Assessing risk in the retail environment during the COVID-19 pandemic.

The COVID-19 pandemic has caused unprecedented disruption, particularly in retail. Where essential demand cannot be fulfilled online, or where more stringent measures have been relaxed, customers must visit shop premises in person. This naturally gives rise to some risk of susceptible individuals (customers or staff) becoming infected. It is essential to minimize this risk as far as possible while retaining economic viability of the shop. We therefore explore and compare the spread of COVID-19 in different shopping situations involving person-to-person interactions: (i) free-flowing, unstructured shopping; (ii) structured shopping (e.g. a queue). We examine which of (i) or (ii) may be preferable for minimizing the spread of COVID-19 in a given shop, subject to constraints such as the geometry of the shop; compliance of the population to local guidelines; and additional safety measures which may be available to the organizers of the shop. We derive a series of conclusions, such as unidirectional free movement being preferable to bidirectional shopping, and that the number of servers should be maximized as long as they can be well protected from infection.

Pressure sores in children--the acute hospital perspective.

There is very little published literature on pressure sores in children and most of the existing literature is qualitative. Using literature from paediatric and adult studies, a schedule was designed to collect quantitative data on aspects that may predispose children to pressure injury. The schedule was piloted in an incidence and a prevalence study at the Royal Liverpool Children's NHS Trust. The sample size was 82 children for the incidence study and 183 children for the prevalence study. Six children in the incidence study and 12 children in the prevalence study sustained pressure injury. Data indicated that factors most strongly associated with pressure injury were nutritional status, mobility and consciousness level. Other factors that were implicated in increasing susceptibility to pressure injury were skin condition, body weight, haemodynamic status and hydration. Infants and young children most frequently sustained pressure injury on the occipital scalp area and heels. Although this was a small study, it produced some useful preliminary data, and was a valuable exercise to develop a tool for data collection on a larger scale.

PDGFbeta receptor blockade inhibits intimal hyperplasia in the baboon.

BACKGROUND: We have evaluated the use of a mouse/human chimeric anti-platelet-derived growth factor-beta receptor antibody in combination with heparin to inhibit intimal hyperplasia in the saphenous artery of the baboon after balloon angioplasty. METHODS AND RESULTS: The study evaluated lesion development in sequential injuries made 28 days apart. Each animal received control treatment after the first injury and antibody/heparin therapy after the second injury to the contralateral artery. The antibody was administered by bolus intravenous injections (10 mg/kg) on study days 1, 4, 8, 15, and 22 and heparin coadministered by continuous intravenous infusion at a dose of 0.13 mg/kg per hour. Morphometric analysis of tissue sections showed a 53% decrease in intimal area after antibody/heparin treatment (P=0.005), corresponding to a 40% decrease in the intima-to-media ratio (P=0.005). Smooth muscle cell proliferation in the injured wall, measured at both 4 and 29 days after balloon injury, were similar in the control and antibody/heparin-treated animals. CONCLUSIONS: These data suggest that platelet-derived growth factor plays a key role in the development of intimal lesions at sites of acute vascular injury in the nonhuman primate.

Conversion of highly malignant colon cancer from an aggressive to a controlled disease by oral administration of a metalloproteinase inhibitor.

In this study, we describe the activity of CT1746, an orally-active synthetic MMP inhibitor that has a greater specificity for gelatinase A, gelatinase B and stromelysin than for interstitial collagenase and matrilysin, in a nude mouse model that better mimics the clinical development of human colon cancer. The model is constructed by surgical orthotopic implantation (SOI) of histologically-intact tissue of the metastatic human colon tumor cell line Co-3. Animals were gavaged with CT1746 twice a day at 100 mg/kg for 5 days after the SOI of Co-3 for 43 days. In this model CT1746 significantly prolonged the median survival time of the tumor-bearing animals from 51 to 78 days. Significant efficacy of CT1746 was observed on primary tumor growth (32% reduction in mean tumor area at day 36), total spread and metastasis (6/20 treated animals had no detectable spread and metastasis at autopsy compared to 100% incidence of secondaries in control groups). Efficacy of CT1746 could also be seen on reducing tumor spread and metastasis to individual organ sites such as the abdominal wall, cecum and lymph nodes compared to vehicle and untreated controls. We conclude that chronic administration of a peptidomimetic MMP inhibitor via the oral route is feasible and results in inhibition of solid tumor growth, spread and metastasis with increase in survival in this model of human cancer, thus converting aggressive cancer to a more controlled indolent disease.

A major role for matrix metalloproteinases in T cell injury in the gut.

