Norwich COVID-19 testing initiative pilot: evaluating the feasibility of asymptomatic testing on a university campus.

BACKGROUND: There is a high prevalence of COVID-19 in university-age students, who are returning to campuses. There is little evidence regarding the feasibility of universal, asymptomatic testing to help control outbreaks in this population. This study aimed to pilot mass COVID-19 testing on a university research park, to assess the feasibility and acceptability of scaling up testing to all staff and students. METHODS: This was a cross-sectional feasibility study on a university research park in the East of England. All staff and students (5625) were eligible to participate. All participants were offered four PCR swabs, which they self-administered over two weeks. Outcome measures included uptake, drop-out rate, positivity rates, participant acceptability measures, laboratory processing measures, data collection and management measures. RESULTS: 798 (76%) of 1053 who registered provided at least one swab; 687 (86%) provided all four; 792 (99%) of 798 who submitted at least one swab had all negative results and 6 participants had one inconclusive result. There were no positive results. 458 (57%) of 798 participants responded to a post-testing survey, demonstrating a mean acceptability score of 4.51/5, with five being the most positive. CONCLUSIONS: Repeated self-testing for COVID-19 using PCR is feasible and acceptable to a university population.

A kinetic study of the folding of nuclease B, a possible precursor of staphylococcal nuclease A.

Nuclease B, which contains an additional flexible amino acid sequence of 19 amino acid residues bound to the NH2-terminus of nuclease A, an extracellular nuclease of Staphylococcus aureus, has been investigated in order to determine the influence of the extra residues on the refolding of the nuclease A portion from the acid denaturated state by monitoring the change in tryptophan fluorescence using a stopped-flow technique. It was found that the kinetic parameters of this refolding is similar within experimental error for nuclease A and nuclease B for the entire course (up to 40 s) studied. Therefore, the extra residues do not appear to have any detectable effect on the dynamic events involved in the refolding process. Thus, the folding of the nuclease A portion of nuclease B appears to be thermodynamically and kinetically independent of the 19 residues at the amino-terminus.

Improved survival with coronary bypass surgery in patients with three-vessel coronary disease and abnormal left ventricular function. Matched case-control study in patients with potentially operable disease.

Recent studies have suggested that patients with three-vessel coronary disease and abnormal left ventricular function have better survival rates with bypass surgery than with medical therapy alone. Case-control studies may give accurate survival estimates, but to be valid, selection biases must be taken into account. A matched case-control method was used to compare survival patterns in patients treated medically or surgically during the 1980s. Fifty medical patients with potentially operable coronary disease and 46 surgical patients were matched for significant three-vessel disease and abnormal ventricular function. These two groups had no significant differences with regard to 24 variables, including age (64 +/- 8 versus 63 +/- 10 years), chest pain class, congestive heart failure signs, ejection fraction (36 +/- 8 versus 37 +/- 9 percent), segmental wall score, or a coronary score evaluating lesion site and severity. There were slight differences between the two groups with regard to congestive heart failure symptoms (p = 0.04). Patients undergoing bypass surgery had improved four-year survival rates compared with the medical group (89 versus 55 percent; p = 0.01). Thus, this study used an effective case-control method to suggest that, in the 1980s, coronary surgery improves prognosis substantially in surgically approachable patients with severe coronary disease and ventricular dysfunction.

Medical and surgical survival in coronary artery disease in the 1980s.

The survival of 1,657 patients with angiographically proved coronary artery disease (CAD) was studied for 4 years (mean 2.0 +/- 1.2) during the 1980s to examine the prognostic importance of multiple clinical variables. One hundred of the 1,049 medically treated patients (9.5%) and 31 of the 608 surgically treated patients (5.1%) died. Multivariate analyses revealed that the strongest prognostic variables for survival in the medical group were indexes of left ventricular function (p less than 0.0001), severity of coronary stenoses (p less than 0.0001) and age (p = 0.005). However, only age (p less than 0.0001) was a significant prognostic variable in the surgically treated group. This study emphasizes the lack of prognostic significance of left ventricular function indexes and severity of coronary stenoses in surgically treated patients with CAD. These results continue the trend toward improved surgical survival shown in recent years.

A comparison of three quality of life instruments in subjects with angina pectoris: the Sickness Impact Profile, the Nottingham Health Profile, and the Quality of Well Being Scale.

