E2F1 mediates death of B-amyloid-treated cortical neurons in a manner independent of p53 and dependent on Bax and caspase 3

Although B-amyloid (AB) is suggested to play an important role in Alzheimer's disease, the mechanisms that control AB-evoked toxicity are unclear. We demonstrated previously that the cell cycle-related cyclin-dependent kinase 4/6/retinoblastoma protein pathway is required for AB-mediated death. However, the downstream target(s) of this pathway are unknown. We show here that neurons lacking E2F1, a transcription factor regulated by the retinoblastoma protein, are significantly protected from death evoked by AB. Moreover, p53 deficiency does not protect neurons from death, indicating that E2F1-mediated death occurs independently of p53. Neurons protected by E2F1 deficiency have reduced Bax-dependent caspase 3-like activity. However, protection afforded by E2F1, Bax, or caspase 3 deficiency is transient. In the case of E2F1, but not with Bax or caspase 3 deficiency, delayed death is accompanied by DEVD-AFC cleavage activity. Taken together, these results demonstrate the required role of E2F1, Bax, and caspase 3 in AB evoked death, but also suggest the participation of elements independent of these apoptosis regulators.

Proliferative heterogeneity in the human prostate: evidence for epithelial stem cells

Clonal analysis of human prostate epithelial cells was undertaken in order to identify stem cells. Two types of colony were distinguished, termed type I and type II. Type I colonies were relatively small and irregular and contained a loose mixture of differentiated and undifferentiated cells. In contrast, type II colonies were large, round, and homogeneous, consisting almost exclusively of small undifferentiated and dividing cells. The colony-forming efficiency was 5.8% +/- 1.8 for freshly isolated epithelial cells. There were approximately 10 times as many type I as type II colonies and about 1 in 200 of the plated cells was capable of forming a type II colony. In three-dimensional culture on Matrigel, the type II colonies produced structures reminiscent of prostate epithelium, with luminal cells expressing markers of prostate epithelial differentiation, including the androgen receptor. On the basis of their proliferative characteristics and pluripotency, the type II colonies may be the progeny of stem cells and the type I colonies of a more differentiated transit-amplifying population.

Langerhans cell tropism of human immunodeficiency virus type 1 subtype A through F isolates derived from different transmission groups

To test the hypothesis that some subtypes of human immunodeficiency virus type 1 (HIV-1), especially subtype E, are more likely to infect mature Langerhans cells (mLC), we titrated a panel of 26 primary HIV-1 isolates of subtypes A through F on peripheral blood mononuclear cells (PBMC) and mLC. The majority of HIV-1 isolates from heterosexually infected patients did not show a preferred tropism for mLC compared to homosexually transmitted HIV-1 isolates. Only 6 of 26 isolates, 2 from patients infected by homosexual contact and 4 from patients infected by heterosexual contact, showed a higher infectivity for mLC than for PBMC. Both syncytium-inducing and non-syncytium-inducing isolates were able to infect mLC which express mRNA for the chemokine receptors CCR3, CCR5, and CXCR4.

Expression of ricin A chain in Escherichia coli

DNA encoding ricin A chain was derived from preproricin cDNA and ligated into the expression vector pDS5/3. Transcription is controlled from the coliphage promoter PN25 fused with the lac operator of E.coli. When induced, E.coli 71.18 cells transformed with the recombinant plasmid express ricin A chain which is soluble and has full biological activity.

Creutzfeldt-Jakob disease in a man with COVID-19: SARS-CoV-2-accelerated neurodegeneration?

We describe a man whose first manifestations of Creutzfeldt-Jakob disease occurred in tandem with symptomatic onset of coronavirus disease 2019 (COVID-19). Drawing from recent data on prion disease pathogenesis and immune responses to SARS-CoV-2, we hypothesize that the cascade of systemic inflammatory mediators in response to the virus accelerated the pathogenesis of our patient's prion disease. This hypothesis introduces the potential relationship between immune responses to the novel coronavirus and the hastening of preclinical or manifest neurodegenerative disorders. The global prevalence of both COVID-19 and neurodegenerative disorders adds urgency to the study of this potential relationship.

