Parenchymal involvement on CT pulmonary angiography in SARS-CoV-2 Alpha variant infection and correlation of COVID-19 CT severity score with clinical disease severity and short-term prognosis in a UK cohort

AIM

To determine if there is a difference in radiological, biochemical, or clinical severity between patients infected with Alpha-variant SARS-CoV-2 compared with those infected with pre-existing strains, and to determine if the computed tomography (CT) severity score (CTSS) for COVID-19 pneumonitis correlates with clinical severity and can prognosticate outcomes.

MATERIALS AND METHODS

Blinded CTSS scoring was applied to 137 hospital patients who had undergone both CT pulmonary angiography (CTPA) and whole-genome sequencing of SARS-CoV-2 within 14 days of CTPA between 1/12/20–5/1/21.

RESULTS

There was no evidence of a difference in imaging severity on CTPA, viral load, clinical parameters of severity, or outcomes between Alpha and preceding variants. CTSS on CTPA strongly correlates with clinical and biochemical severity at the time of CTPA, and with patient outcomes. Classifying CTSS into a binary value of “high” and “low”, with a cut-off score of 14, patients with a high score have a significantly increased risk of deterioration, as defined by subsequent admission to critical care or death (multivariate hazard ratio [HR] 2.76, p<0.001), and hospital length of stay (17.4 versus 7.9 days, p<0.0001).

CONCLUSION

There was no evidence of a difference in radiological severity of Alpha variant infection compared with pre-existing strains. High CTSS applied to CTPA is associated with increased risk of COVID-19 severity and poorer clinical outcomes and may be of use particularly in settings where CT is not performed for diagnosis of COVID-19 but rather is used following clinical deterioration.

Identification of neutralising pembrolizumab anti-drug antibodies in patients with melanoma

Development of anti-drug antibodies (ADAs) can interfere with therapeutic monoclonal antibodies and may lead to drug neutralisation and clinical disease progression. Measurement of circulating drug levels and development of ADAs in the setting of anti-programmed cell death-1 agent pembrolizumab has not been well-studied. Enzyme-linked immunosorbent assays were used to measure pembrolizumab drug level and ADAs in 41 patients with melanoma at baseline, Time-point 1 (3 weeks) and Time-point 2 (21 weeks). Assay results were related to patient demographics and clinical outcome data at 6 months. The median pembrolizumab drug level at 3 weeks was 237 ng/μL and did not correlate with age, sex or body surface area.17/41 patients had an ADA detected at any timepoint, with the highest prevalence at Timepoint 1 (median concentration = 17 ng/μL). The presence of an ADA did not correlate with clinical progression at 6 months. 3/41 (7%) of patients displayed a falling pembrolizumab drug level and rising ADA titre between Timepoint 1 and 2 suggestive of a neutralising ADA. Pembrolizumab drug levels and ADAs can be readily measured. The rates of total and treatment-emergent ADAs may be higher in “real-word” settings than those previously reported. Larger studies are needed to determine effect of neutralising ADAs on long-term clinical outcome.

Chest CT screening for COVID-19 in elective and emergency surgical patients: experience from a UK tertiary centre

AIM

To determine the incidence of possible COVID-19-related lung changes on preoperative screening computed tomography (CT) for COVID-19 and how their findings influenced decision-making. To also to determine whether the patients were managed as COVID-19 patients after their imaging findings, and the proportion who had SARS-CoV2 reverse transcriptionpolymerase chain reaction (RT-PCR) testing.

MATERIALS AND METHODS

A retrospective study was undertaken of consecutive patients having imaging prior to urgent elective surgery (n=156) or acute abdominal imaging (n=283). Lung findings were categorised according to the British Society of Thoracic Imaging (BSTI) guidelines. RT-PCR testing, management, and outcomes were determined from the electronic patient records.

RESULTS

3% (13/439) of CT examinations demonstrated findings of classic/probable COVID-19 pneumonia, whilst 4% (19/439) had findings indeterminate for COVID-19. Of the total cohort, 1.6% (7/439) subsequently had confirmed RT-PCR-positive COVID-19. Importantly, all the patients with a normal chest or alternative diagnoses on CT who had PCR testing within the next 7 days, had a negative RT-PCR (92/407). There was a change in surgical outcome in 6% (10/156) of the elective surgical cohort with no change to surgical management was demonstrated in the acute abdominal emergency cohort requiring surgery (2/283).

CONCLUSION

There was a 7% (32/439) incidence of potential COVID-19-related lung changes in patients having preoperative CT. Although this altered surgical management in the elective surgical cohort, no change to surgical management was demonstrated in the acute abdominal emergency cohort requiring surgery.

Social niche construction and evolutionary transitions in individuality

Social evolution theory conventionally takes an externalist explanatory stance, treating observed cooperation as explanandum and the positive assortment of cooperative behaviour as explanans. We ask how the circumstances bringing about this positive assortment arose in the first place. Rather than merely push the explanatory problem back a step, we move from an externalist to an interactionist explanatory stance, in the spirit of Lewontin and the Niche Construction theorists. We develop a theory of 'social niche construction' in which we consider biological entities to be both the subject and object of their own social evolution. Some important cases of the evolution of cooperation have the side-effect of causing changes in the hierarchical level at which the evolutionary process acts. This is because the traits (e.g. life-history bottlenecks) that act to align the fitness interests of particles (e.g. cells) in a collective can also act to diminish the extent to which those particles are bearers of heritable fitness variance, while augmenting the extent to which collectives of such particles (e.g. multicellular organisms) are bearers of heritable fitness variance. In this way, we can explain upward transitions in the hierarchical level at which the Darwinian machine operates in terms of particle-level selection, even though the outcome of the process is a collective-level selection regime. Our theory avoids the logical and metaphysical paradoxes faced by other attempts to explain evolutionary transitions.

