Bernstein-Greene-Kruskal modes in a three-dimensional plasma

Bernstein-Greene-Kruskal modes in a three-dimensional (3D) unmagnetized plasma are constructed. It is shown that 3D solutions that depend only on energy do not exist. However, 3D solutions that depend on energy and additional constants of motion (such as angular momentum) do exist. Exact analytical as well as numerical solutions are constructed assuming spherical symmetry, and their properties are contrasted with those of 1D solutions. Possible extensions to solutions with cylindrical symmetry with or without a finite magnetic guide field are discussed.

Extracolonic findings in patients undergoing abdomino-pelvic CT for suspected colorectal carcinoma in the frail and disabled patient

AIM

The aims of this study were to evaluate the extracolonic findings identified in patients undergoing minimal preparation abdomino-pelvic CT in place of barium enema or colonoscopy for the detection of possible colorectal carcinoma.

MATERIALS AND METHODS

The CT technique involved helical acquisition (10 mm collimation, 1.5 pitch) following 2 days of preparation with oral contrast medium only. Extracolonic findings were evaluated in the light of subsequent follow-up and accuracy. The evaluation included assessment of the potential contribution of the extracolonic finding(s) to staging the cancer in the subset of patients who had colorectal carcinoma, and to account for the patients' presenting symptoms and signs in the remaining patients.

RESULTS

A total of 344 extracolonic findings were detected in 261 CT examinations, from amongst a total of 1077 cases (24%). Extracolonic findings were potentially important in staging in 32 of the 98 (33%) cases subsequently found to have colorectal cancer. There were 284 extracolonic findings amongst the 221 cases who proved not have colorectal cancer. One hundred and twenty-four (44%) of these 284 findings were actively followed up by clinicians, and 33 (12%) ultimately had a surgical intervention. Fifty-six percent (160/284) of the findings were determined to be correct (by further investigation, autopsy, and/or clinical follow-up); the remainder were incorrect or indeterminate (n = 56) or had no follow-up (n = 68). The commonest extracolonic findings were focal liver lesions (found in 42/1077, 4%) and abdominal aortic aneurysms (31/1077, 3%). Twenty-four (24/1077, 2%) previously unknown extracolonic malignancies were detected. Ten percent (106/1077) of the patients had extracolonic findings that could potentially have accounted for their presenting symptoms.

CONCLUSIONS

CT has the added benefit, compared with colonoscopy and barium enema, of not just evaluating the colon but also of detecting extracolonic abnormalities. Such findings may be useful in staging the cancer, may explain the patient's presenting symptoms, and may detect other potentially serious disorders.

The use of intradepartmental audit to contain cesarean section rate

In one department practicing critical review of indications for cesarean delivery, the overall LSCS rate was maintained at 12.3%, 11.1%, 11.2% and 11.4% for 1987, 1988, 1989 and 1990, respectively. A highly significant (P = 0.0013) reduction of 26.8% was observed in the LSCS rate for cephalo-pelvic disproportion between 1987 and 1990. Perinatal mortality rate per 1000 births remained low at 8.25, 7.05, 9.39 and 5.83 for infants weighing 500 g or more.

Complete spectrum of kinetic eigenmodes for plasma oscillations in a weakly collisional plasma

Kinetic eigenmodes of plasma oscillations in a weakly collisional plasma, described by a collision operator of the Fokker-Planck type, are obtained in closed form for initial-value as well as for boundary-value problems. These eigenmodes, which are smooth and compose a complete discrete spectrum, play the same role for weakly collisional plasmas as the Case-Van Kampen modes do for collisionless plasmas.

Ringworm causing childhood preseptal cellulitis

A 4-year-old girl had redness and swelling of the left upper eyelid of 1 week's duration. She had been treated with topical fusidic add and oral flucloxacillin without resolution. Ophthalmic examination showed a diffuse, erythematous, tender lesion affecting the entire upper eyelid. There was a central area of skin ulceration with marked bleeding and discharge. Also found were small vesicles under the left eyebrow. The child's mother had noticed a scaly rash on her own forearm. Examination under anesthesia was carried out to assess the globe and to obtain samples for microbiology investigation. Microbiology scrapings showed fungal hyphae of the Dermatophyte group. Treatment with Griseofulvin was commenced, and complete resolution of the lesion occurred. To our knowledge there is only one similar case reported in the literature describing ring-worm as a cause of preseptal cellulitis. This case highlights the importance of considering alternative diagnoses when standard antibiotic treatment has failed.

