Display and visualization of three-dimensional reconstructed anatomic morphology: experience with the thorax, heart, and coronary vasculature of dogs.

A new method, termed reprojection, is used to visualize anatomic morphology contained within three-dimensional reconstructions made up of images of multiple parallel cross sections. This method involves the projection, either orthographically into a plane or radially onto a cylinder, of the volume picture elements (voxels) of the reconstruction. Orthographic reprojection images, formed by mathematically summing the magnitudes of the voxels along selected parallel paths through the reconstructed volume, are analagous to conventional radiographs formed by the passage of an X-ray beam through the volume. The reprojection image is a two-dimensional array of picture elements that is displayed on a television monitor using a digital-to-video scan converter. Also described are the techniques of noninvasive selective tissue dissolution and numerical dissection, whereby obscuring portions of the reconstructed volume are either partially "dissolved" or totally eliminated before reprojection. Utilizing these methods, anatomic information present in a three-dimensional reconstruction but not clearly seen in a reprojection image is rendered visible after removal of superposed structures. The usefulness of these methods is demonstrated utilizing three-dimensional reconstructions of the thorax, heart, and coronary arteries of dogs.     

Changes in the N- and C-terminal sequences of the murine R7 Gag-tMos protein affect brain lesion induction

Our preliminary studies suggested that the novel gag-truncated mos (tmos) open reading frame (ORF) of R7, a spontaneous deletion mutant of Moloney murine sarcoma virus 124 (MoMuSV124), may be responsible for R7's unique ability to induce brain lesions in all R7-injected mice. However, when we replaced the gag-tmos ORF with either the MoMuSV124 or the homologous myeloproliferative sarcoma virus env-mos gene, we found that both recombinant viruses also induced brain lesions in all injected mice. Although these studies suggested that the critical determinants for brain lesion induction may reside in the tmos sequence common to all three viruses, they did not demonstrate if the N-terminus of Mos was dispensable for this activity. By inserting the FLAG sequence at the 3' end of the R7 gag-tmos ORF, we demonstrated that R7 does synthesize a Gag-tMos fusion protein. Using R7 gag deletion mutants with and without the FLAG sequence, we further demonstrated that (i) deletion of the entire gag sequence abolished R7's transforming activity; (ii) the ability of the virus to transform cultured NIH/3T3 cells was significantly reduced only when most of gag was deleted; (iii) the ability of the virus to induce brain lesions was inversely proportional to the extent of its gag deletions; and (iv) the insertion of FLAG at the Mos C-terminus did not reduce the in vitro transforming activity of the FLAG-tagged viruses but did reduce their ability to induce brain lesions. Thus, we have demonstrated that altering the N- or C-terminus of the R7 Gag-tMos fusion protein can affect disease manifestation.     

Correlation of cytochrome P450 (CYP) 1A2 activity using caffeine phenotyping and olanzapine disposition in healthy volunteers.

Olanzapine has previously been shown to have predominant metabolism by cytochrome (CYP) P450 1A2. Caffeine has been shown to provide an accurate phenotypic probe for measuring CYP1A2 activity. The purpose of this study is to determine if a significant correlation exists between olanzapine disposition and caffeine metabolic ratios. Subjects were phenotyped for CYP1A2 activity with caffeine probe methodology. After 200-mg caffeine administration, blood (4 h), saliva (6 and 10 h), and urine (8 h total) were collected for high-performance liquid chromatography (HPLC) analysis of caffeine and its metabolites.CYP1A2 activity was measured as plasma (PMR(4 h)), saliva (SMR(6 h) and SMR(10 h)), and three urinary metabolic (UMR1(8 h), UMR2(8 h), and UMR3(8 h)) ratios. Each of the 14 healthy nonsmokers (13 male) received a single 10 mg olanzapine dose after which blood was collected for HPLC determination of olanzapine concentrations at predose and at 0.5, 1, 1.5, 2, 2.5, 3, 4, 5, 6, 8, 10, 12, 24, 48, 72, 96, and 120 h postdose. Olanzapine pharmacokinetic parameters in this study were similar to those previously published. All caffeine metabolic ratios (PMR(4 h), SMR(6 h), SMR(10 h), UMR1(8 h), and UMR2(8 h)) significantly correlated with each other (p <0.001) except for UMR3(8 h), which did not correlate. A significant correlation (p <0.05) was also found between olanzapine clearance and PMR(4 h) (r=0.701), SMR(6 h) (r=0.644), SMR(10 h) (r=0.701), UMR1(8 h) (r=0.745), and UMR2(8 h) (r=0.710). A negative correlation was observed between olanzapine clearance and UMR3(8 h) (r=-0.029, p=NS). A significant correlation was found between olanzapine clearance and various caffeine metabolic ratios. Interpatient variability in CYP1A2 activity may explain the wide interpatient variability in olanzapine disposition. Compounds that modulate CYP1A2 activity may be expected to alter olanzapine pharmacokinetics accordingly.     