Relation between trunk fat volume and reduction of total lung capacity in obese men

Reduction in total lung capacity (TLC) in obese men is associated with restricted expansion of the thoracic cavity at full inflation. We hypothesized that thoracic expansion was reduced by the load imposed by increased total trunk fat volume or its distribution. Using MRI, we measured internal and subcutaneous trunk fat and total abdominal and thoracic volumes at full inflation in 14 obese men [mean age: 52.4 yr, body mass index (BMI): 38.8 (range: 36-44) kg/m(2)] and 7 control men [mean age: 50.1 yr, BMI: 25.0 (range: 22-27.5) kg/m(2)]. TLC was measured by multibreath helium dilution and was restricted (<80% of the predicted value) in six obese men (the OR subgroup). All measurements were made with subjects in the supine position. Mean total trunk fat volume was 16.65 (range: 12.6-21.8) liters in obese men and 6.98 (range: 3.0-10.8) liters in control men. Anthropometry and mean total trunk fat volumes were similar in OR men and obese men without restriction (the ON subgroup). Mean total intraabdominal volume was 9.41 liters in OR men and 11.15 liters in ON men. In obese men, reduced thoracic expansion at full inflation and restriction of TLC were not inversely related to a large volume of 1) intra-abdominal or total abdominal fat, 2) subcutaneous fat volume around the thorax, or 3) total trunk fat volume. In addition, trunk fat volumes in obese men were not inversely related to gas volume or estimated intrathoracic volume at supine functional residual capacity. In conclusion, this study failed to support the hypotheses that restriction of TLC or impaired expansion of the thorax at full inflation in middle-aged obese men was simply a consequence of a large abdominal volume or total trunk fat volume or its distribution.

Reduction of total lung capacity in obese men: comparison of total intrathoracic and gas volumes

Restriction of total lung capacity (TLC) is found in some obese subjects, but the mechanism is unclear. Two hypotheses are as follows: 1) increased abdominal volume prevents full descent of the diaphragm; and 2) increased intrathoracic fat reduces space for full lung expansion. We have measured total intrathoracic volume at full inflation using magnetic resonance imaging (MRI) in 14 asymptomatic obese men [mean age 52 yr, body mass index (BMI) 35-45 kg/m2] and 7 control men (mean age 50 yr, BMI 22-27 kg/m2). MRI volumes were compared with gas volumes at TLC. All measurements were made with subjects supine. Obese men had smaller functional residual capacity (FRC) and FRC-to-TLC ratio than control men. There was a 12% predicted difference in mean TLC between obese (84% predicted) and control men (96% predicted). In contrast, differences in total intrathoracic volume (MRI) at full inflation were only 4% predicted TLC (obese 116% predicted TLC, control 120% predicted TLC), because mediastinal volume was larger in obese than in control [heart and major vessels (obese 1.10 liter, control 0.87 liter, P=0.016) and intrathoracic fat (obese 0.68 liter, control 0.23 liter, P<0.0001)]. As a consequence of increased mediastinal volume, intrathoracic volume at FRC in obese men was considerably larger than indicated by the gas volume at FRC. The difference in gas volume at TLC between the six obese men with restriction, TLC<80% predicted (OR), and the eight obese men with TLC>80% predicted (ON) was 26% predicted TLC. Mediastinal volume was similar in OR (1.84 liter) and ON (1.73 liter), but total intrathoracic volume was 19% predicted TLC smaller in OR than in ON. We conclude that the major factor restricting TLC in some obese men was reduced thoracic expansion at full inflation.

Effects of intra-gene fitness interactions on the benefit of sexual recombination

Whereas spontaneous point mutation operates on nucleotides individually, sexual recombination manipulates the set of nucleotides within an allele as an essentially particulate unit. In principle, these two different scales of variation enable selection to follow fitness gradients in two different spaces: in nucleotide sequence space and allele sequence space respectively. Epistasis for fitness at these two scales, between nucleotides and between genes, may be qualitatively different and may significantly influence the advantage of mutation-based and recombination-based evolutionary trajectories respectively. We examine scenarios where the genetic sequence within a gene strongly influences the fitness effect of a mutation in that gene, whereas epistatic interactions between sites in different genes are weak or absent. We find that, in cases where beneficial alleles of a gene differ from one another at several nucleotide sites, sexual populations can exhibit enormous benefit compared with asexual populations: not only discovering fit genotypes faster than asexual populations, but also discovering high-fitness genotypes that are effectively not evolvable in asexual populations.

Evolution of changes in carbon monoxide transfer factor in men with chronic obstructive pulmonary disease

Progression of chronic obstructive pulmonary disease (COPD) has been studied predominantly by following change in forced expiratory volume in 1s (FEV1) which reflects both primary airway disease and associated alveolar disease. Carbon monoxide transfer (Tlco) (the product of the transfer coefficient Kco and alveolar volume Va) is the only simple, widely available test of alveolar function, but few studies have followed long-term changes in an individual. Seventeen middle-aged men with moderate chronic airflow obstruction (mean FEV1 56% of predicted values) were observed with yearly measurements of FEV1, Tlco and Kco over a mean of 18.9 yr. At the end of follow-up FEV1 had fallen to 29% of predicted values. Va, measured by single breath dilution, fell in each man. Kco at recruitment ranged from 41% to 110% predicted and remained >75% predicted in eight men at the end of follow-up supporting a phenotype of COPD with predominant airway disease and little emphysema. Fall in FEV1 was faster (2.03% predicted FEV1/yr) in seven men with low initial Kco<75% pred. than in men with initial Kco>75% pred. (1.14% predicted FEV1/yr, P=0.006). Repeated measurements of CO transfer in an individual should increase the present poor knowledge of the contribution of alveolar disease to the progression of chronic airflow obstruction.

Postural changes in nasal and pulmonary resistance in subjects with asthma

INTRODUCTION

Subjects with asthma frequently have nasal symptoms and complain of orthopnoea but airflow resistance is usually only assessed during oral breathing and while seated.