Fibroblast growth factor 7, secreted by breast fibroblasts, is an interleukin-1beta-induced paracrine growth factor for human breast cells

Keratinocyte growth factor/fibroblast growth factor 7 (KGF/FGF7) is known to be a potent growth factor for mammary cells but its origin, cellular targets and mode of action in the breast are unclear. In this study, we carried out studies to determine the localisation of FGF7 and its receptor, and the related growth factor FGF10. We also determined the factors that regulate FGF7 release from stromal cells and the effects of FGF7 on normal and neoplastic breast cells. Using an FGF7-specific antibody which does not react with the FGF7 heparan sulphate proteoglycan (HSPG)-binding site, we showed epithelial and myoepithelial immunohistochemical staining in normal breast sections, and epithelial staining in breast carcinomas. Stromal staining was also detected in some lobular carcinomas as well as a subset of invasive ductal carcinomas. FGF10 and FGF receptor (FGFR)2 immunostaining showed a similar epithelial expression pattern, whereas no stromal staining was observed. We purified normal breast stromal, epithelial and myoepithelial cells and showed that FGF7 stimulated proliferation of both epithelial cell types, but not stromal fibroblasts. We also examined the effects of FGF7 on Matrigel-embedded organoids, containing both epithelial and myoepithelial cells, and showed FGF7 induced an increase in cellular proliferation. Furthermore, conditioned medium derived from stromal cells was shown to increase the proliferation of normal and neoplastic breast epithelial cells, which could be abolished by a neutralising antibody to FGF7. Finally, we showed that interleukin-1beta, but not oestradiol or other oestrogen receptor ligands, caused a dose-related FGF7 release. Further results also indicate that the epithelial localisation of FGF7 and FGF10 in breast tissue sections is likely to be due to their binding to their cognate receptor. In summary, our findings suggest that FGF7 is a paracrine growth factor in the breast. FGF7 is produced by the breast stromal fibroblasts and has profound proliferative and morphogenic roles on both epithelial and myoepithelial cells.

Monochloroacetic acid and 60% salicylic acid as a treatment for simple plantar warts: effectiveness and mode of action

Monochloroacetic acid crystals and 60% salicylic acid ointment was found to be more effective than placebo as a treatment for simple plantar warts in a double blind study on 57 patients. Nineteen (66%) patients in the active treatment group compared with five (18%) patients in the placebo group were cured after 6 weeks (P = 0.002). The active treatment was associated with a significantly higher cure rate 6 months after entry (P = 0.04). Treatments were well tolerated. IgG or IgM antibodies or both to human papilloma virus (HPV) types 1 or 2 or both were detected significantly more frequently in the actively treated group 6 weeks after entry (P = 0.0005). Twelve (50%) patients considered to be cured had no detectable secondary immune response. Our results suggest that cure does not depend primarily on the humoral system but rather on mechanical destruction of wart tissue, or occurs as a result of cell mediated immunity.

Cytotoxicity of a recombinant ricin-A-chain fusion protein containing a proteolytically-cleavable spacer sequence

Chimeric proteins composed of ricin toxin A chain (RTA) and staphylococcal protein A (PA) have been produced in E. coli. Constructs consisting of N-terminal RTA and C-terminal PA (RTA-PA) or N-terminal PA and C-terminal (PA-RTA) were capable of binding to immunoglobulin G (via PA) and of specifically depurinating 28 S ribosomal RNA (via RTA). However, neither fusion protein was cytotoxic to antigen-bearing target cells in the presence of an appropriate monoclonal antibody presumably because the RTA could not be released from the PA within the cytosol where the ribosomal substrate of RTA is located. The overcome this, a short amino acid sequence from diphtheria toxin was engineered between the RTA and PA to produce a disulfide-linked loop containing a trypsin sensitive cleavage site. Cleavage of this fusion protein with trypsin converted the RTA-DT-PA to the two chain form consisting of RTA linked by a disulfide bond to PA. The cleaved fusion protein was highly toxic to Daudi cells coated with anti-immunoglobulin antibody suggesting that the RTA could be released from the PA by reduction within the cytosol.

