89 Covid-19 and the Impact on Oncological General Surgery at a District General Hospital

Introduction

Covid-19 has had a significant impact on all aspects of healthcare. We aimed to characterise our experience of oncological general surgery during the first 4-months of the pandemic and compare with the same period in 2019.

Method

A prospective cohort study was performed from 23/03/20 to 08/07/20. All elective oncological operations were included. Data on patient demographics, waiting times, inpatient characteristics and oncological outcomes were recorded. Statistical analysis was used to compare with retrospective data from 2019.

Results

78 patients were included in total, 38 in 2019 and 40 in 2020. There were no differences in length of stay (2.5 vs 3.5 days, p = 0.355) or waiting list time (27.2 vs 24.2 days, p = 0.574).

Oncological outcomes were comparable with no statistical difference in clear resection margin status (94.4 vs 84.6%, p = 0.168) or positive nodal status (24.1 vs 37.1%, p = 0.298).

The percentage of staging CT scans requested externally was higher in 2020 (4 vs 32%, p = <0.05).

There was no difference in time from urgent referral to first assessment (30.5 vs 26.4 days, p = 0.384) or time to operation (96.6 vs 85.7 days, p = 0.618).

Conclusions

Oncological surgery during Covid-19 can be performed safely with favourable oncological outcomes. The longer-term effects from delayed diagnoses remain to be evaluated.

Role of dietary calcium and available phosphorus in the aetiology of tibial dyschondroplasia in growing turkeys

1. Large White male turkeys from a heavy commercial male-line were fed 16 diets containing 4 concentrations of calcium (6, 10, 14 and 18 g/kg) and available phosphorus (3, 5, 7 and 9 g/kg) in a 4 x 4 factorial experiment. There were three replicates (pens) of each treatment and the skeletal health, morphology and mineral status of 4 turkeys from each pen were assessed at 7, 10 and 13 weeks of age. 2. The prevalence of tibial dyschondroplasia increased after 7 weeks of age and was present in 50 and 71% of turkeys respectively at 10 and 13 weeks. The lesion was localised in the caudal aspect of the proximal tibiae. Dietary calcium and available phosphorus did not affect the prevalence of the lesion except in turkeys on the diet containing 6 g calcium/kg, where body weight and the incidence of tibial dyschondroplasia were low. 3. Histological investigation showed no evidence of rachitic changes. 4. Low dietary calcium was associated with lower tibial plateau angles at 10 and 13 weeks of age. Tibial torsion and the angle of rotation were not affected by dietary treatments or age. Tibial torsion and the angle of rotation were not affected by dietary treatments or age. 5. Increasing dietary calcium increased tibial radiodensity, cortical density and the widths of the cortex and proximal tibiotarsus. Radiodensities increased to 10 weeks and were significantly lower at 13 weeks of age. 6. Bone ash, calcium and phosphorus declined with age, particularly between 10 and 13 weeks, whereas bone calcium: phosphorus ratios were not affected by dietary treatment or age. 7. Dietary calcium was positively associated with blood calcium and calcium ion concentrations and was without effect on blood phosphorus. Available phosphorus was associated positively with increased blood phosphorus and lower calcium ion concentrations but had no effect on total calcium. Alkaline phosphatase activity was low at high concentrations of dietary calcium with low available phosphorus and there was higher activity on diets containing low calcium and high available phosphorus.

Severe invasive group A beta-hemolytic streptococcus infection complicating pharyngitis: a case report and discussion

Group A beta-hemolytic streptococcus (GABHS) has long been recognized as a deadly pathogen with manifestations ranging from impetigo to necrotizing fasciitis. Bacteremia from streptococcal pharyngitis is a rare complication. We report a patient presenting with septic shock and diabetic ketoacidosis from streptococcal pharyngitis. The pathophysiology, classification, and treatment of invasive group A streptococcal infection is discussed.

