The utility of routine echocardiography in newborn infants with a persistent oxygen requirement

In the era of antenatal screening for congenital heart disease (CHD), infants presenting with an undiagnosed significant CHD are rare. However, term infants admitted with an initial diagnosis of TTN and a prolonged oxygen requirement often undergo an echocardiogram. We aimed to assess whether this practice yields any additional cases of undiagnosed CHD. We performed a retrospective chart review over a three year period [2013 ­ 2015] of term (> 36 weeks) infants admitted to the NICU for ≥ 5 days with a diagnosis of TTN and received an echocardiogram. The presence of CHD on the echocardiogram was assessed. Forty-seven infants were enrolled. The median age of echocardiogram was day four [2 ­ 8]. No infant had a diagnosis of significant CHD on the postnatal echocardiogram. A small muscular VSD was identified in two infants. Routine echocardiography for this cohort of infants to rule out major CHD appears to be unwarranted.

Evarts Ambrose Graham (1883-1957), doyen of pulmonary surgeons.

Evarts Graham performed the first successful pneumonectomy in 1933. Evarts Ambrose Graham, the son of a Scotch Irish surgeon, was born on 19 March 1883. After early schooling in Chicago, he graduated at Princeton and returned to Chicago to study Medicine, taking his MD at Rush Medical College in 1907. The chemical aspects of pathological changes then occupied him fully until 1919, when he was appointed full-time professor of surgery at the Washington School of Medicine in St Louis. Visualisation of gallstones temporarily took his attention, but bronchogenic carcinoma was seldom far from his thoughts, and he recognised (too late to save himself) the causative association with cigarette smoking by 1950. He died on 4 March 1957.

Franciscus Cornelis Donders (1818-1889).

Franciscus Cornelis Donders was educated at Duizel and Boxmeer before entering the Military Medical School and the medical faculty at Utrecht University in 1835. In 1840, he received his MD from Leiden and spent 2 years in practice at Vlissingen before returning to Utrecht, where he was appointed as an extraordinary professor to lecture on forensic medicine, anthropology, general biology and ophthalmology. Refraction by the eye is complex, since the ray of light passes through many changes of refractive index in its path, and Donders simplified the account of the process by establishing an equivalent refractive system: the reduced eye. When Donders opened an Eye Hospital in 1858, he devoted himself to clinical ophthalmology, making fundamental advances in providing spectacles to correct errors of refraction-which he separated from errors of accommodation. In 1862, Donders was promoted as an ordinary professor at Utrecht and he handed over the greater part of his practice to his pupil Hermann Snellen. From narrow specialisation, Donders was freed to return to the broader physiology; subatmospheric pressure in the pleura was for a while referred to as 'Donders' pressure'; he also devised a method of measuring the mental reaction time taken in making discrimination, rather than the simple reaction time in which no choice is involved. He was widely honoured, presiding at international congresses, and elected as a foreign member of the Royal Society. He died suddenly on 14 March 1889, but his work lives on.

Robert Whytt (1714-1766): from dropsy in the brain to tuberculous meningitis.

Robert Whytt was born and educated in Edinburgh and served the City in the Royal Infirmary. A prolific author, his major work is usually said to be his Essay on the Vital and other Involuntary Movements of Animals (1751), based on his belief that a 'sentient principle' was not limited to the nervous system but was distributed throughout the body, a view that brought him into conflict with Albrecht von Haller, who held that the sentient and motor powers of the body were those of a machine. Whatever about the speculative nature of the sentient principle, Whytt was a clinician blessed with unusual clarity, and he is remembered today for his Observations on the Dropsy in the Brain (1768). Therein he described the clinical signs and symptoms of what later came to be recognised as tuberculous meningitis, the acute disease which appears early in the haemic spread of the infection in a child, and which was fatal until the discovery of chemotherapy and antimicrobials. John Cheyne, in describing two terminal cases, recognised the connexion between hydrocephalus and scrophula, and Dorothy Price provided a precise guide to the clinical picture in 1942. When streptomycin became available Christopher McSweeney used it to alter the bleak picture in Dublin, and was helped by the prevention resulting from neonatal BCG immunisation. Later antimicrobials have facilitated the avoidance of emergent bacillary resistance.

Claude Bernard and his revelations in physiology.

