Pathophysiology and Imaging Findings of COVID-19 Infection: An Organ-system Based Review.

BACKGROUND: COVID-19 commonly presents with upper respiratory symptoms; however, studies have shown that SARS-CoV-2 infection affects multiple organ systems. Here, we review the pathophysiology and imaging characteristics of SARS-CoV-2 infection in organ systems throughout the body and explore commonalities. OBJECTIVE: Familiarity with the underlying pathophysiology and imaging characteristics is essential for the radiologist to recognize these findings in patients with COVID-19 infection. Though pulmonary findings are the most prevalent presentation, COVID-19 may have multiple manifestations and recognition of the extrapulmonary manifestations is especially important because of the potential serious and long-term effects of COVID-19 on multiple organ systems.

A randomised controlled trial of fluid restriction compared to oesophageal Doppler-guided goal-directed fluid therapy in elective major colorectal surgery within an Enhanced Recovery After Surgery program.

There is continued controversy regarding the benefits of goal-directed fluid therapy, with earlier studies showing marked improvement in morbidity and length-of-stay that have not been replicated more recently. The aim of this study was to compare patient outcomes in elective colorectal surgery patients having goal-directed versus restrictive fluid therapy. Inclusion criteria included suitability for an Enhanced Recovery After Surgery care pathway and patients with an American Society of Anesthesiologists Physical Status score of 1 to 3. Patients were intraoperatively randomised to either restrictive or Doppler-guided goal-directed fluid therapy. The primary outcome was length-of-stay; secondary outcomes included complication rate, change in haemodynamic variables and fluid volumes. Compared to restrictive therapy, goal-directed therapy resulted in a greater volume of intraoperative fluid, 2115 (interquartile range 1350 to 2560) ml versus 1500 (1200 to 2000) ml, P=0.008, and was associated with an increase in Doppler-derived stroke volume index from beginning to end of surgery, 43.7 (16.3) to 54.2 (21.1) ml/m(2), P <0.001, in the latter group. Length-of-stay was similar, 6.5 (5 to 9) versus 6 (4 to 9) days, P=0.421. The number of patients with any complication (minor or major) was similar; 0% (30) versus 52% (26), P=0.42, or major complications, 1 (2%) versus 4 (8%), P=0.36, respectively. The increased perioperative fluid volumes and increased stroke volumes at the end of surgery in patients receiving goal-directed therapy did not translate to a significant difference in length-of-stay and we did not observe a difference in the number of patients experiencing minor or major complications.

Clinical characteristics of gout: a hospital case series.

INTRODUCTION: Gout is an increasingly common medical problem. The traditional risk factors of male sex and high red meat or alcohol consumption have been joined with newer risks such as increased life expectancy, and the metabolic syndrome (hypertension, diabetes, dyslipidaemia, truncal obesity). METHODS: This was a retrospective study to determine the epidemiology, clinical features, associated conditions as well as renal related conditions in existing gout patients followed-up in Rheumatology outpatient clinic, Hospital Tuanku Ja'afar, Seremban. RESULTS: Over a three month period, we identified 54 gouty patients on our follow-up, the majority being male, Malay ethnicity, with the age of onset in the third and fourth decades of life. Commonly associated risk factors were hypertension, hyperlipidaemia and obesity. However, underlying history of diabetes mellitus, alcohol consumption, and family history were not commonly associated with gout in our group of patients. Half of our patients had at least two or more joints involvement. About half of the patients with tophaceous gout had renal impairment. CONCLUSION: Our series of gout patients highlight the high prevalence of cardiovascular risk factors. The high prevalence of tophi and renal impairment is a cause for concern.

Training in the private sector: what works and how do we increase opportunities?