Late onset angiotensin-converting enzyme induced angioedema: case report and review of the literature

Angiotensin-converting enzyme inhibitors (ACEI) such as enalapril, captopril, and lisinopril are well established as effective treatments of arterial hypertension and congestive heart failure. They are widely used and generally well tolerated. Angioedema is a rare but serious adverse effect of ACEI therapy. Most frequently, edema involves the face, oral cavity, and the glossopharyngeal or glottic area. Visceral edema induced by ACEI has also occurred. Life threatening and even fatal cases associated with ACEI have been reported. Although angioedema typically occurs within the first weeks of ACEI therapy, some cases with latencies of several months to years have been reported. This paper reports a case of late onset and recurrent angioedema in a patient treated with lisinopril for hypertension. A discussion of ACEI angioedema follows.

Travel medicine: helping patients prepare for trips abroad

One third of persons who travel abroad experience a travel-related illness, usually diarrhea or an upper respiratory infection. The risk of travelers' diarrhea can be reduced by eating only freshly prepared, hot foods. Combination therapy with a single dose of ofloxacin plus loperamide usually provides relief from travelers' diarrhea within 24 hours. Using a diethyltoluamide (deet)-containing insect repellent and wearing permethrin-coated clothing can reduce the risk of malaria, yellow fever and other diseases contracted from insects. Routine immunizations such as tetanus, measles, mumps and rubella, and influenza should be updated if necessary before the patient embarks on the trip. Hepatitis A immunization should be administered to persons traveling to places other than Canada, Australia, New Zealand, Japan and western European countries. Typhoid vaccination should be considered for travelers going to developing countries. Yellow fever immunization is indicated for travelers going to endemic areas of South America and Africa. Malaria prophylaxis with chloroquine is indicated for travelers going to Mexico and Central America. Mefloquine is recommended for those traveling to areas where malaria is resistant to prophylactic treatment with chloroquine. Medical advice for patients planning trips abroad must be individualized and based on the most current expert recommendations.

Active site-directed inhibitors of Rhodococcus 20 S proteasome. Kinetics and mechanism

We have studied the mechanism of inhibition of the recombinant Rhodococcus proteasome by four different chemical classes of active site-directed small molecule inhibitors. Clasto-lactacystin beta-lactone is a time-dependent inhibitor of the Rhodococcus proteasome's ability to hydrolyze Suc-Leu-Leu-Val-Tyr-AMC, a substrate for this proteasome's single type of active site, and proceeds with a kinact/[I] of 1,700 M-1 s-1. Using peptide mapping of tryptic digests, LC/MS, and amino acid sequence analysis, we have established that the Ogamma of the hydroxyl group on the N-terminal threonine of the beta-subunit is the sole modification made by the beta-lactone. Active site titrations of the Rhodococcus proteasome with reversible peptide aldehydes show the expected stoichiometry of one inhibitor molecule per beta-subunit. Prior modification with beta-lactone completely abrogates the binding of peptidyl boronic acid inhibitors, suggesting that these inhibitors also inactivate the enzyme by reacting with the Ogamma moiety on Thr1. High performance liquid chromatography analysis of peptidyl vinyl sulfone-modified intact Rhodococcus proteasome beta-subunit and its tryptic peptides suggests that the peptidyl vinyl sulfone modifies a residue in the N-terminal 20 amino acids. This modification is also blocked by prior treatment with beta-lactone.