Unusual causes of colonic wall thickening on computed tomography

Computed tomography (CT) appearances in "colitis" are often non-specific, and include mural thickening and mesenteric fat stranding. In the western world, the majority of cases will have, or be subsequently diagnosed with, inflammatory bowel disease, pseudomembranous colitis or ischaemic colitis. However, other rare conditions may also produce these rather non-specific signs. We present a number of cases demonstrating colonic wall thickening on CT due to rarer diagnoses, which are correlated with the histopathological features. Some of these CT appearances have not been described previously in the literature.

The impact of helical computed tomography on the diagnosis of unsuspected inflammatory bowel disease in the large bowel

Inflammatory bowel diseases (IBD) are diagnoses that can be easily overlooked clinically. The aim of this study was to investigate if CT is able to make a contribution to the identification of previously unsuspected cases of IBD. We retrospectively identified cases in which the possibility of an IBD was raised in CT reports (over a 4-year period), by utilising a keyword search of the radiology database. Cases with a previously known or suspected IBD were rigorously excluded by review of case notes, and endoscopic, radiological, histological and microbiological findings. The CT images of the identified cases were reviewed by a blinded observer to document the extent of bowel wall thickening, the location of lesion(s), and presence of peri-colic fat abnormality, ascites and/or collections. The observer also attempted to corroborate the presence, and to identify the type, of IBD based on the CT appearances alone. Thirty-five cases (out of approximately 19,000 body CTs performed) of clinically unsuspected IBD were identified, of which 27 underwent further investigation. An IBD was confirmed in 48% (13 of 27): Crohn's disease (n=6), ulcerative colitis (n=2), pseudomembranous colitis (n=3) and other (n=2), of which 70% (9 of 13) were correctly typed by the reviewer. Inflammatory bowel disease was not substantiated in the remainder (14 of 27), although 7 of these had other bowel pathologies: diverticular disease (n=4); and carcinoma (n=3). Prospectively determining the presence, and furthermore type, of IBD on CT is challenging largely because of the considerable overlap in the appearances of the individual IBDs and indeed of normality. Nevertheless, CT is able to identify clinically unsuspected cases and radiologists should be alert to this treatable and not infrequently elusive diagnosis.

Evaluation of CT in identifying colorectal carcinoma in the frail and disabled patient

Frail and physically or mentally disabled patients frequently have difficulty in tolerating formal colonic investigations. The aims of this study were to evaluate the accuracy of minimal-preparation CT in identifying colorectal carcinoma in this population and to determine the clinical indications and radiological signs with the highest yield for tumour. The CT technique involved helical acquisition (10-mm collimation, 1.5 pitch) following 2 days of preparation with oral contrast medium only. The outcome of 4 years of experience was retrospectively reviewed. The gold standards were pathological and cancer registration records, together with colonoscopy and barium enema when undertaken, with a minimum of 15 months follow-up. One thousand seventy-seven CT studies in 1031 patients (median age 80 years) were evaluated. CT correctly identified 83 of the 98 colorectal carcinomas in this group but missed 15 cases; sensitivity and specificity (with 95% confidence interval) 85% (78-92%) and 91% (90-93%), respectively. Multivariate analysis identified: (a) a palpable abdominal mass and anaemia to be the strongest clinical indications, particularly in combination (p<0.0025); and (b) lesion width and blurring of the serosal margin of lesions to be associated with tumours (p<0.0001). Computed tomography has a valuable role in the investigation of frail and otherwise disabled patients with symptoms suspicious for a colonic neoplasm. Although interpretation can be difficult, the technique is able to exclude malignancy with good accuracy.

Appendicitis: spectrum of appearances on helical CT

Acute appendicitis has extremely varied clinical presentations. A delayed or missed diagnosis may result in severe adverse consequences. Helical CT is evolving as an important diagnostic aid, but the CT signs can be varied and can easily be overlooked by the unwary. This pictorial review illustrates the spectrum of radiological signs and appearances of appendicitis on helical CT.