Spontaneously relapsing clonal, mucosal cytotoxic T-cell lymphoproliferative disorder: case report and review of the literature

Primary T-cell lymphoma of the gastrointestinal tract is a rare and usually aggressive disorder that may be associated with celiac disease. The authors describe a unique case of a clonal proliferation of CD8+ T cells involving the oral mucosa, ileum, and colon of a 35-year-old man that has regressed spontaneously and recurred numerous times over a 9-year period without treatment. The patient's symptoms were limited to occasional rectal bleeding and recurring painful oral ulcers. Within the intestine, these collections of small T cells induced minimal architectural distortions and did not show extensive epitheliotrophism. Polymerase chain reaction and sequencing analyses revealed that the identical T-cell clone has been present for more than 9 years and in different mucosal locations in this patient. This may represent a unique T-cell lymphoproliferative process akin to a mucosal counterpart of lymphomatoid papulosis of the skin.     

Failed Caesarean Section: An Obstetrician's Nightmare

EDITORIAL COMMENT: In medicine, human judgment is fallible, but obstetrics is the discipline in which an error of judgment is most rapidly revealed, to the obstetrician, the patient and the labour ward staff, due to the unpredictability of the duration of labour and imminence of delivery in any individual patient. When the editor was a house officer he was called to the antenatal ward because a multipara, near term had abdominal pain. Vaginal examination revealed an undiluted cervix, but within the minute or so it took a walk to the handbasin to wash his hands the woman had delivered a live baby into the bed. It is always wise, and should be a routine. unless operating in haste for an emergency such as bleeding from placenta praevia, to perform a vaginal examination after anaesthesia is established before commencing Caesarean section in a woman in labour. The editor has performed many safe easy-forceps deliveries in this circumstance, in theatre, in women in whom Caesarean section was planned for cephalopelvic disproportion with or without fetal distress. This finesse is more important if the consultant has agreed to perform a Caesarean on the findings recorded by others, but the fact remains that labour and delivery can accelerate most unexpectedly. We accepted this case report for publication, not merely because it is the first such case reported, but also for the opportunity it provided to stress to readers the need for final evaluation of the stage of labour before Caesarean section, when the conditions are most favourable for assessment. Nonetheless, as this case tells us. it is possible for labour and delivery to proceed faster than the obstetrician can perform a Caesarean section.     

香港头颈外科的发展现状

头颈外科包括了头颈部肿瘤及相关疾病的诊断和治疗。香港头颈外科的起源可以追述到本世纪60年代中期。当时的香港大学玛丽医院外科学系主任王源美教授是开创这一领域的先驱。香港最初只有普外科医生涉及到这一区域肿瘤的治疗，经过多年来其它专科的发展，目前香港头颈部的疾病已经可以由三个外科次级专科处理，即耳鼻喉科、整形重建科和普外科。20年来，在外科、放射科及化疗科的共同努力下，头颈部肿瘤在诊断及治疗方面获得的迅速的发展，这就使病人的预后得到了很大程度的改善。     

Second cancers after medulloblastoma: population-based results from the United States and Sweden