Kinetic characterization of the chymotryptic activity of the 20S proteasome

In this paper, we report kinetic studies for the chymotryptic activity of the 20S proteasome. Major observations include the following: (1) Reaction progress curves that are recorded at concentrations of Suc-Leu-Leu-Val-Tyr-AMC greater than about 40 microM are biphasic and characterized by initial velocities that decay by a first-order process to final, steady-state velocities. (2) Also at [Suc-Leu-Leu-Val-Tyr-AMC] > 40 microM, initial and steady-state velocities are smaller than predicted from simple, Michaelis-Menten kinetics. (3) The first-order rate constant for the approach to steady-state has a complex dependence on substrate concentration and decreases sigmoidally as substrate concentration increases. These results indicate that the 20S proteasome is a hysteretic enzyme and is subject to substrate inhibition. To explain these observations we propose a minimal kinetic model with two critical mechanistic features: (1) the 20S proteasome has two cooperative active sites for Suc-Leu-Leu-Val-Tyr-AMC and (2) there are two interconvertible conformers of active 20S proteasome. To probe this mechanism in greater detail, we explored the kinetic mechanism of inhibition of the 20S proteasome-catalyzed hydrolysis of Suc-Leu-Leu-Val-Tyr-AMC by the peptide aldehyde, Ac-Leu-Leu-Nle-H. Our studies reveal a nonlinear dependence of reciprocal steady-state velocity on inhibitor concentration (i.e., parabolic inhibition) as well as a nonlinear dependence of the apparent inhibitor dissociation constant on substrate concentration. Both of these observations are explained by binding of inhibitor at multiple sites on the enzyme. Taken together, the results of this study indicate that the 20S proteasome is a conformationally flexible protein that can adjust to the binding of ligands and that has multiple and cooperative active sites. These results support a view of the proteasome's substrate specificity in which (1) substrates are recognized and hydrolyzed by more than one active site; (2) each active site can bind substrates that possess a variety of P1 residues; and (3) the P1 residue plays a relatively minor role as a specificity determinant. Finally, we interpret the results of this study to suggest that, in vivo, the 20S proteasome requires conformational plasticity for its interactions with regulatory complexes and, after it has combined with appropriate regulatory complexes, to catalyze hydrolysis of proteins.

Comparative development of the antitrochanter in three strains of domestic fowl

Lameness and musculoskeletal disease were more frequent in two strains of broilers (selected [S] and relaxed [R]) than in an unselected layer (J). Defective fibrocartilage accounted for 0.15 of the total area of antitrochanteric cartilage at 29 weeks of age in the S-strain birds. There was more retained hyaline cartilage in the R- and S-strain birds at 15 weeks, and at 22 and 29 weeks there was delayed ossification. Occluded blood vessels, death of chondrocytes and degenerate areas of fibrocartilage occurred only in the broiler strains; they were worse in the S-strain and degenerate fibrocartilage occurred more frequently and in larger amounts. The area, length and depth of cartilage were larger in the heavier strains but the differences were considerably smaller than the difference in their relative bodyweights. The degeneration of the antitrochanter appeared to be associated with a reduction in the blood supply to the underlying hyaline cartilage and with the death of chondrocytes and the degeneration of matrix within the fibrocartilage of the antirochanter.

Inhibitors of the proteasome block the degradation of most cell proteins and the generation of peptides presented on MHC class I molecules

Reagents that inhibit the ubiquitin-proteasome proteolytic pathway in cells have not been available. Peptide aldehydes that inhibit major peptidase activities of the 20S and 26S proteasomes are shown to reduce the degradation of protein and ubiquitinated protein substrates by 26S particles. Unlike inhibitors of lysosomal proteolysis, these compounds inhibit the degradation of not only abnormal and short-lived polypeptides but also long-lived proteins in intact cells. We used these agents to test the importance of the proteasome in antigen presentation. When ovalbumin is introduced into the cytosol of lymphoblasts, these inhibitors block the presentation on MHC class I molecules of an ovalbumin-derived peptide by preventing its proteolytic generation. By preventing peptide production from cell proteins, these inhibitors block the assembly of class I molecules. Therefore, the proteasome catalyzes the degradation of the vast majority of cell proteins and generates most peptides presented on MHC class I molecules.

Effects of dietary acidity on calcium balance and mobilisation, bone morphology and 1,25 dihydroxyvitamin D in prepartal dairy cows

The effect of an acid or alkali diet was investigated in 14 mature dairy cows during the last 28 days of pregnancy. The acid diet reduced the incidence of parturient hypocalcaemia compared with the alkali diet and was associated with higher blood ionised calcium and plasma chloride concentrations and lower blood pH and acid-base excess before parturition. Plasma 1,25-dihydroxyvitamin D concentrations before parturition were increased by the acid diet but the concentrations of parathyroid hormone and intact 1-86 parathyroid-hormone-related peptide were unaffected. The estimated fractional calcium absorption and calcium mobilisation rate during an ethylenediamine tetraacetic acid infusion were increased by the acid diet 14 days before parturition. Cortical bone remodelling occurred in all the animals during late pregnancy but was particularly evident in the cows given the acid diet. The data suggest that an acid diet ameliorates parturient hypocalcaemia by enhancing calcium mobilisation before parturition by increasing calcium absorption and bone resorption, these increases possibly being mediated by increases in the plasma concentration of 1,25-dihydroxyvitamin D.

