberg equilibrium estimates. Expression of iron overload in those of various genotypes was based on available estimates of serum ferritin from population screening studies. Estimates for the likelihood of clinical iron overload requiring follow-up screening or treatment are provided by gender and genotype. The probability of inheriting HFE mutations and developing iron overload can be estimated in family members of a proband with HFE mutations. Many C282Y homozygotes will not have clinical iron overload. The risk is highest in men and their C282Y homozygous brothers and significantly lower in homozygous women. Iron overload is uncommon in compound heterozygotes and H63D homozygotes.

Does breast tumor location influence success of sentinel lymph node biopsy?

BACKGROUND

Controversy exists regarding the influence of sentinel lymph node (SLN) mapping technique or patient variables on the success rate of SLN mapping. We undertook a prospective study in a single institution series to evaluate multiple variables that could adversely affect SLN identification rates.

STUDY DESIGN

Data were collected on 174 patients who underwent 177 SLN mapping procedures followed by axillary dissection from October 1996 through January 2000. Patient demographics, body mass index (BMI), biopsy method, tumor size, palpability, and location were recorded. SLNs were identified by blue dye only (n = 31), Tc-99m sulfur colloid only (n = 34), or combined techniques (n = 112). Data were analyzed by logistic regression analysis and expressed as the probability of failure to map the SLN.

RESULTS

SLNs were identified successfully in 150 of 177 procedures (85%) with a false negative rate of 3.7%. Mapping success reached 93% using combination blue dye and isotope. Variables found to adversely affect SLN mapping success and the odds ratio of failure (OR) included lower inner quadrant (LIQ) location (OR 35.6), blue dye only (OR 42.4), BMI >30 and upper outer quadrant (UOQ) location (OR 14.6), and nonpalpable UIQ location (OR 25). LIQ location adversely affects mapping success independent of technique, tumor size, or obesity. Obesity and nonpalpability were adverse factors when tumors were located in the UOQ and UIQ, respectively. Age, biopsy technique, and tumor diameter did not affect SLN mapping success.

CONCLUSIONS

SLN mapping success is influenced by technique and tumor location, with best results achieved using combined techniques and for lesions located in quadrants other than the LIQ. Obesity and tumor palpability influence success in the context of tumor location.

Characteristics of patients in restraint: six year analysis of the Assaulted Staff Action Program (ASAP)

Emergency service providers, including mental health care providers, are often called upon to impose restraint procedures. These procedures may result in physical injury and psychological distress and provide a unique opportunity for emergency mental health personnel to be of assistance. Reviews of the literature on restrained patients have suggested that clinical variables studied need to be added to demographic factors in order to better clarify those at high risk for restraint procedures. This study compared restrained and non-restrained subjects on basic demographic variables and the clinical variables of histories of violence toward others, personal victimization and substance use disorder. The clinical variables did not enhance the prediction of the use of restraints. The implications for reducing the use of restraints, for needed emergency mental health services and future research directions are explored.

Hepatic failure and hemochromatosis of Salers and Salers-cross cattle

Hemochromatosis is rare in domestic mammals. Five clinical cases and one preclinical case of hemochromatosis were diagnosed in Salers and Salers-cross cattle. Clinical disease developed between 9 and 22 months of age. Animals were healthy until weaning but then lost weight, developed rough hair coats, and lost incisor teeth. In two animals, hemochromatosis was identified by liver biopsy, biochemical evidence of hepatic injury, and/or elevated transferrin saturation values. At necropsy, carcasses were thin, with firm dark brown livers and lymph nodes, soft bones, and brown-colored small bowel. The principal histologic changes were hepatocellular siderosis and periportal, bridging, and perivenular fibrosis. Siderocalcinosis involved collagen, elastin, reticulin, and basement membrane components in liver, lymph nodes, spleen, duodenum, and kidney. Hepatic iron concentrations in clinically affected cattle were 1,500-10,500 microg/g wet weight (reference range for cattle = <300 microg/ g). Ultrastructurally, the heaviest intrahepatic deposition was in hepatocytes, which contained large intracytoplasmic siderosomes. Iron deposition in bone was associated with osteopenia. Genetic analysis indicated a common ancestral bull in the pedigrees of five of six affected cattle; no pedigree was available for the remaining animal. Four dams of five affected animals were phenotypically normal and had histologically normal livers. Test mating of four cows to the ancestral bull resulted in a female calf that developed clinicopathologic and histologic evidence of preclinical hemochromatosis by 40 days of age. It was not possible to establish the pattern of inheritance because of the small number of pedigrees from affected cattle.