METHOD

We have used a forced oscillation technique to measure total respiratory resistance (Rrs) at 6Hz during mouth breathing (Rrs,mo) and during nose breathing (Rrs,na) in the sitting and supine postures; resistance of the nasal airway (Rnaw) was estimated as Rrs,na--Rrs,mo. Forced oscillations were applied during normal tidal breathing and the mid-tidal lung volume (MTLV) was determined for each breathing route and posture.

SUBJECTS

Three groups of subjects were studied: 10 normal subjects without lung or nasal disease (N; five males, mean age 33.5 [range 23-58] years, mean FEV1 105%pred, FEV1/VC 86%); seven subjects with asthma alone (A; four males, 40.3 [23-57] years, mean FEV1 66%pred, FEV1/VC 74%); 10 asthmatic subjects with nasal obstructive symptoms (AN; six males, 62.8 [38-80] years, mean FEV1 56%pred, FEV1/VC 75%).

RESULTS

In all three groups of subjects, mean Rrs,mo and Rrs,na were higher in the supine than sitting posture. In normal subjects the increase in supine Rrs,mo was associated with a 0.6 liter fall in MTLV. In asthma supine Rrs,mo increased despite a much smaller fall in MTLV; supine increases in Rrs,na were particularly large in presence of nasal disease.

DISCUSSION

Values of airflow resistance are 2-3 times higher in both normal and asthmatic subjects when breathing via the nose and supine than under normal laboratory conditions of oral breathing and seated.

Postural changes in lung volumes and respiratory resistance in subjects with obesity

Reduced functional residual capacity (FRC) is consistently found in obese subjects. In 10 obese subjects (mean +/- SE age 49.0 +/- 6 yr, weight 128.4 +/- 8 kg, body mass index 44 +/- 3 kg/m2) without respiratory disease, we examined 1) supine changes in total lung capacity (TLC) and subdivisions, 2) whether values of total respiratory resistance (Rrs) are appropriate for mid-tidal lung volume (MTLV), and 3) estimated resistance of the nasopharyngeal airway (Rnp) in both sitting and supine postures. The results were compared with those of 13 control subjects with body mass indexes of <27 kg/m2. Rrs at 6 Hz was measured by applying forced oscillation at the mouth (Rrs,mo) or the nose (Rrs,na); Rnp was estimated from the difference between sequential measurements of Rrs,mo and Rrs,na. All measurements were made when subjects were seated and when supine. Obese subjects when seated had a restrictive defect with low TLC and FRC-to-TLC ratio; when supine, TLC fell 80 ml and FRC fell only 70 ml compared with a mean supine fall of FRC of 730 ml in control subjects. Values of Rrs,mo and Rrs,na at resting MTLV in obese subjects were about twice those in control subjects in both postures. Relating total respiratory conductance (1/Rrs) to MTLV, the increase in Rrs,mo in obese subjects was only partly explained by their reduced MTLV. Rnp was increased in some obese subjects in both postures. Despite the increased extrapulmonary mass load in obese subjects, further falls in TLC and FRC when supine were negligible. Rrs,mo at isovolume was increased. Further studies are needed to examine the causes of reduced TLC and increases in Rrs,mo and sometimes in Rnp in obese subjects.

Multiphasic Helical CT Criteria for Differentiation of Recurrent Neoplasm and Desmoplastic Reaction after Laparoscopic Resection of Renal Mass Lesions

BACKGROUND AND PURPOSE

Differentiation of recurrent neoplasm and desmoplastic reaction following laparoscopic resection of renal mass lesions poses a problem. The usefulness of multiphasic helical CT-generated criteria based on enhancement and morphologic characteristics was investigated.

PATIENTS AND METHODS

The findings in 5 female and 12 male patients aged 29 to 68 years having renal-cell carcinoma (11-38 mm; N = 15) or solitary angiomyolipomas (N = 2) treated by laparoscopic resection (N = 15) or open segmental surgery (N = 2) were analyzed. Multiphasic helical CT was performed in the preenhancement, arterial corticomedullary, parenchymal, and excretory phases generating 2.5- to 7-mm slices.

RESULTS

Both recurrent neoplasms showed median postcontrast enhancement of 119 HU in the arterial corticomedullary phase; the median enhancement of desmoplastic masses was 48 HU. In the parenchymal and excretory phase, recurrent neoplasms showed progressive loss of enhancement, whereas desmoplastic lesions sustained enhancement at about the same level. Recurrent neoplasms presented a defined mass with characteristic spiculation, whereas desmoplastic reaction was characterized by an ill-defined mass with spidery projections extending to abutting fat and residual fascial planes. On 2- to 3-month follow-up scans, recurrent neoplasms showed progressive increases in size and desmoplastic reaction a sharp decrease.

CONCLUSION

Enhancement of the mass at the operative site on arterial corticomedullary-phase CT to >90 HU strongly suggests recurrent renal-cell carcinoma, while progressive decrease in size on 1- to 3-month follow-up CT suggests a desmoplastic reaction.

Multiphasic Helical CT Diagnosis of Early Medullary and Papillary Necrosis

PURPOSE

The feasibility of identifying early manifestations of renal papillary necrosis (RPN) and medullary necrosis (RMN) on multiphasic helical CT, leading to prompt treatment for the causative conditions, and its impact on reducing the incidence of late-stage RML and RPN, was investigated.

PATIENTS AND METHODS

Sixty-eight patients (35 male, 33 female) aged 19 to 88 years were examined by multiphasic helical CT for complaints of microscopic hematuria (N=49), macroscopic hematuria (N=2), bacteriuria (N=45), pyuria (N=10), fever (N=15), and flank pain (N=27). Preenhancement, arterial corticomedullary, parenchymal, and excretory phase scans generated 1.25 to 7-mm-thick slices. Follow-up CTs were performed at 1 month (N=62) and 3 months (N=58).

