ABE8e Corrects Pax6-Aniridic Variant in Humanized Mouse ESCs and via LNPs in Ex Vivo Cortical Neurons

INTRODUCTION

Aniridia is a rare congenital vision-loss disease caused by heterozygous variants in the PAX6 gene. There is no vision-saving therapy, but one exciting approach is to use CRISPR/Cas9 to permanently correct the causal genomic variants. Preclinical studies to develop such a therapy in animal models face the challenge of showing efficacy when binding human DNA. Thus, we hypothesized that a CRISPR gene therapy can be developed and optimized in humanized mouse embryonic stem cells (ESCs) that will be able to distinguish between an aniridia patient variant and nonvariant chromosome and lay the foundation for human therapy.

METHODS

To answer the challenge of binding human DNA, we proposed the "CRISPR Humanized Minimally Mouse Models" (CHuMMMs) strategy. Thus, we minimally humanized Pax6 exon 9, the location of the most common aniridia variant c.718C > T. We generated and characterized a nonvariant CHuMMMs mouse, and a CHuMMMs cell-based disease model, in which we tested five CRISPR enzymes for therapeutic efficacy. We then delivered the therapy via lipid nanoparticles (LNPs) to alter a second variant in ex vivo cortical primary neurons.

RESULTS

We successfully established a nonvariant CHuMMMs mouse and three novel CHuMMMs aniridia cell lines. We showed that humanization did not disrupt Pax6 function in vivo, as the mouse showed no ocular phenotype. We developed and optimized a CRISPR therapeutic strategy for aniridia in the in vitro system, and found that the base editor, ABE8e, had the highest correction of the patient variant at 76.8%. In the ex vivo system, the LNP-encapsulated ABE8e ribonucleoprotein (RNP) complex altered the second patient variant and rescued 24.8% Pax6 protein expression.

CONCLUSION

We demonstrated the usefulness of the CHuMMMs approach, and showed the first genomic editing by ABE8e encapsulated as an LNP-RNP. Furthermore, we laid the foundation for translation of the proposed CRISPR therapy to preclinical mouse studies and eventually patients with aniridia.

Human MiniPromoters for ocular-rAAV expression in ON bipolar, cone, corneal, endothelial, Müller glial, and PAX6 cells

Small and cell-type restricted promoters are important tools for basic and preclinical research, and clinical delivery of gene therapies. In clinical gene therapy, ophthalmic trials have been leading the field, with over 50% of ocular clinical trials using promoters that restrict expression based on cell type. Here, 19 human DNA MiniPromoters were bioinformatically designed for rAAV, tested by neonatal intravenous delivery in mouse, and successful MiniPromoters went on to be tested by intravitreal, subretinal, intrastromal, and/or intravenous delivery in adult mouse. We present promoter development as an overview for each cell type, but only show results in detail for the recommended MiniPromoters: Ple265 and Ple341 (PCP2) ON bipolar, Ple349 (PDE6H) cone, Ple253 (PITX3) corneal stroma, Ple32 (CLDN5) endothelial cells of the blood-retina barrier, Ple316 (NR2E1) Müller glia, and Ple331 (PAX6) PAX6 positive. Overall, we present a resource of new, redesigned, and improved MiniPromoters for ocular gene therapy that range in size from 784 to 2484 bp, and from weaker, equal, or stronger in strength relative to the ubiquitous control promoter smCBA. All MiniPromoters will be useful for therapies involving small regulatory RNA and DNA, and proteins ranging from 517 to 1084 amino acids, representing 62.9-90.2% of human proteins.

Germline CRISPR/Cas9-Mediated Gene Editing Prevents Vision Loss in a Novel Mouse Model of Aniridia

Aniridia is a rare eye disorder, which is caused by mutations in the paired box 6 (PAX6) gene and results in vision loss due to the lack of a long-term vision-saving therapy. One potential approach to treating aniridia is targeted CRISPR-based genome editing. To enable the Pax6 small eye (Sey) mouse model of aniridia, which carries the same mutation found in patients, for preclinical testing of CRISPR-based therapeutic approaches, we endogenously tagged the Sey allele, allowing for the differential detection of protein from each allele. We optimized a correction strategy in vitro then tested it in vivo in the germline of our new mouse to validate the causality of the Sey mutation. The genomic manipulations were analyzed by PCR, as well as by Sanger and next-generation sequencing. The mice were studied by slit lamp imaging, immunohistochemistry, and western blot analyses. We successfully achieved both in vitro and in vivo germline correction of the Sey mutation, with the former resulting in an average 34.8% ± 4.6% SD correction, and the latter in restoration of 3xFLAG-tagged PAX6 expression and normal eyes. Hence, in this study we have created a novel mouse model for aniridia, demonstrated that germline correction of the Sey mutation alone rescues the mutant phenotype, and developed an allele-distinguishing CRISPR-based strategy for aniridia.