Violence against women and the assaulted staff action program

Women have been subjected to high rates of victimization at home, in the community, and at work. An earlier study found female inpatient staff to be at risk for same-gender patient assaults in psychiatric hospitals and female community residential staff to be at increased risk for assaults from male patients in residences. This study sought to revisit the original 2-year findings during a subsequent 6-year period. Inpatient and community assault data were gathered within the context of the Assaulted Staff Action Program (ASAP), a post-incident crisis response approach. Female inpatient staff were again found to be at increased risk in both inpatient and community settings. However, in this second study, female community residential staff were found to be at increased risk for assault from both male and female patients. The findings and their implications are discussed.

Past violence and substance use disorder and subsequent violence towards others: six year analysis of the Assaulted Staff Action Program (ASAP)

Recent research has begun to document evidence of associations between past violence toward others, untreated personal victimization, and substance use disorder and later acts of violence toward others. This appears true for many types of individuals, including psychiatric patients who have been victims of violence. This six-year retrospective study sought to evaluate these possible associations in assaultive psychiatric patients. Data were gathered in the context of the Assaulted Staff Action Program (ASAP), a crisis intervention program for staff victims of patient assault. Both histories of violence (violence toward others and/or personal victimization) and substance use disorder in assaultive psychiatric patients were individually and jointly examined and found to be associated with subsequent assaults by these patients. Increased levels of both past violence toward others, personal victimization, and substance use disorder were associated with the largest increased frequency of subsequent assault. The implications and possible links to emergency mental health services are discussed [International Journal of Emergency Mental Health, 2(4), 241-247].

Genetic hemochromatosis: detection, management, and population screening

Genetic hemochromatosis (GH) is an inherited disease that results in iron overload, and, if untreated, causes irreversible organ damage. Knowledge and understanding of the early features of the condition, often nonspecific, and of the diagnostic route are necessary to detect iron overload and diagnose GH before irremedial damage has been done. Genetic testing now plays an important role in diagnosis. Management of the patient with established GH centers on venesection to return body iron levels to normal, treatment of the complications of GH, and family screening for GH. Population screening for GH, the ideal strategy to prevent any morbidity from iron overload, has not yet been accepted by public health professionals, largely because of the lack of data on the disease penetrance in genetically susceptible individuals.

Nonviolent psychiatric inpatients and subsequent assaults on community patients and staff

Health care staff on psychiatric inpatient units are at high risk for work-related assaults by patients. Recent studies have begun to document similar patient assaults toward staff in community-based residences. Earlier community studies did not control for the level of patient assault prior to community discharge, and it remains unknown whether the community residence assaults were a function of community placement or a reflection of ongoing control issues by the recently discharged patients. This preliminary inquiry retrospectively tracked the nature and frequency of assaults by patients newly discharged to community residences from a state hospital setting where there had been no assaults by these patients for a two-and-one half-year period. While base rates remain to be determined, the findings in this study suggest the assaultive patients to be younger males with diagnoses of schizophrenia and histories of violence toward others, substance abuse, and violence toward self. Nine patients committed the majority of the assaults. There was a significant decline in the frequency of assaults nine months post-discharge. The implications are discussed.

Characteristics of staff victims of patient assault: ten year analysis of the Assaulted Staff Action Program (ASAP)

Patient assaults on staff have been a continuing risk for inpatient and community-based psychiatric healthcare providers. This study presents a ten-year analysis of the characteristics of staff victims of patient assaults in one public mental health system of care, a period which included the transition to managed care initiatives within this system. Assault data was gathered within the context of the Assaulted Staff Action Program (ASAP), a voluntary, system-wide, peer-help, crisis intervention program that is designed to assist employees with the psychological sequelae of these patient events. In general, the findings were consistent with previously reported inpatient and community studies. Less experienced, less formally trained employees remain at high risk. The impact of managed care initiatives was found in community residences where younger female staff were most at risk. The implications of the findings and possible risk management strategies are discussed.

