Global prevalence of non-alcoholic fatty liver disease in type 2 diabetes mellitus: an updated systematic review and meta-analysis

INTRODUCTION

Non-alcoholic fatty liver disease (NAFLD) is the leading cause of chronic liver disease, with type 2 diabetes mellitus (T2DM) as a major predictor. Insulin resistance and chronic inflammation are key pathways in the pathogenesis of T2DM leading to NAFLD and vice versa, with the synergistic effect of NAFLD and T2DM increasing morbidity and mortality risks. This meta-analysis aims to quantify the prevalence of NAFLD and the prevalence of clinically significant and advanced fibrosis in people with T2DM.

METHODS

MEDLINE and Embase databases were searched from inception until 13 February 2023. The primary outcomes were the prevalence of NAFLD, non-alcoholic steatohepatitis (NASH) and fibrosis in people with T2DM. A generalised linear mixed model with Clopper-Pearson intervals was used for the analysis of proportions with sensitivity analysis conducted to explore heterogeneity between studies.

RESULTS

156 studies met the inclusion criteria, and a pooled analysis of 1 832 125 patients determined that the prevalence rates of NAFLD and NASH in T2DM were 65.04% (95% CI 61.79% to 68.15%, I2=99.90%) and 31.55% (95% CI 17.12% to 50.70%, I2=97.70%), respectively. 35.54% (95% CI 19.56% to 55.56%, I2=100.00%) of individuals with T2DM with NAFLD had clinically significant fibrosis (F2-F4), while 14.95% (95% CI 11.03% to 19.95%, I2=99.00%) had advanced fibrosis (F3-F4).

CONCLUSION

This study determined a high prevalence of NAFLD, NASH and fibrosis in people with T2DM. Increased efforts are required to prevent T2DM to combat the rising burden of NAFLD.

PROSPERO REGISTRATION NUMBER

CRD42022360251.

An algorithmic clinicoradiological approach to paediatric cranial vault lesions: distinguishing normal variants from pathologies

Lesions of the paediatric cranial vault are diverse both in their presentation and aetiology. As such, they pose a diagnostic challenge to the paediatric neurosurgeon and neuroradiologist. In this article, we delineate the spectrum of paediatric calvarial pathology into four distinct groups: (1) lytic lesion(s); (2) focal sclerotic lesion(s); (3) diffuse cranial vault sclerosis; and (4) abnormal shape of the cranial vault. It is our aim that this more pragmatic, algorithmic approach may mitigate diagnostic uncertainty and aid the more accurate diagnosis of paediatric calvarial lesions.

Meta-analysis: Prevalence of significant or advanced fibrosis in adults with alpha-1-antitrypsin deficiency

BACKGROUND

The prevalence of liver fibrosis detected by non-invasive imaging in alpha-1-antitrypsin (AAT) deficiency has not been systematically assessed.

AIMS

We conducted a systematic review and meta-analysis to determine the prevalence of significant fibrosis and advanced fibrosis in AAT deficiency based on non-invasive imaging.

METHODS

Medline and Embase electronic databases were searched for studies from inception to 13 November 2022 that provided data for the prevalence of fibrosis in adults with AAT deficiency. A generalised linear mixed model with Clopper-Pearson intervals was used to pool single-arm outcomes.

RESULTS

Of the 214 records identified, 8 studies were included. Five studies assessed fibrosis using vibration-controlled transient elastography. The prevalence of significant fibrosis (defined as ≥7.1 kPA) in Z homozygosity, Z heterozygosity and non-carrier status was 22.10% (five studies, 95% CI: 17.07-28.12), 9.24% (three studies, 95% CI: 4.68-17.45) and 5.38% (one study, 95% CI: 3.27-8.73), respectively, p < 0.0001, and the prevalence of advanced fibrosis (defined as ≥9.5 kPa) was 8.13% (five studies, 95% CI: 4.60-13.96), 2.96% (three studies, 95% CI: 1.49-5.81) and 1.08% (one study, 95% CI: 0.35-3.28), respectively, p = 0.003. There were limited data regarding the use of magnetic resonance elastography or acoustic radiation force impulse to assess for fibrosis.

CONCLUSION

More than one in five adult individuals with AAT deficiency and Z homozygosity harbour significant fibrosis, and nearly 1 in 10 harbours advanced fibrosis. The risk of fibrosis increases incrementally with the frequency of Pi*Z mutations.

Cauda equina thickening: an approach to MRI findings

There are many causes of cauda equina (CE) thickening on neuroimaging of the lumbar spine. The imaging features of CE thickening for the various conditions often overlap and are non-specific to clinch a definite diagnosis. Hence, the imaging findings have to be discerned in accordance with the patient's presenting history, clinical examination findings, and results from electrophysiology and laboratory studies. In this review, the authors aim to supplement the existing literature on imaging findings of CE thickening with a diagnostic framework for clinical workup. The authors also aim to familiarise readers with the interpretation of CE thickening on magnetic resonance imaging (MRI) and would like to illustrate the normal variants and pitfalls that could be mistaken for abnormal results.

Internal cerebral vein asymmetry is an independent predictor of poor functional outcome in endovascular thrombectomy

BACKGROUND

Endovascular thrombectomy (EVT) in large vessel occlusion (LVO) in anterior circulation acute ischaemic stroke (AIS) results in good functional outcomes in only approximately 60% of the patients. Internal cerebral veins (ICVs) are easily visible, with a consistent midline location, and are linked to stroke outcomes. We hypothesize that ICV asymmetry on multiphasic CT angiogram (mCTA) can be an adjunctive predictor for poor functional outcomes.

METHODS

We studied consecutive AIS patients from 2017 to 2019 with anterior circulation LVO treated with EVT regardless of intravenous thrombolysis. Asymmetrical ICV was defined as the presence of hypodensity (less opacification) on the ipsilateral occlusion side as compared with the contralateral side. The primary outcome was modified Rankin Score (mRS) score at 3 months. Secondary outcomes were good recanalization (modified Thrombolysis In Cerebral Infarction (mTICI) 2b-3), symptomatic hemorrhage, and mortality.