Expression of BCL-2 in primary breast cancer and its correlation with tumour phenotype. For the International (Ludwig) Breast Cancer Study Group

BACKGROUND

The role of apoptosis (programmed cell death) in the development and progression of breast cancer is unknown. Recently the bcl-2 gene has been shown to block apoptosis and thus may promote tumour development. BCL-2 is localized to the luminal cells of the normal breast, which are considered to be the origin of malignant breast disease.

PATIENTS AND METHODS

Immunocytochemistry using anti bcl-2- antibody was performed on 107 breast cancer specimens belonging to node-positive patients from the Ludwig Breast Cancer Studies I-IV and the results were correlated with survival, tumour grade, S-phase, oestrogen and progesterone receptor status and c-erb B-2 expression. Western and Southern blotting together with immunofluorescence were performed on the breast cancer cell lines BT-20, BT-474, MDA-MB-361, T47-D and MCF-7.

RESULTS

In the breast cancer derived cell line MCF-7 BCL-2 is expressed to a level similar to that of the B-lymphoma cell line Karpas 231 with t(14;18)(q32.3;q21.3), but no evidence of a rearrangement or gene amplification was identified. In a study of 107 breast cancers from the International Breast Cancer Study Group Trials I-IV we have demonstrated a very significant inverse correlation of BCL-2 with c-erbB-2 expression (p = 0.002), and a positive correlation with oestrogen receptors (p = 0.001) and progesterone receptors (p = 0.05). In this study there was no correlation of expression with S-phase fraction in the tumours or with any stage in the cell cycle as assessed in MCF-7 cells.

CONCLUSION

We conclude that BCL-2 might contribute to the malignant phenotype of breast cancer by modulation of biological behaviour of cancer cells.

Regional distribution of neuropeptide Y and its receptor in the porcine central nervous system

The regional distribution of neuropeptide Y (NPY) immunoreactivity and receptor binding was studied in the porcine CNS. The highest amounts of immunoreactive NPY were found in the hypothalamus, septum pellucidum, gyrus cinguli, cortex frontalis, parietalis, and piriformis, corpus amygdaloideum, and bulbus olfactorius (200-1,000 pmol/g wet weight). In the cortex temporalis and occipitalis, striatum, hippocampus, tractus olfactorius, corpus mamillare, thalamus, and globus pallidus, the NPY content was 50-200 pmol/g wet weight, whereas the striatum, colliculi, substantia nigra, cerebellum, pons, medulla oblongata, and medulla spinalis contained less than 50 pmol/g wet weight. The receptor binding of NPY was highest in the hippocampus, corpus fornicis, corpus amygdaloideum, nucleus accumbens, and neurohypophysis, with a range of 1.0-5.87 pmol/mg of protein. Intermediate binding (0.5-1.0 pmol/mg of protein) was found in the septum pellucidum, columna fornicis, corpus mamillare, cortex piriformis, gyrus cinguli, striatum, substantia grisea centralis, substantia nigra, and cerebellum. In the corpus callosum, basal ganglia, corpus pineale, colliculi, corpus geniculatum mediale, nucleus ruber, pons, medulla oblongata, and medulla spinalis, receptor binding of NPY was detectable but less than 0.5 pmol/mg of protein. No binding was observed in the bulbus and tractus olfactorius and adenohypophysis. In conclusion, immunoreactive NPY and its receptors are widespread in the porcine CNS, with predominant location in the limbic system, olfactory system, hypothalamoneurohypophysial tract, corpus striatum, and cerebral cortex.