It was in Saint-Julien near Villefranche that Claude Bernard was born on 12 July 1813. About 20 years later he moved to Paris to become a dramatist but was directed into the study of medicine, the service at the Hôtel Dieu of Magendie that led him to the Collège de France. He entered Magendie's laboratory as a voluntary assistant and within a year became official préparateur. His early work on the chorda tympani and his MD thesis on gastric juice in 1843 set him on his lifelong discoveries in physiology. The central role of hepatic glycogenesis in the formation of sugar in animals was established around 1850, and he proceeded to show that section of the cervical fibres of the sympathetic chain led to congestion and increased temperature on that side of the face-resulting from paralysis of the vasomotor nerves. And there were vasodilator as well as vasoconstrictor fibres. After the salivary glands, the pancreas caught his attention and he discovered its ability to emulsify fatty material. Toxic and therapeutic substances were analysed: carbon monoxide paralyses carriage of oxygen by taking its place on haemoglobin; and curare abolishes voluntary movement by paralysis at the motor end-plate. But Bernard was above all a general physiologist, exemplified in 1872 and 1873 in his Lectures on the phenomena of life common to animals and plants, summarised in the aperçu 'the constancy of the internal environment is the condition of the free and independent life'. Claude Bernard died on Sunday 10 February 1878 in Paris.

First ladies in laying the foundation of neuroendocrinology.

Although women were welcomed into medical practice in increasing numbers by the close of the nineteenth century, it was not until the second quarter of the twentieth century that they were recognised as valuable collaborators and contributors in the nascent field of neuroendocrinology, wherein they soon made advances that have stood the test of time. Mary Pickford at Edinburgh measured the action of acetyl choline in the supraoptic nucleus of the hypothalamus and helped to establish that vasopressin and oxytocin are formed in separate and distinct neurons. Berta Scharrer, like her future husband Ernest Scharrer, was born in Munich. Their great contribution was the proof that the posterior pituitary is not a gland, but the location of the release into the circulation of vasopressin and oxytocin from fibres in the hypothalamico-hypophysial tract. Their work succeeded in establishing against high-powered, vehement opposition the value of histological evidence in elucidating synthesis, storage and release of secretion from neuro-endocrine cells. A Rockefeller travelling fellowship allowed Marthe Vogt to move from Berlin in 1932 to London and then to Cambridge. The relations between the cortex and medulla of the suprarenal gland and the control of adrenocorticotropin were her main concerns. Dora Jacobsohn emigrated to Sweden after graduating in Berlin in 1934. She investigated control of the anterior pituitary gland by the hypothalamus, and co-operated with Geoffrey Harris in establishing the role of the hypothalamico-hypophysial portal venous system that conveys the releasing factors that preside over anterior pituitary cells. Laboratory discoveries do not constitute the whole of science, for the interpretation of evidence and recognition of general principles deserve attention. Dorothy Price, from Aurora, Illinois, received her BS in 1922 at the University of Chicago, and was glad to find employment as a histology technician in the zoology laboratory, where she was quietly appropriated by Carl Moore (1892-1955), an investigator seeking the key to hormonal control of gonadal function. The burning question was the part played by what was (then) called hormone antagonism in the biology of the testis. Price recognised that the common factor in explaining the deleterious effects of oestrin and testosterone on the testes could be traced to the anterior pituitary: the pituitary controlled testicular secretion, and the male hormone in turn controlled gonadotropin release in the pituitary. This seesaw balance explained the problem, and was the first of many regulatory systems to be recognised as ensuring stability--and later became known as negative feedback. The contributions of these five women helped place neuro-endocrinology on a firm foundation for its later expansion.

Allvar Gullstrand and the slit lamp 1911.

The Swedish ophthalmologist and self-taught mathematician Allvar Gullstrand (1862-1930) invented the slit lamp to illuminate the anterior of the eye. With its rectangular beam of very bright light, he studied the structure of the cornea and the function of the lens. His dioptric investigations showed that, as well as the extracapsular mechanism described by Helmholtz, changes in the substance of the lens, that he termed intracapsular, also contribute to accommodation. However, his invention has been appropriated by clinical ophthalmologists and is now routinely used in examination of the eye.

Jonathan Osborne (1794-1864) and his recognition of conduction aphasia in 1834.

