Direct and long-range action of a DPP morphogen gradient

During development of the Drosophila wing, the decapentaplegic (dpp) gene is expressed in a stripe of cells along the anteroposterior compartment boundary and gives rise to a secreted protein that exerts a long-range organizing influence on both compartments. Using clones of cells that express DPP, or in which DPP receptor activity has been constitutively activated or abolished, we show that DPP acts directly and at long range on responding cells, rather than by proxy through the short-range induction of other signaling molecules. Further, we show that two genes, optomotor-blind and spalt are transcriptionally activated at different distances from DPP-secreting cells and provide evidence that these genes respond to different threshold concentrations of DPP protein. We propose that DPP acts as a gradient morphogen during wing development.

Dispatched, a novel sterol-sensing domain protein dedicated to the release of cholesterol-modified hedgehog from signaling cells

Members of the Hedgehog (Hh) family of secreted signaling proteins function as potent short-range organizers in animal development. Their range of action is limited by a C-terminal cholesterol tether and the upregulation of Patched (Ptc) receptor levels. Here we identify a novel segment-polarity gene in Drosophila, dispatched (disp), and demonstrate that its product is required in sending cells for normal Hh function. In the absence of Disp, cholesterol-modified but not cholesterol-free Hh is retained in these cells, indicating that Disp functions to release cholesterol-anchored Hh. Despite their opposite roles, Disp and Ptc share structural homology in the form of a sterol-sensing domain, suggesting that release and sequestration of cholesterol-modified Hh may be based on related molecular pathways.

Refining a case-mix measure for nursing homes: Resource Utilization Groups (RUG-III)

A case-mix classification system for nursing home residents is developed, based on a sample of 7,658 residents in seven states. Data included a broad assessment of resident characteristics, corresponding to items of the Minimum Data Set, and detailed measurement of nursing staff care time over a 24-hour period and therapy staff time over a 1-week period. The Resource Utilization Groups, Version III (RUG-III) system, with 44 distinct groups, achieves 55.5% variance explanation of total (nursing and therapy) per diem cost and meets goals of clinical validity and payment incentives. The mean resource use (case-mix index) of groups spans a nine-fold range. The RUG-III system improves on an earlier version not only by increasing the variance explanation (from 43%), but, more importantly, by identifying residents with "high tech" procedures (e.g., ventilators, respirators, and parenteral feeding) and those with cognitive impairments; by using better multiple activities of daily living; and by providing explicit qualifications for the Medicare nursing home benefit. RUG-III is being implemented for nursing home payment in 11 states (six as part of a federal multistate demonstration) and can be used in management, staffing level determination, and quality assurance.

Dpp receptors are autonomously required for cell proliferation in the entire developing Drosophila wing

The mammalian growth factor TGFbeta negatively regulates cell proliferation in various systems. Here we provide evidence that another TGFbeta superfamily member, Drosophila Decapentaplegic (Dpp), stimulates cell proliferation. In the developing wing blade, somatic clones lacking the Dpp receptors Punt or Thick veins (Tkv), or lacking Schnurri, a transcription factor involved in Dpp signal interpretation, fail to grow when induced early in larval development. Furthermore the spatial requirement for these signaling components indicates that Dpp has to travel several cell diameters from its source in order to reach all cells that require its signal. The requirement for Tkv also depends on the distance of cells from the source of the Dpp signal. We propose that Dpp can act at a distance to positively control cell proliferation.

Inhibition of toxicity in the beta-amyloid peptide fragment beta -(25-35) using N-methylated derivatives: a general strategy to prevent amyloid formation

