Comparative growth dynamics and actin concentration between cultured human myofibroblasts from granulating wounds and dermal fibroblasts from normal skin

The normal contraction of open wounds and many forms of pathologic contracture are related by the presence of a contractile fibroblast known as a myofibroblast. The function of this cell has been postulated as a result of previous pharmacological, immunological, and biochemical testing on strips of contracted connective tissue. The purpose of this study was to develop a specific assay that could measure the concentration of one contractile element (actin) within cultured myofibroblasts isolated from a contracting wound and in normal fibroblasts from uninjured dermis. Rates of growth and actin concentration through 15 days of culture were compared among populations of paired control fibroblasts from normal dermis and granulating wound myofibroblasts from three patients. Growth curves showed that myofibroblasts always grew slower than fibroblasts. An enzyme-linked immunosorbent assay showed that actin concentration was generally greater in mass cultures of granulating wound myofibroblasts than in fibroblasts from uninjured dermis. During exponential growth (1-6 days) the average actin concentration among myofibroblast lines ranged from 24 to 62 pg/cell. Average actin levels among control fibroblasts ranged from 3 to 47 pg/cell during the same interval. After 15 days of culture, actin concentration peaked twice. The first actin peak occurred within the period of exponential growth. At confluency, cellular actin levels dropped. Superconfluent cultures exhibited a second actin peak that displayed an irregular pattern of actin concentration. The latter observation suggested an artifact that might be the result of three-dimensional matrix of cells that altered points of cell adhesion and produced an irregular pattern of actin concentration. These data show that the phenotype of increased actin in cultured myofibroblasts was carried over by myofibroblasts from contracted skin wounds to culture. Because of a higher concentration of actin in myofibroblasts than in undifferentiated fibroblasts, these data suggest that the differentiation process of myofibroblasts may be associated with an increased availability of monomeric actin for filament synthesis. This study demonstrates that the use of tissue culture and our enzyme-linked immunosorbent assay will be a useful method to study factors affecting myofibroblast phenotypic modulation. Future studies should be directed toward developing procedures for isolation of pure populations of myofibroblasts as well as extracellular matrices that would maintain the morphology of both differentiated myofibroblasts and normal undifferentiated fibroblasts.     

Dehydrochlorination of poly(sulfonyl-co-2-chloroethylene)

Poly(sulfonyl-co-2-chloroethylene)s were shown to have an enhanced tendency to undergo dehydrochlorination compared with poly(vinyl chloride). Dehydrochlorination was observed under the following conditions: (a) during preparation of the copolymers by γ-radiation initiated copolymerization of vinyl chloride and sulfur dioxide, (b) by γ-irradiation of the polymer, (c) during ageing, (d) on heating and (e) in solution in basic solvents, such as DMSO. The dehydrochlorination was studied by microanalysis, by IR and UV spectroscopy and by ¹H and ¹³C NMR. Hydrogen chloride was eliminated preferentially from chloroethylene units occurring between two sulfonyl units. The proportion chloroethylene units: sulfonyl units in poly(sulfonyl-2-chloroethylene) decreased from ≈ 2:1 at a copolymerization temperature of 0°C to ≈ 1:1 at a temperature of ?78°C. The results show, that dehydrochlorination of copolymers prepared at low temperatures is a serious problem, especially with initiation by γ-irradiation.     

Wide spread scars, hypertrophic scars, and keloids

Patients with a wide scar may complain of having a "keloid," yet have a hypertrophic or a wide spread scar. The plastic surgeon should make the appropriate clinical diagnosis, because therapy varies depending on the condition present. A wide spread scar is best treated with excision and closure. A buried dermal flap may help to prevent recurrence, which is nevertheless likely to some degree. A hypertrophic scar can be distinguished from a keloid on clinical grounds. Although both may be red, nodular, and itchy, the keloid overgrows the original wound boundary and is much more likely to recur after surgical excision. Nonsurgical treatment of hypertrophic scars and keloids is similar, using repeated intralesional injections of Kenalog 40 mg per cc and sustained pressure on the lesion when possible. Surgical treatment differs for hypertrophic scars or keloids. Scar excision and closure, and selective Z-plasty, may be used in hypertrophic scars. In keloids, aggressive surgery is usually avoided, unless the lesion has a narrow pedicle. Surgery of keloids should be accompanied by intra- and postoperative Kenalog-40 injections, and on occasion by sustained pressure. Very large keloids may be resistant to medical management, and too aggressive for surgery owing to a high likelihood of recurrence. These difficult lesions serve as the impetus for continued biochemical and tissue culture research, seeking a biochemical means of control keloids.     