In Australia 61% of elective surgery takes place in private hospitals where current opportunities for surgical education and training (SET) are limited. The situation will shortly be compounded because of the large increase in local medical graduates, many of whom will aspire to be surgeons. How and where to train these extra surgeons to meet the expanding needs of the community must be addressed. Two models of private sector training are reviewed both of which involved combined training in both private and public sectors. Two second-year (SET 2) positions were created from one public hospital SET position by using the private sector for 3.5 days per week for 3 months of a 6-month rotation. The second model was applicable to post-fellowship training with a fairly even split between public and private sector responsibilities. In the first year, four registrars shared the two 6-month rotations for the SET 2 position. Trainees did the required minimum procedures (range 109-139) with primary operating targets of 20-25% (range 21-32%). The post-fellowship position in colorectal surgery was greatly enhanced by the private sector involvement with regard to operating experience as well as meeting part of the remuneration of the trainee. Successful models for training within the private sector in Australia can be found. To expand training in the private sector there will need to be a cultural shift in the perceptions of surgeons, patients, administrators, and trainees. Funding for posts may be available to those private hospitals that can meet the Royal Australasian College of Surgeons' accreditation standards for posts and hospitals.

The many facets of Notch ligands.

The Notch signaling pathway regulates a diverse array of cell types and cellular processes and is tightly regulated by ligand binding. Both canonical and noncanonical Notch ligands have been identified that may account for some of the pleiotropic nature associated with Notch signaling. This review focuses on the molecular mechanisms by which Notch ligands function as signaling agonists and antagonists, and discusses different modes of activating ligands as well as findings that support intrinsic ligand signaling activity independent of Notch. Post-translational modification, proteolytic processing, endocytosis and membrane trafficking, as well as interactions with the actin cytoskeleton may contribute to the recently appreciated multifunctionality of Notch ligands. The regulation of Notch ligand expression by other signaling pathways provides a mechanism to coordinate Notch signaling with multiple cellular and developmental cues. The association of Notch ligands with inherited human disorders and cancer highlights the importance of understanding the molecular nature and activities intrinsic to Notch ligands. Oncogene (2008) 27, 5148-5167; doi:10.1038/onc.2008.229.

Pituitary-thyroid state correlates with central dopaminergic and serotonergic activity in healthy humans.

Data from lower animals suggest anatomic and physiological interactions between brain dopamine and serotonin (5-hydroxytryptamine, 5-HT) systems and the hypothalamic-pituitary-thyroid axis. However, in humans, investigations of interactions between these central neurochemical systems (especially the dopaminergic system) and thyroid function are rare; in healthy humans they are practically nonexistent. Using cerebrospinal fluid (CSF) and blood samples simultaneously obtained from indwelling subarachnoid and venous catheters in healthy humans, we determined the CSF concentrations of homovanillic acid (HVA) and 5-hydroxyindolacetic acid, the major metabolites of dopamine and 5-HT, and plasma concentrations of TSH, total triiodothyronine (T(3)), free T(3), total thyroxine (T(4)) and free T(4). CSF HVA concentrations were significantly and negatively correlated with plasma TSH and T(3) (free and total), but not with T(4) (free or total). CSF 5-HIAA concentrations were significantly and negatively correlated with plasma TSH and total T(3) but not with free T(3) or T(4) (free or total). These results indicate that CNS monoamine-thyroid interactions are of physiological significance in the normal, euthyroid human.

The bfl-1 gene is transcriptionally upregulated by the Epstein-Barr virus LMP1, and its expression promotes the survival of a Burkitt's lymphoma cell line.

The recently identified bfl-1 gene (also known as A1 or GRS), a homologue of bcl-2, encodes an antiapoptotic protein that suppresses apoptosis induced by the p53 tumor suppressor protein and exhibits proliferative and potent cooperative transforming activities. We show that elevated levels of bfl-1 mRNA are a feature of Epstein-Barr virus (EBV)-immortalized B-cell lines and Burkitt's lymphoma cell lines expressing the full spectrum of EBV latent proteins. Using an EBV-negative Burkitt's lymphoma cell line in which the expression of EBV latent membrane protein 1 (LMP1) is inducibly regulated by tetracycline, we demonstrate that LMP1 expression coincides with a dramatic increase in the level of bfl-1 mRNA. Also in this system, an increase in the level of Bcl-2 protein was seen to occur earlier than that of bcl-2 mRNA, suggesting that both transcriptional and translational mechanisms are involved in the control of Bcl-2 expression by LMP-1. We show that elevated bfl-1 mRNA stability can contribute to this effect of LMP-1, thus providing evidence of a novel mechanism of gene regulation by this EBV protein. Upregulation of bfl-1 by LMP1 was not observed in the T-cell line Jurkat or the epithelial cell line C33A. Ectopic expression of Bfl-1 in an EBV-positive cell line exhibiting a latency type I infection protects against apoptosis induced by growth factor deprivation, thereby providing a functional role for Bfl-1 in this cellular context and adding Bfl-1 to the list of antiapoptotic proteins whose expression is modulated by EBV. This is the first report of the regulation of bfl-1 expression by a viral protein, and this novel finding may thus represent an important link between the EBV oncoprotein LMP1 and its cellular growth-transforming properties.