Oxidative-phosphorylation defects in liver of patients with Wilson's disease

BACKGROUND

Wilson's disease (WD) is caused by mutations in a P-type ATPase and is associated with copper deposition in liver and brain. The WD protein is present in the trans-Golgi network and may also be imported into mitochondria. The WD protein functions as a P-type copper transporting ATPase in the Golgi but any action in mitochondria is at present unknown.

METHODS

We studied mitochondrial function and aconitase activity in WD liver tissue and compared the results with those in a series of healthy controls and patients without WD.

FINDINGS

There was evidence of severe mitochondrial dysfunction in the livers of patients with WD. Enzyme activities were decreased as follows: complex I by 62%, complex II+III by 52%, complex IV by 33%, and aconitase by 71%. These defects did not seem to be secondary to penicillamine use, cholestasis, or poor hepatocellular synthetic function.

INTERPRETATION

The results show that there is a defect of energy metabolism in WD. The pattern of enzyme defects suggests that free-radical formation and oxidative damage, probably mediated via mitochondrial copper accumulation, are important in WD pathogenesis. These results provide a rationale for a study of the use of antioxidants in WD.

An atypical kindred with X-linked adrenal hypoplasia congenita, normal puberty, and normal Dax-1 promoter and coding sequence

We report a Chinese kindred with an atypical sex-linked form of isolated adrenal hypoplasia without hypogonadotropic hypogonadism. Evidence of sex linkage was supported by DNA analysis using three polymorphic markers from the X-chromosome: a restriction fragment length polymorphism 200 kb centromeric of the DAX-1 gene, a tetranucleotide repeat marker in the DAX-1 promoter (DAX-P), and a microsatellite in the Duchenne muscular dystrophy locus (3'-19). This pedigree therefore presents the novel phenotype of sex-linked hypoadrenalism without hypogonadotropic hypogonadism, with evidence of possible linkage to the DAX-1 gene. However, all three affected individuals were examined for mutations in the DAX-1 gene, and found to have no sequence anomalies in the coding region, splice sites or 5' non-coding region. This presentation may be due to a defect in the DAX-1 gene outside its known coding region, possibly modulated by functional polymorphisms at other loci, and/or environmental effects, or to a defect in a novel gene on the X chromosome which selectively influences adrenal development.

Characteristics of patient and staff victims of assaults in community residences by previously nonviolent psychiatric inpatients

There currently exists a large body of empirical research examining patient assaults in inpatient psychiatric facilities. These studies have focused primarily on staff and have found younger, male mental health workers with lower levels of formal education and experience as well as nurses involved in restraint procedures to be most at risk. However, despite the increased utilization of community-based services, little attention has been directed toward patient assaults on patients and staff in community settings, particularly residential services. This study began to respond to this need by examining patient assaults toward other patients and staff in community residences during the first twelve months post-discharge for a group of newly discharged patients who were not violent as inpatients. This study found female patients and staff to be at greater risk for assault than male patients. Lack of experience by staff was also a risk factor. The clinical, administrative, and research implications of these findings are discussed.

Atypical haemochromatosis: phenotypic spectrum and beta2-microglobulin candidate gene analysis

Beta2-microglobulin was investigated in atypical haemochromatosis patients not homozygous for the C282Y mutation of HFE (OMIM *235200), because the HFE protein binds beta2-microglobulin, and in mice beta2-microglobulin gene knockout causes hepatic iron overload. Six unrelated patients with atypical haemochromatosis were studied. Five patients had normal HFE coding sequence and the sixth was heterozygous for C282Y. We show that the spectrum of atypical haemochromatosis includes two distinct familial forms: juvenile haemochromatosis (OMIM *602390) and a novel form of familial iron overload, with apparently autosomal dominant inheritance, predominant Kupffer cell siderosis, and possible minimal dyserythropoiesis on bone marrow examination. Serial serum beta2-microglobulin estimation showed normal levels in all patients. Southern blot analysis showed normal beta2-microglobulin gene structure, excluding major gene rearrangement. Several corrections to the published beta2-microglobulin sequence were identified, but all six patients had normal beta2-microglobulin sequence. Western blot analysis of serum showed beta2-microglobulin protein of normal size. In conclusion, we found no evidence to implicate beta2-microglobulin mutation in atypical haemochromatosis. Two forms of familial iron overload appear unrelated to either HFE or beta2-microglobulin. Linkage studies are required to identify the genes involved, which may encode novel proteins crucial to the regulation of iron metabolism. Identification of these loci will aid the diagnosis, counselling, and treatment of iron overload disorders.