RESULTS

While the attenuation coefficients of areas suspect for RMN and RPN were similar on preenhancement CT, they differed substantially on the arterial corticomedullary phase (lesions 55 HU mean; normal medulla 120 HU mean) and parenchymal phase (lesions 58 HU mean, normal medulla 210 HU mean). Investigation for predisposing conditions identified diabetes in 18 patients, upper urinary-tract infections in 48, sickle-cell disease or trait in 17, urinary obstruction in 7, and cirrhosis of the liver in 1. On follow-up examinations, enhancement had normalized in 26 compromised areas of 14 patients at 1 month, and 47 areas (23 patients) at 3 months, remained stationary in 28 patients at 1 month and 9 at 3 months, and progressed in 20 at 1 and 26 at 3 months (P<0.001; Fisher's exact test). Patients (N=35) treated for underlying conditions causing ischemia showed reperfusion in 12 cases at 1 month and 20 at 3 months, while of the untreated patients (N=10), none showed reperfusion, and all lesions increased in size.

CONCLUSIONS

Multiphasic helical CT is recommended for identification of RMN and RPN at a stage when effective treatment of underlying causative conditions can arrest or reverse the process of devascularization and prevent loss of medullary tissue.

Detection of medullary and papillary necrosis at an early stage by multiphasic helical computerized tomography

PURPOSE

Multiphasic helical computerized tomography (CT) is advocated to identify early manifestations of papillary and medullary necrosis based on decreased enhancement of circumscribed areas in the medullary pyramid. At this stage the devascularizing process can be reversed if causative conditions such as infections or diabetes mellitus are effectively treated.

MATERIALS AND METHODS

Multiphasic helical CTs were performed in 31 male and 26 female patients with complaints of microscopic hematuria (41), macroscopic hematuria (2), bacteriuria (39) and pyuria (9). Pre-enhancement, arterial, early corticomedullary, parenchymal and excretory phase helical CTs generated 1.25 to 5 mm. thick slices. Followup examination included multiphasic helical CT at 1 and 3 months, and excretory urography for some patients at 3 months.

RESULTS

Bacteriuria was identified as the probable cause of medullary and papillary necrosis in 39 patients, of whom 28 were treated with effective antibiotic therapy, resulting in normalization and re-perfusion of the initial lesion in 16, no change in 5 and progressive disease in 7 at 3-month followup. Of 8 lesions not treated with specific antibiotic therapy 4 progressed and 4 remained unchanged.

CONCLUSIONS

Multiphasic helical CT unlike the excretory urogram can identify medullary and papillary necrosis at an early stage when effective treatment of the underlying cause can reverse the process of devascularization and prevent sloughing of medullary tissues.

Chemo-ablation of the prostate with dehydrated alcohol for the treatment of prostatic obstruction

PURPOSE

We confirmed clinically whether chemo-ablation of the prostate with absolute ethanol may be an innovative transurethral approach for the relief of obstructive benign prostatic hyperplasia.

METHODS

Using the InjecTx endoscopic device (Injectx Inc., San Jose, California) an initial cohort of 15 patients, including 13 who have now been followed more than 1 year, underwent elective transurethral chemo-ablation of the prostate.

RESULTS

Preoperative and postoperative comparisons of the American Urological Association symptom score, maximum urine flow rate and prostatic volume reveal significant improvement with minimal discomfort and no major complication.

CONCLUSIONS

The InjecTx technique proved encouragingly successful in this initial small-scale clinical trial.

Endourologic management of malignant ureteral strictures

PURPOSE

This retrospective analysis assessed the efficacy of balloon dilatation, endoureterotomy, percutaneous ureteroneocystostomy with stenting, and insertion of Wallstents in the management of malignant ureteral strictures with an intact or compromised vascular supply.

PATIENTS AND METHODS

A series of 127 patients with ureteral strictures secondary to malignancies were assessed after at least 2-year follow-up (range 2-5 years; mean 3.5 years). Balloon dilation (antegrade approach) was applied in 46 patients, endoureterotomy with temporary stenting in 37, percutaneous ureteroneocystostomy with stenting in 34, bougie and stents in 13, and Wallstents in 31.

RESULTS

Balloon dilatation was successful in only two of four malignant midureteral stenoses with intact vascular supplies and was even less successful (10%) in midureteral strictures with a compromised vascular supply. Endoureterotomy failed in all cases to prevent ureteral obstruction. Percutaneous ureteroneocystostomy achieved patency in 11 of 34 patients (33%) having a compromised ureteral vascular supply. Wallstents were successful in 18 of 31 patients (58%) with stenoses of the pelvic ureter.

CONCLUSIONS

Percutaneous ureteroneocystostomy with stenting meets the requirement for palliation in patients with obstruction secondary to pelvic neoplasms. Wallstents proved to be most successful when used in the pelvic ureter.

Endourologic management of benign ureteral strictures with and without compromised vascular supply

OBJECTIVES

To retrospectively assess the efficacy of balloon dilation, endopyelotomy/ureterotomy, and stenting alone in the management of benign ureteral strictures with intact or compromised vascular supply.

METHODS

One hundred fourteen patients with benign ureteral strictures were assessed after at least a 2-year follow-up (range 2 to 16 years, mean 6.3). Balloon dilation was performed in 81, endopyelotomy/ureterotomy with temporary stenting in 27, and ureteral stenting alone in 6 patients. Ureteral strictures were divided into strictures with intact or with compromised vascular supply.

RESULTS

Balloon dilation was successful in short ureteral strictures with intact vascular supply in 33 of 37 (89.2%), but only in 3 of 8 (37.5%) long ureteral strictures and in 1 of 2 (50%) recurrent ureteropelvic junction strictures. Balloon dilation was less successful when the vascular supply was compromised in 2 (40%) of 5 short strictures, 1 (16.7%) of 6 long strictures, and 2 (33.3%) of 6 recurrent ureteropelvic junction strictures. Endopyelotomy/ureterotomy was successful in 17 (89.5%) of 19 strictures with compromised vascular supply.

CONCLUSIONS

Balloon dilation is recommended for management of short strictures with intact vascular supply. Endoureterotomy with stenting is recommended for all long ureteral strictures, for ureteropelvic junction stenoses, and for short ureteral strictures with compromised vascular supply and benign underlying etiology.