Developmental alterations in hepatic UDP-glucuronosyltransferase. A comparison of the kinetic properties of enzymes from adult sheep and fetal lambs

The kinetic properties of hepatic microsomal UDP-glucuronosyltransferase were studied in sheep in the perinatal period, using acetaminophen as the aglycone. Kinetic analyses indicated that activity at Vmax was significantly less in fetal microsomes (113, 135 or 141 days) as compared with the adult sheep. However, these differences between fetal and adult animals were not due simply to smaller amounts of UDP-glucuronosyltransferases catalyzing conjugation of acetaminophen in fetuses versus adults. Thus, the kinetic properties of UDP-glucuronosyltransferase(s) were different in fetus and adult. The "fetal" versus "adult" enzyme had a higher affinity for UDP-glucuronic acid, but a poorer affinity for acetaminophen. Furthermore, enzyme in fetal liver (113 days of gestation) was activated about 30% by the allosteric effector UDP-N-acetylglucosamine, whereas enzyme in adult liver was activated by 500%. These differences between fetal and adult enzymes diminished just prior to parturition (141-day fetus). Enzyme in microsomes from the 141-day fetus responded to UDP-N-acetylglucosamine-like enzyme in adult microsomes and had affinities for substrates that were similar to "adult" enzymes. These data indicate that maturation of the system that glucuronidates acetaminophen is a complex process. It may involve the expression in fetuses of a type of UDP-glucuronosyltransferase that is different from that expressed in the adult. An alternative but not mutually exclusive possibility is that maturation of the glucuronidation system involves modification of enzyme function by alteration of the phospholipids in the immediate environment of UDP-glucuronosyltransferase within the microsomal membrane.     

Shifting US Patterns of COVID-19 Mortality by Race and Ethnicity From June–December 2020

ObjectivesThe COVID-19 pandemic has disproportionately affected racial and ethnic minorities in the United States and has been devastating for residents of nursing homes (NHs). However, evidence on racial and ethnic disparities in COVID-19–related mortality rates within NHs and how that has changed over time has been limited. This study examines the impact of a high proportion of minority residents in NHs on COVID-19–related mortality rates over a 30-week period.DesignLongitudinal study.Setting and ParticipantsCenters for Medicare & Medicaid Services Nursing Home COVID-19 Public Use File data from 50 states from June 1, 2020, to December 27, 2020.MethodsWe linked data from 11,718 NHs to (1) Nursing Home Compare data, (2) the Long-Term Care: Facts on Care in the U.S., and (3) US county-level data on COVID cases and deaths. Our primary independent variable was proportion of minority residents (blacks and Hispanics) in NHs and its association with mortality rate over time.ResultsDuring the first 6 weeks from June 1, 2020, NHs with a higher proportion of black residents reported more COVID-19 deaths per 1000 followed by NHs with a higher proportion of Hispanic residents. Between 7 and 12 weeks, NHs with a higher proportion of Hispanic residents reported more deaths per 1000, followed by NHs with a higher proportion of black residents. However, after 23 weeks (mid-November 2020), NHs serving a higher proportion of white residents reported more deaths per 1000 than NHs serving a high proportion of black and Hispanic residents.Conclusions and ImplicationsThe disparities in COVID-19–related mortality for nursing homes serving minority residents is evident for the first 12 weeks of our study period. Policy interventions and the equitable distribution of vaccine are required to mitigate the impact of systemic racial injustice on health outcomes of people of color residing in NHs.     

Autogenous Arteriovenous Bundle Implantation Maintains Viability Without Increased Immune Response in Large Porcine Bone Allotransplants

BackgroundTransplantation of living allogeneic bone segments may permit reconstruction of large defects, particularly if viability is maintained without immunosuppression. Development of a new autogenous osseous blood supply accomplishes this goal in rodent experimental models. This study evaluates potential systemic and local inflammatory responses to this angiogenesis in a large-animal model.MethodsVascularized allogeneic tibia segments were transplanted orthotopically into matched tibial defects in Yucatan minipigs. Microvascular anastomoses of bone nutrient artery and vein were supplemented by intramedullary placement of an autogenous arteriovenous (AV) bundle in group 1. Group 2 served as a no-angiogenesis control. A 3-drug immunosuppression regimen was withdrawn after 2 weeks. During the 20-week survival period, periodic leukocyte counts and inflammatory cytokine levels were measured. Thereafter, osteocyte survival was quantified and transplant rejection graded by histologic examination and quantitative real-time polymerase chain reaction of immunologic markers.ResultsBoth groups developed an initial systemic response, which resolved after 4 to 6 weeks. No differences were seen in blood cytokine levels. Interleukin 2 expression was diminished in group 1 tibiae. As expected, nutrient pedicles had thrombosed without sustained immunosuppression, occluded by intimal hyperplasia. In group 1, angiogenesis from the autogenous AV bundle resulted in significantly less osteonecrosis (P = .04) and fibrosis (P = .02) than group 2 allotransplants.ConclusionsSystemic immune responses to large-bone allotransplants were not increased by generation of an autogenous osseous blood supply within porcine tibial bone allotransplants. Implanted AV bundles diminished inflammation and fibrosis and improved bone viability when compared to no-angiogenesis controls.     