A novel mutation of HFE explains the classical phenotype of genetic hemochromatosis in a C282Y heterozygote

BACKGROUND & AIMS

Most patients with genetic hemochromatosis are homozygous for a single mutation of the HFE gene (C282Y). There is a second mutation, H63D, but its role in iron overload is less conclusive. The aim of this study was to investigate the basis of iron overload in a patient with classical hemochromatosis who was only heterozygous for C282Y and negative for H63D.

METHODS

Genotype for the C282Y, H63D, and S65C mutations of HFE was determined in patient RFH, his family members, and 365 controls. The HFE gene was sequenced in patient RFH. Allele-specific reverse-transcription polymerase chain reaction was performed to investigate RNA splicing. Allele frequency was determined by allele-specific oligonucleotide hybridization.

RESULTS

The patient is compound heterozygous for C282Y and a novel splice site mutation (IVS3 + 1G --> T). His sister has an identical genotype and elevated serum ferritin and transferrin saturation. The novel mutation functionally alters messenger RNA splicing, causing obligate skipping of exon 3. However, the IVS3 + 1G --> T mutation was found to be rare and was not detected in 630 control European chromosomes.

CONCLUSIONS

IVS3 + 1G --> T in the compound heterozygous state with C282Y results in iron overload that can progress to a severe phenotype of classical hemochromatosis. The demonstration of IVS3 +1G --> T highlights the possibility of other rare HFE mutations, particularly in C282Y heterozygotes with iron overload.

False-positive radiographic diagnosis of breast implant rupture because of breast abscess

A case of a periprosthetic abscess simulating breast implant rupture is presented. Both clinical findings and film-screen mammography suggested extravasation of a radiodense material adjacent to an implant. Ultrasonography was thought to confirm the extraluminal silicone. However, at surgery the mass was found to be a breast abscess that had herniated through the capsule. The double-lumen implant outer saline-filled chamber had deflated, but the silicone-containing inner chamber was intact. Magnetic resonance imaging would have distinguished between abscess and silicone.

Monocyte-macrophage ferric reductase activity is inhibited by iron and stimulated by cellular differentiation

The enzyme ferric reductase catalyses the reduction of Fe(III) as a prerequisite to its transportation across the cell membrane. Duodenal mucosal biopsies from iron overloaded patients with genetic haemochromatosis (GH) have increased ferric reductase activity and iron absorption compared with controls, yet the GH mucosa is iron deficient. A similar GH-related iron deficiency is also seen in macrophages. The aim of this study was to investigate whether macrophage ferric reductase activity is altered in GH, and to determine ferric reductase activity in monocytes and differentiated macrophages. The erythroleukaemic K562 cell line was studied as a clonal reference cell line. The basal K562 ferric reductase activity is characteristic of a membrane bound enzyme, being both temperature and protease sensitive. Ferric reductase activity was also demonstrated in human leucocyte, monocyte and macrophage preparations. Assays of K562 and macrophage cell supernatants confirmed that the ferric reductase activity was not due to a secreted factor. Assay of ferric reductase in normalized-iron and iron-enriched (100 microM ferric citrate) conditions showed no significant difference between Cys282Tyr (Cys282-->Tyr) homozygous GH macrophages and Cys282-Tyr negative control activities (P>0.05). However, a 900% increase in ferric reductase activity was observed during monocyte to macrophage differentiation (P<0.05), possibly reflecting the co-ordinate up-regulation of iron metabolism in these cells. The demonstration of approx. 25% activity after macrophage differentiation at high free-iron concentrations compared with 'normalized' iron is consistent with repression of human ferric reductase activity by iron. The identification of the human ferric reductase gene and its protein will ultimately provide insight into its regulation and role in mammalian iron metabolism.

A 6p22 reference map of leukocyte DNA: exclusion of rearrangement in four cases of atypical haemochromatosis

We describe a 4 Mb reference map of the haemochromatosis gene region in leukocyte DNA from seven controls and four atypical haemochromatosis patients. Three patients had normal coding sequence for HFE, the candidate gene for genetic haemochromatosis (GH). The fourth patient had classical GH but was heterozygous for Cys282Tyr with otherwise normal coding sequence. The genomic DNA was mapped by pulsed-field gel electrophoresis (PFGE) using five rare-cutting enzymes. Seventeen probes including HFE were positioned on the map. Despite proximity to the highly polymorphic major histocompatibility complex (MHC), no polymorphism was observed in the control group with these telomeric probes. Furthermore, major rearrangement of the HFE region was excluded as a mutation contributing to iron overload in these atypical patients. Maps of cloned DNA are linked through genes and other probes to this reference map of the HFE region in uncloned genomic DNA.