New MiniPromoter Ple345 (NEFL) Drives Strong and Specific Expression in Retinal Ganglion Cells of Mouse and Primate Retina

Retinal gene therapy is leading the neurological gene therapy field, with 32 ongoing clinical trials of recombinant adeno-associated virus (rAAV)–based therapies. Importantly, over 50% of those trials are using restricted promoters from human genes. Promoters that restrict expression have demonstrated increased efficacy and can limit the therapeutic to the target cells thereby reducing unwanted off-target effects. Retinal ganglion cells are a critical target in ocular gene therapy; they are involved in common diseases such as glaucoma, rare diseases such as Leber's hereditary optic neuropathy, and in revolutionary optogenetic treatments. Here, we used computational biology and mined the human genome for the best genes from which to develop a novel minimal promoter element(s) designed for expression in restricted cell types (MiniPromoter) to improve the safety and efficacy of retinal ganglion cell gene therapy. Gene selection included the use of the first available droplet-based single-cell RNA sequencing (Drop-seq) dataset, and promoter design was bioinformatically driven and informed by a wide range of genomics datasets. We tested seven promoter designs from four genes in rAAV for specificity and quantified expression strength in retinal ganglion cells in mouse, and then the single best in nonhuman primate retina. Thus, we developed a new human-DNA MiniPromoter, Ple345 (NEFL), which in combination with intravitreal delivery in rAAV9 showed specific and robust expression in the retinal ganglion cells of the nonhuman-primate rhesus macaque retina. In mouse, we also developed MiniPromoters expressing in retinal ganglion cells, the hippocampus of the brain, a pan neuronal pattern in the brain, and peripheral nerves. As single-cell transcriptomics such as Drop-seq become available for other cell types, many new opportunities for additional novel restricted MiniPromoters will present.

PAX6 MiniPromoters drive restricted expression from rAAV in the adult mouse retina

Current gene therapies predominantly use small, strong, and readily available ubiquitous promoters. However, as the field matures, the availability of small, cell-specific promoters would be greatly beneficial. Here we design seven small promoters from the human paired box 6 (PAX6) gene and test them in the adult mouse retina using recombinant adeno-associated virus. We chose the retina due to previous successes in gene therapy for blindness, and the PAX6 gene since it is: well studied; known to be driven by discrete regulatory regions; expressed in therapeutically interesting retinal cell types; and mutated in the vision-loss disorder aniridia, which is in need of improved therapy. At the PAX6 locus, 31 regulatory regions were bioinformatically predicted, and nine regulatory regions were constructed into seven MiniPromoters. Driving Emerald GFP, these MiniPromoters were packaged into recombinant adeno-associated virus, and injected intravitreally into postnatal day 14 mice. Four MiniPromoters drove consistent retinal expression in the adult mouse, driving expression in combinations of cell-types that endogenously express Pax6: ganglion, amacrine, horizontal, and Müller glia. Two PAX6-MiniPromoters drive expression in three of the four cell types that express PAX6 in the adult mouse retina. Combined, they capture all four cell types, making them potential tools for research, and PAX6-gene therapy for aniridia.

rAAV-compatible MiniPromoters for restricted expression in the brain and eye

BACKGROUND

Small promoters that recapitulate endogenous gene expression patterns are important for basic, preclinical, and now clinical research. Recently, there has been a promising revival of gene therapy for diseases with unmet therapeutic needs. To date, most gene therapies have used viral-based ubiquitous promoters-however, promoters that restrict expression to target cells will minimize off-target side effects, broaden the palette of deliverable therapeutics, and thereby improve safety and efficacy. Here, we take steps towards filling the need for such promoters by developing a high-throughput pipeline that goes from genome-based bioinformatic design to rapid testing in vivo.