Guillain-Barré Syndrome Presenting as Facial Diplegia after COVID-19 Vaccination: A Case Report

Background: Guillain-Barré Syndrome (GBS) is a rapidly progressive immune-mediated polyneuropathy often associated with an antecedent infectious illness or vaccination. The classic presentation of GBS is characterized by ascending limb weakness and numbness with loss of reflexes. However, atypical variants involving the face and arms or with purely sensory symptoms also exist. In up to 30% of cases, GBS progresses to respiratory failure, with patients requiring mechanical ventilation.

Case Report: We report a case of atypical GBS occurring after Coronavirus disease 2019 (COVID-19) vaccination in an otherwise healthy 38-year-old man. The patient's clinical presentation was characterized by bilateral hand and foot paresthesias, dysarthria, bilateral facial weakness, and an absence of classic ascending limb weakness. Albuminocytological dissociation within the cerebrospinal fluid was suggestive of GBS. The patient received intravenous immunoglobulin therapy, with modest improvement in his symptoms at the time of his discharge from the hospital.

Why Should an Emergency PhysicianBe Aware of This? Patients with GBS are at risk for life-threatening complications, including respiratory failure requiring mechanical ventilation. It is critical for emergency physicians to be aware of the manifold presentations of GBS for early recognition and treatment. This may be of particular importance in the context of a worldwide vaccination campaign in response to the COVID-19 pandemic.

Establishment of long-term myogenic cultures from patients with Duchenne muscular dystrophy by retroviral transduction of a temperature-sensitive SV40 large T antigen

We have established long-term human myogenic cultures from adult human skeletal muscle biopsies by infecting primary explant cultures with an amphotropic retroviral construct encoding a temperature-sensitive SV40 large T antigen, tsA58-U19. Infected myoblasts expressed the large T antigen and showed greatly enhanced proliferative capacity when cultured at 33 degrees C, compared with noninfected cells. When the infected cultures were incubated at 39 degrees C, the cells withdrew from cycle, aligned, and fused to form multinucleated myotubes which expressed certain antigens that are similarly expressed in nontransduced differentiating muscle cells. Myogenic clones with greatly increased proliferative capacity were generated, for the first time, from biopsies obtained from Duchenne muscular dystrophy patients as well as from normal, dystrophin-positive individuals. Cell lines produced by this approach may prove valuable for in vitro studies of myogenesis and for investigating the cellular and molecular consequences of inherited muscle diseases.

Does gastric acid release plasma somatostatin in man?

Food and insulin hypoglycaemia raise plasma concentrations of somatostatin. Both also stimulate gastric acid secretion but it is not clear whether gastric acid itself has any effect on somatostatin secretion. We, therefore, studied the effect on plasma concentrations of somatostatin of infusion of 0.1 N HC1 into the stomach and duodenum of healthy subjects. Plasma somatostatin did not rise with a small dose of HC1 given intragastrically (15 mmol) or intraduodenally (4 mmol). After an intraduodenal infusion of 60 mmol HC1 over 30 minutes, sufficient to reduce intraluminal pH to 2, plasma somatostatin rose moderately in five subjects from a mean value (+/- SEM) of 32 +/- 3 pg/ml to a peak at 10 minutes of 54 +/- 11 pg/ml. It is concluded that: (a) intragastric acid infusions do not release circulating somatostatin in man; and (b) that intraduodenal acidification albeit at grossly supraphysiological doses is a moderate stimulus of plasma somatostatin release. Therefore, gastric acid is unlikely to be a major factor mediating postprandial plasma somatostatin release in man.

Expression of the common acute lymphoblastic leukaemia antigen (CALLA) in the human breast

A biochemical and immunohistological study has been carried out to characterize the antigen in human breast reacting with antibodies to the common acute lymphoblastic leukaemia antigen (CALLA). Four different monoclonal antibodies to the CALLA antigen all stain the membrane of adult human myoepithelial cells. Surface labelling studies of freshly prepared human breast cells demonstrate that the anti-CALLA antibody, J5, immunoprecipitates a 100 kDa protein that co-electrophoreses with the CALLA antigen identified in the leukaemia cell line NALM-6. These results indicate that the CALLA antigen is expressed on myoepithelial cells and that the staining is not due to reactivity with a shared epitope on an unrelated molecule.