Population study of common glucose-6-phosphate dehydrogenase mutations in Kuwait.

DNA samples from 206 unrelated Kuwaitis of both sexes, i.e. 200 randomly selected individuals and 6 glucose-6-phosphate-dehydrogenase (G6PD)-deficient probands, have been analyzed by the PCR/RFLP technique for mutations underlying the most common G6PD-deficient variants (Mediterranean and A-). At the first step all samples were studied for the 563C-->T and 376A-->G mutations, then the samples positive for 376A-->G were further analyzed for 202G-->A, 680G-->T and 968T-->C mutations. Three mutations (563C-->T, 376A-->G and 202G-->A) were found to be present in the Kuwaiti population at polymorphic frequencies (0.0503, 0.0215 and 0.0111, respectively). Nineteen out of 20 unrelated Kuwaiti chromosomes with 563C-->T had Mediterranean haplotype as judged by 1311C-->T polymorphism. The frequency of G6PD-deficient genotypes was 4.5% (5.73% in males and 2.56% in females).

Extra and central pontine myelinolysis in a child with adrenal insufficiency.

We report a 5-year-old patient with adrenal insufficiency (AI) who had a subacute monophasic neurologic illness and brainstem and striatal lesions on brain imaging. The prominent electrolyte abnormalities in AI indicate that extra and central pontine myelinolysis is the likely cause. An association between AI and extra pontine myelinolysis has not previously been reported in children.

TaqI polymorphism in the 3' flanking region of the PI gene among Kuwaiti Arabs and Russians.

The Taq1 polymorphism in the 3' flanking region of the PI gene has been reported to be associated with chronic obstructive pulmonary disease (COPD). We have studied the frequency of the Taq1 polymorphism in 117 Kuwaiti Arabs and 110 Russians using PCR/RFLP. The frequency of this polymorphism was found to be 0.235 in the Arabs and 0.027 in the Russians. Such a striking difference in allele frequencies could be due to a 'founder effect' in the Kuwaiti population. However: it may also be that this mutation provides a selective advantage, thus accounting for its fixation at a rather high frequency in some populations. Our results suggest that ethnic composition is a very important factor which should be taken into consideration when studying the association of the Taq1 polymorphism with COPD.

Deletion analysis of the SMN and NAIP genes in Kuwaiti patients with spinal muscular atrophy.

Two genes are known to be involved in spinal muscular atrophy (SMA), namely, SMN (survival motor neuron) and NAIP (neuronal apoptosis inhibitory protein). Deletion analysis of these genes has been reported for many ethnic groups. We have extended this analysis to include 15 Arabic patients (11 unrelated cases of type I, which represent practically all of the patients diagnosed within the last 2 years in Kuwait, and 4 type-II cases from a single kinship). Also, 41 healthy relatives (parents and sibs) and 44 control individuals of Arabic origin were analyzed. The homozygous deletions of exons 7 and 8 of the SMN gene were found in all SMA patients studied. Exon 5 of NAIP was homozygously absent in all type-I patients, but was retained in type-II cases. Among members of SMA families, one mother was found to be homozygously deleted for NAIP. All of the control individuals had both normal SMN and NAIP. Our results are in agreement with the general consensus that the incidence of NAIP deletion is higher in the more severe SMA cases. Furthermore, they suggest that SMA type-I chromosomes, with the dual deletion of the SMN and NAIP genes, are more common in Arabs than in patients of other ethnic origin.

The value of critical incident analysis as an educational tool and its relationship to experiential learning.