METHODS

For much of this work, therapeutically interesting Pleiades MiniPromoters (MiniPs; ~4 kb human DNA regulatory elements), previously tested in knock-in mice, were "cut down" to ~2.5 kb and tested in recombinant adeno-associated virus (rAAV), the virus of choice for gene therapy of the central nervous system. To evaluate our methods, we generated 29 experimental rAAV2/9 viruses carrying 19 different MiniPs, which were injected intravenously into neonatal mice to allow broad unbiased distribution, and characterized in neural tissues by X-gal immunohistochemistry for icre, or immunofluorescent detection of GFP.

RESULTS

The data showed that 16 of the 19 (84 %) MiniPs recapitulated the expression pattern of their design source. This included expression of: Ple67 in brain raphe nuclei; Ple155 in Purkinje cells of the cerebellum, and retinal bipolar ON cells; Ple261 in endothelial cells of brain blood vessels; and Ple264 in retinal Müller glia.

CONCLUSIONS

Overall, the methodology and MiniPs presented here represent important advances for basic and preclinical research, and may enable a paradigm shift in gene therapy.

Pregnancy luteoma presenting as ovarian torsion with rupture and intra-abdominal bleeding

We report a case of pregnancy luteoma, which had undergone torsion in a 33-year-old Indian woman, who presented with severe abdominal pain and decreasing haemoglobin levels at 33 weeks gestation. Ultrasonography showed a right adnexal mass, probably ovarian in origin, with suspicious intratumoral bleed. The pain was treated symptomatically, and the symptoms improved. A successful induction of labour was then performed at 36 weeks gestation. The pain recurred almost immediately after the delivery, and she experienced another intra-abdominal bleed. A diagnostic laparotomy and a right salpingo-oophorectomy were performed, and the diagnosis of luteoma was made based on histology. We discuss the clinical presentation of this unusual tumour, though often asymptomatic, can rarely present with severe abdominal pain from complications like torsion with rupture, leading to massive intra-abdominal bleeding. We also discuss the possible radiological investigations which can be done during pregnancy.

Clinics in diagnostic imaging (110). Right-sided tubal ligation clips complicated by the formation of an infected retention cyst

A 35-year-old Chinese woman presented with a five-day history of right iliac fossa pain and mass. She had no significant past medical history apart from laparoscopic tubal ligation performed years ago. Pelvic ultrasonography demonstrated a well-rounded cystic mass with homogeneous internal echoes and a brightly echogenic component, compatible with tubal ligation clips. Right adnexal infected retention cyst secondary to tubal ligation clips was diagnosed. Complications of female sterilisation are rare but nevertheless have been reported and accounted for symptoms of lower abdominal pain, and should be considered as a differential diagnosis.

Clinics in diagnostic imaging (106). Viable left tubal twin ectopic pregnancy

Live twin ectopic gestations are extremely rare. There are more than 100 reported twin tubal pregnancies but less than ten have foetal cardiac motions demonstrated in both embryos. We describe an additional patient with live twin ectopic gestation. A 32-year-old woman presented with increasing left-sided abdominal pains. She had a high beta-hCG level and a significant history of subfertility with previous surgical intervention. Transvaginal ultrasonography showed viable left tubal twin ectopic pregnancy. The diagnosis was confirmed at surgery. Factors that contribute to the risk of ectopic pregnancy, diagnosis and the management of this condition are described.

Imaging findings in acute neck infection due to pyriform sinus fistula

INTRODUCTION

Pyriform sinus fistula is a congenital branchial pouch abnormality that is often overlooked as a cause of acute neck infection in children. Our aim is to demonstrate the value of various imaging modalities (ultrasound, computed tomography [CT], barium oesophagraphy) in its diagnosis.

MATERIALS AND METHODS

The preoperative imaging findings of 5 patients with surgically proven pyriform sinus fistula who presented with acute neck infection between September 2001 and March 2003 were retrospectively reviewed. CT was performed in all patients, 4 patients had barium oesophagraphy and 3 had an ultrasound scan.

RESULTS

All 5 patients suffered from upper respiratory tract infection within a week of developing a tender swelling on the left side of the neck. Four patients had a history of recurrent neck infections. CT depicted inflammation of the left perithyroid soft tissue and adjacent left thyroid lobe in every case. In 2 cases, CT demonstrated the presence of a pyriform sinus fistula. Ultrasound, performed in 3 patients, correlated strongly with the CT findings. It also showed gas within a fistula in 1 case. Barium oesophagraphy clearly delineated the fistula in 3 out of 4 cases.