Agraphia in dementia of the Alzheimer type

This study describes graphic errors made in writing a simple sentence in 368 healthy older adults and individuals in different stages of dementia of the Alzheimer type. Errors of agraphia were present in both healthy and demented people and, in general, increased with the severity of dementia. The errors of agraphia were not correlated with measures of aphasia or psychometric measures of language and motor performance. Writing skill may represent procedural memory, and agraphia errors indicate alterations in long-term memory in dementia of the Alzheimer type.

Nociceptive considerations in treating with counterstrain

The proprioceptive mechanistic model of somatic dysfunction proposed by Korr is accepted as the neurophysiologic basis of counterstrain by the developer of that manipulative technique. We suggest that the physician should also take into account the physical damage, if any, that the original trauma produced. We propose that with tissue injury, nociceptive reflexes could produce patterns of motion restriction opposite that predicted by a solely proprioceptive model. A nociceptive component is suggested as an explanation for the origin and maintenance of somatic dysfunction and its response to the counterstrain technique. In actuality, both proprioceptive and nociceptive responses may occur in dysfunctional states. Other physiologic responses also may be involved. These views are consistent with clinical experience.

Radiologic insertion of Hickman catheters in HIV-positive patients: infectious complications

Ninety-six patients undergoing radiologically guided placement of 104 Hickman catheters were grouped according to their human immunodeficiency virus (HIV) serologic status. Infectious complications were categorized according to their severity (local or systemic) and time of occurrence (periprocedural or late). The number of infectious complications per 100 indwelling catheter days was calculated. Among the 14 catheter placements in 13 HIV-positive patients, two systemic infections occurred, resulting in a 14% overall infection rate and 0.18 infectious complications per 100 indwelling catheter days. The remaining 83 HIV-negative patients underwent 90 Hickman catheter placements. Nine infectious complications (10%) were noted in the 90 catheters, translating into 0.19 infectious complications per 100 indwelling catheters days. These results suggest no significant (relative risk [RR] of 1.4 and .95) difference in infectious complication rates encountered in HIV-positive patients compared with the general population. This supports the clinical usefulness of Hickman catheter placement in HIV-positive patients, although many additional HIV-positive patients must be evaluated to achieve an acceptable level of statistical confidence.

Metabolism of vasoactive peptides by plasma and purified renal aminopeptidase M

Aminopeptidase M (AmM; EC 3.4.11.2) is a membrane-bound peptidase present on renal brush border and vascular plasma membrane. In the present study, AmM, purified from rabbit kidney cortex, produced a single immunoprecipitin line against AmM antisera, hydrolyzed alanyl-, leucyl- and arginyl-beta-naphthylamides at rates of 5.1 +/- 0.5, 3.9 +/- 0.5 and 2.6 +/- 0.3 mumol/min/mg, respectively, exhibited little or no alpha-glutamyl-, aspartyl- or glycyl-prolyl-naphthylamidase activities (less than or equal to 0.14 mumol/min/mg), and was inhibited by o-phenanthroline, amastatin (IC50 = 400 nM) and bestatin (IC50 = 6 microM). The alanyl-naphthylamidase activity of unfractionated rabbit plasma was found to be identical to purified AmM regarding relative rates of hydrolysis of alanyl-, leucyl- and arginyl-naphthylamides (100:79:42), pH optimum, and inhibition profile. In comparative studies with the purified enzyme, immunoreactive AmM accounted for essentially all of the alanyl-2-naphthylamidase activity of rabbit plasma. N-Terminal metabolism of (Met5)enkephalin by purified renal AmM was 3.92 +/- 0.69 mumol/min/mg, followed by somatostatin (1.25 mumol/min/mg), hepta(5-11)substance P (1.14 +/- 0.13 mumol/min/mg), (Asn1)angiotensin II (1.11 +/- 0.06 mumol/min/mg), angiotensin III (0.45 +/- 0.04 mumol/min/mg) and des(Asp1)-angiotensin I (0.36 +/- 0.04 mumol/min/mg). In contrast, substance P, bradykinin, (Sar1,Ala8)angiotensin II and neurokinin analogs containing modified N-termini (e.g. Ac-Arg) were resistant to hydrolysis by AmM. Peptide degradation was optimal at neutral pH and was inhibited by amastatin (IC50 = 200 nM) and bestatin (IC50 = 5 microM). Apparent Km values ranged from 15.7 +/- 0.4 microM for angiotensin III to 102 +/- 2 microM for (Met5)enkephalin. These data support a significant role for vascular and plasma AmM in the metabolism of circulating vasoactive peptides.