Experiential learning and teaching strategies designed to facilitate this, have become popular in nursing and midwifery education in recent years. It is advocated that such learning enables the development of knowledge, skills and attitudes grounded in practice through the use of reflection on action. One strategy that may be utilised by nursing/midwifery educators to develop reflective ability in both themselves and students is critical incident analysis. It is suggested that critical incident analysis has value and is appropriate for developing interpersonal skills and self-awareness. It is proposed that critical incident analysis is a valuable educational tool which enables nursing/midwifery students to draw on past experiences and make sense of them, not only facilitating learning from clinical practice but also going some way towards bridging the gap between theory and practice.

Branching morphogenesis of human mammary epithelial cells in collagen gels.

To study the morphogenesis of human epithelial cells in vitro we have used a three-dimensional collagen matrix and a newly developed mammary epithelial cell line, 1-7 HB2. In standard medium 1-7 HB2 cells formed compact balls/spheres inside collagen type I gels, while cocultivation with various fibroblast cell lines or growth in fibroblast-conditioned media resulted in the appearance of branching structures. At least two different soluble factors secreted by fibroblasts were found to be implicated in the branching morphogenesis. Firstly, hepatocyte growth factor/scatter factor could induce branching in a concentration-dependent manner. Moreover, a polyclonal serum against hepatocyte growth factor/scatter factor completely inhibited the branching morphogenesis induced by medium conditioned by MRC-5 fibroblast cells. In contrast, a morphogenetic activity secreted by human foreskin fibroblasts was identified that appears to be different from hepatocyte growth factor/scatter factor and from a number of other well-characterized growth factors or cytokines. This model system has been used to examine the role of integrins in mammary morphogenesis. The expression of the alpha 2 beta 1, alpha 3 beta 1 and alpha 6 beta 4 integrins was decreased when cells were plated on collagen gels. The addition of specific blocking monoclonal antibodies directed to the alpha 2- and beta 1-integrin subunits to growth media impaired cell-cell interactions and interfered with the formation of compact structures inside collagen gels, suggesting that the alpha 2 beta 1 integrin can control intercellular adhesion in mammary morphogenesis. In contrast one of the blocking monoclonal antibodies against the alpha 3-integrin subunit (P1B5) mimicked the effect of soluble 'morphogens'. Our results suggest that the modulation of alpha 3 beta 1 activity may represent an important event in the induction of branching morphogenesis of human mammary epithelial cells.

Overexpression of ERBB2 in human mammary epithelial cells signals inhibition of transcription of the E-cadherin gene.

Overexpression of the ERBB2 receptor in transfectants of a human mammary epithelial cell line (MTSV1-7) is associated with a reduced ability to undergo morphogenesis in vitro and with a decreased level of expression of the E-cadherin and alpha 2 integrin genes. The inhibition of expression of the adhesion molecules has been shown to be at the level of transcription by using nuclear run-on assays and by following transcription of a reporter gene fused to 5' sequences of the E-cadherin gene. To relate the effects on gene transcription to a functional ERBB2 protein, signaling from the receptor was inhibited by the antibody 4D5, which blocks phosphorylation of ERBB2 on tyrosine residues and association of the protein with the GRB2/Sem5 protein. After treatment with the antibody 4D5, the ERBB2 transfectants regain the ability to form three-dimensional structures in collagen gels and the rates of transcription of the genes encoding the E-cadherin and the alpha 2 integrin subunit are restored to the levels seen in MTSV1-7neo cells. These results demonstrate that the inhibition of morphogenesis and transcription of specific adhesion molecules in human mammary epithelial cells can be affected by signals generated by the ERBB2 receptor and suggest a role for ERBB2 overexpression in tumor progression and metastasis.

Collagen-induced morphogenesis and expression of the alpha 2-integrin subunit is inhibited in c-erbB2-transfected human mammary epithelial cells.