Activated lamina propria T cells responding to luminal Ags are thought to be important in celiac disease and Crohn's disease, and T cells responding to foreign MHC products are also important in intestinal graft-vs-host disease and intestinal transplant rejection. However, the mechanism(s) by which T cells mediate damage in the gut is not known. We have previously shown that activation of lamina propria T cells by PWM in explant cultures of second trimester human small intestine produces severe tissue injury, with epithelial cell shedding and loss of villi. In this study, we have investigated the role of matrix metalloproteinases in this system. Organ culture supernatants of explants stimulated with PWM showed a 3-fold increase in the concentration of interstitial collagenase and a 10-fold increase in stromelysin-1 compared with control explant culture supernatants. Tissue inhibitors of metalloproteinase-1 and -2 concentrations were unchanged. Increased metalloproteinase enzymatic activity was detected by gelatin and casein zymography. Western blotting revealed the active forms of interstitial collagenase and stromelysin-1 in PWM-stimulated culture supernatants. Up-regulation of mRNA for interstitial collagenase, stromelysin-1, and gelatinase-B was also seen. Nanomolar amounts of recombinant stromelysin-1 added directly to explants produced rapid severe tissue injury. PWM-induced mucosal injury was inhibited by a synthetic peptidomimetic inhibitor of matrix metalloproteinases. Mesenchymal cells isolated from the mucosa of human fetal small intestine produced increased amounts of interstitial collagenase, gelatinase A, and stromelysin-1 when stimulated with IL-1beta or TNF-alpha. These results suggest that T cell activation in the lamina propria results in increased production of matrix metalloproteinases, which by degrading the lamina propria matrix represent a major pathway by which T cells cause injury in the gut.

Matrix metalloproteinase-2 and tissue inhibitor of metalloproteinase-2 expression and synthetic matrix metalloproteinase-2 inhibitor binding in ovarian carcinomas and tumor cell lines.

Enhanced matrix metalloproteinase-2 (MMP-2/72-kd type IV collagenase) action correlates with invasion in neoplasia. MMP-2 is inhibited in vivo by tissue inhibitors of metalloproteinases (TIMPs)-TIMP-1 and, especially, TIMP-2. A synthetic, biotinylated inhibitor specific for activated MMP-2 in solution phase, and immunohistochemistry were used to detect MMP-2 and TIMP-2 expression in cell lines and ovarian tumors and to analyze the surface-binding capacity of the inhibitors, which are potential therapeutic agents. Characterization of novel monoclonal antibodies to MMP-2 and TIMP-2 is described together with immunocytochemical staining of 83 paraffin-embedded ovarian tumors (67 malignant, 7 borderline, 9 benign) and 9 cell lines. Synthetic MMP-2 inhibitor binding under controlled conditions was visualized by immunofluorescence and avidin-biotin complex immunoperoxidase methods in cell lines and cryostat sections of ovarian tumors. MMP-2 and TIMP-2 showed heterogenous immunoreactivity, with enhanced staining on high-grade tumors, specifically at the invasive front and in vascular invasion. TIMP-2 immunoreactivity was maximal in malignant cell cytoplasm and less intense in desmoplastic fibroblasts. One monoclonal antibody to MMP-2 showed membrane immunoreactivity, apically polarized in benign and low-grade tumors but depolarized and strong in 37 of 44 cases of high-grade invasive tumors. Eleven of eighteen ovarian carcinomas and six of nine cell lines showed membrane localization of the synthetic inhibitor. Maximal binding occurred in the ovarian cell line OVCA 432 and the breast cell lines MCF 7 and MDA MB 435, all of which were immunoreactive for MMP-2. Cell lines propagated on type I collagen showed no enhancement in inhibitor binding. This study demonstrates cell surface binding of a synthetic MMP-2 inhibitor and provides new evidence of MMP-2 and TIMP-2 immunoreactivity in ovarian carcinomas and cell lines.

Plasma assay of gelatinase B: tissue inhibitor of metalloproteinase complexes in cancer.