beta-(25-35) is a synthetic derivative of beta-amyloid, the peptide that is believed to cause Alzheimer's disease. As it is highly toxic and forms fibrillar aggregates typical of beta-amyloid, it is suitable as a model for testing inhibitors of aggregation and toxicity. We demonstrate that N-methylated derivatives of beta-(25-35), which in isolation are soluble and non-toxic, can prevent the aggregation and inhibit the resulting toxicity of the wild type peptide. N-Methylation can block hydrogen bonding on the outer edge of the assembling amyloid. The peptides are assayed by Congo red and thioflavin T binding, electron microscopy, and a 3-(4, 5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) toxicity assay on PC12 cells. One peptide (Gly(25) N-methylated) has properties similar to the wild type, whereas five have varying effects on prefolded fibrils and fibril assembly. In particular, beta-(25-35) with Gly(33) N-methylated is able to completely prevent fibril assembly and to reduce the toxicity of prefolded amyloid. With Leu(34) N-methylated, the fibril morphology is altered and the toxicity reduced. We suggest that the use of N-methylated derivatives of amyloidogenic peptides and proteins could provide a general solution to the problem of amyloid deposition and toxicity.

Experts recommend minimum nurse staffing standards for nursing facilities in the United States

The experts concluded that current data show that the average nurse staffing levels (for RNs, LVN/LPNs, and NAs) in nursing homes are too low in some facilities to provide high quality of care. Caregiving, the central feature of a nursing home, needs to be improved to ensure high quality of care to residents. Because detailed time studies have not been conducted on the amount of time that is required to provide high quality of care to residents, expert opinion is currently the best approach to addressing the problem of inadequate staffing. Increases in the education level and training of nursing staff are also strongly recommended as a step to improving quality of care and reducing turnover rates in nursing homes. These recommendations are designed for consideration by Congress, HCFA regulators, policymakers, nursing home administrators, and nurses. Ideally, Congress would pass legislation establishing these recommendations as minimum standards for all nursing homes or direct HCFA to establish detailed minimum nurse staffing standards to ensure that staffing levels take into account the number and the case-mix of the residents. Alternatively, HCFA could introduce minimum staffing standards through the regulatory process. In 1999 there were a number of efforts at the state level to increase minimum staffing levels. Mohler (1999) surveyed selected states and found that 21 states had either proposed new legislation or were considering proposals for new legislation or new regulations. In California, for example, in 1999 the state budget approved $31 million in new state funds (to be matched with $31 million in federal Medicaid dollars) to increase nursing home staffing minimum requirements from 2.8 to 3.2 hr per resident day and to increase wage rates. Overall, nursing facilities need to be held accountable by HCFA for providing adequate levels and types of staffing to meet the needs of their residents, especially because government is paying for 61% of the expenditures. Adopting these minimum standards will have an important impact on improving the quality of the nation's nursing home care. Additional research is needed to determine appropriate levels and types of staff to provide high quality of care to residents. These studies could test the proposed staffing standards against existing staffing levels to examine the impacts on quality. As new data become available on staffing levels, revisions of staffing standards should be made if necessary to ensure that high standards are maintained.

Schnurri is required for Drosophila Dpp signaling and encodes a zinc finger protein similar to the mammalian transcription factor PRDII-BF1

Cytokines of the TGF beta superfamily regulate many aspects of cellular function by activating receptor complexes consisting of two distantly related serine/threonine kinases. Previous studies have indicated that Drosophila dpp uses similar signaling complexes and strictly requires the punt and thick veins receptors to transduce the signal across the membrane. Here, we show that the schnurri (shn) gene is required for many aspects of dpp signaling. Genetic epistasis experiments indicate that shn functions downstream of the dpp signal and its receptors. The shn gene encodes a large protein similar to a family of mammalian zinc finger transcription factors. The shn protein might therefore act as a nuclear target in the dpp signaling pathway directly regulating the expression of dpp-responsive genes.

Laparoscopic versus open appendectomy: what is the real difference? Results of a prospective randomized double-blinded trial

BACKGROUND

The comparison of laparoscopic to open appendectomy has been reviewed in many retrospective and prospective studies. Some report shorter hospital stays, less postoperative pain, and earlier return to work while others fail to demonstrate such differences. We performed a prospective, randomized double-blinded trial to evaluate this ongoing debate.

METHODS

Fifty-two consecutive men presenting with signs and symptoms suggestive of acute appendicitis were randomized to undergo either laparoscopic appendectomy or open appendectomy. Length of operative times, hospital stay, lost work days, visual analog pain scores, and operative costs were compared.