In 1833 an accomplished 26-year-old linguist suffered a non-paralytic stroke. After he recovered, though he could utter a variety of syllables with ease, he spoke an unintelligible jargon that caused him to be mistaken as a foreigner. He was examined repeatedly over the course of a year by Jonathan Osborne (1794-1864), a Dublin physician and professor of materia medica, who found that the patient understood whatever was said to him, that he could read and write fluently, but had difficulty repeating words read to him or in reading aloud. Osborne recommended that he learn to speak English, his natural language, de novo and over 8 months measured his considerable improvement. To explain the patient's singular difficulty in repeating spoken words Osborne argued it was 'highly probable that, having been conversant with five languages, the muscular apparatus ranged among them, forming a kind of polyglot jargon [that was] wholly unintelligible' and the patient was 'unable to penetrate into and select the contents of the store according as the [words] were required'. The discrepancy between comprehension and repetition was later termed conduction aphasia.

William Wilde and the early records of consumption in Ireland.

Absence of documentary or bony evidence before the seventeenth century in Ireland is not conclusive evidence of freedom from tuberculosis. Clear records begin with Bills of Mortality kept in Dublin, the city at the centre of English administration of Ireland, and they show that the basis for an epidemic was firmly established therein before 1700. In the middle of the nineteenth century the cataclysmic Famine opened the floodgates of poverty and urban overcrowding that resulted in an alarming death rate that continued to increase until the early years of the twentieth century. It is to William Wilde (1815-1876) we owe the nuanced investigation of the earliest numerical records of consumption and related disorders in Ireland.

Douglas Argyll Robertson (1837-1909) and his pupil.

Douglas Argyll Robertson's (1837-1909) experimental work with physostigmine in 1863 sharpened his knowledge of the innervation of the internal muscles of the eye. So he was ideally prepared in 1869 to analyse the conundrum when he saw patients with spinal cord disease who had lost the response to light even though accommodation to near objects was normal. By translating his knowledge of basic science to a clinical problem he drew attention to this phenomenon, known subsequently as the Argyll Robertson pupil that came to be considered pathognomonic of tabes dorsalis, general paresis and neurovascular syphilis.

Vaccination of ponies with the IE gene of EHV-1 in a recombinant modified live vaccinia vector protects against clinical and virological disease.

The control of EHV-1 infection by cytotoxic T-cell responses (CTL) via a reduction in cell associated viremia remains an important goal in horses. Unfortunately, current vaccines are inefficient at inducing these responses. We have identified the immediate early (IE) gene of EHV-1 as a potent stimulator of virus-specific CTL responses in ponies expressing a specific MHC class I serological haplotype (A3/B2). This study was designed to determine if vaccination of A3/B2 MHC I positive ponies with the IE gene could induce protection and immune responses associated with cell mediated immunity. Ponies expressing the MHC-I A3/B2 haplotype (A3/B2 vaccinates) and ponies with a different MHC I haplotype (either non-A3 vaccinates or A3-non-B2 vaccinates) were vaccinated with a recombinant modified vaccinia Ankara (rMVA) vector expressing the IE gene on 3 occasions and vaccinates and unvaccinated controls were challenge infected 8 weeks after the last vaccination. Interferon gamma (IFN-gamma) mRNA and antibody titers were determined throughout the study and clinical signs, nasal virus shedding and viremia were determined following challenge infection. Vaccination of A3/B2 vaccinates conferred significant clinical protection and a significant reduction in EHV-1 viremia. IFN-gamma mRNA increased significantly following vaccination in the A3/B2 vaccinates. Antibody titers remained low until after challenge infection, indicating that no accidental field acquired or recrudescent EHV-1 infection had occurred. In summary, this is an important study showing that vaccination of ponies with the EHV-1 IE protein provides not only reduction in clinical disease but also reduction of cell associated viremia, which is a prerequisite for the prevention of abortion and neurological disease.

Advanced age in horses affects divisional history of T cells and inflammatory cytokine production.