Accuracy of diagnosis by guided biopsy of renal mass lesions classified indeterminate by imaging studies

OBJECTIVES

To define the accuracy, safety, and impact of percutaneous biopsies of indeterminate mass lesions as an additional diagnostic tool. The vast majority of renal mass lesions are routinely diagnosed by radiographic features alone. However, with the increased use of computed tomography scanning and ultrasound, many smaller renal masses, which are "indeterminate" (refractory to categorization on the basis of imaging alone), are now being discovered.

METHODS

We retrospectively reviewed 583 patients (364 male and 219 female) with indeterminate renal mass lesions diagnosed by imaging studies that were further investigated by percutaneous biopsy. Patients were followed up for at least 5 years if the biopsy result demonstrated a benign lesion, or they underwent surgical exploration if the biopsy result demonstrated a malignancy. Biopsy or aspiration material was assessed by histopathologic and cytologic evaluation and, when appropriate, with biochemistry, Gram stain, culture, and sensitivity. The biopsy site was localized by computed tomography, ultrasound, or fluoroscopy.

RESULTS

Five hundred eighty-three patients with indeterminate renal mass lesions (representing 7.2% of all renal masses diagnosed from 1967 through 1996) were diagnosed by imaging studies complemented by guided biopsy. Sixty-six patients were lost to follow-up, leaving 517 patients who were analyzed. In 393 cases (76%), the imaging-guided biopsy provided a definitive diagnosis. The incidence of false diagnoses was 1.2% (7 biopsies). In 124 of the cases (21%), imaging-guided biopsy was unable to determine the etiology of the lesion with acceptable confidence; of these, 21 biopsies did not provide enough material to establish the diagnosis (16.9%).

CONCLUSIONS

Overall, percutaneous biopsy of the kidney has proved to be a safe and accurate diagnostic procedure, with impact on the management of cystic or solid renal lesions.

Penile Kaposi's sarcoma preceded by chronic penile lymphoedema

Kaposi's sarcoma localized to the penis with striking lymphoedema is extraordinary. We report a middle-aged Haitian man who was human herpesvirus-8 seropositive, without evidence of immunosuppression or human immunodeficiency virus infection. He was first seen with Kaposi's sarcoma of 6 months duration localized to his penis, preceded by a 3-year history of chronic penile lymphoedema. His tumour regressed completely after radiotherapy. We propose that chronic lymphoedema in this patient predisposed to the development of Kaposi's sarcoma.

Cross-Correlation of Tenerife Data with Galactic Templates-Evidence for Spinning Dust?

The recent discovery of dust-correlated diffuse microwave emission has prompted two rival explanations: free-free emission and spinning dust grains. We present new detections of this component at 10 and 15 GHz by the switched-beam Tenerife experiment. The data show a turnover in the spectrum and thereby support the spinning dust hypothesis. We also present a significant detection of synchrotron radiation at 10 GHz, which is useful for normalizing foreground contamination of cosmic microwave background experiments at high galactic latitudes.

Percutaneous nephrostomy as adjunct management in advanced upper urinary tract infection

OBJECTIVES

To determine by retrospective review of 315 percutaneous nephrostomies, performed for pyonephrosis, whether this intervention has major clinical advantages.

METHODS

From 1977 to 1996, under the direct supervision of the senior author of this report (E.K.L.), at seven hospital sites, 315 patients (181 males, 134 females; 17 to 88 years of age) were treated with percutaneous nephrostomy and antibiotic therapy for infected hydronephrosis.

RESULTS

Additional or disparate pathogens were identified in 116 (36.8%) of 315 patients, leading to a clinically significant change in, or addition of, antibiotics and/or antifungal agents in 84 (73%) of 116. Most notably, we often found a clinically important disparity between the results of cultures obtained from the nephrostomy and those obtained from bladder-urine specimens.

CONCLUSIONS

This retrospective review confirms previously reported advantages of percutaneous upper urinary tract drainage as a potentially life-saving adjunct in the treatment of pyonephrosis. Several case studies highlight the advantage of this maneuver in difficult cases involving obstruction due to extensive fungus or debris. In particular, our review focuses attention on the clinically important insight that urine cultures from percutaneous nephrostomy drainage often identify pathogens that differ from those detected in concurrent bladder cultures.

Placement of metallic stents in ureters obstructed by carcinoma of the cervix to maintain renal function in patients undergoing long-term chemotherapy

OBJECTIVE

Metallic stents, sometimes augmented by "J" endostents, were placed in ureters obstructed by advanced carcinoma of the cervix to improve or maintain renal function in these patients at a level necessary to pursue long-term chemotherapy and radiation therapy.

SUBJECTS AND METHODS

Seventeen ureters in 11 patients were treated with metallic stents, which were placed by an anterograde approach in 10 patients and by a retrograde approach in one. An anterograde ureteroneocystostomy was necessary in two of the 11 patients. J endostents were placed for I month in all patients. In 10 ureters, J endostents were reintroduced during follow-up 1-48 months later.

RESULTS

In 17 ureters, metallic stents were successfully placed; in the remaining three ureters, the procedures were aborted because of technical difficulties. The goal of improving and maintaining renal function was met in 10 patients. Serum creatinine levels returned to normal in four patients and stabilized at a range of 2.7-3.2 mg/dl in six more patients, permitting treatment with chemotherapy, radiation therapy, or both. Four of the 11 patients died within 4 months after treatment, and three more died within 2 years. At the time of death or last follow-up, seven metallic stents and eight combinations of metallic stents and J endostents were patent. Complications were minor.

CONCLUSION

Placement of metallic stents is recommended as an effective method to ensure patency and to facilitate cystoscopic replacement of J endostents in ureters compromised by carcinoma of the cervix. Renal function can be maintained, allowing chemotherapy. Survival is governed by the effectiveness of chemotherapy and radiation therapy.