RESULTS

Length of stay averaged 21.5 h for the laparoscopic group and was not statistically different when compared to the open group. Perceived postoperative pain on postoperative days 1 and 7 were not statistically different between the two groups. Mean time to return to work was 11 days, and there was no statistical difference between groups. Operative costs were >600 dollars greater for the laparoscopic approach.

CONCLUSIONS

In this prospective randomized double-blinded trial, laparoscopic appendectomy appears to confer no significant advantage over open appendectomy for postoperative pain or lost work days. It does carry an increase in operating room costs and, contrary to other reports, hospital stay is not shortened. Further studies are needed to determine if specific populations, such as the obese or women, may benefit from a minimally invasive approach to appendicitis.

American Society of Transplant Surgeons transplant center outcomes requirements--a threat to innovation

The transplant center regulations recently published by the Centers for Medicare and Medicaid (CMS) mandate that observed program-specific survival outcomes to fall within expected risk-adjusted outcomes. Meeting these outcomes is essential to continued participation in the Medicare program. Both donor and recipient variables not considered in current risk adjustment models can result in inferior outcomes and therefore may cause an overestimation of transplant center expected performance, precluding participation in the federally funded Medicare program. We reviewed the most recent four reporting periods published by the Scientific Registry for Transplant Recipients on their public website. We identified kidney, liver and heart transplant programs that were flagged for having outcomes statistically lower than expected as well as those that failed to meet CMS criteria. We also analyzed whether center volumes correlated with outcomes in these centers. We highlight the need for mitigating factors that could justify inferior outcomes under specific circumstances. Failure to reach consensus on such a mechanism for appeal may result in risk-averse behavior by transplant centers with respect to innovation and therefore hamper the ability to advance the field of transplantation. We propose a methodology that may address this emerging dilemma.

Identification, prevention and treatment of iron deficiency during the first 1000 days

Iron deficiency is a global problem across the life course, but infants and their mothers are especially vulnerable to both the development and the consequences of iron deficiency. Maternal iron deficiency during pregnancy can predispose offspring to the development of iron deficiency during infancy, with potentially lifelong sequelae. This review explores iron status throughout these "first 1000 days" from pregnancy through two years of age, covering the role of iron and the epidemiology of iron deficiency, as well as its consequences, identification, interventions and remaining research gaps.

Radiologic placement of subcutaneous infusion chest ports for long-term central venous access

OBJECTIVE

The technical success and complications associated with radiologic placement of subcutaneous implantable chest ports for long-term central venous access were evaluated.

MATERIALS AND METHODS

Between May 1, 1996, and December 31, 1996, 80 chest ports were placed in 80 consecutive patients using the right internal jugular vein as the preferred access route. All procedures occurred in interventional radiology suites with patients receiving conscious sedation. Both sonography and fluoroscopy were used for venipuncture and to guide port insertion. Follow-up was obtained by the clinical service and by performing chart reviews electronically.

RESULTS

Technical success was 100%, and follow-up was obtained in all patients. One procedural complication occurred that was unrelated to actual catheter placement. Mean catheter use was 155 days (total, 12,168 days; range, 18-303 days). Confirmed catheter-related infection rate was 3%, or 0.016 per 100 access days; symptomatic catheter-related central venous thrombosis rate was 1%, or 0.008 per 100 access days; and 5% of catheters were removed prematurely. No instances of hematoma formation, catheter tip migration or malposition, symptomatic air embolism, spontaneous catheter fracture, or pneumothorax were found.

CONCLUSION

With the benefit of both sonographic and fluoroscopic guidance, subcutaneous implantable chest ports can be inserted by radiologists with equal or lower complication rates than those reported in surgical series. Image-guided insertion of chest ports should replace rather than supplement unguided placement.