RESULTS

A total of 185 patients were included with a median age of 70 years (IQR 59-77); 87 patients (47%) were female. 82 patients (44.3%) achieved good functional outcomes (mRS 0-2) at 3 months. On multivariate analysis, National Institutes of Health Stroke Scale (NIHSS) (OR 1.076, 95% CI 1.015 to 1.140; p<0.013), poor collateral score (OR 0.285, 95% CI 0.162 to 0.501; p<0.001), asymmetrical ICV on the peak venous phase (OR 2.47, 95% CI 1.115 to 5.471; p<0.026), and late venous phase of the mCTA (OR 2.642, 95% CI 1.161 to 6.016; p<0.021) were independent risks factors of poor outcomes.

CONCLUSION

ICV asymmetry is a novel radiological sign which is independently associated with poor functional outcomes in EVT, even after correction for collateral circulation. Further studies are needed to validate this finding.

Clinical application of "black bone" imaging in paediatric craniofacial disorders

For decades, CT has been the primary imaging modality for the diagnosis and surveillance of paediatric craniofacial disorders. However, the deleterious effects of ionising radiation in the paediatric population are well established and remain an ongoing concern. This is especially so in the head and neck region, which has relatively poor soft tissue shielding with many radiosensitive organs. The development of "black bone" imaging utilising low flip angles and short echo time (TE) has shown considerable promise in alleviating the use of ionising radiation in many cases of craniofacial disorders. In this review article, we share our experience of utilising "black bone" sequence in children with craniofacial pathologies, ranging from traumatic injuries to craniosynostosis and focal osseous/fibro-osseous lesions such as fibrous dysplasia and Langerhans cell histiocytosis (LCH). A detailed discussion on the technical aspects of "black bone" sequence, including its potential pitfalls and limitations, will also be included.

Low-dose 'boom-boom' radiotherapy for ocular lymphoma arising from IgG4-related ophthalmic disease: Case report and literature review

Ocular adnexal extranodal marginal zone lymphoma (OA-EMZL) and immunoglobulin G4-related ophthalmic disease (IgG4-ROD) may exist on a continuum. Presence of immunoglobulin light-chain restriction and clonal gene rearrangement suggests presence of lymphoma; whereas bilateral, infraorbital nerve and systemic involvement accompanied by elevated serum IgG4 levels may indicate synchronous IgG4-ROD. Although steroids have been the mainstay for the treatment of IgG4-ROD, radiotherapy (RT) has been used occasionally. The reported RT doses range between 24 and 30 Gy, which can result in acute and late toxicities. A low-dose regimen of four Gy has not been previously described. We describe a patient with bilateral OA-EMZL arising from IgG4-ROD successfully treated with low dose 'boom-boom' radiotherapy. In addition, we review the literature for the association between these two conditions and the role of RT in their management.

NIMG-32. THE PREDICTIVE CAPACITY OF PRE-OPERATIVE IMAGING ANALYSIS IN DIFFUSE GLIOMA: A COMPARISON OF CONNECTOMICS, RADIOMICS, AND CLINICAL PREDICTIVE MODELS

BACKGROUND

Radiomics and connectome analysis are distinct and non-invasive methods of deriving biologic information from MRI. Radiomics analyzes features intrinsic to the tumor, and connectomics incorporates data regarding the tumor and surrounding neural circuitry. In this study we used both techniques to predict glioma survival.

METHODS

We retrospectively identified 305 adult patients with histopathologically confirmed WHO grade II–IV gliomas who had presurgical, 3D, T1-weighted brain MRI. Available clinical variables included tumor lobe, hemisphere, multifocal nature grade, histology extent of surgical resection, patient age gender. For connectomics, we calculated nodal efficiencies, network size and degree for all pairs of 33 voxel cubes spanning the entire gray matter volume using similarity-based extraction and graph theory. Radiomic features were extracted using Pyradiomics and subjected to patient-level and population-level clustering (N=172). These clusters were then used to construct a multi-regional spatial interaction matrix for model building. Cox proportional hazards models were fit for clinical variables alone, connectomics alone, radiomics alone, connectomics+clinical and radiomics+clinical. We implemented 10-folds cross-validation and examined the mean area under the curve (AUC) across validation loops.

RESULTS

Median survival time was 134.2 months. The mean AUC for the clinical model was 0.79 +/- 0.01, the connectome model was 0.88 +/- 0.01, the combined connectome + clinical model was 0.93 +/- 0.01, the radiomic model was 0.64 +/- 0.05 and the radiomics+clinical model was 0.89+/-0.03. Radiomic analysis of the entire dataset as well as comparisons of radiomic+connectomics +/- clinical models are pending.

CONCLUSIONS

The combination of clinical variables and connectome analysis provided a more robust predictive model than other models. This suggests that connectome analysis incorporates valuable clinically-predictive information which can augment our capacity for prognostication of patients with diffuse glioma. These methods warrant further evaluation in larger prospective study of patients with diffuse glioma.

Unusual case of lipoma arborescens in the subacromial-subdeltoid bursa

A 38-year-old female presented with a 10-month history of right shoulder pain with impingement symptoms. She was diagnosed on magnetic resonance (MR) imaging to have supraspinatus tendon tear and degenerative changes contributing to subacromial impingement. She also had lipoma arborescens of the subacromial-subdeltoid bursa, an uncommon condition in a particularly rare location. Lipoma arborescens is a benign intra-articular condition characterized by lipomatous proliferation of synovium with replacement of subsynovial tissue by mature adipocytes. It is typically a monoarticular process affecting the knee. Due to the presence of pathognomonic fat, diagnosis is usually straightforward with MR as the preferred imaging modality.

Abstract P4-06-12: Different patterns of risk reducing decisions in affected or unaffected BRCA mutation carriers

BACKGROUND

Risk-reducing (RR) management decreases the risk of breast cancer and BRCA related gynecologic cancer. However, there are fewer reports on the RR management in Asia compared to Western countries.The aim of this study is to identify risk reducing management patterns with BRCA1 or BRCA2 mutation carriers.

METHODS

The study group consisted of all consecutive 1104 breast cancer, ovarian patients and their families of high-risk patients who underwent BRCA gene testing in National Cancer Center, Korea from 2008 to 2016. A total 220 BRCA mutations (19.9%) were detected with 125(11.3%) of BRCA1 gene and 95 (8.6%) of BRCA2 gene.

RESULTS

Out of 220 BRCA mutations carriers, they were consisted of 83 breast cancers, 10 ovarian cancers, 7 both cancers, and 120 unaffected carriers. Among them, 42 were men and 178 were women. About 90 % (198/ 220) had the familial history of breast, ovarian or both malignancies (113 in BRCA1 and 85 in BRCA2 mutation (p=0.821)).