Three instruments for the assessment of quality of life, the Quality of Well Being index (QWB), the Nottingham Health Profile (NHP) and the Sickness Impact Profile (SIP) were assessed in 59 patients with angina pectoris. The NHP showed increased statistically significant impairment with higher New York Heart Association (NYHA) class in 4 out of 6 subscales but not in single responses to questions on daily life. In the SIP 9 out of 11 dimensions increased with NYHA grade as did the physical and psychosocial subscores and the total score. There were statistically significant increases in six of the eleven dimensions. In the QWB an increase was observed only for two out of four categories employed in this instrument. The QWB was the most difficult to administer and thought likely to be insensitive to changes in anginal pain. There was a high level of agreement in similar dimensions of NHP and SIP. A psychological distress score was evaluated using the Symptom Rating Test and correlated with all summary dimensions of both instruments. The coefficients of variation were lower in SIP than in NHP categories. In conclusion quality of life instruments like NHP and SIP may be able to identify treatment effects in angina patients and so yield a useful addition to the traditional measures employed for the assessment of their condition.

Cardiogenic shock due to ventricular rupture. A surgical approach.

Following a posterolateral myocardial infarction, a 57-year-old man developed severe shock which did not respond to catecholamine infusion and intra-aortic balloon counterpulsation. Implantation of a left ventricular assist pump was planned, but at sternotomy free ventricular rupture was identified and repaired. Repair of free-wall ventricular rupture is uncommon because of infrequent antemortem diagnosis. A more aggressive surgical approach of instituting left ventricular assist pumping in those patients with cardiogenic shock refractory to medical therapy and intra-aortic balloon pumping should yield the additional benefit of repair of the rather common but rarely recognized lesion of ventricular rupture.

Predicting aortic valve prosthesis size. A step toward better matching of patient and prosthesis.

We have developed a simple method of predicting aortic valve prosthesis size from supravalvular aortic cineangiograms, taken in the 30 degree right anterior oblique projection, during routine diagnostic cardiac catheterization. Measurements made on the aortogram were corrected to true size by means of a 1 cm2 grid reference plate filmed at the conclusion of the catheterization. This method was utilized prospectively to predict the anulus size in 26 patients undergoing aortic valve replacement alone or as part of a more extensive procedure. The catheterization prediction of anulus size was perfectly predictive of the prosthesis size used in eight of 26 (31%) cases, within 1 mm of the prosthesis size used in 20 of 26 (77%), and within one prosthesis size in all 26 (100%) cases. Comparing the measured anulus diameter to the actual prosthesis diameter yielded r = 0.93. When both systolic and diastolic frames were available for analysis, the diastolic frame was more accurately predictive than the systolic frame (diastolic r = 0.93; systolic r = 0.88), although both yielded acceptable results. Utilization of this method has significantly altered operative plans in four patients with a small anulus. Such preoperative assessment should allow improved matching of patient and valve prosthesis and thereby yield improved long-term results in aortic valve replacement.

The conduction system of the swine heart.

Although the pig has been used as an experimental model for ischemic heart disease and sudden death, relatively little is known about the anatomy of the conduction system (CS) of this animal. We attempted to correlate electrophysiologic and anatomic differences between the pig and human CS. Invasive electrophysiologic studies were performed in five healthy anesthetized pigs. In contrast to the adult human, the pig has sinus tachycardia, shortened PR and H-V intervals, and a relatively short sinoatrial conduction time. Compared with the human CS, serial sections of the CS of pig hearts showed the following differences: (1) the atrioventricular node is located more to the right of the summit of the ventricular septum; (2) the penetrating bundle is very short, and the bifurcation of the bundle into bundle branches occurs more proximally; (3) there is more connective tissue and less elastic tissue; and (4) there is a copious amount of nerve fibers (about 50 percent throughout the CS). The presence of the abundant neural tissue implies that there is an important neurogenic component to conduction in the pig. Because of the above differences from the human, the pig should be used with caution as an experimental model in ischemic heart disease and sudden death where arrhythmias are studied.

Coarctation in Taussig-Bing malformation of the heart. Surgical significance.

In a review of 126 heart specimens of simple complete transposition of the great arteries with ventricular septal defect (VSD), coarctation was noted in eight (6%). In 105 Taussig-Bing heart specimens, coarctation and/or aortic outflow tract obstruction was noted in 56 (53%) (p less than 10(-10). This was similar to our surgical experience in 26 patients with transposition and VSD or Taussig-Bing heart. Six of nine patients with Taussig-Bing heart also had coarctation of the aorta, whereas all 17 patients with transposition and VSD had a normal aorta. Four patients with Taussig-Bing heart underwent coarctation repair and pulmonary artery banding at 2 to 7 days of age. The remaining two patients with Taussig-Bing heart did not have a hemodynamically significant coarctation. Five of the six patients with Taussig-Bing heart and coarctation underwent a Senning procedure between the ages of 7 weeks and 3 1/2 years. In four (all less than 4 months of age) the VSD could not be closed through the tricuspid valve. A right ventriculotomy was done in two and contributed to their deaths. In the other two patients the VSD was left alone and the pulmonary artery banded. Both remain well. The fifth child, aged 3 1/2 years, had the VSD closed through the tricuspid valve but died in the postoperative period of renal failure. The sixth patient is awaiting further operation following coarctation repair and pulmonary artery banding. We conclude that the presence of coarctation strongly suggests that Taussig-Bing heart malformation exists rather than transposition and VSD. Pulmonary artery banding and coarctation repair are the initial procedures of choice in the management of these critically ill newborn infants. Increasing cyanosis and failure to thrive will necessitate further operation. Closure of the VSD through the tricuspid valve in these infants is difficult. Pulmonary artery banding in association with a Senning procedure is preferable to a right ventriculotomy. Closure of the VSD is then planned at a later stage.