Pharmacoeconomic analysis of ampicillin-sulbactam versus cefoxitin in the treatment of intraabdominal infections

We conducted a retrospective pharmacoeconomic analysis of a prospective, multicenter, double-blind, randomized, controlled trial comparing the beta-lactamase inhibitor combination ampicillin-sulbactam (96 patients) and the cephalosporin cefoxitin (101) in the treatment of intraabdominal infections. An institutional perspective was adopted for the analysis. The primary outcomes of interest were cure and failure rates, development of new infection, and antibiotic-related adverse events. Epidemiologic data pertaining to outcomes was retrieved primarily from the trial, although results of other published studies were taken into consideration through extensive sensitivity analyses. Data pertaining to potential resource use and economic impact were retrieved mainly from the University Health Consortium and hospital-specific sources. When considering only costs associated with drug acquisition through cost-minimization analysis, a potential savings of $37.24/patient may be realized with ampicillin-sulbactam relative to cefoxitin based on an average 7-day regimen. Outcome data collected for the entire hospitalization during the trial revealed an approximately 9% greater frequency of failure with cefoxitin relative to ampicillin-sulbactam. When considering all outcomes of interest in the initial base-case analysis, a potential cost savings of approximately $890/patient may be realized with ampicillin-sulbactam relative to cefoxitin. In assessing the impact of the significant variability in probability and cost estimates, Monte Carlo analysis revealed a savings of $425/patient for ampicillin-sulbactam over cefoxitin (95% CI -$618 to $1516 [corrected]). Given the model assumptions, our analysis suggests a 78% certainty level that savings will be experienced when ampicillin-sulbactam is chosen over cefoxitin.

Haemochromatosis: a gene at last?

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Penetration of meropenem in plasma and abdominal tissues from patients undergoing intraabdominal surgery

We assessed the penetration of a new carbapenem antibiotic, meropenem, into abdominal tissues. A single 1,000-mg intravenous dose was administered to 66 patients undergoing elective intraabdominal surgery. Plasma, body fluid (peritoneal fluid and bile), and tissue samples (colon, gallbladder, omentum, stomach, fascia, muscle, and skin) were taken at various times up to 8 hours after administration of the dose. Meropenem concentrations were determined by means of validated bioassay techniques. Peak meropenem concentrations in most tissue specimens and one body fluid occurred within approximately 1 hour; the exceptions were bile and muscle specimens, in which peak concentrations were present in approximately 2 to approximately 4 hours. The bile concentration increased with time, thus indicating active excretion of drug into bile. Only one adverse event (mild nausea) was attributable to meropenem. Our results show that meropenem achieves adequate tissue concentrations for the treatment of intraabdominal infections due to susceptible bacteria.

Mutations and phenotype in isolated glycerol kinase deficiency

We demonstrate that isolated glycerol kinase (GK) deficiency in three families results from mutation of the Xp21 GK gene. GK mutations were detected in four patients with widely differing phenotypes. Patient 1 had a splice-site mutation causing premature termination. His general health was good despite absent GK activity, indicating that isolated GK deficiency can be silent. Patient 2 had GK deficiency and a severe phenotype involving psychomotor retardation and growth delay, bone dysplasia, and seizures, similar to the severe phenotype of one of the first described cases of GK deficiency. His younger brother, patient 3, also had GK deficiency, but so far his development has been normal. GK exon 17 was deleted in both brothers, implicating additional factors in causation of the severe phenotype of patient 2. Patient 4 had both GK deficiency with mental retardation and a GK missense mutation (D440V). Possible explanations for the phenotypic variation of these four patients include ascertainment bias; metabolic or environmental stress as a precipitating factor in revealing GK-related changes, as has previously been described in juvenile GK deficiency; and interactions with functional polymorphisms in other genes that alter the effect of GK deficiency on normal development.