Vasopressin neuron survival in neonatal Brattleboro rats; critical factors in graft development and innervation of the host brain

Previously it was found that grafts of supraoptic plus paraventricular areas from 19-day-old foetal normal rats survived in the third ventricle of the brain of 4- to 6-day-old, vasopressin-deficient Brattleboro pups, but could not alleviate their polyuria. In the present series, factors important in graft development were analysed. Again using day-19 fetuses as donors, anterohypothalamus grafts as well as grafts placed near a crushed median eminence survived relatively poorly, but showed the presence of vasopressin neurons immunocytochemically one month post-grafting. Homotopic grafting in the supraoptic nucleus, however, even failed to show surviving vasopressin neurons. Graft survival was improved by the use of donor tissue of fetuses younger than day 19. Parvocellular vasopressin cells were frequently seen, organized into clusters resembling the normal suprachiasmatic nucleus. However, magnocellular neurons, as normally seen in supraoptic and paraventricular nuclei, only survived grafting when taken between days 11 and 15 of fetal age. It was concluded that only immature vasopressin neurons survived grafting under the condition employed. Magnocellular neurons had a limited fiber outgrowth into the host brain and median eminence. Most large neurons only stained with non-specific neurophysin antiserum, not with specific vasopressin-associated neurophysin antiserum. Thin fibers of the parvocellular vasopressin neurons provided only occasional and sparse innervation of the host median eminence and lateral septum (one case), but several examples of massive fiber bundles running dorsally from graft into host brain were observed. These fibers terminated in the thalamic periventricular area, a nucleus that is normally innervated by the vasopressin neurons of the suprachiasmatic nucleus. The failure of the grafts to provide adequate vasopressinergic innervation of the host median eminence probably explains why none of the nearly 200 Brattleboro neonates operated upon showed any sign of relief of their diabetes insipidus. It suggests, however, that the present procedures might be useful in restoring central vasopressinergic functions in the developing Brattleboro rat.

Effect of defibrillation energy on pacing threshold

After an episode of electrical defibrillation, periods of increased pacing threshold may cause lack of pacing in pacemaker patients. This effect is independent of the energy applied during defibrillation, although the data suggest that the most rapid return to prefibrillation pacing thresholds occurs after minimal energy countershocks.

An experimental method for thermal control of heart rate: work in progress

Evaluation of the postoperative course of coronary artery bypass patients shows that a number develop supraventricular arrhythmias that may be responsive to sino-atrial node (SAN) cooling. The sinus rate can be controlled within a clinically useful range with topical cooling probes (thermodes). The data on the variations of heart rate caused by modest nodal hypothermia indicate that a nonpharmacologic clinical system for control of supraventricular tachyarrhythmias is feasible. Prototype thermodes suitable for SAN implantation have been developed.

Perioperative suppression of the leukocyte migration inhibition assay in patients undergoing elective operations

The effect of anesthesia and operation on immunity measured by leukocyte migration inhibition using streptokinase-streptodornase is reported in normal patients undergoing elective surgical procedures. Eight-five per cent of the patients exhibited postoperative immunosuppression, and this persisted for 60 days or longer in more than half of them. Despite this, no complication was encountered relating to wound healing or sepsis.

Perspectives in malpractice

Medical malpractice dates from Biblical days. And since then, much has been written on the subject. This article is a general overview of the historical, legal, and professional aspects of medical malpractice.