Use of mouth pressure twitches induced by cervical magnetic stimulation to assess voluntary activation of the diaphragm

There is a need for a simple method to assess the adequacy of diaphragm activation during voluntary inspiratory efforts in patients with suspected respiratory muscle weakness. We have compared mouth (Pmo,t), oesophageal (Poes,t) and transdiaphragmatic (Pdi,t) twitch pressure elicited by cervical magnetic stimulation (CMS) in five normal men (mean (SD) age 32.2 (1.8) yrs) on two separate study days. Single magnetic stimuli were delivered at functional residual capacity during relaxation and during graded voluntary inspiratory efforts against a closed airway. As voluntary-effort transdiaphragmatic and oesophageal pressure increased, Pdi,t and Poes,t decreased linearly (r range, respectively, 0.82-0.98 and 0.87-0.95). During relaxation, Pmo,t was unreliable due to the poor transmission of intrathoracic pressure, but during inspiratory efforts, the relation between voluntary mouth pressure and Pmo,t was also linear (r range 0.84-0.95). On average, our subjects voluntarily generated 99, 100 and 102% of the maximum transdiaphragmatic, oesophageal and mouth pressures predicted by the respective linear regression equations. Pmo,t was correlated to both Poes,t and Pdi,t during inspiratory efforts, but not during relaxation. These studies confirm that twitch pressures induced by CMS during inspiratory efforts can be assessed at the mouth in normal subjects, providing a simple and non-invasive technique for assessing diaphragm activation during voluntary inspiratory efforts. Potentially, this technique could be made more sensitive and accurate and applied to detect submaximal efforts in patients.

Abdominal compartment syndrome

BACKGROUND

The abdominal compartment syndrome (ACS) is a newly appreciated and potentially fatal consequence of increased intra-abdominal pressure. It can be due to either trauma or surgery, as well as numerous medical conditions. Prolonged, unrelieved elevation of intra-abdominal pressure can produce pulmonary compromise, renal impairment, cardiac failure, shock, and death. A high index of suspicion is imperative. Measurement of the intravesical pressure provides a urometric window for detecting and monitoring this condition.

CONCLUSIONS

Reopening the abdominal incision (decompressive celiotomy) has proven a life-saving intervention. Use of delayed wound closure (staged celiotomy) may prevent development of this condition in high-risk surgical patients. It is urgent that all physicians, and surgeons in particular, be alerted to this potentially lethal complication.

Use of nasal peak flow to assess nasal patency

Nasal patency is usually assessed in the laboratory by measuring nasal airflow conductance (Gnaw); peak inspiratory and/or expiratory flow measurements via the nose (PIFna, PEFna) have been proposed as simple alternatives suitable for home monitoring of rhinitis. We have compared the scale of changes in PIFna and PEFna (measured with a pneumotachograph) with changes in Gnaw (measured by the forced-oscillation technique) when nasal patency was increased by a topical alpha-adrenergic agonist, xylometazoline (five control subjects, seven with seasonal rhinitis, studied when asymptomatic) or decreased by topical histamine (eight control subjects). In further experiments, we altered intrapulmonary airway calibre by having subjects inhale histamine or salbutamol aerosols and examined effects on the configuration of nasal flow-volume curves (six subjects with rhinitis and mild asthma). After topical xylometazoline, there was a mean 283% increase in Gnaw, 80% increase in PEFna, and 63% increase in PIFna. After topical histamine, there was a mean 72% decrease in Gnaw, 38% decrease in PEFna, and 39% decrease in PIFna. Inducing intrapulmonary airway obstruction sometimes obscured changes in nasal patency by removing the effects of added nasal resistance on expiration and preventing development of flow limitation in the nose on inspiration. Thus, after topical drug treatment to the nose, changes in Gnaw were considerably larger than in PEFna or PIFna, which were proportionately similar. Because PIFna is usually restricted by nasal flow limitation, it is probably superior to PEFna for assessing nasal patency. When effort is submaximal, intrapulmonary dynamic resistance is increased, or nasal dynamic resistance is low, PEFna and PIFna can give a misleading impression of nasal patency. These errors can be avoided by comparisons with mouth PEF and/or PIF, suggesting that nasal and mouth peak flow should both be measured during home monitoring.

Incidence of stool guaiac conversion following extracorporeal shock wave lithotripsy

OBJECTIVES

To study, in a prospective fashion, acute traumatic effects on the gastrointestinal tract of patients treated by extracorporeal shock wave lithotripsy (ESWL).

METHODS

Stool samples from each of 54 patients were tested before and after ESWL for conversion to hemoccult positive. A minimum of one negative pre-ESWL stool guaiac test was required for inclusion into the study. A minimum of two stool guaiac tests were done after ESWL to verify negativity. Patients who converted to a positive hemoccult test after ESWL were then evaluated by colonoscopy for the source of bleeding.

RESULTS

Fifty patients completed the study. A single patient (2.0%) converted to a positive post-ESWL hemoccult test and was evaluated with colonoscopy. This patient was found to have two benign adenomatous polyps in the sigmoid and descending colon after treatment for a left renal pelvis calculus. An additional patient with a slightly positive post-ESWL conversion refused further evaluation. The overall post-ESWL conversion rate to guaiac positive, therefore, was less than 4% (2 of 51 patients).

CONCLUSIONS

There is no evidence of significant trauma or detectable bleeding in the normal gastrointestinal tract caused by ESWL as measured by postprocedure stool guaiac testing. Guaiac testing of the stool after ESWL may unmask pre-existing gastrointestinal disease. Therefore a positive guaiac test after ESWL warrants further evaluation. This study reaffirms that ESWL is a safe, minimally invasive technique for the treatment of urolithiasis, without significant adverse side effects on the gastrointestinal tract.