BACKGROUND: Matrix metalloproteinases (MMPs), especially gelatinase A and gelatinase B (GLB), are believed to be important components of the metastatic process. Tissue Inhibitors of Metalloproteinases (TIMPs) form complexes with MMPs and inhibit cancer dissemination. After local secretion, MMPs and their complexes with TIMPs leach into the blood stream where their concentration can be measured, thereby serving as surrogate markers of disease. Elevated plasma gelatinase B levels have been detected in gastrointestinal cancer and breast cancer. The goal of this study was to determine whether plasma GLB:TIMP complexes also are increased in cancer and whether these tests have potential use as prognostic tumor markers. METHODS: An enzyme-linked immunosorbent assay (ELISA) was developed to measure the plasma concentration of GLB:TIMP complexes in patients with cancer. Correlation between ELISA results and clinical outcome was sought. RESULTS: Plasma GLB:TIMP complexes were significantly increased in patients with gastrointestinal cancer and gynecologic cancer, but not in patients with breast cancer. When results from plasma GLB:TIMP complexes and plasma GLB assays were combined (GLB/complexes), abnormal levels of one or both assays were found in 36% and 65% of patients with gastrointestinal and gynecologic cancer, respectively. In Stage IV gastrointestinal cancer, patient survival was shorter (P < 0.001) in the group with increased plasma GLB/complexes than for those with normal plasma levels (4 months vs. 20 months, respectively). CONCLUSIONS: The assay of plasma gelatinase B and GLB:TIMP complexes may be clinically useful in predicting survival in subsets of patients with cancer. The possibility of using these assays in early stage cancer to predict metastasis should be studied.

Elevated plasma stromelysin levels in arthritis.

OBJECTIVE: To determine whether plasma concentrations of stromelysin-1 and gelatinase A are increased in patients with various forms of arthritis. METHODS: A sensitive and specific sandwich enzyme linked immunosorbent assay (ELISA), which employs a murine monoclonal antibody and a rabbit polyclonal antibody to human stromelysin-1, was used to measure plasma stromelysin-1 in 53 healthy subjects, 113 patients with various forms of arthritis and connective tissue diseases, and 65 patients with cancer. Gelatinase A was also measured in these patients using specific polyclonal and monoclonal antibodies to gelatinase A in an ELISA: RESULTS: The plasma concentration of stromelysin-1 (X +/- SEM) was significantly increased (p < 0.001) in patients with rheumatoid arthritis (RA) (187 +/- 14 ng/ml) and systemic lupus erythematosus (SLE) (258 +/- 35 ng/ml) as compared to both healthy control subjects (50 +/- 4 ng/ml) or patients with cancer (61 +/- 20 ng/ml). Plasma stromelysin-1 was also significantly increased in smaller groups of men with osteoarthritis (OA) and gout. In contrast, plasma concentrations of gelatinase A were not significantly increased in patients with RA, OA or gout. In healthy subjects, the concentration of stromelysin-1 was significantly higher in men than women. No correlation was noted between plasma stromelysin-1 levels and age. CONCLUSION: The detection of elevated plasma levels of stromelysin-1 in patients with RA is consistent with increased stromelysin-1 concentrations in inflamed synovial tissues in this disease. The origin of increased plasma stromelysin-1 in SLE is speculative. Measurement of plasma stromelysin-1 may be useful in the diagnosis and management of patients with various forms of arthritis.

Serum metalloproteinases and their inhibitors: markers for malignant potential.

Death from cancer results from the development of metastases or local progression of tumour. Metastasis and local progression may result from the inappropriate activity of metalloproteinases released by tumour cells or of their regulatory peptides. We have developed quantitative assays for interstitial collagenase, stromelysin 1 and tissue inhibitors of metalloproteinase (TIMP) 1 and 2, which have allowed the study of serum levels of these proteins. Sera from 40 patients with prostatic cancer, stored prior to and after 6 and 12 months' treatment with a gonadotrophin-releasing hormone agonist and an anti-androgen were analysed. Levels were compared with two control groups, comprising 21 patients with active rheumatoid arthritis and 56 age-matched hospital attenders without arthritis or cancer. Contrasting levels have been found in patients with prostatic cancer as compared with hospital controls without cancer and patients with rheumatoid arthritis. Patients with prostatic cancer had higher levels of TIMP-1 and collagenase (P = 0.0001) and lower levels of TIMP-2 (P = 0.003) than controls. Patients with metastatic cancer had significantly higher levels of collagenase than those without metastases (P = 0.02). Patients with rheumatoid arthritis had significantly higher levels of stromelysin than either controls (P = 0.002) or patients with cancer (P = 0.008). Serum tissue inhibitor of metalloproteinase 1 in combination with collagenase levels was as sensitive as prostate-specific antigen as a marker of metastatic disease. These findings provide a basis for the investigation of the role of metalloproteinases and their inhibitors in other malignancies.

Mutation of the active site glutamic acid of human gelatinase A: effects on latency, catalysis, and the binding of tissue inhibitor of metalloproteinases-1.