A number of model systems have been employed to investigate age-associated changes in immune function. The purpose of the current study was to characterize senescent T cells and to investigate the inflamm-aging phenomenon both in vitro and in vivo using the old horse as a model. We examined whether decreased T cell proliferation induced by Con A is caused by increased apoptosis. We also utilized intracellular CFSE to analyze changes within each round of cell proliferation, in particular cytokine production. Intracellular staining with flow cytometry, RT-PCR, and ELISA were used to measure pro-inflammatory cytokines both in vitro and in vivo. While lymphocytes from old horses exhibit decreased proliferation, this is not the result of increased apoptosis. Instead, a larger percentage of the T cells remain in the parent generation and produce significant amounts of IFNgamma. Likewise, old horses have increased frequency of CD8-IFNgamma+ T cells and TNFalpha producing cells. We also show that old horses have elevated levels of IL-1beta, IL-15, IL-18 and TNFalpha gene expression in peripheral blood and significant levels of TNFalpha protein in serum, all characteristics of inflamm-aging.

In vitro and in vivo modulation of the equine immune response by parapoxvirus ovis.

REASON FOR PERFORMING STUDY: While immune modulators are used routinely in equine medicine, their mechanism of action is not always known. OBJECTIVES: To determine the effect of a commercial preparation of inactivated parapoxvirus ovis (Orf virus; PPVO) on cytokine gene expression by equine peripheral blood mononuclear cells (PBMC) both in vitro and in vivo. METHODS: PBMC were prepared from 6 mixed-breed yearlings and cultured in vitro with PPVO with or without Concanavalin A (Con A) for 24 h. Effects on the expression of IFNalpha, IFNbeta IFNgamma, TNFalpha and IL-18 were analysed by real time quantitative PCR (RT-PCR). In addition, 12 yearling horses were treated with PPVO and whole blood RNA samples were prepared at regular intervals to assess effects on in vivo cytokine gene expression. Six of those yearlings were later treated with saline and served as treatment controls. Nine additional yearlings were injected intradermally with a single dose and their injection sites biopsied at 24 and 48 h for cytokine expression. RESULTS: In vitro culture of PBMC with PPVO led to a significant increase in IFNalpha and IFNbeta gene expression compared to mock-stimulated cultures. In addition, expression of IFNgamma and TNFalpha was significantly higher in PBMC stimulated with PPVO and Con A, than those stimulated with Con A alone. No changes were observed in IL-18 gene expression in vitro. Treatment of horses with a 3-dose regimen of PPVO resulted in elevation of IFNgamma gene expression, which was detected 24 h after the first dose and declined thereafter. Intradermal inoculation led to increased expression of IFNgamma along with IFNbeta, IL-15 and IL-18. CONCLUSIONS: Together these results indicate that PPVO stimulated IFNgamma production both in vitro and in vivo. Increased cytokine expression could account for its immunomodulatory activity. POTENTIAL RELEVANCE: The absence of adverse reactions and clear indications of increased expression of cytokine gene expression supports previous clinical uses for this immune modulator in those situations when increased expression of IFNgamma is warranted.

Quantification by real-time PCR of the magnitude and duration of leucocyte-associated viraemia in horses infected with neuropathogenic vs. non-neuropathogenic strains of EHV-1.

REASONS FOR PERFORMING STUDY: Neurological disease in horses caused by infection with certain 'paralytic' strains of equine herpesvirus-1 (EHV-1) is a potentially devastating condition the pathogenesis of which is poorly understood. Preliminary observations in both experimentally induced and naturally occurring cases of the central nervous system disease have revealed a more robust cell-associated viraemia in horses infected with paralytic isolates of EHV-1, relative to horses infected with abortigenic isolates. To investigate further this pathogenesis-relevant question, the present study was performed using a greater number of horses and a more precise method for quantification of EHV-1 DNA present in viraemic leucocytes. OBJECTIVE: To compare the magnitude and duration of leucocyte-associated viraemia in seronegative, age-matched foals following infection with paralytic vs. abortigenic isolates of EHV-1. METHODS: Peripheral blood mononuclear cells (PBMC) were collected from 20 weanling foals at 2, 4, 7, 9, 11, 14 and 21 days after intranasal inoculation with either paralytic or abortigenic isolates of EHV-1. The amount of EHV-1 DNA present in each PBMC sample was measured by real-time quantitative PCR. RESULTS: Foals inoculated with paralytic strains of EHV-1 developed both a greater magnitude and longer duration of PBMC-associated viraemia than foals inoculated with abortigenic strains of the virus. CONCLUSIONS: Both the higher magnitude and longer duration of cell-associated viraemia contribute to the risk for development of neurological signs in horses infected with paralytic strains of EHV-1. POTENTIAL RELEVANCE: Our results provide empirically derived, scientific data that contributes to a better understanding of the pathogenetic basis for the differing abilities of paralytic and abortigenic strains of EHV-1 to cause post infection central nervous system disease in the horse. The findings identify the importance of minimising the quantitative burden of viraemic leucocytes that follows exposure to the virus, by the use of effective therapeutic antiviral drugs and efficacious prophylactic vaccines that stimulate cytotoxic immune responses against EHV-1 infected cells.