Cardio-oncology Part I: chemotherapy and cardiovascular toxicity

Cancer and cardiovascular disease are the most common causes of mortality in the US, causing approximately 1.2 million deaths annually. The incidence of cancer is expected to increase as the population ages. The prognosis of cancer patients has improved over the last few decades primarily because of newer chemotherapeutic drugs; however, many of these drugs have cardiotoxic side effects. The short-term cardiovascular toxicities of more established drugs are well described; however, understanding of the underlying pathogenesis is increasing. The delayed cardiotoxic effects of cancer treatments have become an important issue contributing to mortality and morbidity as cancer survivorship increases. Chemotherapy-induced cardiotoxicity can manifest in many ways, from asymptomatic decreases in left ventricular ejection fraction to congestive heart failure. Hypertension is commonly seen both as a co-morbidity and a side effect of chemotherapy. In this article, we discuss the pathogenesis, scope, presentation and potential prevention of these toxicities.

Biological activity of recombinant Ricinus communis agglutinin A chain produced in Escherichia coli

DNA encoding Ricinus communis agglutinin A chain was ligated into the E. coli expression vector pDS 5/3. Induced E. coli 71.18 cells which had been transformed with this plasmid express Ricinus communis agglutinin A chain in a soluble and biologically active form. Recombinant Ricinus communis agglutinin A chain had ribosomal RNA N-glycosidase activity and was approximately 10-fold less active than ricin A chain in a cell-free protein synthesis inhibition assay.

Update on Ocular Myasthenia Gravis

Myasthenia gravis is an antibody-mediated autoimmune disorder of the post-synaptic neuromuscular junction resulting in fluctuating, fatigable weakness. Most patients first present with extraocular symptoms (diplopia and/or ptosis), and in 15% of cases symptoms will remain restricted to only the extraocular muscles (ocular myasthenia gravis [OMG]). The history and clinical examination are of the utmost importance in correctly identifying OMG patients, as supportive serologic or electrodiagnostic studies are frequently nondiagnostic. In this review, we outline a diagnostic approach to OMG (focusing on key clinical features), discuss therapeutic options, and highlight recent developments in the understanding of OMG.

Retroviral transduction of human periodontal cells with a temperature-sensitive SV40 large T antigen

The periodontal ligament (PDL) is considered to contain subpopulations of cells responsible for the development, repair and regeneration of the periodontium. Cell cultures have been used as model systems in order to understand the complex cellular and biochemical events underlying these processes. In order to obtain long-term cultures of these cells that can be cloned and characterized, primary cultures of PDL and gingival cells were infected with an amphotropic retroviral construct encoding a temperature-sensitive SV40 large T antigen (tsT). After selection for drug resistance, the cells expressed the T antigen and proliferated at 34 degrees C for more than 40 passages. However, when the T antigen was inactivated by incubation at 39 degrees C, the cultures became growth-arrested and the granularity of the cells increased, possibly as a result of differentiation. Reverse transcribed-polymerase chain reaction and flow cytometry showed that the tsT-transduced cells expressed a number of soft and hard connective-tissue antigens, including osteocalcin, osteonectin, osteopontin, collagen type I and alkaline phosphatase. Moreover, incubation of the transduced PDL cells at 39 degrees C was found to upregulate the expression of osteocalcin, osteopontin and collagen type I, but downregulate osteonectin. At this temperature, the presence of the dexamethasone downregulated type I collagen, while vitamin D3 had no effect on the expression of any of the antigens examined. Under all culture conditions, antigen expression was far higher in the transduced PDL cells than the gingival cells. The findings thus show that growth of the tsT-transduced PDL and gingival cells is temperature-dependent and that the presence of the T antigen increases their lifespan but does not ablate the expression of certain of their characteristic phenotypic and functional features.