All 42 men chose surveillance. Among 178 female BRCA mutation carriers, 98(55.1%) underwent risk reducing management including 18(10.1%) of chemoprevention, and 80(49.9%) had risk-reducing surgeries (RRSs) (1 case of risk-reducing mastectomy, 76 of risk reducing bilateral salphingo-oophorectomy (RRSO), and 3 of both) and 80 (54.9%) chose only intensive surveillance for both of breast and ovary cancer.

In affected carriers with breast cancer, 59 (71.1%) underwent RR management (1 case of risk reducing mastectomy, 53 of RRSO, 3 of both surgery, and 2 of chemoprevention). There was no risk reducing management in affected carrier with ovarian cancer patients. In 78 unaffected women carriers, 39(50.0%) women received RR management (23(29.5%) cases of RRSO and 16(20.5%) cases of chemoprevention). The rates of RRSs have increased annually since the 2013 year, (prior to 2013 vs. since 2013, RRSs 28.6% (6 cases/21 carriers) vs. 37.2% (74/199), p&lt;0.01).

CONCLUSION

This study was conducted on the largest numbers of BRCA mutation carriers in Asian countries. RRSO is the more preferred management for affected carriers with breast cancer or unaffected carriers. The results might be explained by the severity of the illness and that RRSO was only reimbursed RR strategy from the Korean Government Insurance. Tailored genetic counseling and insurance policy may enhance overall levels of RR management.

Citation Format: Lee EG, Kang H, Park SJ, Han JH, Jung S-Y, Lee S, Kang H-S, Park B, Kong S-Y, Lim MC, Park S-Y, Lee ES. Different patterns of risk reducing decisions in affected or unaffected BRCA mutation carriers [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P4-06-12.

Neurogenic heterotopic ossification after a stroke: diagnostic and radiological challenges

Heterotopic ossification (HO) is the aberrant formation of ectopic bone within the soft tissues, of which the aetiology is usually either traumatic or neurogenic. Neurogenic HO is a known but uncommon complication that occurs after a cerebral or spinal insult. The condition may present with a spectrum of symptoms and is often difficult to diagnose clinically. Although different imaging modalities have been used to diagnose HO, clinicians and radiologists may occasionally encounter radiological features of HO that may mimic other disease conditions. We herein report a rare case of neurogenic HO occurring in the non-paretic limb of a patient, and the diagnostic and radiological challenges encountered.

Dislocation of the penis: a rare complication after traumatic pelvic injury

Traumatic injury to the male external genitalia is frequently encountered, but acute traumatic dislocation of the penile structure is extremely rare, with only a few reports found in the literature. We herein report the case of a 21-year-old man who sustained blunt trauma to the pelvis following a motor vehicle accident, and had features suspicious of penile dislocation. With the use of computed tomography and bedside ultrasonography, a diagnosis of penile dislocation was made, which was subsequently confirmed intraoperatively. Immediate surgical intervention via gentle manipulation of the penile tissue back to its native position was performed in order to restore normal anatomy. The exact mechanism of penile dislocation is not known. However, circumferential laceration around the foreskin causing degloving injury of the penis is suggested in our patient.

CT volumetry of the liver: where does it stand in clinical practice?

Imaging-based volumetry has been increasingly utilised in current clinical practice to obtain accurate measurements of the liver volume. This is particularly useful prior to major hepatic resection and living donor liver transplantation where the size of the remnant liver and liver graft, respectively, affects procedural success and postoperative mortality and morbidity. The use of imaging-based volumetry, with emphasis on computed tomography, will be reviewed. We will explore the various technical factors that contribute to accurate volumetric measurements, and demonstrate how the accuracies of these techniques are influenced by their methodologies. The strengths and limitations of using anatomical imaging to estimate liver volume will be discussed, in relation to laboratory and functional imaging methods of assessment.

High control rate for lymph nodes in cervical cancer treated with high-dose radiotherapy using helical tomotherapy

The purpose of this study was to evaluate whether bulky lymphadenopathy located in the abdominopelvic cavity in cervical cancer can be controlled without severe toxicity by increasing radiation dose using helical tomotherapy. From January 2007 to December 2010, 26 patients with cervical cancer with metastatic lymph nodes (LNs) having at least one short diameter > 1.5 cm were treated with helical tomotherapy. A total of 58 LN sites were treated and the largest LN of each site was evaluated for response. Median follow-up time was 28 months (4-50 months). Median short diameter of the LNs was 1.7 cm (0.7-4.2 cm) with median radiation dose of 62.6 Gy(10) in 2 Gy equivalent dose (53.3-77.9 Gy(10)). Initial LN response was evaluated on imaging obtained within 4 months after radiotherapy. Initial complete response (CR), partial response (PR), and stable disease (SD) were observed in 54, 2 and 2 lesions, respectively. Recurrence occurred in two with CR and progression in one with PR. Therefore, final CR, PR, SD, and progression of disease were observed in 52, 1, 2, and 3, respectively. Actuarial 3-year LN progression-free survival and overall survival (OS) were 63% and 65%, respectively. Multivariate analysis revealed final LN response (CR vs. non-CR) as a strong prognostic factor for OS (p = 0.016). Radiation Therapy Oncology Group grade 2 or more acute and late toxicity was observed in 8 and 1 patients, respectively. The treatment of bulky lymphadenopathy using helical tomotherapy in advanced cervical cancer is highly effective and has acceptable toxicity.

Laparoscopic and laparotomic staging in stage I epithelial ovarian cancer: a comparison of feasibility and safety

The aim of this study was to compare laparoscopic and laparotomic surgical staging in patients with stage I epithelial ovarian cancer in terms of feasibility and safety. A retrospective chart review was undertaken of all patients with apparent stage I epithelial ovarian cancer who underwent laparoscopic (laparoscopy group) or laparotomic (laparotomy group) surgical staging at the Center for Uterine Cancer, National Cancer Center, Korea, between January 2001 and August 2006. During the study period, 19 patients underwent laparotomic surgical staging and 17 patients underwent laparoscopic surgical staging. No cases were converted from laparoscopy to laparotomy. The two groups were similar in terms of age, body mass index, procedures performed, number of lymph nodes retrieved, and operating time. The laparoscopy group had less estimated blood loss (P = 0.001), faster return of bowel movement (P < 0.001), and a shorter postoperative hospital stay (P = 0.002) compared to the laparotomy group. Transfusions were required only in two laparotomy patients, and postoperative complications occurred only in four laparotomy patients. However, two patients with stage IA grade 1 and 2 disease in laparoscopy group had recurrence with one patient dying of disease. The accuracy and adequacy of laparoscopic surgical staging were comparable to laparotomic approach, and the surgical outcomes were more favorable than laparotomic approach. However, the oncologic safety of laparoscopic staging was not certain. This is the first report on the possible hazards of laparoscopic staging in early-stage ovarian cancer. In the absence of a large prospective trial, this technique should be performed cautiously.