Medulloblastoma, one of the most common central nervous system(CNS)tumors in children, requires aggressive multimodality therapy including surgery, radiation therapy, and occasionally chemotherapy. Given its intensive treatment regimen and improved survival during the past 20 years, it is likely that a cohort of survivors will result who may incur consequences of therapy, including a second cancer. We used population-based data from the United States and Sweden to estimate risks of second neo plasms in patients with histologically confirmed medulloblastoma (n = 1,262).Overall, there was a 5.4-fold excess of second neoplasms (95 percent confidence interval = 3.3-8.4) based on 20 observed and 3.7 expected cancers. The second cancers occurred eight to 432 months after initial diagnosis(median, 73 months) with significantly elevated ratios for all intervals examined except for less than one year after initial diagnosis. Significantly elevated risks were seen for cancers of the salivary glands, cervix uteri, brain and CNS, thyroid gland, and acute lymphoblastic leukemia. Of the 15second cancers with treatment data, seven occurred in the radiation field or within areas of scatter while two others may have been radiation-related. Although based on small numbers of second cancers, the results suggest that as survival increases, some patients with medulloblastoma will have an increased risk of a second cancer, particularly a radiation-related cancer. Thus, as survival improves, late-occurring consequences of diagnosis and treatment will need to be carefully assessed. Identification of patients hypersensitive to radiation therapy, such as those with Gorlin Syndrome, should also be attempted in order to reduce the sequelae from intensive radiation exposure. This revised version was published online in July 2006 with corrections to the Cover Date.     

Radioenhancement by cisplatin with accelerated fractionated radiotherapy in a human tumour xenograft

The aim of the present study was to investigate whether cisplatin would enhance the radioresponse of a human tumour xenograft when given in different schedules combined with accelerated fractionated radiation therapy. A human squamous carcinoma of the hypopharynx, FaDu, was grown in the thigh of athymic nude mice. Tumours were exposed to twice-daily 2-Gy fractions, applied 6 h apart over 2 weeks, 5 days a week, alone or combined with cisplatin given at maximally tolerated doses in three different schedules: (1) i.p. as a single bolus (SB) or (2) i.p. as a daily bolus at 30 min before the first daily radiation fraction or (3) s.c. as a continuous infusion through a mini-osmotic pump over 13 days, commencing 24 h prior to the first daily radiation fraction. The end point for the study was tumour growth delay (TGD), calculated as the difference between the delay in regrowth to 200% of the initial tumour size in treated versus control mice. SB cisplatin plus radiation showed only an additive effect on TGD, whereas daily-bolus and continuous-infusion cisplatin demonstrated a greater than additive effect when combined with accelerated fractionated radiation in this human tumour model. Cisplatin appears to be especially beneficial as a radiation enhancer when given throughout the course of radiation. Received: 15 December 1996 / Accepted: 25 March 1997     

Hepatocellular carcinoma after kidney transplantation: analysis of Hong Kong Renal Registry

Kidney transplant recipients have increased risk of cancers when compared with the general population. Hepatocellular carcinoma (HCC) is extremely important in Asia where hepatitis B virus (HBV) infection is endemic. The aim is to study the epidemiological and clinical aspects of all de novo HCC in our kidney transplant recipients. Moreover, various preventive strategies which may help to optimize the outcome will also be discussed. A retrospective review of all patients who developed HCC after kidney transplantation between May 1972 and December 2011 in Hong Kong, based on the data from Hong Kong Renal Registry. After a follow-up period of 40,246 person-years, 20 patients (males 15: females 5) developed HCC. The annual incidence was 49.7/100,000 persons per year. Among them, 16 were HBV carriers, 2 were hepatitis C (HCV) carriers and 2 had HBV and HCV co-infection. Presence of HBV infection was associated with 78-fold higher risk for HCC development. Majority (85%) were asymptomatic when HCC was diagnosed by ultrasound or alpha-fetoprotein surveillance. All patients diagnosed by surveillance received active treatment while 2/3 of symptomatic patients could only receive symptomatic care and died rapidly. In conclusion, HBV infection is the major etiological factor for HCC development in kidney transplant recipients in HBV endemic areas. Regular HCC surveillance appeared to be able to detect early stage cancers which are amenable to treatment and offer the best hope of cure.