Cardio-oncology Part II: the monitoring, prevention, detection and treatment of chemotherapeutic cardiac toxicity

Cancer treatment has advanced in recent years with new drugs, complex regimes and multiple modalities of treatment; which has improved survival of cancer patients. Cardiotoxicity from chemotherapy is an emerging, important issue. Currently, echocardiographic evaluation of ejection fraction is the most commonly employed diagnostic tool for detecting chemotherapy-induced cardiotoxicity. However, novel echocardiographic techniques assessing myocardial mechanics using strain imaging can detect earlier changes. New imaging techniques and biomarkers can risk stratify patients to identify those requiring closer monitoring. Cardiologists collaborating with oncologists can detect and treat cardiovascular chemotherapeutic complications earlier, reducing morbidity and mortality. While cardiac MRI and multigated acquisition nuclear scanning are alternatives, echocardiography has become the mainstream for assessing cardiac function due to its portability, efficiency and low cost. Current recommendations regarding cardiac monitoring of cancer patients are based on expert consensus opinion. There is a need for prospective controlled trials to support specific guidelines.

Secretion-coupled protein degradation: studies on mammary casein

Mammary explants from midpregnant rabbits were cultured for 18 h at 37 degrees C with insulin, prolactin and cortisol. Subsequently, explants were labelled for 2 h with inorganic [32P]phosphate, L-[5-3H]proline or L-[4,5-3H]leucine, washed and chased for up to 3 h. The radiolabelling profile of [32P]casein or [3H]casein during the chase period, obtained by isoelectric focussing or immunoprecipitation indicates extensive destruction of neosynthesized casein. The extent of casein destruction in mammary explants in culture (measured after radiolabelling with L-[5-3H]proline), is inversely related to casein secretion. Least casein degradation is observed in explants after 48 h in culture when casein secretion is maximal (observed histochemically). Subsequently, when the extracellular alveolar lumen is filled with secretion products (72 h), rapid intracellular casein destruction is again observed. When the chase was carried out in the presence of drugs which inhibit degradation and/or secretion, the results indicate that secretion-coupled casein degradation is dependent on an intact functional microfilamentous-microtubular network, casein is not degraded by an autophagosome requiring process, degradation is inhibited by leupeptin, amino-acid analogue containing casein does not undergo secretion-coupled degradation and inhibition of N-glycosylation of intracellular vesicular membrane proteins prevents secretion-coupled degradation. Secretion-coupled protein destruction is discussed in relation to the post-translational regulation of the net production of secretory proteins in eukaryotic cells.

Ondansetron usage in HIV positive patients: a pilot study on the control of nausea and vomiting in patients on high dose co-trimoxazole for Pneumocystis carinii pneumonia

This was an open, single centre study, to evaluate the safety and efficacy of ondansetron in the treatment of co-trimoxazole associated nausea and vomiting in AIDS patients. Sixteen patients presenting with their first episode of HIV-associated Pneumocystis carinii pneumonia (PCP) on high dose co-trimoxazole were given ondansetron 8 mg orally, every 8 h. Measurements were made from data recorded by each patient on diary cards. In this study 11 out of 16 (69%) patients on ondansetron experienced good control of emesis (2 or less emetic episodes) on their 'worst day' of therapy and 8 out of 16 (50%) of patients demonstrated good control of emesis throughout their treatment with co-trimoxazole. Good control of nausea (mild or none) was achieved in 7 out of 16 (47%) patients. A total of 7 patients were able to complete the full course of co-trimoxazole whilst on ondansetron. One serious adverse event (Stevens-Johnson syndrome) was reported and felt to be unrelated to ondansetron. If conventional anti-emetics fail to achieve control of symptoms or have unacceptable side effects, ondansetron may represent a possible alternative.