Laccases and other polyphenol oxidases in ecto- and ericoid mycorrhizal fungi

Polyphenol oxidases are known to be produced by a range of ectomycorrhizal (ECM) and ericoid mycorrhizal fungi. These enzymes include laccase (EC 1.10.3.2), catechol oxidase (EC 1.10.3.1) and tyrosinase (EC 1.14.18.1), between which there exists considerable overlap in substrate affinities. In this review we consider the nature and function of these enzymes, along with the difficulties associated with assigning precise enzymatic descriptions. The evidence for production of laccase and other polyphenol oxidases by ECM and ericoid mycorrhizal fungi is critically assessed and their potential significance to the mycorrhizal symbioses discussed.

Hedgehog-dependent patterning in the Drosophila eye can occur in the absence of Dpp signaling

The progression of retinal morphogenesis in the Drosophila eye is controlled to a large extent by Hedgehog (Hh), a signaling protein emanating from differentiating photoreceptor cells. Adjacent, more anterior cells in the morphogenetic furrow respond to Hh by expressing decapentaplegic (dpp), suggesting that the relationship between Hh and Dpp might be similar to that in the limb imaginal discs where Dpp mediates the organizing activity of Hh. In this study we show that this is not the case. Analysis of somatic clones of cells lacking the Dpp receptors Punt or Tkv reveals that Dpp plays only a minor role in furrow progression and no critical role in subsequent ommatidial development. In contrast, Hh-independent dpp expression around the posterior and lateral margins of the first and second instar eye discs is important for the growth of the eye disc and for initiation of the morphogenetic furrow at these margins.

Septic tanks as larval habitats for the mosquitoes Aedes aegypti and Culex quinquefasciatus in Playa-Playita, Puerto Rico

Adult Aedes aegypti (Linnaeus) (Diptera: Culicidae) were previously recovered from emergence traps on septic tanks in southeastern Puerto Rico. In this study we quantified immature mosquito abundance and its relationship with structural variables of the septic tanks and chemical properties of the water containing raw sewage. A miniaturized floating funnel trap was used to sample 89 septic tanks for larvae in the Puerto Rican community of Playa-Playita. Aedes aegypti larvae were recovered from 18% of the sampled tanks (10.3 larvae per septic tank per day). Larval presence was positively associated with cracking of the septic tank walls and uncovered access ports. Larval abundance was positively associated with cracking of the septic tank walls and larger tank surface areas, and inversely associated with the total dissolved solids (TDS). Culex quinquefasciatus (Say) larvae were also recovered from 74% of the septic tanks (129.6 larvae per septic tank per day). Larval presence was negatively associated with TDS in the water and larval abundance was positively associated with cracking of the septic tank walls. A screened, plastic emergence trap was used to sample 93 septic tanks within the community for Ae. aegypti and Cx. quinquefasciatus adults. Aedes aegypti adults were recovered from 49% of the sampled tanks (8.7 adults per septic tank per day) and Cx. quinquefasciatus adults were recovered from 97% of the sampled tanks (155.5 adults per septic tank per day). Aedes aegypti adult presence was positively associated with cracking, uncapped openings and septic water pH. The Ae. aegypti adult counts were positively associated with cracking and inversely associated with TDS and conductivity. This study marks the first published record of the recovery of Ae. aegypti larvae from holding tanks containing raw sewage in the Caribbean region. Our study indicates that Ae. aegypti larvae are present in sewage water and that septic tanks have at least the potential to maintain dengue transmission during the dry season.

Herpes simplex virus glycoprotein treatment of recurrent genital herpes

We investigated the possibility that herpes simplex virus (HSV) glycoproteins might provide potential immunotherapy for recurrent HSV disease by using the guinea pig model of genital HSV infection. In two experiments, after recovery from initial genital herpes, 58 animals were randomized either to receive a glycoprotein vaccine or to serve as controls. Both a mixture of HSV-2 glycoproteins derived from infected tissue cultures and a mixture of HSV-1 glycoproteins B and D, prepared by genetic engineering in mammalian cells, reduced the frequency (P less than .05) and severity (P less than .05) of subsequent herpetic recurrences. We conclude that recurrences of established herpesvirus disease may be altered by administering immunogenic viral proteins; thus, HSV glycoproteins may be useful as immunotherapeutic agents for controlling recurrent HSV infection in humans.