Port-site and liver metastases after laparoscopic pelvic and para-aortic lymph node dissection for surgical staging of locally advanced cervical cancer

Recently, we experienced a case of port-site and liver metastases after 75 cases of laparoscopic transperitoneal pelvic lymph node dissection (PLND) and para-aortic lymph node dissection (PALND) for surgical staging of locally advanced cervical cancer. A 45-year-old-woman with stage IIB cervical adenocarcinoma underwent laparoscopic PLND and PALND for surgical staging. There was no intraperitoneal disease and cervical tumor was not manipulated at the time of laparoscopic surgery. Pathologic examination revealed only one micrometastasis in left internal iliac lymph node (LN), measuring 1 mm, of the 60 pelvic and para-aortic LNs removed. She received concurrent chemoradiation therapy and pelvic mass disappeared completely. One month after the completion of therapy, both lateral and umbilical port-site and liver metastases were detected. We conclude that although cases of port-site metastasis have mostly occurred after extensive disease, the possibility of such complication should be kept in mind at laparoscopy of early cancer and laparoscopy which does not manipulate primary tumor.

Decreased macular leukocyte velocity in human immunodeficiency virus-infected individuals

PURPOSE

To determine whether human immunodeficiency virus (HIV)-infected individuals have decreased macular capillary blood flow in vivo.

DESIGN

Case control study.

METHODS

Macular leukocyte velocity and perceived leukocyte density were determined in 41 HIV-infected individuals without cytomegalovirus retinitis and 31 HIV-negative control subjects using the blue field simulation technique (BFS-2000, Oculix, Inc., Jenkintown, PA). Velocity and density measurements for HIV-infected individuals were compared to current and lowest previous CD4+ T-lymphocyte counts, HIV RNA blood levels, and blood leukocyte counts.

RESULTS

Mean macular leukocyte velocity was lower in HIV-infected individuals than in controls (P = 0.0006). No correlations were identified between velocity measurements and the following factors in HIV-infected individuals: current or lowest previous CD4+ T-lymphocyte count; or HIV RNA blood level. Mean perceived leukocyte density in HIV-infected individuals was lower than in controls (P = 0.003), but was not correlated with blood leukocyte count in HIV-infected individuals. No relationships were identified between macular leukocyte velocity and duration of medication use or duration of elevated CD4+ T-lymphocyte count in patients receiving potent antiretroviral therapy.

CONCLUSIONS

Reduced macular leukocyte velocity may have important implications for understanding the retinal microvasculopathy of HIV disease, the pathogenesis of opportunistic retinal infections, and visual dysfunction in HIV-infected individuals who do not have opportunistic retinal infections. We found no evidence that macular leukocyte velocity increased with immune reconstitution.

Late onset lens particle glaucoma as a consequence of spontaneous dislocation of an intraocular lens in pseudoexfoliation syndrome

PURPOSE

To report acute onset lens particle glaucoma associated with pseudoexfoliation-related dislocation of an intraocular lens implant 12 years after cataract surgery.

METHODS

Case report.

RESULTS

An 80-year-old woman presented with acute onset of left eye pain that was associated with white fleck-like particles circulating in the anterior chamber and an intraocular pressure of 48 mm Hg. The posterior chamber intraocular lens within the capsular bag was positioned more posteriorly to the iris plane than usual, and pseudoexfoliative material was present on the lens capsule and the zonules. Anterior chamber aspirate confirmed the presence of lens cortical fibers.

CONCLUSION

Spontaneous dislocation of the posterior chamber intraocular lens in patients with pseudoexfoliation syndrome several years after cataract surgery may liberate lens cortical material, causing lens particle glaucoma.

Depolarization counteracts glucocorticoid inhibition of adenohypophysical corticotroph cells

In AtT20 mouse corticotroph tumour cells large conductance Ca2+-activated K+-channels (BK-channels) have an essential role in the early glucocorticoid inhibition of adrenocorticotrophin (ACTH) secretion evoked by corticotrophin-releasing factor. The present study examined whether or not BK-channels are also pivotal to glucocorticoid inhibition of normal rat anterior pituitary cells. A membrane-permeant, non-metabolizable cyclic AMP analogue, 8-(4-Chlorophenylthio)adenosine-3',5'-cyclic-monophosphate (CPT-cAMP) was used as the primary secretagogue stimulus, as this mimics the increase of intracellular cyclic AMP caused by corticotrophin-releasing factor, but is not subject to the complex Ca2+-dependent regulation of cyclic AMP metabolism that is evident in corticotroph cells. Experiments in AtT20 cells showed that ACTH secretion stimulated by 1 mM CPT-cAMP was suppressed to 34+/-1.5% (n = 12) of the control stimulus by a maximal dose of 100 nM dexamethasone. The ACTH secretion evoked by the combination of 1 mM CPT-cAMP with either 5 microm (-)BayK8644 (L-type Ca2+-channel activator) or 5 mM TEA (K+-channel blocker) was respectively 69.1+/-7.6% and 69.3+/-11.8% of control after 2 h preincubation with 100 nM dexamethasone (P<0.05 vs CPT-cAMP). The ACTH response elicited by 5 microM (-)BayK8644 and 5 mM TEA given together was completely resistant to inhibition by 100 nM dexamethasone. Furthermore, TEA and (-)BayK8644 given together synergistically stimulated ACTH release in combination with 0.1 mM or 1 mM CPT-cAMP, and these ACTH responses were not inhibited by 100 nM dexamethasone. In primary cultures of rat anterior pituitary cells, TEA (up to 20 mM), charybdotoxin (30 nM) or apamin (100 nM) failed to modify the glucocorticoid inhibition of 0.1 mM CPT-cAMP-induced ACTH release. The combination of 5 mM TEA and 5 microM (-)BayK8644 elicited a small but significant increase in ACTH secretion but did not modify the inhibition of 0.3 mM CPT-cAMP-induced ACTH secretion by 100 nM dexamethasone. In primary cultures of rat anterior pituitary cells, depolarization of the membrane potential with 40 mM KCl enhanced the ACTH response to CPT-cAMP and markedly reduced the maximal inhibitory effect of dexamethasone to 55+/-1.2% as well as that of corticosterone to 33+/-2.1% vs 100+/-2.5% and 100+/-1.9% inhibition respectively, when 0.1 mM CPT-cAMP was used alone. Introduction of 5 microM (-)BayK8644 with 40 mM KCl in this system had no additional effect on glucocorticoid inhibition. No glucocorticoid inhibition of ACTH release to any of the stimuli applied was observed in cells pretreated with the mRNA synthesis inhibitor, 5,6-dichloro-furanosyl-benzimidazole riboside (DRB) (0.1 mM) or the protein synthesis blocker, puromycin (0.1 mM). In summary, early glucocorticoid inhibition of stimulated ACTH release by cultured rat anterior pituitary cells was dependent on the synthesis of new mRNA and protein. Depolarization of the membrane potential potentiated CPT-cAMP-induced ACTH secretion in AtT20 cells as well as cultured rat corticotrophs and this was associated with a resistance to the early inhibitory effect of glucocorticoids. Glucocorticoid inhibition in rat anterior pituitary corticotrophs was unaltered by TEA, charybdotoxin as well as apamin, and hence it is unlikely to involve predominantly BK-or SK-type Ca2+-activated K+-channels. These results support the thesis that a prime target of glucocorticoid feedback inhibition in anterior pituitary corticotrophs is the membrane potential and indicate that glucocorticoid-induced proteins regulate the activities of several distinct plasma membrane ion channels.