Effects of posture on respiratory mechanics in obesity

Increased abdominal mass in obesity should enhance normal gravitational effects on supine respiratory mechanics. We have examined respiratory impedance (forced oscillation over 4-26 Hz applied at the mouth during tidal breathing), maximum inspiratory and expiratory mouth pressures (MIP and MEP), and maximum effort flow-volume curves seated and supine in seven obese subjects (O) (mean age 51 yr, body mass index 43.6 kg/m2) and seven control subjects (C) (mean age 50 yr, body mass index 21.8 kg/m2). Seated mean total lung capacity was smaller in O than in C (82 vs. 100% of predicted); ratio of functional residual capacity (FRC) to total lung capacity averaged 43% in O and 61% in C (P < 0.01). Total respiratory resistance (Rrs) at 6 Hz seated was higher in O (4.6 cmH2O.l-1.s) than in C (2.2 cmH2O.l-1.s; P < 0.001); total respiratory reactance (Xrs) at 6 Hz was lower in O than in C. In C, on changing to the supine posture, mean Rrs at 6 Hz rose to 2.9 cmH2O.l-1.s, FRC fell by 0.68 liter, and Xrs at 6 Hz showed a small fall. In O, despite no further fall in FRC, supine Rrs at 6 Hz increased to 7.3 cmH2O.l-1.s, and marked frequency dependency of Rrs and falls in Xrs developed. Seated, MIP and MEP in C and O were similar; supine there were small falls in MEP and maximum expiratory flow in O. The site and mechanism of the increase in supine Rrs and reduction in supine Xrs and the mechanism maintaining supine FRC in obesity all need further investigation.

Comparison of four methods of assessing airflow resistance before and after induced airway narrowing in normal subjects

Four methods for assessing airflow resistance were compared in seven normal adults at baseline and after inducing airway narrowing with inhaled methacholine. Airway resistance (Raw) was measured during panting at 1-2 Hz within a body plethysmograph; total lung resistance was measured by using an esophageal balloon during quiet breathing (RLq) and with doubling of frequency while maintaining the original tidal volume; total respiratory resistance (Rrs) was measured at 6 Hz during forced oscillation applied at the airway opening, and interruption resistance (Rint) was measured at midtidal expiratory flow. Three methods of obtaining Rint after airflow interruption were compared [smooth curve fit of mouth pressure (Pm) back extrapolated to valve closure; two-point linear fit of Pm back extrapolated to 15 ms after closure; and Pm at 100 ms after valve closure]. We found similar basal median values (cmH2O.l-1.s) of Raw (1.3), RLq (1.4), RL of double resting frequency (1.9), Rrs (1.7), and smooth curve fit of Pm back extrapolated to valve closure (1.5); basal values of two-point linear fit of Pm back extrapolated to 15 ms after closure (2.4) and Pm at 100 ms after valve closure (4.4) were considerably larger. After induced airway narrowing, all methods of measuring resistance showed significant increases; these were largest with RLq (median %change of 265) and smallest with the three Rint methods (median %change of 62-72). Rint and Rrs methods had poorer sensitivity for detecting bronchoconstriction than lung resistance of Raw. Of the Rint methods, end interruption pressure was the most sensitive.(ABSTRACT TRUNCATED AT 250 WORDS)

Reflections on the Rorschach and the Millon Adolescent Personality Inventory

Although no significant relationships were found between presence of Rorschach reflection responses and scores on Millon Adolescent Personality Inventory Scales 5 and 6 of 26 boys and 30 girls who were psychiatric inpatients, significant differences within the reflection group were found for diagnosis on Scale 5.

Accuracy and sensitivity of the interrupter technique for measuring the response to bronchial challenge in normal subjects

The interrupter technique is a non-invasive method for measuring airway calibre. Since the calculation of interrupter resistance (Rint) is critically dependent upon the analysis of the mouth pressure/time (Pmo(t)) curve obtained after flow interruption, we wanted to assess the relative merits of four different analyses of Pmo(t) curves, obtained under basal conditions and following methacholine-induced airway narrowing, in 10 healthy adults. Four methods of analysing the Pmo(t) curves were used to calculate Rint values: RintC-a smooth curve fit with back-extrapolation; RintL-two-point linear fit with back-extrapolation; RintEO-calculated from the pressure change after the post-interruption oscillations had decayed (end-oscillation); and RintEI-calculated from the pressure change at the end of the period of interruption. The airway response measured with the four Rint methods was compared with plethysmographic airway resistance (Raw). The sensitivity of the methods was determined by calculating a sensitivity index (SI), the change in resistance after challenge expressed in multiples of baseline standard deviation. Values of RintC were similar to Raw values under all conditions. Resistance values from the remaining Rint methods significantly exceeded Raw (mean basal difference: 0.13-0.34 kPa.l-1 x s; mean difference after challenge: 0.12-0.42 kPa.l-1 x s. Raw was the most sensitive method for detecting bronchoconstriction (doubling of Raw was equivalent to SI of 10.5). Of the Rint methods, RintEI gave the highest sensitivity index (SI = 3.1), with a 42% mean change; RintC produced the greatest proportionate change after challenge (55%), but with a lower SI (2.2).(ABSTRACT TRUNCATED AT 250 WORDS)

Accuracy and sensitivity of the interrupter technique for measuring the response to bronchial challenge in normal subjects

The interrupter technique is a non-invasive method for measuring airway calibre. Since the calculation of interrupter resistance (Rint) is critically dependent upon the analysis of the mouth pressure/time (Pmo(t)) curve obtained after flow interruption, we wanted to assess the relative merits of four different analyses of Pmo(t) curves, obtained under basal conditions and following methacholine-induced airway narrowing, in 10 healthy adults. Four methods of analysing the Pmo(t) curves were used to calculate Rint values: RintC-a smooth curve fit with back-extrapolation; RintL-two-point linear fit with back-extrapolation; RintEO-calculated from the pressure change after the post-interruption oscillations had decayed (end-oscillation); and RintEI-calculated from the pressure change at the end of the period of interruption. The airway response measured with the four Rint methods was compared with plethysmographic airway resistance (Raw). The sensitivity of the methods was determined by calculating a sensitivity index (SI), the change in resistance after challenge expressed in multiples of baseline standard deviation. Values of RintC were similar to Raw values under all conditions. Resistance values from the remaining Rint methods significantly exceeded Raw (mean basal difference: 0.13-0.34 kPa.l-1 x s; mean difference after challenge: 0.12-0.42 kPa.l-1 x s. Raw was the most sensitive method for detecting bronchoconstriction (doubling of Raw was equivalent to SI of 10.5). Of the Rint methods, RintEI gave the highest sensitivity index (SI = 3.1), with a 42% mean change; RintC produced the greatest proportionate change after challenge (55%), but with a lower SI (2.2).(ABSTRACT TRUNCATED AT 250 WORDS)