Minimal increase in use of breast-conserving surgery from 1986 to 1990

Substantial geographic and hospital-based variations have been documented in the use of breast-conserving surgery (BCS) in 1986. The authors studied the patterns of adoption of this procedure from 1986 to 1990. National Medicare inpatient claims were used to study women aged 65 to 79 who underwent an operation for local or regional breast cancer in 1986 (38,679 patients) or 1990 (43,083 patients). Breast-conserving surgery was used for 5,509 (14.1%) of the Medicare patients in 1986 and 6,476 (15.0%) in 1990. The only region with an increase in BCS use from 1986 to 1990 was New England. Many hospitals had low volumes of operations, with a median of six to seven patients annually. Ten percent of the hospitals performed 55% of the conservative operations. Large hospitals, urban hospitals, and those with higher patient volumes or a cancer center were somewhat more likely to have increased use of BCS by 1990. Despite the substantial evidence supporting BCS as an alternative to mastectomy, the overall use of BCS in Medicare inpatients increased minimally from 1986 to 1990. Many patients are treated in hospitals with little experience with BCS. Hospitals using more BCS in 1986 were somewhat more likely to increase the use of BCS by 1990.

Penetration of ciprofloxacin and fleroxacin into biliary tract

Forty patients with chronic cholecystitis or cholelithiasis were prospectively randomized for therapy with either ciprofloxacin or fleroxacin to study the penetration of these two agents into gallbladder tissue, plasma, and bile. Patients received a 3-day course of ciprofloxacin (500 mg twice a day) or fleroxacin (400 mg once daily) and were subdivided into four groups reflecting intraoperative sample collection at 4, 7, 14, and 25 to 26 h following the last quinolone dose. Mean concentrations in plasma for ciprofloxacin and fleroxacin at 4 and 25 to 26 h postdose were 2.5 and 10 micrograms/ml and 0.3 and 1.8 micrograms/ml, respectively. The concentrations of ciprofloxacin and fleroxacin in bile and gallbladder wall tissue at 25 to 26 h postdose were 4.5 and 8.6 micrograms/ml and 1.2 and 4.4 micrograms/ml, respectively. Both agents demonstrate rapid tissue penetration with persistence at levels appropriate for treatment of biliary pathogens.

Meropenem versus tobramycin plus clindamycin for treatment of intraabdominal infections: results of a prospective, randomized, double-blind clinical trial

The efficacy of meropenem was compared to that of the combination of tobramycin plus clindamycin (T/C) in a multiinstitutional clinical trial of treatment for patients suffering intraabdominal infection. Among the 177 patients enrolled and randomized, 127 were clinically evaluable and 86 were microbiologically evaluable. Analysis of data on an intent-to-treat basis for all randomized patients and on the basis of a successful outcome (absence of any infection) for clinically evaluable patients failed to detect any difference in efficacy between the two treatments. Infection was cleared in 92% of meropenem- and 89% of T/C-treated clinically evaluable patients. Eradication of pathogens also was similar in the two treatment groups. Overall, adverse drug experiences were comparable between the two treatment groups, with the exception of an increase in serum creatinine level (which occurred more frequently in patients receiving T/C). Meropenem appears to be efficacious for the treatment of intraabdominal infections.

WASP gene mutations in Wiskott-Aldrich syndrome and X-linked thrombocytopenia

The WASP gene has been recently cloned from Xp11.23 and shown to be mutated in three patients with the Wiskott-Aldrich syndrome (WAS). We have developed a screening protocol for identifying WASP gene alterations in genomic DNA and have identified a spectrum of novel mutations in 12 additional unrelated families. These missense, nonsense and frameshift mutations involve eight of the 12 exons of the gene. Two mutations creating premature termination codons were associated with lack of detectable mRNA on Northern blots. Four amino acid substitutions, Leu27Phe, Thr48Ile, Val75Met and Arg477Lys, were found in patients with congenital thrombocytopenia and no clinically evident immune defect indicating that the WASP gene is the site for mutations in X-linked thrombocytopenia as well as in WAS. A T-cell line from a WAS patient contained two independent DNA alterations, a constitutional frameshift mutation, also present in peripheral blood leukocytes from the patient, and compensatory splice site mutation unique to the cell line. The distribution of eight missense mutations provides valuable information on amino acids which are essential for normal protein function, and suggests that sites in the first two exons are hot-spots for mutation.