Clinical and echocardiographic features of mitral valve prolapse patients in a local population

Mitral valve prolapse (MVP) is a commonly diagnosed condition with varied clinical presentations but local data is lacking. In our study, we reviewed 98 patients (54 males, 44 females) with echocardiographic mitral valve prolapse diagnosed between 1991 and 1993 to study the clinical profile and echocardiographic features of patients with this condition in our local population. The mean and median age at presentation/detection were 42 years and 38 years respectively. The majority of the patients were asymptomatic (59%); the rest presented with palpitations (21%), congestive heart failure (4%) and infective endocarditis (5%). On clinical examination, 64 patients had mitral regurgitation (13 patients had both mitral regurgitation murmur and a systolic click), while one or more systolic clicks were heard in another 32 patients. Six patients also had associated Marfan syndrome. 2D echo revealed isolated anterior and posterior leaflet involvement in 55 and 19 patients respectively. Another 24 patients had involvement of both leaflets. Mitral regurgitation was detected on colour Doppler study in 78 patients. Nine patients had associated tricuspid valve prolapse. Of the 98 patients, 8 patients developed flail mitral valve. Four were detected at presentation/diagnosis, while the other 4 were diagnosed incidentally on routine follow-up 2D echo. Of these 8 patients, one developed cardiac failure. The patients had been on follow-up for a mean period of 9 months. During this period, mitral regurgitation progressed in 3 patients resulting in valve surgery. Only 20 patients had arrhythmias detected on ambulatory ECG monitoring, most of them were frequent atrial and ventricular premature beats. No patient was found to have haemodynamically significant arrhythmia. In summary, most patients with MVP had anterior mitral valve leaflet prolapse and mitral regurgitation. Although most patients with MVP are asymptomatic or have minor symptoms, it is associated with significant morbidity.

Effects of loratadine and terfenadine on the induced nasal allergic reaction

OBJECTIVE

To evaluate the effect of terfenadine and loratadine on the early nasal allergic response to challenge and the subsequent cellular influx and hyperresponsiveness.

DESIGN

Double-blind, placebo-controlled, triple-crossover study.

SUBJECTS

Fourteen, asymptomatic, allergic volunteers.

INTERVENTIONS

After an initial challenge with methacholine chloride, subjects received treatment with placebo, loratadine (10 mg by mouth daily), or terfenadine (60 mg by mouth twice daily) for 1 week, followed by a nasal allergen challenge with lavages; 24 hours later, while the subjects were still receiving medication, the quantity of cells in the nasal lavage was determined, and another challenge with methacholine was done. Mediator levels were quantified in the nasal lavages after the allergen c hallenge, and the weight of the methacholine-induced nasal secretions was measured.

RESULTS

Both loratadine and terfenadine treatment resulted in significant reductions in allergen-induced sneezing and the levels of histamine, kinins, albumin, and N-alpha-tosyl-L-arginine methyl ester-esterase activity in recovered nasal lavages compared with the reductions that resulted from placebo treatment, with no significant difference among the treatments. Treatment had no effect on the levels of tryptase, prostaglandin D2 or leukotriene C4. A significant eosinophil influx into nasal secretions 24 hours after the allergen challenge in patients who were receiving placebo (P=.006) was not affected by loratidine or terfenadine treatment. Comparing methacholine-induced secretions between screening challenges and challenges with the patients who were being treated with either loratadine or terfenadine, there was a significant decrease in secretions after the use of these antihistamines (P<.05).

CONCLUSION

Both loratadine and terfenadine partially inhibit the early nasal response to allergen challenge and the subsequent reactivity to a challenge with methacholine without affecting the influx of eosinophils into nasal secretions.

Diagnosis of deep vein thrombosis using duplex ultrasonography

Duplex ultrasonography is a safe, accurate, efficient, inexpensive, noninvasive diagnostic test for deep vein thrombosis (DVT). The sensitivity and specificity of this technique is comparable to venography in symptomatic patients in many studies. The diagnostic accuracy of this test can be further enhanced by serial studies. We report our experience with the use of this technique for study of 180 patients with clinically suspected DVT. Only 55 (30.6%) patients were confirmed to have DVT on duplex ultrasonography which illustrates the inaccuracy of bedside diagnosis of this potentially life-threatening condition. Almost all our DVT patients have proximal vein involvement, indicating that venous thrombosis usually do not cause signs or symptoms until they become large, occlusive and extend into the proximal veins. It is also observed in our study cohort that half of the patients with proximal vein thrombosis has incomplete recanalisation on follow-up study. None of them with normal study developed significant sequelae of untreated DVT, suggesting that it is safe to withhold treatment based on result of this non-invasive test. Duplex ultrasonography is the diagnostic modality of choice for suspected DVT in symptomatic patients and is an excellent substitute for conventional contrast venography.