CONCLUSION

Ultrasound and CT accurately showed the presence of acute neck infection and could demonstrate the pyriform sinus fistula. Barium oesophagraphy most clearly depicted the presence and course of the fistula. Recurrent left-sided neck infection in a child should alert the physician to the possibility of an underlying pyriform sinus fistula and imaging should be performed to confirm its presence.

Clinics in diagnostic imaging (98). Heterotopic pregnancy with an intrauterine blighted ovum and a live tubal ectopic pregnancy

A 26-year-old woman who was six weeks amenorrhoeic presented with vaginal spotting and mild abdominal pain. She had been coming to the 24 hours women's clinic at two-day intervals for the past week with the same symptoms. Ultrasonography two days ago showed one intrauterine gestational sac (IUGS) with a yolk sac within. Her pregnancy was clomiphene-related. Repeat transvaginal ultrasonography during this admission showed an IUGS, together with a left live tubal ectopic pregnancy. Heterotopic pregnancies used to be a rare entity. Now, given the increasing rise in assisted reproduction techniques, there should be a high index of suspicion for heterotopic pregnancy as this would impact upon clinical management. The ultrasonographical features of heterotopic pregnancy and its differential diagnoses are discussed.

Clinics in diagnostic imaging (92)

A 43-year-old woman presented with a 10-day history of lower abdominal pain and two days of vaginal bleeding. Ultrasonography showed a sac-like structure within the endocervical canal. The structure had a thick echogenic rim. No foetal heartbeat was seen. Intramuscular methotrexate was given and evacuation of the uterus yielded a small amount of tissue which was revealed histologically as products of conception, confirming the diagnosis of a cervical ectopic pregnancy. The clinical and imaging features of cervical ectopic pregnancy are highlighted.

Foreign signal peptides can constitute a barrier to functional expression of periplasmic proteins in Haemophilus influenzae

To study the periplasmic branch of iron (ferric ion) uptake systems in Gram-negative bacteria, genetic reconstitution experiments were initiated in Haemophilus influenzae involving exchange of the periplasmic iron-binding protein. The expression of many of the heterologous periplasmic ferric-binding proteins (FbpAs) was quite limited. Transformation experiments with the fbpA gene from Neisseria gonorrhoeae yielded two colony sizes with different phenotypic characteristics. The small colonies contained the intact N. gonorrhoeae fbpA gene and were deficient in utilization of transferrin iron. The large colonies contained hybrid H. influenzae/N. gonorrhoeae fbpA genes, were proficient in transferrin iron utilization and had enhanced levels of expression of FbpA. These hybrid genes included several that encoded the mature N. gonorrhoeae FbpA with the H. influenzae signal peptide. To more fully evaluate the effect of foreign signal peptides, a series of hybrid genes were prepared that exchanged the signal peptides from H. influenzae FbpA, N. gonorrhoeae FbpA and the TEM-1 beta-lactamase. The presence of the H. influenzae leader was required for functional expression of FbpAs and was shown to dramatically increase the level of beta-lactamase activity.

A countrywide approach to the control of non-communicable diseases--the Singapore experience

INTRODUCTION

Many developed and developing countries are grappling with recent epidemics of non-communicable diseases and how to effectively control them. Singapore as a small, compact and highly urbanized country has similarly experienced a rapid increase in its chronic disease load and has adopted a national approach to control them.

METHODS

This paper traces the strategies taken in the 80s and the 90s to control non-communicable diseases and evaluates the effectiveness of the two approaches.

RESULTS

In the 80s, the control programme was largely a Ministry of Health responsibility using a persuasive approach to reach out to the target groups. This produced some results through the lowering of hypertension and cholesterol. For the 90s, the approach was one of leadership by government working with relevant agencies to reach out to all relevant sectors in the population. This National Healthy Lifestyle Programme was given top political support. The integrated and comprehensive approach used showed some improvements in health and gave the direction where efforts should be channelled.

CONCLUSION

The countrywide approach taken in Singapore for the control of non-communicable diseases illustrates a model where a national framework was adopted, harnessing health promotion and disease prevention and involving personal responsibility as a key success factor. This rides on a well-developed continuum of healthcare which aims to become an integrated and seamless one.