The c-erbB2 (or Her2) oncogene is amplified and/or overexpressed in a significant proportion of breast cancers. To assess the role of the c-erbB2 oncogene in mammary tumorigenesis, we have transfected the corresponding human c-erbB2 cDNA into an immortalized human mammary epithelial cell line, MTSV1-7, that was derived from luminal epithelial cells cultured from milk. Three transfectants expressing different levels of the c-erbB2 gene product have been isolated which form colonies in agar and produce tumours in nude mice with high efficiency. We have observed that MTSV1-7 cells form three-dimensional structures in collagen gels and that alpha 2 beta 1-integrin plays a crucial role in the process of morphogenesis. We now find that the c-erbB2 transfectants exhibit an impaired ability to undergo morphogenesis in collagen gels as compared with the parental cell line or the control neomycin transfectant, and that the degree of impairment is related to the level of c-erbB2 expression. Moreover, overexpression of the c-erbB2 product was found to be correlated with a specific decrease in the expression of alpha 2-integrin subunit and in the alpha 2-mRNA. The breast cancer cell line SKBr3, which carries multiple copies of the c-erbB2 gene and overexpresses the 185-kDa product, was also found to express very low levels of the alpha 2-integrin protein and mRNA. Our results confirm the involvement of the alpha 2 beta 1-integrin in collagen-induced morphogenesis of mammary epithelial cells and suggest that the c-erbB2 gene product may inhibit this morphogenesis by inhibiting the expression of the alpha 2-integrin subunit.

Human models of breast cancer.

Experimental systems using human mammary tissue, secretions and tumours may be based on in vitro culture or on growth of tissue or tumour fragments in the nude mouse. In the development of in vitro culture systems, a detailed characterization of the cultured cells within the framework of the epithelial cell lineages found in vivo is crucial. Monoclonal antibodies are useful tools for defining the profile of antigens expressed by the basal and luminal cells in the normal gland and in distinguishing subclasses between these two major groups. When these same reagents are used to characterize breast cancers, the majority are found to show the phenotype of luminal cells, with a small subset showing some evidence of basal markers. Luminal epithelial cells cultured from milk or reduction mammoplasty tissue have a short life span in vitro but can be immortalized using SV40TAg. Demonstrably malignant cells are difficult to culture from primary breast cancer, but ER+ and ER- cell lines showing the luminal phenotypes have been readily developed from metastases: some ER- breast cancer cell lines show a more undifferentiated phenotype, and these may have developed from tumours expressing basal markers. As with in vitro culture, it is difficult to obtain tumour growth in the nude mouse from primary breast cancer specimens, and established cell lines are also difficult to grow in this animal. We have focused our studies on cell lines with the luminal phenotype developed from milk. These non-tumorigenic cell lines differ from breast cancer cell lines (a) in being able to form organized three dimensional structures in the presence of an extracellular matrix and (b) in the correct glycosylation of the polymorphic epithelial mucin, which is expressed and aberrantly glycosylated in cancers. These cell lines are therefore being used to study the mechanisms underlying morphogenesis and the processing of PEM, and also as recipients for oncogenes and proto-oncogenes.

Attenuation of cAMP-mediated responses in MA-10 Leydig tumor cells by genetic manipulation of a cAMP-phosphodiesterase.

In order to assess the effect of increased cAMP degradation on the responsiveness on an endocrine cell, we have obtained stable transfectants of MA-10 Leydig tumor cells that overexpress a mammalian cAMP-phosphodiesterase. Two novel cell lines, designated MA-10(P+8) and MA-10(P+29), that express high levels of the transfected enzyme were characterized. Although the basal levels of cAMP in the mutant cell lines are comparable to those of the wild-type cells, the increase in cAMP accumulation elicited by human choriogonadotropin (hCG) is severely blunted. Further studies with MA-10(P+29) show that the ability of hCG to stimulate adenylyl cyclase activity is normal. The failure of MA-10(P+29) cells to accumulate cAMP in response to hCG can be correlated with a similar reduction in hCG-stimulated steroidogenesis. On the other hand, the maximal steroidogenic response of MA-10(P+29) cells to dibutyryl cAMP, a cAMP analogue that is fairly resistant to phosphodiesterase degradation, is normal. We also show that the ability of these cells to respond to hCG with increased cAMP accumulation and steroid synthesis can be restored with a specific phosphodiesterase inhibitor. These results demonstrate that overexpression of a cAMP-phosphodiesterase in MA-10 cells limits the levels of cAMP attained under hCG stimulation and supresses the steroidogenic response of these cells to hCG. Since gonadotropins increase the cAMP-phosphodiesterase activity in their target cells, these findings also provide evidence that this regulation plays a major role in the modulation of cell responsiveness. Last, these new cell lines should be valuable in the study of the actions of cAMP because they express a conditional and reversible cAMP-resistant phenotype.