Successful management of right ventricular failure with the ventricular assist pump following aortic valve replacement and coronary bypass grafting.

Right ventricular failure is an infrequent but potentially lethal complication of cardiac surgical procedures. We have successfully treated a patient with right ventricular failure with the use of a right ventricular assist pump (RVAP). This patient had aortic stenosis and coronary artery disease involving the circumflex and right coronary arteries. He also had chronic obstructive pulmonary disease with mild pulmonary hypertension (mean pulmonary artery pressure of 26 mm Hg) and evidence of mild right ventricular failure (right ventricular pressure of 40/14 mm Hg). Gated radionuclide angiography, performed preoperatively, showed that the right ventricle had normal wall motion. Right ventricular failure prevented discontinuation of cardiopulmonary bypass despite use of an intra-aortic balloon pump. The right atrial pressure was 20 mm Hg with a left atrial pressure of 8 to 10 mm Hg. Bypass was readily discontinued following implantation of the RVAP. Recovery of the patient's right ventricle was evaluated with serial determinations of right ventricular work. The RVAP was removed on the fifth postoperative day and the patient made a complete recovery. Postoperatively, gated radionuclide angiography demonstrated moderate recovery of right ventricular function. We suspect that the perioperative right ventricular failure was a result of unsatisfactory myocardial protection due to total occlusion of the proximal right coronary artery, which resulted in a maldistribution of the cardioplegic solution. This case demonstrates that right ventricular function can be restored following circulatory support with a mechanical assist device.

Pericardial-fluid complement: normal values.

Reports of low pericardial-fluid complement levels in systemic lupus erythematosus and rheumatoid arthritis have been difficult to interpret, as few data are available to describe complement concentrations in patients without pericardial disease. The authors therefore determined normal values under standardized conditions of collection, storage, and assay. The normal ranges for pericardial-fluid C3, C4, and total hemolytic complement were 35-127 mg/dl, 6.3-23 mg/dl, and 1.9-9.1 CH50 units, respectively. Storage at -20 C resulted in a 50% reduction in values. Hence, storage at -70 C is recommended. As the level of pericardial-fluid total hemolytic complement is normally low, caution is needed in interpreting its apparent reduction in various immunologic diseases.

Surgical repair of dissection of the upper descending thoracic aorta and discrete ascending aortic aneurysm.

This report describes successful staged surgical repair in 2 patients with dissection of the upper descending thoracic aorta (DeBakey type III) with coexisting discrete Marfan's aneurysms of the ascending aorta. Initial repair of the descending aortic dissection was done through a left thoracotomy using a transverse aorta--femoral artery shunt in 1 patient and a left ventricular apex--femoral artery shunt without systemic heparinization in the other. Emphasis is placed on the need for pharmacological reduction of blood pressure during aortic cross-clamping as well as the use of a shunt to prevent dissection of the ascending aortic aneurysm. In both patients, subsequent repair of the ascending aortic aneurysm was accomplished using composite graft replacement of the aortic valve and ascending aorta. This operation is advised for such patients even in the absence of notable aortic valve incompetence.

The early risk of re-replacement of aortic valves.

One hundred two patients underwent re-replacement of the aortic valve, 95 having a first reoperation, 6 a second, and 1 a third. The early (30-day) mortality among the 81 patients undergoing an elective first reoperation was 3.7% (with 70% confidence limits of 1.63% and 7.32%). Fourteen patients undergoing their first reoperation did so urgently, and 6 (42.9%) died early postoperatively. Technical problems during reoperation were uncommon. Fifteen of the 102 patients underwent reoperation because of infection in or around the device; 2 (13.3%) died early postoperatively, and at least 3 more died within nine months of operation. These data, with their 70% confidence limits, are useful in arriving at a decision for or against reoperation in individual patients.

One hundred neodymium-YAG laser ablations of obstructing tracheal neoplasms.