Ultrasonography and computed tomography in a clinical algorithm for the evaluation of suspected acute appendicitis in children

AIM

To evaluate the roles and effectiveness of US and CT in a clinical algorithm for the evaluation of children with suspected appendicitis.

METHODS

Patients with suspected appendicitis were prospectively evaluated with ultrasound (US), and in some cases with CT, after they were graded to have high, intermediate or low clinical likelihood for appendicitis. Imaging findings were made known to clinicians who then decided on a line of management. Patho-histological examination and clinical follow-up established the final diagnoses, which were correlated with the imaging findings. The effect of imaging on the management of patients was examined.

RESULTS

Overall, the sensitivity of US was 92.9%, specificity 96.9%, accuracy 96.0%, positive predictive value 89.7% and negative predictive value 97.9%. Imaging did not affect the decision to operate in 13/14 (92.9%) patients in the high likelihood subgroup. Imaging guided the clinicians to the right management pathway in 26/30 (86.7%) patients in the intermediate group. 77/82 (93.9%) of US was truly negative in the low likelihood group. CT was performed in 12 patients because of unsatisfactory US scans or incompatibility between the US and the clinical findings. CT correctly diagnosed the presence or absence of appendicitis in all 12 patients.

CONCLUSION

US and CT are accurate modalities in the diagnosis of acute appendicitis in children. US is most useful in patients with equivocal clinical findings. US should be the first modality used to evaluate children with suspected appendicitis. CT should be reserved for cases where US is sub-optimal or where the findings are inconsistent with the clinical findings.

Subungual squamous cell carcinoma: report of 2 cases

Subungual squamous cell carcinoma (SCC) is a rare malignant tumor with an indolent course. Its etiology is unknown. It often involves the distal phalanx of the thumb or the index finger, and often presents as a chronic ulcer that is commonly misdiagnosed as chronic paronychia, pyogenic granuloma or verruca vulgaris. Approximately 150 cases of subungual SCC, including one in a Taiwanese patient, have been reported. Here, we report two cases of subungual SCC presenting as a chronic ulcer of the nail bed refractory to antibiotic treatment. One case involved the right thumb, while the other involved the right index finger. Radiographs of both cases showed an osteolytic bone lesion involving the distal phalanx. Excision biopsy revealed SCC in both cases. Both patients received amputation of the involved distal phalanx and showed no signs of reoccurrence during 5 years of follow-up. These findings suggest that all recalcitrant ulcers of the nail bed should be biopsied to facilitate early diagnosis and treatment of subungual SCC.

HealthLine--a telephone health information and promotion service in Singapore

HealthLine is a toll-free telephone information service on healthy living. Provided by Singapore's Ministry of Health, it augments national health promotion programmes and simultaneously feels the pulse of the common health concerns of the population. The development of the telephone information service is described and the ease of the use of telecommunication in the provision of health information and promotion is highlighted in the paper.

Sequence-specific local structural variations in solution structures of d(CGXX'CG)2 and d(CAXX'TG)2 self-complementary deoxyribonucleic acids

In this study, the solution structures of eight self-complementary deoxyribonucleic acid molecules, d(CGXX'CG)2 and d(CAXX'TG)2 (where X = C, G, T or A and X' is complementary to X), have been determined using NMR interproton distances, endocyclic sugar torsion angles, backbone torsion angles and hydrogen bond constraints. Based on the structural data obtained in solution, a novel sequence-specific local structure function, sigma LS, composed of the sum of the contributions from the helix twist omega, base roll rho, base-pair slide delta delta and propeller twist omega, is introduced to describe their sequence-specific local structures. Sigma LS is found to produce an acceptable correlation (r = 0.96) with the relative local stability (delta G0 10) of a base-pair-step. This result demonstrates that in addition to the inter-strand purine-purine clashes, the base morphology of nearest-neighbor base-pairs is also important in defining the local geometry of base-pairs. Thus, in analyzing the base-pair structural parameter blocks of trimers are used as the basic unit whereas for the base-pair-step structural parameters, the basic unit is composed of blocks of tetramers. The omega LS-delta G(zero) 10 correlation is the first experimental evidence demonstrating the relationship between the relative local stabilities and the sequence-specific local structures of DNA duplexes. It also forms the basis for using the trimer-tetramer model for the prediction of sequence-specific local structures of deoxyribonucleic acid molecules.

