Coronary microvascular dysfunction: prevalence and aetiology in patients with suspected myocardial ischaemia

AIM

To evaluate the prevalence, aetiology, and corresponding morbidity of coronary microvascular dysfunction (CMD) in patients with suspected myocardial ischaemia.

MATERIALS AND METHODS

The present study included 115 patients with suspected myocardial ischaemia who underwent stress perfusion cardiac magnetic resonance imaging. CMD was assessed visually based on the myocardial perfusion results. The CMR-derived myocardial perfusion reserve index (MPRI) and left ventricular (LV) strain parameters obtained using the post-processing software CVI42 were employed to evaluate LV myocardial perfusion and deformation. LV strain parameters included global longitudinal, circumferential, and radial strain (GLS, GCS, and GRS), global systolic/diastolic longitudinal, circumferential, and radial strain rates (SLSR, SCSR, SRSR, DLSR, DCSR, and DRSR).

RESULTS

Of the 115 patients, 12 patients were excluded and 103 patients were finally included in the study. CMD was observed in 79 % (81 patients, aged 53 ± 12 years) of patients. Regarding aetiology, 91 (88 %) patients had non-obstructive coronary artery disease (CAD), eight (8 %) had obstructive CAD, and four (4 %) had hypertrophic cardiomyopathy (HCM). The incidence of CMD was highest (100 %) in patients with HCM, followed by those with non-obstructive CAD (up to 79 %). There were no statistical differences between CMD and non-CMD groups in GCS, GRS, GLS, SRSR, SCSR, SLSR, DCSR, DRSR and DLSR.

CONCLUSION

The incidence of CMD was higher in patients with signs and symptoms of ischaemia. CMD occurred with non-obstructive CAD, obstructive CAD, and HCM, with the highest prevalence of CMD in HCM.

Cambridge hybrid closed-loop algorithm in children and adolescents with type 1 diabetes: a multicentre 6-month randomised controlled trial

BACKGROUND

Closed-loop insulin delivery systems have the potential to address suboptimal glucose control in children and adolescents with type 1 diabetes. We compared safety and efficacy of the Cambridge hybrid closed-loop algorithm with usual care over 6 months in this population.

METHODS

In a multicentre, multinational, parallel randomised controlled trial, participants aged 6-18 years using insulin pump therapy were recruited at seven UK and five US paediatric diabetes centres. Key inclusion criteria were diagnosis of type 1 diabetes for at least 12 months, insulin pump therapy for at least 3 months, and screening HbA1c levels between 53 and 86 mmol/mol (7·0-10·0%). Using block randomisation and central randomisation software, we randomly assigned participants to either closed-loop insulin delivery (closed-loop group) or to usual care with insulin pump therapy (control group) for 6 months. Randomisation was stratified at each centre by local baseline HbA1c. The Cambridge closed-loop algorithm running on a smartphone was used with either (1) a modified Medtronic 640G pump, Medtronic Guardian 3 sensor, and Medtronic prototype phone enclosure (FlorenceM configuration), or (2) a Sooil Dana RS pump and Dexcom G6 sensor (CamAPS FX configuration). The primary endpoint was change in HbA1c at 6 months combining data from both configurations. The primary analysis was done in all randomised patients (intention to treat). Trial registration ClinicalTrials.gov, NCT02925299.

FINDINGS

Of 147 people initially screened, 133 participants (mean age 13·0 years [SD 2·8]; 57% female, 43% male) were randomly assigned to either the closed-loop group (n=65) or the control group (n=68). Mean baseline HbA1c was 8·2% (SD 0·7) in the closed-loop group and 8·3% (0·7) in the control group. At 6 months, HbA1c was lower in the closed-loop group than in the control group (between-group difference -3·5 mmol/mol (95% CI -6·5 to -0·5 [-0·32 percentage points, -0·59 to -0·04]; p=0·023). Closed-loop usage was low with FlorenceM due to failing phone enclosures (median 40% [IQR 26-53]), but consistently high with CamAPS FX (93% [88-96]), impacting efficacy. A total of 155 adverse events occurred after randomisation (67 in the closed-loop group, 88 in the control group), including seven severe hypoglycaemia events (four in the closed-loop group, three in the control group), two diabetic ketoacidosis events (both in the closed-loop group), and two non-treatment-related serious adverse events. There were 23 reportable hyperglycaemia events (11 in the closed-loop group, 12 in the control group), which did not meet criteria for diabetic ketoacidosis.