Caecal carcinomas in the elderly: useful signs in minimal preparation CT

OBJECTIVE

Frail, elderly and immobile patients frequently have difficulty in tolerating formal colonic investigations. Caecal tumours may account for up to 35% of colonic tumours. Barium enema and colonoscopy have limitations in assessing this region. The aims of this study were to evaluate the accuracy of a minimal preparation CT technique (merely with prolonged oral contrast medium) in identifying caecal carcinomas and to determine helpful radiological signs.

MATERIALS AND METHODS

The CT technique involved helical acquisition following 2 days of preparation with oral contrast medium. The outcome of 4 years' experience (1995-1998) was reviewed. The gold-standards were pathological and cancer registration records, together with colonoscopy and barium enema where available, with a minimum of 15 months' follow-up.

RESULTS

CT correctly identified 27 of 30 caecal carcinomas, and missed three, in a total of 1077 CT studies in 1031 patients (median age 80 years). There were also 21 false-positive cases in which CT incorrectly raised the possibility of a caecal tumour. The sensitivity, specificity, negative predictive value (NPV) and positive predictive value (PPV) were 90%, 98%, 99% and 56%, respectively. Serosal margin blurring, tumour length, presence of abnormal peri-colic fat and terminal ileal wall thickening were identified as useful radiological signs.

CONCLUSIONS

Minimal preparation CT is able to identify caecal carcinomas with fair accuracy. Such evaluation may become important given the increasing population age and evidence of a 'proximal shift' in the site of colonic tumours in the elderly.

Histopathological correlates of abnormal pericolic fat on CT in the assessment of colorectal carcinoma

The aim of this study was to assess the pathological significance of abnormal pericolic fat shown by CT in the context of colorectal carcinoma. CT and histopathological findings of 63 resected colorectal carcinomas were retrospectively reviewed. CT examinations were assessed by two observers for the presence or absence of abnormal pericolic fat (typically linear or nodular opacities) at tumour sites. Specimens were reviewed histopathologically for depth of tumour invasion, extramuscular tissue reaction, and number and largest size of tumour-involved and tumour-free lymph nodes. The sensitivity, specificity, positive predictive value and negative predictive value of pericolic fat in identifying extension of tumour infiltration beyond the muscle coat were 79% (42/53), 33% (2/6), 91% (42/46) and 15% (2/13), respectively. Despite these indicators of efficacy, the association between the presence of pericolic fat abnormality on CT and extramuscular extension of tumour (infiltration and/or nodal disease) or tissue reaction alone or in combination did not reach statistical significance (p>0.3 in all cases). Abnormal ("misty" or "mucky") pericolic fat in the assessment of colorectal cancer on CT is not a precise indicator of extramuscular extension of tumour, as it cannot clearly distinguish between tumour infiltration and tissue reaction beyond the muscle coat, or pericolic nodal involvement. However, it is a very helpful CT sign that may draw attention to the presence and site of a potential colonic abnormality.

Giant pulmonary bulla

The present report describes a case of a giant pulmonary bulla in a 32-year-old man that progressed to occupy almost the entire left hemithorax. This report is unique in documenting the natural history of progression of this condition. Bullectomy was performed using the video-assisted thoracoscopic surgery approach.

Evaluation of ultra-thin poly(epsilon-caprolactone) films for tissue-engineered skin

Various natural and synthetic polymeric materials have been used as scaffold matrices for tissue-engineered skin. However, the commercially available skin replacement products pose problems of poor mechanical properties and immunological rejection. We have thus developed a film of 5 microm thickness, via biaxial stretching of poly(epsilon-caprolactone) (PCL), as a potential matrix for living skin replacements. The aim of this study was to evaluate the feasibility of using biaxially stretched PCL films as matrices for culturing human dermal fibroblasts. For this purpose, we cultured human dermal fibroblasts for 7 days on the films. Glass cover slips and polyurethane (PU) sheets were used as controls. The data from phase contrast light, confocal laser, and scanning electron microscopy suggested that biaxially stretched PCL films support the attachment and proliferation of human dermal fibroblasts. Thymidine-labeling results showed quantitatively that cell proliferation on the PCL films was superior to that on the PU samples. These results indicated that biaxially stretched PCL films supported the growth of human dermal fibroblasts and might have potential to be applied in tissue engineering a dermal equivalent or skin graft.