Isolation and characterization of a MAGE gene family in the Xp21.3 region

A human gene with strong homology to the MAGE gene family located in Xq27-qter has been isolated by using exon-trapping of cosmids in the Xp21.3 region. We have mapped and sequenced cDNA and genomic clones corresponding to this gene, MAGE-Xp, and shown that the last exon contains the open reading frame and is present in a minimum of five copies in a 30-kb interval. MAGE-Xp is expressed only in testis and, unlike the Xq27-qter MAGE genes, it is not expressed in any of 12 different tumor tissues tested. However, the gene and predicted protein structure are conserved, suggesting a similar function. MAGE-Xp is located in the 160-kb critical interval defined for the locus involved in sex determination within Xp21 and is 50 kb distal to the DAX-1 gene, which is responsible for X-chromosome-linked adrenal hypoplasia congenita.

Comparison of the up-and-down, conventional LD50, and fixed-dose acute toxicity procedures

The up-and-down procedure (UDP), fixed-dose procedure (FDP) and conventional LD50 tests were compared to determine their consistency in chemical hazard classification for acute oral toxicity according to the European Economic Community (EEC) system. There was consistent classification for 23 out of 25 cases between the UDP and the conventional LD50 results, in 16 out of 20 cases between the FDP and the conventional LD50, and in seven out of 10 cases between the UDP and the FDP. The UDP needed only between six and 10 animals of one sex (fewer than either the LD50 or the FDP). Available literature indicates that the sexes are usually similar in their acute toxicity responses and that of females are often more sensitive than males when acute toxicity differences do exist, thus obviating the need for both sexes to be tested in most cases. Unlike the FDP, the UDP also estimates an LD50, thus providing data directly applicable to all current hazard classification systems based on acute oral toxicity.

Mutations in the DAX-1 gene give rise to both X-linked adrenal hypoplasia congenita and hypogonadotropic hypogonadism

Adrenal hypoplasia congenita (AHC) is an X-linked disorder characterized by primary adrenal insufficiency. Hypogonadotropic hypogonadism (HHG) is frequently associated with this disorder but is thought not to be caused by the low adrenal androgen levels due to adrenal hypoplasia. It is uncertain whether there are two distinct yet physically linked genes responsible for AHC and HHG or a single gene responsible for both diseases. AHC can occur as a part of a contiguous deletion syndrome together with Duchenne muscular dystrophy (DMD) and/or glycerol kinase deficiency (GKD). From the analysis of deletions, the following gene order has been deduced: Xpter-AHC-GKD-DMD-cen. An AHC critical region of 200-500 kilobases has been defined by physical mapping and partially overlaps with a 160-kilobase dosage-sensitive sex (DSS) reversal critical region. The DAX-1 (DSS-AHC critical region on the X, gene 1) gene was isolated and found to encode a new member of the nuclear hormone receptor family. Here we report that DAX-1 is deleted in 14 patients and point mutations were found in the coding region in DNA from 12 unrelated individuals. All AHC patients over 14 years old and with only point mutations in DAX-1 were also diagnosed with HHG, confirming that the DAX-1 gene is responsible for both X-linked AHC and HHG. But in four sporadic cases and a single familial case, no point mutations were found, suggesting genetic heterogeneity or differential expression of DAX-1.

An unusual member of the nuclear hormone receptor superfamily responsible for X-linked adrenal hypoplasia congenita

X-linked adrenal hypoplasia congenita is a developmental disorder of the human adrenal gland that results in profound hormonal deficiencies and is lethal if untreated. We have isolated the gene responsible for the disease, DAX-1, which is deleted or mutated in X-linked adrenal hypoplasia patients. DAX-1 encodes a new member of the nuclear hormone receptor superfamily displaying a novel DNA-binding domain. The DAX-1 product acts as a dominant negative regulator of transcription mediated by the retinoic acid receptor.

A new RFLP marker, SP282, at the btk locus for genetic analysis in X-linked agammaglobulinaemia families

X-linked agammaglobulinaemia is an inherited recessive disease in which the primary defect lies in the failure of pre-B cells to develop into mature circulating B cells, due to a defective B-cell cytoplasmic tyrosine kinase (btk). For this study we introduced a new RFLP marker, SP282, which is tightly linked to the XLA locus. In conjunction with the marker DXS178, SP282 was used to identify a carrier female and predict her male offspring to be normal. Subsequently the fetus was shown to have a normal number of circulating B cells, and at 2.5 years of age, the non-affected phenotype of the child was confirmed.