The J-coupling restrained molecular mechanics (JrMM) protocol--an efficient alternative for deriving DNA endocyclic torsion angle constraints. Part II: Experimental application of the JrMM protocol

The J-coupling restrained molecular mechanics (JrMM) protocol, which correlates deoxyribose endocyclic torsion angles and vicinal proton-proton torsion angle phi 1'2' in Part I of this study, is demonstrated to be a viable alternative to efficiently derive the endocyclic torsion angle constraints for the determination of the solution structures of DNA molecules. Extensive testing demonstrating the validity of the JrMM-derived torsion angle constraints in the restrained molecular dynamics and energy minimization structural refinement processes is performed theoretically using an energy-minimized B-DNA model and experimentally using a DNA hexamer d(CGTACG)2. The results show that only a 0.2 A difference exists between the RMSD values of the refined structures using the ideal and the JrMM-derived endocyclic torsion angle constraints. The JrMM-derived torsion angles are also determined to be in good agreement with the torsion angles derived through the use of the vicinal J-derived torsion angles. These results show that through the use of reliably measured J1'2' values and computer simulation method, the endocyclic torsion angle constraints can be derived reliably and efficiently. Thus the JrMM method serves as an alternative strategy to generate endocyclic torsion angle constraints for the determination of the solution structures of DNA molecules.

The J-coupling restrained molecular mechanics (JrMM) protocol--an efficient alternative for deriving DNA endocyclic torsion angle constraints. Part I: Correlation of endocyclic torsion angles and vicinal torsion angle phi 1'2'

An efficient alternative which makes use of the reliable 3J1'2' value to derive the endocyclic torsion angle constraints is proposed in this study. Based on the information embedded in the two plots, (i) the vicinal proton-proton J-couplings, 3J1'2', 3J1'2", 3J2'3', 3J2"3' and 3J3'4' against the pseudorotation phase angle, and (ii) 3J1'2", 3J2'3', 3J2"3' and 3J3'4' against 3J1'2'; using the calculated J-couplings obtained for a range of sugar geometries of deoxyribose ring in nucleosides and nucleotides encountered along the pseudorotation itinerary [J. van Wijk, B.D. Huckriede, J.H. Ippel and C. Altona, Methods Enzymol. 211, 286-306 (1992)], it is suggested that the vicinal 3J1'2' possesses structural information other than the vicinal torsion angle phi 1'2'. This study is divided into two parts. In Part I, a correlation diagram between the endocyclic torsion angles nu(i) (i = 0,1,2,3,4) and the restrained vicinal torsion angle phi 1'2' is obtained through the use of the J-coupling restrained molecular mechanics (JrMM) protocol. The established phi 1'2'-nu(i) correlation shows nu(i) can be deduced from the reliable 3J1'2' value and it forms the basis for developing an alternative protocol to derive endocyclic torsion angle constraints. In Part II of this series, extensive testing demonstrating the validity of the JrMM protocol to derive nu(i) for defining the sugar geometry of solution DNA molecules is presented.

Secular trend of growth in pre-school children in Singapore

An anthropometric study was conducted on more than 13 500 children aged 04 years in 1988. Percentile charts were plotted for height for age, weight for age, weight for height and head circumference for age. When compared to an earlier study done in 1972, it was found that Singapore pre-school children had increased in height by 4.4 %; weight by 10.9 %; and head circumference by 4.1 %. When the median height for age, weight for age and head circumference for age were plotted against those of the NCHS charts (1978), Singapore's pre-school children were generally shorter, lighter and had smaller head circumferences than their American counterparts of the same age. But, the median weight-for-height for each age group was comparable to the Americans. The results indicate the secular trend of growth in Singapore children and a trend towards reaching their full genetic potential for growth.

Quantitative determination of glucose in blood plasma and in fruit juices by combined WATR-CPMG 1H NMR spectroscopy

The quantitative analysis of pure glucose solution < or = 225 mM (< or = 40.8 mg/mL) in 90/10 H2O/D2O was successfully completed in dilute aqueous solution by the WATR-CPMG method whereby the T2 of the water resonance is manipulated by the WATR method followed by elimination of the water peak by the CPMG pulse sequence. The method was applied to the quantitative analysis of total glucose in blood plasma from human subjects undergoing the oral glucose tolerance test in the teaching hospital, and the results were compared to those obtained using a standard glucose oxidase method in a hospital chemical pathology laboratory. The accuracy of the results obtained using the WATR-CPMG method were generally within 5% of the glucose oxidase method. The coefficient of variation was determined to be better than 4% using plasma samples of diabetic subjects. Application to the quantitative analysis of orange and guava juice was also successfully demonstrated.