Human papillomavirus infection in non-neoplastic uterine cervical disease in Hong Kong

The polymerase chain reaction (PCR) was used to detect and identify human papillomavirus (HPV) in 108 cases of formalin-fixed, paraffin-embedded, non-neoplastic uterine cervical biopsy tissue retrieved from the surgical pathology archives of the Department of Pathology, Caritas Medical Centre, Hong Kong. After DNA extraction, HPV L1 gene primers were used to detect the presence of HPV, and type-specific primers (to HPV types 6, 11, 16, 18, 31 and 33) were used to identify the specific HPV type on HPV L1-positive cases. PCR amplification of the beta-globin gene was used to ensure the quality of amplifiable DNA extracted. Of 94 cases that yielded sufficient good-quality DNA for PCR analysis, three (one endocervical polyp, one chronic inflammation with erosion, and a normal biopsy) had detectable HPV infection. Two of these had high-risk HPV type 16; the other had an uncommon HPV type. In view of the low incidence of HPV found in these patients, large-scale population screening of clinical samples using PCR to detect the presence of HPV and identify high-risk asymptomatic patients would not be cost-effective.

Medical and surgical therapy of the cystine stone patient

Cystinuria is an inherited defect in renal tubular and intestinal transport of dibasic amino acids that results in elevated urinary excretion of cystine, ornithine, lysine, and arginine. The only clinical manifestation of this disease is the development of urinary tract cystine calculi. Cystinuric patients suffer recurrent stone episodes, requiring an aggressive multi-modal approach to management. This article reviews the results of medical prevention regimens, the role of minimally invasive urologic intervention, and the recent insights into the complex genetic basis for the varied cystinuric phenotypes.

Unusual 1/r-dependent radiation intensity in any biaxial crystal

Lighthill's prediction of an unusual 1/r-dependent radiation intensity from a small monochromatic source is found to exist in any homogeneous and lossless biaxial crystal along the two optical ray axes, where r is the radial distance from the source. This is a consequence of the special shape of the wave-vector surface on which there is, around each singular point of self-intersection (or "dimple"), a circular locus of points all having the same surface normal direction and thus sharing a common tangent plane. A heuristic derivation of the result is given and a simple optical experiment is proposed to detect such an unusual distance dependence.

Thoracoscopy in the management of pneumothorax

Spontaneous pneumothorax is a common condition that impacts significantly on healthcare expenditure. However, optimal management of spontaneous pneumothorax remains a subject of considerable controversy. A thoracic surgeon's perspective on the use of thoracoscopy and video-assisted thoracic surgery with a focus on surgical techniques in the current management of this condition is presented.

Subcutaneous panniculitis-like T-cell lymphoma: an elusive case presenting as lipomembranous panniculitis and a review of 72 cases in the literature

We present a remarkable case of subcutaneous panniculitic T-cell lymphoma (SPTL) that eluded diagnosis for 14 years and illustrates the importance of continued follow-up with repeat biopsy when SPTL is suspected. This case is unusual in that multiple biopsies demonstrated either a nonspecific panniculitis or lipomembranous panniculitis with calcified lipomembranes. A clinicopathologic review of 72 cases of SPTL from the English language literature is also presented, and approaches to diagnosis and treatment are reviewed.

Incidence of concomitant procedures for pelvic organ prolapse and reconstruction in women who undergo surgery for stress urinary incontinence

OBJECTIVES

To determine the incidence of concomitant procedures performed for pelvic organ prolapse or vaginal reconstruction at the time of surgery for stress urinary incontinence in contemporary practice.

METHODS

We recorded all concomitant procedures for pelvic organ prolapse or vaginal reconstruction in 264 women who underwent surgery for stress urinary incontinence at our institution from January 1995 to August 1997.

RESULTS

Of 264 women, 111 (42%) had at least one concomitant procedure performed for pelvic organ prolapse or vaginal reconstruction, including 87 cystocele repairs, 31 rectocele repairs, 8 sacrospinous fixations, 5 enterocele repairs, 5 abdominal sacrocolpopexies, 4 perineoplasties, 3 urethral diverticulectomies, and 1 vaginal hysterectomy. Furthermore, 9% of patients had two or more procedures.

CONCLUSIONS

We found that women who undergo surgery for stress urinary incontinence have a high incidence (42%) of associated pelvic organ prolapse requiring surgical repair. These additional repairs contribute to the overall success of surgery and should not be overlooked.