Paratesticular fibrous pseudotumor in a patient with Gorlin's syndrome: nevoid basal cell carcinoma syndrome

An 18-year-old man with Gorlin's syndrome (the nevoid basal cell carcinoma syndrome) underwent excisional biopsy of a fibrous pseudotumor of the tunica vaginalis. Preoperative ultrasound confirmed the extraparenchymal nature of this paratesticular lesion, permitting a transscrotal approach. The pathophysiological considerations suggest that this finding (to our knowledge the first such case reported in association with Gorlin's syndrome) may be more than coincidental.

Interaction of unfused tricyclic aromatic cations with DNA: a new class of intercalators

Unfused tricyclic aromatic ring systems 1-6 with one or two cationic side chains have been synthesized and their interactions with DNA and synthetic polymers probed with a variety of techniques. Molecular mechanics calculations indicate that the torsional angle between ring planes in the minimum energy conformation of the tricyclic molecules can range from 0 degree to as high as 50 degrees depending on the type of rings and substituents. Viscometric titrations with linear and supercoiled DNA, linear dichroism, and NMR studies indicated that all compounds with torsional angles of approximately 20 degrees or less bind to DNA by intercalation. The more highly twisted intercalators caused significant perturbation of DNA structure. Unfused intercalators with twist angles of approximately 20 degrees have reduced binding constants, suggesting that they could not form an optimum interaction with the DNA base pairs. Unfused intercalators with twist less than 20 degrees formed strong complexes with DNA. The structures of these unfused intercalators are more analogous to typical groove-binding molecules, and an analysis of their interaction with DNA provides a better understanding of the subtle differences between intercalation and groove-binding modes for aromatic cations. The results indicate that intercalation and groove-binding modes should be viewed as two potential wells on a continuous energy surface. The results also suggest design strategies for intercalators that can optimally complement DNA base pair propeller twist or that can induce bends in DNA at the intercalation site.

Molecular basis for bleomycin amplification: conformational and stereoelectronic effects in unfused amplifiers

Sixteen unfused heterobiaromatic and biphenyl compounds substituted with an amino side chain (protonated in water) have been tested for (i) binding with DNA and (ii) their effect on the digestion of the DNA double helix by a bleomycin-iron complex. Only the DNA intercalating molecules amplify the digestion of DNA. One 2,2'-bipyridine derivative tested is an inhibitor of the bleomycin reaction because it removes ferrous ion from the bleomycin complex. Polarity of the intercalating unfused biaromatic system is of primary importance for effective binding of the molecule with native DNA and, at the same time, for its amplification activity. The molecules that have the biaromatic system polarized extensively in the direction of the side cationic chain, so that the intercalating sites constitutes a positive part of the dipole, show strong binding with DNA and good amplification activity. For strong intercalative forces that determine the amplification activity, it is important that both the heteroaromatic subsystems of the molecule have positive ends of their dipoles positioned away from the side chain. This work provides general guidelines for synthesis of new highly effective bleomycin amplifiers.

Selective catalysis of A.T base pair proton exchange in DNA complexes: imino proton NMR analysis

Polyaromatic molecules with amino chain substituents, upon binding with DNA, selectively catalyze exchange of the A.T base pair protons with bulk water protons. The amine-catalyzed exchange is mediated by compounds which are A.T and G.C base sequence specific, intercalators, and outside binders. A mechanism for the selective exchange, involving transient opening and closing of individual A.T base pairs in the duplex, is discussed.

Home hyperalimentation for common variable hypogammaglobulinemia with malabsorption secondary to intestinal nodular lymphoid hyperplasia

Common variable hypogammaglobulinemia (immunodeficiency), a disorder characterized by late-onset immunoglobulin deficiency and lack of humoral immunity, has a variable association with bronchiectasis, cholelithiasis, nodular lymphoid hyperplasia, gastrointestinal neoplasia, megaloblastic anemia, and malabsorption. The patient described in this report had all of the above except neoplasia. In addition, he had calcium oxalate renal stones probably secondary to his malabsorption. The first case demonstrating the beneficial effect of home hyperalimentation in patients with severe malabsorption refractory to other treatments is described. Home hyperalimentation overnight allows the patient freedom for daily activities while also being more cost-effective than in-hospital parenteral nutrition.

Amplification of bleomycin-mediated degradation of DNA

Three simple and independent tests have been introduced for studying the effect of DNA intercalating compounds on the bleomycin-mediated digestion of DNA in vitro. These methods are based on hyperchromic changes of DNA solution, changes in viscosity of DNA solution, and HPLC quantitative analysis of the four bases released from digested DNA. All three tests give comparable results. However, the viscometric method is technically the simplest and at the same time the most sensitive. The amplification of the bleomycin-mediated degradation of DNA by three unfused heteropolyaromatic intercalator molecules, namely N-[2''-(dimethylamino)ethyl]-4-thien-2'-ylpyrimidin-2-amine (1N), N,N-dimethyl-2-[(4'-thien-2''-ylpyrimidin-2'-yl)thio] ethylamine (1S), and newly synthesized 2,5-bis[2'-[[2''-(dimethylamino)ethyl]thio]pyrimidin-4'yl]thiophene (2) correlates well with the respective DNA binding constants for these compounds and is concentration dependent. The amplification activity of these compounds increases with increasing concentrations. The strongly binding compound 2 is the best amplifier of bleomycin in vitro found so far. Fused heteropolyaromatic systems, like ethidium bromide, are modest amplifiers of bleomycin at low concentrations but strongly inhibit the bleomycin chemistry at high concentrations.