double-time is identical to discs overgrown, which is required for cell survival, proliferation and growth arrest in Drosophila imaginal discs

We have isolated the discs overgrown gene of Drosophila and shown that it encodes a homolog of the Casein kinase I(delta)/(epsilon) subfamily and is identical to the double-time gene. However, in contrast to the weak double-time alleles, which appear to affect only the circadian rhythm, discs overgrown alleles, including bona fide null alleles, show strong effects on cell survival and growth control in imaginal discs. Analysis of their phenotypes and molecular lesions suggests that the Discs overgrown protein is a crucial component in the mechanism that links cell survival during proliferation to growth arrest in imaginal discs. This work provides the first analysis in a multicellular organism of Casein kinase I(delta)/(epsilon) functions necessary for survival. Since the amino acid sequences and three-dimensional structures of Casein kinase I(delta)/(epsilon) enzymes are highly conserved, the results suggest that these proteins may also function in controlling cell growth and survival in other organisms.

Characterisation of equine matrix metalloproteinase 2 and 9; and identification of the cellular sources of these enzymes in joints

The cellular production by resident articular cells and infiltrating inflammatory cells of the gelatinase matrix metalloproteinases (MMP) was investigated by tissue culture methods and analysis of cell supernatants by gelatin zymography. Peripheral blood neutrophils in short term culture produced MMP-9, as did peripheral blood monocytes in culture. Isolated articular chondrocytes in monolayer culture produced both MMP-2 and MMP-9, although articular cartilage maintained as explant culture produced MMP-2 alone. Synovial fibroblasts grown in monolayer culture produced MMP-2 alone, although synovial membrane in explant culture produced both MMP-2 and the active form of MMP-2. Lysis of blood polymorph neutrophils produced large quantities of MMP-9, but lysis of blood monocytes, synovial fibroblasts and articular chondrocytes produced little enzyme indicating that, unlike the other cell types, polymorph neutrophils store MMPs intracellularly. Equine MMP-2 was purified from synovial fibroblast cell culture supernatant, and equine MMP-9 from polymorph neutrophil cell culture supernatant, by gelatin-sepharose affinity chromatography. The 2 enzymes were identified from their molecular weights and by their respective N-terminal amino acid sequences which showed homology with the enzymes from other species. The demonstration that invasive cells and resident articular cells can produce enzymes which are capable of digestion of certain component molecules of the articular cartilage matrix, shows that therapeutic targeting of these enzymes could be a valid proposition in the prevention of cartilage destruction in osteoarthritis.

Estimating the early impact of the US COVID-19 vaccination programme on COVID-19 cases, emergency department visits, hospital admissions, and deaths among adults aged 65 years and older: an ecological analysis of national surveillance data

BACKGROUND

In the USA, COVID-19 vaccines became available in mid-December, 2020, with adults aged 65 years and older among the first groups prioritised for vaccination. We estimated the national-level impact of the initial phases of the US COVID-19 vaccination programme on COVID-19 cases, emergency department visits, hospital admissions, and deaths among adults aged 65 years and older.

METHODS

We analysed population-based data reported to US federal agencies on COVID-19 cases, emergency department visits, hospital admissions, and deaths among adults aged 50 years and older during the period Nov 1, 2020, to April 10, 2021. We calculated the relative change in incidence among older age groups compared with a younger reference group for pre-vaccination and post-vaccination periods, defined by the week when vaccination coverage in a given age group first exceeded coverage in the reference age group by at least 1%; time lags for immune response and time to outcome were incorporated. We assessed whether the ratio of these relative changes differed when comparing the pre-vaccination and post-vaccination periods.