Foals are interferon gamma-deficient at birth.

The increased vulnerability of foals to specific pathogens such as Rhodococcus equi is believed to reflect an innate immunodeficiency, the nature of which remains poorly understood. Previous studies have demonstrated that neonates of many species fail to mount potent Th1 responses. The current research investigates the ability of circulating and pulmonary lymphocytes of developing foals to produce interferon gamma (IFNgamma). Peripheral blood mononuclear cells (PBMC) were prepared from up to 10 horse foals at regular intervals throughout the first 6 months of life. Bronchoalveolar lavage (BAL) samples were collected at 1, 3 or 6 months of age from three groups of five foals. The PBMC and BAL cells were stimulated in vitro and IFNgamma production was measured by intracellular staining. In addition, RNA was extracted from freshly isolated and in vitro stimulated PBMC and BAL cells for quantitation of IFNgamma gene expression by real time PCR. Newborn foals exhibited a marked inability to express the IFNgamma gene and produce IFNgamma protein. This deficiency was observed in both circulating and pulmonary lymphocytes. However, IFNgamma gene expression and protein production increased steadily throughout the first 6 months of life, reaching adult levels within the first year of life. These findings suggest that foals are born with an inherent inability to mount a Th1-based cell mediated immune response which may contribute to their susceptibility to intracellular pathogens.

Report of the equine herpesvirus-1 Havermeyer Workshop, San Gimignano, Tuscany, June 2004.

Amongst the infectious diseases that threaten equine health, herpesviral infections remain a world wide cause of serious morbidity and mortality. Equine herpesvirus-1 infection is the most important pathogen, causing an array of disorders including epidemic respiratory disease abortion, neonatal foal death, myeloencephalopathy and chorioretinopathy. Despite intense scientific investigation, extensive use of vaccination, and established codes of practice for control of disease outbreaks, infection and disease remain common. While equine herpesvirus-1 infection remains a daunting challenge for immunoprophylaxis, many critical advances in equine immunology have resulted in studies of this virus, particularly related to MHC-restricted cytotoxicity in the horse. A workshop was convened in San Gimignano, Tuscany, Italy in June 2004, to bring together clinical and basic researchers in the field of equine herpesvirus-1 study to discuss the latest advances and future prospects for improving our understanding of these diseases, and equine immunity to herpesviral infection. This report highlights the new information that was the focus of this workshop, and is intended to summarize this material and identify the critical questions in the field.

Detection of equine herpesvirus-specific effector and memory cytotoxic immunity in the equine upper respiratory tract.

Immunological protection of horses from equine herpesvirus-1 (EHV-1) infection and disease depends on the cooperation of virus-specific humoral and cellular immune responses. EHV-specific mucosal immunity may be an important component of such immune responses. This study demonstrates the induction of anti-EHV cytotoxic cellular immune responses in various mucosal and systemic lymphoid tissues associated with the upper respiratory tract (URT) of the horse. Four young horses (1-2 years of age) were inoculated intranasally with the Army 183 strain of EHV-1 and euthanized 1 week later. One untreated foal served as a non-infected control. Mucosa-associated tonsillar tissues, draining lymph nodes and PBMC were harvested. Virus-specific memory and effector cytolytic activity were individually assessed using 4 h chromium release assays, with and without in vitro restimulation with EHV-1, respectively. EHV-specific cytotoxic activity was detected ex vivo in several URT-associated mucosal lymphoid tissues of horses, particularly within the lining of the nasopharynx, a principal site of EHV-1 replication. This activity was also detected in the circulation of some horses 1 week post-challenge. Virus-specific memory cytotoxic activity was elevated in the circulation, and detectable in the draining lymph nodes of all horses following challenge infection.