Human gelatinase A, a member of the matrix metalloproteinase family, is secreted from cells as the M(r) 72,000 latent precursor, progelatinase A. The autolytic removal of an N-terminal propeptide generates the M(r) 66,000 active form. Mutants of recombinant progelatinase A, altered such that the proposed active site glutamic acid residue (E375) was replaced by either an aspartic acid (proE375-->D), an alanine (proE375-->A) or a glutamine (proE375-->Q), were purified from medium conditioned by transfected NS0 mouse myeloma cells. Like wild-type progelatinase A, the mutant proenzymes were inactive and could bind tissue inhibitor of metalloproteinases (TIMP)-2 but not TIMP-1 to their C-terminal domains. Their rates of autolytic processing induced by the organomercurial (4-aminophenyl) mercuric acetate, however, were markedly slower and, of the three M(r) 66,000 forms so produced, only E375-->D displayed any proteolytic activity against either a synthetic substrate (kcat/Km = 10% that of the wild-type enzyme) or denatured type I collagen (specific activity = 0.9% that of the wild-type enzyme). ProE375-->A and proE375-->Q could be more rapidly processed to their M(r) 66,000 forms by incubation with a deletion mutant of gelatinase A that has full catalytic activity but lacks the C-terminal domain [delta (418-631) gelatinase A]. These two M(r) 66,000 forms displayed low activity on a gelatin zymogram (approximately 0.01% that of the wild-type enzyme) but, like E375-->D were able to bind TIMP-1 with an affinity equal to that of the activated wild-type enzyme.(ABSTRACT TRUNCATED AT 250 WORDS)

Immunoassays for the detection of human collagenase, stromelysin, tissue inhibitor of metalloproteinases (TIMP) and enzyme-inhibitor complexes.

Immunoassays have been developed for human collagenase, stromelysin, tissue inhibitor of metalloproteinases (TIMP) and TIMP complexed with both of the active enzymes. Selection of antibodies of defined specificity enabled measurement of both the pro and active forms of the metalloproteinase. Free TIMP was quantified by the selection of a monoclonal antibody which did not recognise TIMP when complexed with metalloproteinases. Detection of enzyme-inhibitor complexes was achieved by capturing the TIMP component of the complex and revealing the metalloenzyme using specific antibodies.

The effect of age and menstrual cycle upon proliferative activity of the normal human breast.

The aim of this study was to determine the proliferative activity within the epithelial cells of the normal human breast in 122 patients (6 reduction mammoplasties and 116 fibroadenoma excisions) in relation to age and the phase of the menstrual cycle. Thirty three of the patients were on oral contraceptives and 33 were parous. Thin tissue slices were incubated with tritiated thymidine and processed for autoradiography. Other samples were fixed directly and prepared for histology. The labelling, mitotic and apoptotic indices (LI, MI and AI) were determined and all illustrated considerable variability. The labelling indices are significantly (P less than 0.05) influenced by both patient age and stage during the menstrual cycle and ranged from 0-11.5%. Maximum LI values were obtained on the 20.8th day of the cycle. A square root transformation of the data was used to reduce the skewness of the data to a more normal distribution. The square root of the LI declined by 0.22 per decade. The mitotic data showed similar significant (P less than 0.05) correlations against age and day of cycle with a peak on the 21.5th day of the cycle, a decline by 0.072 per decade and a range from 0-0.6%. The data for apoptotic cells were less clearly influenced by the stage of the menstrual cycle but showed a significant (P less than 0.5) decline with age. The AI in parous patients was significantly higher than that in non-parous patients. There was no significant effect of oral contraceptives on any of the parameters measured when age and stage of cycle were taken into account. The considerable variability in the data could not be fully accounted for by either technical factors, the age of the patients, or the day of the cycle. We conclude that proliferation is negatively related to age and is influenced by the menstrual cycle but that additional as yet unknown factors must account for a large part of the variability seen in the data.

Cell kinetic studies in the epidermis of mouse. III. The percent labelled mitosis (PLM) technique.

Full PLM curves have been obtained for four sites in the mouse. The first peaks have been analysed by computer and the duration of the G2 + M and S phases determined together with their standard deviations. The full curves showed a general similarity for all four sites with no clear second peak. The data are compared with the published data for mouse and human epidermis using the in vivo PLM technique. The timing and shape of the first peak can vary considerably even for one site in mice. Hence, both G2 + M and S can vary in their durations. Cells labelled at one time of day exhibit different kinetic properties to those labelled at another time of day. The duration of G2 + M is shortest in dorsum labelled at 03.00 hours (3 X 2 hr) and longest in tail (up to 7 X 5 hr). The S-phase is shortest in dorsum (6 X 3-7 X 2 hr) and longest in tail or ear (13 X 3-14 X 1 hr). There is also a very large standard deviation in tail and foot. There is little general variability when the psoriatic human data are considered, which is surprising. The general variability amongst the data from experimental mice might also be expected amongst humans which might make comparisons between the cell kinetics of normal and diseased skin difficult.