Stenting of stenosis of the abdominal aorta

Isolated abdominal aortic stenosis resulting in bilateral lower limb claudication is uncommon in Asians. We report a 75-year-old Oriental man with isolated abdominal aortic stenosis who underwent intraluminal stenting, resulting in the abolishment of a 76 mmHg gradient. As the stenotic segment was local, only the mid-segment of the Palmaz stent was apposed to the aortic wall. Follow-up ultrasound scans showed that the partially apposed stent was potent, with no thrombosis in the free space between the stent and the wall. Hence, although aortic stenting in this patient resulted in partial apposition of the stent to the aortic wall, there was no thrombosis or migration of the stent. The patient remained symptom-free one year post-stenting. Stenting in this patient with failed balloon angioplasty was a safe and efficacious method of treating significant isolated abdominal aortic stenosis.

Vortex vein exit sites. Scleral coordinates

PURPOSE

The authors determined the frequency and scleral coordinates of vortex vein exit sites in 46 autopsy eyes to provide topographic data that will enable surgeons to locate these vessels more precisely.

METHODS

Forty-six autopsy eyes were examined under a dissecting microscope to measure the frequency of vortex veins and the cord lengths between the vortex vein scleral exit sites and the limbus, rectus muscle insertions, and oblique muscle insertions.

RESULTS

Data from this study showed that 32 (70%) of the 46 individual eyes studied had more than four vortex veins. The number of second or third vortex veins found in the nasal quadrants was significantly higher than the number found in the temporal quadrants (P < 0.01). Statistical analyses of the measurements provided mean values for distances between vortex vein scleral exit sites and the three nearest extraocular muscle insertions; these positions among eyes were found to be relatively uniform (standard deviation, 0.7-2.5 mm).

CONCLUSION

The authors suggest that the majority of adult eyes encountered by a surgeon will have more than four vortex vein exit sites and that more vortex veins may be expected in the nasal quadrants than in the temporal quadrants. This study delineates the locations of vortex vein exit sites so that surgeons can reliably predict their surface positions to avoid vessel laceration and its ensuing complications.

Implicating adhesion molecules in nasal allergic inflammation

Allergic rhinitis is now considered an inflammatory disorder where many leukocyte types, including eosinophils and T-lymphocytes, accumulate in increased numbers. Along with mast cells and other cells, they release a wide variety of mediators, cytokines, and granule constituents that can directly cause inflammation or activate the local vascular endothelium to further enhance the recruitment of leukocytes through the expression and function of adhesion molecules. While the understanding of the importance of leukocyte and endothelial adhesion molecules is still at a very early stage, recent evidence has already begun to implicate these cell surface molecules in the pathogenesis of allergic diseases such as rhinitis and asthma. Additional studies, including the use of adhesion molecule antagonists when available, will clarify the importance of these structures in the pathophysiology of these disorders.

The histology of allergic rhinitis and its comparison to cellular changes in nasal lavage

To better understand how changes in cells in nasal secretions reflect changes in the nasal mucosa occurring during allergic reactions, we obtained nasal lavage and biopsy specimens from normal (n = 11) asymptomatic, seasonally allergic (n = 18), and perennially allergic (n = 18) subjects. Initial baseline lavages showed that perennially, and seasonally allergic subjects, out of their allergy seasons, had significantly higher numbers of eosinophils (p < 0.01) and neutrophils (p < 0.01) and total cell counts (p < 0.05) than normal subjects. Biopsy results showed that at baseline, seasonally allergic subjects had thicker mucosa (p < 0.01), greater numbers of intraepithelial mononuclear cells and total cells (p < 0.01), and greater numbers of subepithelial neutrophils (p < 0.001) than perennially allergic subjects. Twenty-four hours after antigen provocation, nasal lavage of allergic subjects showed an increase in the number of eosinophils (p < 0.05). Seasonally allergic subjects also had significant increases in numbers of intraepithelial mononuclear cells (p < 0.05) and total cells (p < 0.01), and in subepithelial eosinophils (p < 0.001) and mononuclear cells (p < 0.05), which were localized to the side challenged. Despite an influx in eosinophils, the epithelial layer was not changed from baseline. The data provide evidence that nasal secretions and the nasal mucosa represent two distinct cellular compartments.

Nasal challenge with allergen upregulates the local expression of vascular endothelial adhesion molecules

To understand the events involved in selective eosinophil migration into allergic inflammatory sites, we studied the expression of vascular endothelial adhesion molecules in the nasal mucosa. Ten subjects with asymptomatic seasonal allergic rhinitis and 13 nonallergic subjects underwent localized allergen challenge of one inferior turbinate. Twenty-four hours later, biopsy specimens were obtained from the inferior turbinates, bilaterally in the seasonally allergic subjects and unilaterally in the nonallergic control subjects. The specimens were divided, sectioned, and either stained for identification of eosinophils or analyzed immunohistochemically for intercellular adhesion molecule-1, E-selectin, vascular cell adhesion molecule-1 (VCAM-1), and von Willebrand's factor. Intercellular adhesion molecule-1 expression was observed in all mucosal specimens, with no significant difference among groups. E-selectin showed minimal baseline expression, and low levels were significantly induced on the challenged mucosa of the allergic compared with nonallergic subjects (p < 0.05). VCAM-1 was expressed basally and was significantly upregulated by allergen challenge, compared with the nonchallenged side and nonallergic control subjects (p < 0.05). Submucosal eosinophils increased significantly in allergic subjects 24 hours after antigen challenge, compared with nonallergic control subjects and weakly correlated with VCAM-1 expression (rs = 0.33, p = 0.06). Our results suggest that endothelial activation accompanies allergic inflammation. Furthermore, because the counterligand for VCAM-1, very late activation antigen-4, is present on eosinophils, VCAM-1 upregulation may contribute to the selective recruitment of these cells to the nasal mucosa.

Severe aortic regurgitation due to Neisseria mucosa endocarditis

A rare occurrence of Neisseria mucosa endocarditis on a native aortic valve not known to be diseased is reported. Despite vigorous antibiotic therapy, severe aortic regurgitation developed necessitating aortic valve replacement. At operation, the right coronary cusp was retracted with two small nodules attached to its edge and the non-coronary cusp was perforated. Neisseria mucosa endocarditis is very rare, and involves abnormal mitral or prosthetic valves predominantly. Infection of a native aortic valve, with no known history of disease, is exceptional.