Air in the cervical annulus--the lucent cleft sign

The lucent cleft sign is a sign of soft tissue injury. It was first described as a sign of acute cervical injury but it is neither confined to cases of trauma nor the cervical region. The sign is also seen in degenerative disease and in the lumbar spine. The lucent cleft sign is seen anteriorly, as an area of hyperlucency above the superior end plate of the vertebra. It is the result of a partial tear of the annulus. In complete avulsion, the sign may be absent and the radiograph, completely normal. We report our experience of 15 patients with the lucent cleft sign. Our patients are relatively young (commonest age group 30-35 years) and the majority (10 patients) had a history of acute trauma. Four patients had non-specific (3 cervical and one lumbar) aches while in the last patient, the lucent cleft was an incidental finding. Although we only documented the disappearance of the sign in 4 patients, we believe that with healing, the sign will eventually disappear. Although the sign is transient, it is useful as it may be the only sign present in cases of trauma.

Knowledge and concerns of newly diagnosed NIDDM patients in Singapore

This paper describes the findings of a questionnaire survey of the knowledge and concern of 152 newly diagnosed NIDDM patients presenting at the Government Polyclinic (primary health care centre). This study is part of a project on outpatient diabetic care in Singapore. It was found that 23.7% of the subjects had no education and 51.3% had only primary school education. More than eighty percent of the subjects understood the importance of diet control and weight control in their condition. More than half of the subjects, 61% of males and 52.7% of females were aware that diabetes could not be cured and that once diabetes is controlled, that medication cannot be stopped and that one must still take the medication even if one feels well. Less than 30% knew about the interpretation of blood and urine sugar findings. The two major concerns amongst the subjects were complications and the need for long-term medication. These findings will be incorporated into the next phase of the project where a health education programme for NIDDM patients will be developed and evaluated.

The pattern of diabetes in a primary health care setting in Singapore

This is a study of Diabetes mellitus and its treatment in a single doctor government primary health care clinic in Singapore. Data was collected on the entire 349 patients with diabetes attending this clinic over a three month period in 1987. We found there was an increasing number of diabetics with age and a substantial proportion was above 70 years of age. Only 7% had their diabetes treated with diet alone and 9.6% were treated with insulin. Most (61%) patients were on tolbutamide, with 17.6% on glibenclamide and 5.9% on chlorpropamide. Hypertension was found in 38% of the diabetic patients but was not associated with increase in age of the patient. The duration of diabetes, but not the age of the patient, was positively associated with the number of drugs taken by the patient (chi-squared, p less than 0.05).

Child-rearing practices of Chinese parents and their relationship to behavioural problems in toddlers

The aim of this study was to examine the relationship between behavioural deviance and parental involvement in childrearing and disciplinary practices in a sample of 401 toddlers. Mothers of each subject were interviewed to assess for the degree of parental involvement and the disciplinary methods used with the child. A Behavioural Screening Questionnaire (BSQ) was used to assess for behavioural deviance in the toddlers. Results indicated that father involvement in childrearing was significantly lower than mother involvement (p = 0.0001). Although consistent with cultural expectations, both low paternal involvement and punitive types of discipline were significantly related to behavioural deviance.

Role of leaves in phototropism

Experiments with green seedlings of sunflower (Helianthus annuns L.) indicate the existence of a phototropic mechanism which involves the leaves or cotyledons, and which can produce an asymmetry of auxin content without the involvement of lateral auxin transport, the classic explanation of phototropism in etiolated seedlings. The basic lines of evidence for the leaf-mediated tropism are: 1) darkening of one cotyledon will cause curvature of the stem toward the lighted cotyledon: 2) the darkened cotyledon sustains an enhanced growth rate in the stem below it: 3) conversely, light suppresses the growth-stimulating effects of a single cotyledon: and 4) more diffusible auxin is obtained from the stem below darkened cotyledons than below lighted ones.