FINDINGS

The ratio of relative changes comparing the change in the COVID-19 case incidence ratio over the post-vaccine versus pre-vaccine periods showed relative decreases of 53% (95% CI 50 to 55) and 62% (59 to 64) among adults aged 65 to 74 years and 75 years and older, respectively, compared with those aged 50 to 64 years. We found similar results for emergency department visits with relative decreases of 61% (52 to 68) for adults aged 65 to 74 years and 77% (71 to 78) for those aged 75 years and older compared with adults aged 50 to 64 years. Hospital admissions declined by 39% (29 to 48) among those aged 60 to 69 years, 60% (54 to 66) among those aged 70 to 79 years, and 68% (62 to 73), among those aged 80 years and older, compared with adults aged 50 to 59 years. COVID-19 deaths also declined (by 41%, 95% CI -14 to 69 among adults aged 65-74 years and by 30%, -47 to 66 among those aged ≥75 years, compared with adults aged 50 to 64 years), but the magnitude of the impact of vaccination roll-out on deaths was unclear.

INTERPRETATION

The initial roll-out of the US COVID-19 vaccination programme was associated with reductions in COVID-19 cases, emergency department visits, and hospital admissions among older adults.

FUNDING

None.

Wallstent deployment to salvage dialysis graft thrombolysis complicated by venous rupture: early and intermediate results

OBJECTIVE

The feasibility of deploying Wallstents to treat venous rupture occurring during dialysis graft thrombolysis was determined.

SUBJECTS AND METHODS

Between June 24, 1994, and February 19, 1997, 23 patients with venous rupture attributed to balloon angioplasty during dialysis graft thrombolysis were treated by Wallstent deployment across the area of rupture. Twenty-one ruptures occurred in peripheral veins and two occurred in central veins. Follow-up was provided by the clinical service at our institution and by electronic review of patients' charts.

RESULTS

Stent placement allowed completion of graft thrombolysis in all 23 patients. Complications were limited to four moderate-sized hematomas of the arm, and a single pseudoaneurysm developed 6 months after stent placement in one 27-year-old patient. The primary patency rate of stents was 52% at 60 days, 26% at 180 days, and 11% at 360 days. The secondary patency rate was 74% at 60 days, 65% at 180 days, and 56% at 360 days.

CONCLUSION

Treatment of venous ruptures using Wallstents is a safe alternative to intentional graft thrombosis. The patency rates of these devices are similar to those of venous stents placed for other indications.

Mental dysfunction and resource use in nursing homes

The role of dementia and other mental disorders in nursing home case-mix classification systems has been an area of controversy. The role of mental dysfunctions was considered in developing a new case-mix measurement system for facility payment in a national demonstration to understand staff time use in nursing homes. Nursing staff (nurses and aides) time and resident assessment data were collected for 6,663 nursing home residents in 6 states. Measures of signs and symptoms of cognitive impairment (dementia), depression, and delirium were created based on items from the new National Minimum Data Set. These measures then were used to determine whether mental dysfunctions were predictive of resource use (nursing staff times and costs) when controlling for other case-mix variables. Cognitive impairment was associated with slightly higher staff time only in less physically-impaired residents without serious medical conditions and not receiving heavy rehabilitation. Similarly, depression and delirium were associated with higher resource use only in selected types of residents. Based on these findings, the new Resource Utilization Groups Version III (RUG-III) contain a major category of residents who are cognitively impaired but not severely dependent in Activities of Daily Living. Depression is used to differentiate subgroups of residents with major medical conditions such as hemiplegia and aphasia. Delirium, when used together with other resident characteristics, was not found useful in explaining resource use. Case-mix groups defined by mental dysfunctions can foster improved care, but careful consideration must be given to appropriate incentives and documentation requirements for providers.

Transplant center regulations--a mixed blessing? An ASTS Council viewpoint

The Centers for Medicare and Medicaid Services (CMS) has developed a set of regulations that spell out the Conditions of Participation (CoPs) for provider hospitals that wish to be certified (and thus eligible for reimbursement) by Medicare for transplant services. The American Society of Transplant Surgeons (ASTS) Council has played a major role in providing CMS with advice and guidance in the development and ongoing implementation of these conditions through a process of fruitful dialogue. In this report, we highlight the events that led to the development of the regulations and describe the process to date in implementing the CoPs. We have raised some important questions regarding the effectiveness of the regulations for improving safety, and we have highlighted the cost associated with their implementation. This report has been vetted by and represents the opinions of the Council of the ASTS.