Pregnancy outcome and mitral valve prolapse

Mitral valve prolapse (MVP) comprises a large proportion of obstetric cardiac problems and has a general prevalence of 4%. We examined the obstetric outcome of patients with MVP delivered between 1988-1991 at the National University Hospital, Singapore. During this interval, deliveries totalled 16,755 of which 85 (0.51%) had maternal cardiac disease. Of these, 28 (32.9%) had echocardiographic evidence of non-myxomatous MVP. Ten patients (37.5%) had demonstrable mitral regurgitation and 4 (14.3%) had benign ventricular ectopics. All patients remained well throughout pregnancy. Gestation at delivery and use of analgesia did not differ significantly from non-cardiac patients. However, the labour induction rate was twice the department average at 17.9%. Twenty-four (85.7%) patients achieved vaginal delivery and 4 (14.3%) patients were delivered abdominally. All babies were liveborn. Eight patients (28.6%) did not receive antibiotic prophylaxis during labour and postpartum period and remained afebrile. The role of antibiotics in this category of patients is discussed. Patients with MVP without myxomatous valve changes may expect excellent pregnancy outcome.

The new titanium Greenfield vena cava filter: initial experience and review

The Greenfield vena cava filter is an established therapeutic option in the prevention of pulmonary embolism. The development of a 12 French modified titanium Greenfield filter (TGF) has made it possible to insert the filter percutaneously and to have a low complication rate. We report our initial experience with percutaneous insertion of the 12-French titanium Greenfield vena cava filter for 6 patients who all had major extensive deep venous thrombosis (DVT) and contraindications to anticoagulation. The inferior vena cava (IVC) filters were inserted in all the 6 patients via the internal jugular route without difficulty. There was no bruising, haematoma or bleeding complications despite the use of the 12 French system. The IVC filter was opened without cross-snaring of the filter legs in all 6 patients. This was confirmed with cranio-caudal, left anterior oblique and right anterior oblique views of the deployed filter. There was however some asymmetry of the filter leg positions but it did not cause any significant angulation of the filter in relation to the IVC. The IVC filters were firmly secured with no filter migration immediately post-procedure. The 12-French titanium Greenfield vena cava filter was safely deployed percutaneously with no complications in our small series of patients. With the use of titanium in the design of Greenfield filter, the clinical effectiveness and performance is maintained while providing for easier insertion and reduction of patient discomfort.(ABSTRACT TRUNCATED AT 250 WORDS)

Prevalence of peripheral artery disease in patients with coronary artery disease

The incidence of coronary artery disease in Singapore has shown a rapid rise in recent years, however, there is a subjective impression that the prevalence of atherosclerotic peripheral artery diseases, although sharing common aetiological factors with coronary artery disease, has not shown a similar rise. We set out to determine the incidence of occlusive peripheral artery diseases of the lower limb in a selected population of Asian patients using a non-invasive test and we analysed the risk factors. The overall prevalence of peripheral artery disease of the subjects as determined by an abnormal ankle brachial index less than 0.9 in at least one limb was 19.1%. Increasing age, hypercholesterolemia and smoking were risk factors. In patients with proven coronary artery disease, abnormal ankle brachial indices were present in 21.3% of patients with angiographic evidence of coronary artery disease but in only 13.0% of those without. In this study, the incidence of peripheral artery disease in this selected Asian population was high. With the increasing availability of vascular laboratories and awareness of the diseases, we can expect to see increasing numbers of patients presenting with these problems.

Review of patients with infective endocarditis of native valves over a five-year period

The clinical characteristics, echocardiographic features, bacteriologic data, morbidity and mortality of patients who were admitted to our hospital with infective endocarditis of their native valves over a five-year period were reviewed. There were 32 patients with a mean age of 38.2 +/- 16.2 years (range: 17 to 71 years) in our study population; 24 patients had underlying valvular abnormalities, six patients had congenital heart disease and two patients had no structural cardiac abnormality. Echocardiography was performed for all patients. Vegetations were absent in three (9.4%) patients, single in 19 (59.4%) patients and multiple in ten (31.3%) patients. Of the 24 (75%) patients who had left-sided endocarditis, mitral valve disease was the commonest valvular abnormality (16 patients). Ventricular septal defect was the commonest underlying abnormality in patients with right-sided endocarditis. Blood cultures were positive in 26 (81.3%) patients; the commonest organism was streptococcal (16 or 50% patients). Complications were present in 13 (40.6%) patients, of which eight patients had evidence of embolism, four patients had cardiac failure and one patient had a paravalvular abscess. Four (12.5%) patients died, two as a result of refractory heart failure and two as a consequence of septic embolism. Advances in medicine have resulted in a better outcome for patients with infective endocarditis, however, it remains an important disease with significant morbidity and mortality.

Early experiences of intra-operative trans-oesophageal echocardiography (TEE) in mitral valve repair

Whenever possible Mitral valve repair should be performed instead of Mitral valve replacement. It is important to assess the adequacy of the repair during the operation so that any corrective steps may be taken immediately. We present three cases of Mitral valve repair in which the intraoperative TEE was used to assess the adequacy of the repair. There was good correlation of the immediate post bypass TEE findings and early post operative transthoracic echocardiographic findings. Intraoperative TEE is a useful tool in the early assessment of Mitral Valve Repair.

Efficacy and cost-effectiveness of simvastatin and gemfibrozil in the treatment of hyperlipidaemia

The aim of this study is to compare the efficacy and cost-effectiveness of simvastatin with gemfibrozil in regulating the serum lipid profiles in the local population. In this study, we reviewed the effect of medication on 75 patients with hypercholesterolaemia with or without hypertriglyceridaemia; 26 patients were on simvastatin 10 mg nightly, 24 patients were on gemfibrozil 300 mg twice daily and 25 patients were on gemfibrozil 600 mg twice daily. The average follow-up period was 10.8 weeks, 19.0 weeks and 16.2 weeks for simvastatin 10 mg, gemfibrozil 300 mg and gemfibrozil 600 mg groups respectively. Prior to drug therapy, patients were put on dietary control. The pre-treatment and post-treatment serum lipid profiles were monitored. The mean changes in the lipid profiles of the patients on gemfibrozil 600 mg twice daily were a 21.6% reduction in total cholesterol, a 21.8% reduction in low-density lipoprotein cholesterol (LDL-C), a 46.3% reduction in serum triglyceride and an 11.2% increase in high density lipoprotein cholesterol (HDL-C). The patients in all three groups had raised HDL-C and lowered triglyceride levels post-treatment but patients on gemfibrozil had a greater increase in HDL-C and a greater decrease in triglycerides as compared to the simvastatin group. In comparison to gemfibrozil, simvastatin was more efficacious in the reduction of LDL-C. The mean reduction in the LDL-C was 21.8% for gemfibrozil 600 mg twice daily group as compared to 28.0% for simvastatin 10 mg nightly group.(ABSTRACT TRUNCATED AT 250 WORDS)

Cushing's disease in pregnancy

Cushing's disease in pregnancy is rare and is associated with an increased incidence of maternal morbidity, premature delivery, spontaneous abortions and stillbirths. We report a successful term pregnancy in a patient with Cushing's disease due to a pituitary microadenoma. The literature is reviewed.