Overview and update on molecular testing in non-small cell lung carcinoma utilizing endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) samples

Lung carcinoma remains one of the most frequent and aggressive human neoplasms. Fortunately, in the last decades, the increasing knowledge of the molecular mechanisms leading to cancer development has allowed the use of targeted therapies with improvement of prognosis in many patients. Clinical management has also changed after the introduction of endobronchialultrasonographic bronchoscopy that allows a conservative staging of lung tumors, avoiding the need of mediastinoscopy for lymph node staging. Lung pathologists and cytopathologists are facing the challenge of giving the more comprehensive prognostic and predictive information with ever smaller tissue or cytological samples. The aim of this review is to summarize the molecular testing for non-small cell lung carcinoma and how pathologists can contribute to the patient's outcome with a conscious management of biological samples.     

Improved biological properties of synthetic distearoyl phosphatidyl choline-based liposome in the conscious rat

We have previously produced and tested a liposome preparation based on hydrogenated soy lecithin (HSL-L) for the purpose of designing blood replacement in the form of liposome encapsulated hemoglobin (LEH). While these liposomes had acceptable physicochemical properties which addressed many of the desirable characteristics of "artificial blood," they produced hypotension, hemoconcentration, and thrombocytopenia when administered to rats. The following studies present improved synthetic distearoyl phosphatidylcholine-based liposomes (sDSPC-L) which were compared to the HSL-L for their biological effects in the conscious normovolemic rat (n = 6 - 11). HSL-L induced hypotension (-25 +/- 3 mmHg, P less than 0.01), tachycardia (+88 +/- 11 beats/min, P less than 0.01), decrease in cardiac index (-33 +/- 4%, P less than 0.01), and elevation of the total peripheral resistance index (+0.450 +/- 0.003 mmHg/ml/min/kg, P less than 0.01). The hematologic responses to HSL-L were: leukocytosis (+6,070 +/- 1,064/microliters, P less than 0.01), hemoconcentration (+4.0 +/- 0.1%, P less than 0.01), 0.01), and thrombocytopenia (-160 +/- 18 X 10(3)/microliters, P less than 0.01). Plasma thromboxane B2 (TXB2) was elevated to 30.4 +/- 5.6 pg/100 microliters (P less than 0.01). In contrast, the only effects induced by sDSPC-L were slight tachycardia (+37 +/- 9 beats/min, P less than 0.05) and a marginal increase in plasma TXB2 to 9.7 +/- 3.3 pg/100 microliters (P less than 0.05). All effects, except for those related to cardiac output and peripheral resistance, were transient. These data underscore the importance of pure synthetic DSPC in improving the biological effects of liposomes and suggest sDSPC-L as a promising vehicle for encapsulating hemoglobin.     

Aging trends: Indonesia

The authors discuss causes and consequences of aging trends in Indonesia. Aspects considered include median age and support ratios; life expectancy; marital status and living arrangements; health, mobility, and disability; education; and work and income.     

Mortality in a cohort of licensed pesticide applicators in Florida

OBJECTIVES: Although the primary hazard to humans associated with pesticide exposure is acute poisoning, there has been considerable concern surrounding the possibility of cancer and other chronic health effects in humans. Given the huge volume of pesticides now used throughout the world, as well as environmental and food residue contamination leading to chronic low level exposure, the study of possible chronic human health effects is important. METHODS: This was a retrospective cohort study, analysed by general standardised mortality ratio (SMR) of licensed pesticide applicators in Florida compared with the general population of Florida. A cohort of 33,658 (10% female) licensed pesticide applicators assembled through extensive data linkages yielded 1874 deaths with 320,250 person-years from 1 January 1975 to 31 December 1993. RESULTS: The pesticide applicators were consistently and significantly healthier than the general population of Florida. As with many occupational cohorts, the risks of cardiovascular disease and of diseases associated with alcohol and tobacco use were significantly lower, even in the subpopulations--for example, men, women, and licence subcategories. Among male applicators, prostate cancer mortality (SMR 2.38 (95% confidence interval (95% CI) 1.83 to 3.04) was significantly increased. No cases of soft tissue sarcoma were confirmed in this cohort, and non-Hodgkin's lymphoma was not increased. The number of female applicators was small, as were the numbers of deaths. Mortality from cervical cancer and breast cancer was not increased. Additional subcohort and exposure analyses were performed. CONCLUSIONS: Consistent with previous publications on farmers but at odds with current theories about the protective effects of vitamin D, prostate cancer was increased in these pesticide applicators. Female breast cancer was not increased despite theories linking risk of breast cancer with exposure to oestrogen disruptors--such as the organochlorines. The lack of cases of soft tissue sarcoma is at odds with previous publications associating the use of the phenoxy herbicides with an increased risk of these cancers.