INTERPRETATION

The Cambridge hybrid closed-loop algorithm had an acceptable safety profile, and improved glycaemic control in children and adolescents with type 1 diabetes. To ensure optimal efficacy of the closed-loop system, usage needs to be consistently high, as demonstrated with CamAPS FX.

FUNDING

National Institute of Diabetes and Digestive and Kidney Diseases.

Mid-treatment Fluorodeoxyglucose Positron Emission Tomography in Human Papillomavirus-related Oropharyngeal Squamous Cell Carcinoma Treated with Primary Radiotherapy: Nodal Metabolic Response Rate can Predict Treatment Outcomes

AIMS

To evaluate whether biomarkers derived from fluorodeoxyglucose positron emission tomography-computed tomography (FDG PET-CT) performed prior to (prePET) and during the third week (interim PET; iPET) of radiotherapy can predict treatment outcomes in human papillomavirus (HPV)-positive oropharyngeal squamous cell carcinoma (OPC).

MATERIALS AND METHODS

This retrospective analysis included 46 patients with newly diagnosed OPC treated with definitive (chemo)radiation and all patients had confirmed positive HPV status (HPV+OPC) based on p16 immunohistochemistry. The maximum standardised uptake value (SUV_max), metabolic tumour volume (MTV) and total lesional glycolysis (TLG) of primary, index node (node with the highest TLG) and total lymph nodes and their median percentage (≥50%) reductions in iPET were analysed, and correlated with 5-year Kaplan-Meier and multivariable analyses (smoking, T4, N2b-3 and AJCC stage IV), including local failure-free survival, regional failure-free survival, locoregional failure-free survival (LRFFS), distant metastatic failure-free survival (DMFFS), disease-free survival (DFS) and overall survival.

RESULTS

There was no association of outcomes with prePET parameters observed on multivariate analysis. A complete metabolic response of primary tumour was seen in 13 patients; the negative predictive value for local failure was 100%. More than a 50% reduction in total nodal MTV provided the best predictor of outcomes, including LRFFS (88% versus 47.1%, P = 0.006, hazard ratio = 0.153) and DFS (78.2% versus 41.2%, P = 0.01, hazard ratio = 0.234). More than a 50% reduction in index node TLG was inversely related to DMFFS: a better nodal response was associated with a higher incidence of distant metastatic failure (66.7% versus 100%, P = 0.009, hazard ratio = 3.0).

CONCLUSION

The reduction (≥50%) of volumetric nodal metabolic burden can potentially identify a subgroup of HPV+OPC patients at low risk of locoregional failure but inversely at higher risk of distant metastatic failure and may have a role in individualised adaptive radiotherapy and systemic therapy.

[Application of three-staged paramedian forehead flap in reconstruction and repair of full-thickness nasal defect]

Objective: To evaluate the application of three-staged paramendian forehead flap technique in reconstruction of severe full-thickness nasal defect. Methods: Clinical data of 7 cases with nasal reconstruction by three-staged forehead flap technique in the First Affiliated Hospital of Xinjiang Medical University and HongKong University Shenzhen Hospital between June 2016 and October 2019 was retrospectively reviewed. All were males aged from 10 to 71 years. There were 4 cases of basal cell carcinoma of the external nose, 2 cases of traumatic nasal defects and 1 case of large rhinophyma. All the operations were performed with the paramedian forehead flap in three stages. In stage Ⅰ, full layered forehead flap was transposed to the nasal detect. Lining flaps were reconstructed with folded forehead skin (n=4), turn-over flap plus septal chondro mucosal pivotal flap (n=2), or bipedicled vestibular skin and nasal mucosa advancement flap (n=1). According to the reconstruction mode of the lining flaps, whether to implant cartilage to reconstruct the external nasal stent at stage Ⅰ was determined. At stage Ⅱ, the folded flaps were partly or completely separated from the covering flaps along the free edges of nasal alar. All the excess soft tissue including subcutaneous fat and frontalis muscle were excised, cartilage grafts were placed or sculpted to make an ideal nasal contour. The covering flaps were then returned on the recontoured, three-dimensional recipient bed. At stage Ⅲ, the pedicles were divided. Descriptive statistical method was used to analyze the data. Results: In all cases, restoration of the nasal contour was remarkably good, no flap necrosis occurred. All patients were followed up for 6 months to 2 years, and the appearance and function of the nose recovered well. All patients were satisfied with their final aesthetic results. Conclusions: Three-staged paramedian forehead flap technique ensures maximal blood supply for the lining flap and the inserted cartilage graft, and restores an ideal three-dimensional nasal contour for reconstruction of large full thickness nasal defects.