Treatment of adrenal cortical carcinoma with mitotane: outcome and complications

Adrenal cortical carcinoma is a rare tumour with a poor prognosis. We report a patient with metastatic adrenal cortical carcinoma who responded dramatically to Mitotane (o,p'-DDD). Unlike previous reports of metastatic adrenal cortical carcinoma in which complete remission was obtained with high dose Mitotane treatment, the dose of Mitotane used in this patient was low. However, she developed unusual side-effects such as hyperpigmentation, low plasma cortisol and high adrenocorticotropic (ACTH) levels. The side effects closely resemble those in Nelson's syndrome and were reversed by cortisone replacement. The mechanism of actions of Mitotane is discussed with emphasis on its effect on corticosteroid metabolism.

A Chinese family with Wolfram syndrome presenting with rapidly progressing diabetic retinopathy and renal failure

We describe a Chinese family with three siblings, all females, presenting with the Wolfram Syndrome. All three cases had almost similar clinical presentation of insulin-dependent diabetes mellitus, with rapid development of severe renal and retinal complications. Two siblings died at age thirty and thirty-one years of end-stage renal failure. All three cases had visual symptoms since early childhood progressing rapidly to loss of vision. Two of the three siblings had severe diabetic retinopathy requiring laser photocoagulation. These presentations are in contrast to most reported cases of the Wolfram syndrome where advanced diabetic eye complication is a rare feature. We also present several features present in one of the siblings, viz., microcephaly, microstomia, clinodactylyl, brachydactylyl, empty sella syndrome and severe hypoplasia of the right internal carotid vessels associated with mild narrowing of the left internal carotid artery which have not been previously described.

Relapsing polychondritis--a report on two Chinese patients with severe costal chondritis

Relapsing polychondritis is a rare multisystemic connective tissue disorder found mainly in Caucasians. Oriental patients with relapsing polychondritis are uncommon. We report 2 Chinese patients with relapsing polychondritis who had severe laryngotracheal narrowing requiring tracheostomy. Unlike most patients, there was marked costal chondritis resulting in depression of the anterior chest wall with minimal involvement of other joints. One of the patients had treatment with prednisolone, dapsone, azathioprine, cyclophosphamide and cyclosporin A at various stages of the disease without significant remission of the disease.

Diepoxybutane-induced male-transmissible X-autosome translocations in Drosophila melanogaster: a test of the supporting evidence for the Lifschytz-Lindsley model of spermatogenesis

The Lifschytz-Lindley model of spermatogenesis in heterogametic animals postulates a stage of gene inactivation during spermatogenesis, which affects the X-chromosome and the autosomes at different times. The frequent male infertility of X-ray induced X-autosome translocations is attributed to disruption in the timing of this stage by breaks that occur in the interior euchromatic portion of the X. Indeed, all male-fertile X-ray induced translocations between the X and an autosome had their breakpoints in the proximal or distal portion of the X. We now show that this was true also for 16 male-fertile X-autosome translocations that had been induced by an alkylating agent, diepoxybutane (DEB). The significantly higher proportion of male-fertile X-translocations in this experiment than in experiments with ionizing radiation apparently is due to a preference of diepoxybutane for the induction of breaks in the "permissive" regions of the X. Older data suggest that this preference is even stronger for mustard gas as chromosome-breaking agent. While these data do not add further evidence to the Lifschytz-Lindley model, they remove a potential objection to it.

A quantitative study of the second meiotic metaphase in male mice (Mus musculus)

Over 11,000 second meiotic metaphase spreads stained for the pericentromeric region have been studied quantitatively in male mice of 14 strains. The sex-chromosome constitution of a cell could be judged objectively if X and Y chromosomes and ploidy were all scored. A bias arose if only Y chromosomes and ploidy were scored but could be corrected statistically. There was no sign of other forms of bias. The original contiguity of X and Y second metaphases in vivo was very occasionally evident in the preparations. Most of the subhaploid aneuploid counts were assumed to be artifactual. The incidence of truly aneuploid second metaphases in 13 strains was estimated as 0.38+/-0.12%. The estimated average rate per chromosome was 0.019+/-0.006%, with a comparable order of magnitude for the sex chromosomes alone. Simultaneous aneuploidy of two or more chromosomes of the haploid set was estimated to be very rare. Of the spreads from 13 strains, 9.6% were polyploid (2N, 3N, 4N) and showed most of the possible combinations of sex chromosomes. Nearly all the polyploid spreads were considered to arise by artifactual cell fusion at the time of second metaphase during the preparative technique, especially of the X and Y daughter-cell products of the first meiotic division. Other modes of origin (true polyploidy, accidental superposition of cells during preparation) were unlikely. The data could be accommodated by a statistical model with only four parameters. It allowed for artifactual fusion mainly between daughter cells but also between non-daughter cells, bias in one scoring method, and bias in the numbers of cells with given ploidy successfully mounted. Current techniques of chromosome preparation were thought to be wholly unsuitable for the recognition of true polyploidy. The artifactual origin of polyploid spreads was borne out by an absence of polyploid spermatozoa in 14 strains. There appeared to be a virtually constant transmission rate of paternal X and Y chromosomes from early meiosis to late blastocyst. The estimated rate of 49.05+/-0.67% with a Y chromosome also estimated the primary sex ratio. There was evidence of polymorphism in autosomal pericentromeric staining in 3 strains. No measure of the numbers of autosomes or sex chromosomes varied significantly between duplicate preparations or between duplicate males of a strain.