Forty patients with obstructing, nonresectable tracheal neoplasms underwent 100 ablations with the neodymium-yttrium-aluminum garnet (YAG) laser. The laser allows bloodless resection and vaporization of tumors. Unlike the carbon dioxide laser, the neodymium-YAG laser can be used with the flexible bronchoscope and has an excellent effect on coagulation. Thirty-four patients had primary lung malignancies (epidermoid in 24); 4 had metastatic malignancies; and 2 had benign lesions. Results have been excellent in 22, fair in 10, and poor in 8. No patient has died or had a deleterious result. Complications have occurred in only 1 of 89 ablations done with the flexible bronchoscope. We believe that the neodymium-YAG laser is effective in opening major tracheal or bronchial obstructions and offers substantial symptomatic improvement in patients who are short of breath. Although this treatment is only palliative, the results have been excellent in more than half of the patients.

Obstruction of the true lumen during retrograde perfusion of type I aortic dissections: a simplified solution.

Retrograde perfusion of the false lumen in cases of type I dissection of the thoracic aorta may not permit reperfusion of the coronary arteries when the aortic cross-clamp is removed. We have employed a Y connector between the coronary perfusion outlet of the oxygenator and cardioplegia delivery system. This allows reperfusion of the coronary arteries through the ascending aortic graft. As cardiopulmonary bypass is discontinued, the true aortic lumen is reexpanded and the false lumen collapsed by forward flow of blood from the heart. The successful use of this system is described.

The performance of the Braunwald-Cutter aortic prosthetic valve.

Four hundred seventy-five patients underwent aortic valve replacement with the Braunwald-Cutter ball-valve prosthesis at two institutions. The early (30-day) hospital mortality was 4.7% for those with isolated aortic valve replacement and 6.9% for the entire group. For the former, 5-year actuarial survival of the hospital survivors was 72 +/- 5.7%; for the latter group it was 71 +/- 4.4%. Eleven patients (5 since the date of follow-up inquiry) have suffered poppet escape, 9 of whom died. The actuarial incidence of known poppet escape is 4 +/- 2.6% at 47 months; when the 5 patients suffering poppet escape since the date of follow-up inquiry are included, with certain assumptions, the incidence is 3.7 +/- 1.14%. The projected probability of poppet escape using all 11 patients is 12.2% at 5 years; the 70% confidence bands of projected probability of poppet escape separate from those of the risk of re-replacement at 61 months. This and other analyses indicate that in general, patients with the Braunwald-Cutter aortic prosthesis should have it replaced 4 1/2 to 5 years after its insertion.

Hetastarch as a prime for cardiopulmonary bypass.

Hetastarch, a synthetic colloid osmotic plasma volume expander, was employed in a prime for cardiopulmonary bypass in 37 patients undergoing myocardial revascularization. Comparison of laboratory values to those of 42 patients undergoing myocardial revascularization using an albumin-containing prime showed lower postoperative platelet counts (p less than 0.02) with hetastarch. There were no differences in chest tube drainage, blood use, plasma hemoglobin, fibrinogen levels, of coagulation times. The hetastarch prime cost $119.50 per patient, whereas the albumin-containing prime cost $321.35 per patient.

Effects of sphygmomanometer type and position of the arm on blood pressure measurement.

Random zero and standard sphygmomanometers were compared in a balanced study performed by 36 members of a General Practitioner Clinical Research Group. In addition the influence of arm position, supported versus dependent, was examined. There was minimal difference between the mean blood pressures measured by the two sphygmomanometers, although the results from the random zero were more variable. The mean blood pressures with the arm supported were consistently lower than with the arm dependent: 127/79 mmHg arm supported vs 131/83 mmHg arm dependent. It is recommended that the position of the arm should be standardised to that of being supported roughly horizontally at heart level. The random zero machine should be used for clinical trial work where the elimination of observer bias is important, and when proper training of observers can be undertaken.

Osteoblast activity at the dental implant-bone interface: transmission electron microscopic and high voltage electron microscopic observations.

The purpose of this report is to present transmission electron microscopic and high voltage transmission electron microscopic (HVEM) observations of a longitudinal investigation examining the activities of osteoblasts and associated tissues apposing titanium and alumina oxide ceramic endosteal dental implants. The HVEM permitted 3-dimensional stereologic observations. All observations were obtained from undecalcified interfacial tissues from this in vivo experimental dog model using commercially available implants placed into the mandible. Two similar implants were placed in both sides of the mandible, with implants in 12 of the 18 dogs supporting fixed bridges for either 6 or 12 months. From the study, we observed that a mineralized matrix exists in direct apposition to the implant. Since bone does not interface the entire length of the implant, other interfacial zones were found to exist which consisted of unmineralized tissues. In such zones, we observed that osteoblasts were routinely found directly at the implant interface to the mandibular bone. These interfacial tissues included unmineralized collagen fibers, proteinaceous material, a finely fibrillar matrix, and the osteoblasts. This study has reinforced the concept that the oral tissue-dental implant interface is a dynamic zone consisting of remodeling activities of the osseous cells and extracellular matrices.