HbA1c values and hospital admissions in children and adolescents receiving continuous subcutaneous insulin infusion therapy

AIMS

To assess HbA_1c values and hospitalization rates before, during and after continuous subcutaneous insulin infusion (CSII) therapy.

METHODS

Demographic and hospitalization data were extracted from 161 individuals with Type 1 diabetes who received continuous subcutaneous insulin infusion (CSII) therapy between 2002 and 2013 at the Leeds Children and Young People's Diabetes Service for those aged < 20 years. The median (range) age at CSII start was 11.9 (1.1-17.6) years. The median (range) follow-up time was 2.3 (0-8.1) years. Random intercept models were used to compare HbA_1c values before and during CSII initiation (and after CSII for those who discontinued it). Hospitalization rates were calculated for diabetic ketoacidosis and severe hypoglycaemia.

RESULTS

The mean HbA_1c concentration decreased by 7 mmol/mol [95% CI 6-8; 0.6% (95% CI 0.5-0.7%)]. For the discontinued group (n=30), mean HbA_1c decreased by 5 mmol/mol [95% CI 2-8; 0.4% (95% CI 0.2-0.7%)]. HbA_1c returned to pre-CSII start levels at the end of this therapy. Diabetic ketoacidosis admissions increased threefold during CSII compared with before CSII start [2.2 per 100 person-years (95% CI 1.3 to 3.6) vs 7.4 per 100 person-years (95% CI 5.1 to 10.8)] and was highest during the first year of CSII. No difference in severe hypoglycaemia incidence rate was found during CSII compared with the pre-CSII period.

CONCLUSIONS

Despite significant reductions in HbA_1c levels for individuals treated with CSII, improvements are needed to reduce diabetic ketoacidosis hospitalizations for those new to the therapy.

Home Use of an Artificial Beta Cell in Type 1 Diabetes

BACKGROUND

The feasibility, safety, and efficacy of prolonged use of an artificial beta cell (closed-loop insulin-delivery system) in the home setting have not been established.

METHODS

In two multicenter, crossover, randomized, controlled studies conducted under free-living home conditions, we compared closed-loop insulin delivery with sensor-augmented pump therapy in 58 patients with type 1 diabetes. The closed-loop system was used day and night by 33 adults and overnight by 25 children and adolescents. Participants used the closed-loop system for a 12-week period and sensor-augmented pump therapy (control) for a similar period. The primary end point was the proportion of time that the glucose level was between 70 mg and 180 mg per deciliter for adults and between 70 mg and 145 mg per deciliter for children and adolescents.

RESULTS

Among adults, the proportion of time that the glucose level was in the target range was 11.0 percentage points (95% confidence interval [CI], 8.1 to 13.8) greater with the use of the closed-loop system day and night than with control therapy (P<0.001). The mean glucose level was lower during the closed-loop phase than during the control phase (difference, -11 mg per deciliter; 95% CI, -17 to -6; P<0.001), as were the area under the curve for the period when the glucose level was less than 63 mg per deciliter (39% lower; 95% CI, 24 to 51; P<0.001) and the mean glycated hemoglobin level (difference, -0.3%; 95% CI, -0.5 to -0.1; P=0.002). Among children and adolescents, the proportion of time with the nighttime glucose level in the target range was higher during the closed-loop phase than during the control phase (by 24.7 percentage points; 95% CI, 20.6 to 28.7; P<0.001), and the mean nighttime glucose level was lower (difference, -29 mg per deciliter; 95% CI, -39 to -20; P<0.001). The area under the curve for the period in which the day-and-night glucose levels were less than 63 mg per deciliter was lower by 42% (95% CI, 4 to 65; P=0.03). Three severe hypoglycemic episodes occurred during the closed-loop phase when the closed-loop system was not in use.

CONCLUSIONS

Among patients with type 1 diabetes, 12-week use of a closed-loop system, as compared with sensor-augmented pump therapy, improved glucose control, reduced hypoglycemia, and, in adults, resulted in a lower glycated hemoglobin level. (Funded by the JDRF and others; AP@home04 and APCam08 ClinicalTrials.gov numbers, NCT01961622 and NCT01778348.).

Chondroitin sulfate and/or glucosamine hydrochloride for Kashin-Beck disease: a cluster-randomized, placebo-controlled study

OBJECTIVE

To evaluate the efficacy and safety of chondroitin sulfate and/or glucosamine hydrochloride in alleviating symptoms and improving the dysfunction of Kashin-Beck disease (KBD) patients.

METHODS

We undertook a cluster-randomized, placebo-controlled trial in 251 patients with KBD. Participants were randomly allocated to comparing (1) chondroitin sulfate, (2) glucosamine hydrochloride, (3) a combination of chondroitin sulfate and glucosamine hydrochloride, or (4) placebo, for 6 months duration. The primary outcome measures of interest were 20% and 50% reductions in pain from baseline, measured by pain subscale in the Western Ontario and McMaster Universities Osteoarthritis (WOMAC) Index. Secondary outcome measures included parameters in the WOMAC Index such as pain, stiffness, and physical function, as well as patients' quality of life by the 12-item Short-Form General Health Survey. The trial registration number is ChiCTR-TRC-11001480 (http://www.chictr.org/).

RESULTS

A combination therapy of chondroitin sulfate and glucosamine hydrochloride was effective in reducing WOMAC pain by 20% (differences of 23.4%, P=0.006) and 50% (differences of 15.7%, P=0.016), WOMAC pain (P=0.032), WOMAC stiffness (P=0.043), and WOMAC total score (P=0.035). Chondroitin sulfate used alone was also found to be effective in reducing WOMAC total score and stiffness score (P=0.038 and P=0.023, respectively). No significant positive effects in improving WOMAC Index scores were observed with glucosamine hydrochloride alone.

CONCLUSION

The findings of this study indicate that a combination of chondroitin sulfate and glucosamine hydrochloride was more effective than placebo in treating KBD.

Ovarian vasculitis in an adult with fatal systemic lupus erythematosus

Vasculitis of the ovary is a rare condition that can occur as an isolated finding or in association with systemic vasculitis. We describe a case of a 36-year-old female with vasculitis involving the left ovary on a background of severe active systemic lupus erythematosus (SLE). Despite a florid histopathological picture of ovarian vasculitis, the clinical and imaging findings were nonspecific. We have compared the current case to the literature on ovarian vasculitis, including relating to SLE. Ovarian vasculitis in SLE may be an underestimated entity as it may not be looked for routinely in the context of vasculitic involvement of other organs.

Differentiation of mouse nuclear transfer embryonic stem cells into functional pancreatic beta cells

AIMS/HYPOTHESIS

Therapeutic cloning has been reported to have potential in the treatment of several degenerative diseases. However, it has yet to be determined whether mouse nuclear transfer-embryonic stem cells (NT-ESCs) can be differentiated into pancreatic beta cells and used to reverse diabetes in an animal model.

METHODS

We first used the somatic nuclear transfer technique to generate mouse NT-ESCs and then developed a chemically defined stepwise protocol to direct the NT-ESCs into functional pancreatic beta cells. We examined the gene expression pattern of the differentiated NT-ESCs and transplanted the NT-ESC-derived insulin-producing cells into recipient diabetic mice.

RESULTS

Four mouse NT-ESC lines were first established using an improved nuclear transfer technique and insulin-producing cells were efficiently generated from NT-ESCs by mimicking pancreatic in vivo development. Most of the insulin-producing cells that we generated co-produced pancreatic and duodenal homeobox 1, but not glucagon at the final stage of this differentiation method, which differed from the insulin and glucagon co-production reported by other groups. The differentiated NT-ESCs were able to release insulin in response to glucose stimuli and normalise the blood glucose level of diabetic mice for at least 2 months.

CONCLUSIONS/INTERPRETATION

These results demonstrate the potential of therapeutic cloning for cell therapy of type 1 diabetes in a mouse model.

Severe intimal hyperplasia with ischaemic colitis in two patients with hepatitis C

Many extrahepatic manifestations of hepatitis C have been described, including renal disease and vasculitis. We describe the novel finding of intimal hyperplasia associated with severe ischaemic events in two patients with hepatitis C. The combination of genotype 1a hepatitis C virus, rapidly progressive mesangiocapillary glomerulonephritis and intimal hyperplasia with ischaemic sequelae, may represent a new syndrome.

The SMN complex: an assembly machine for RNPs

In eukaryotic cells, the biogenesis of spliceosomal small nuclear ribonucleoproteins (snRNPs) and likely other RNPs is mediated by an assemblyosome, the survival of motor neurons (SMN) complex. The SMN complex, composed of SMN and the Gemins (2-7), binds to the Sm proteins and to snRNAs and constructs the heptameric rings, the common cores of Sm proteins, on the Sm site (AU(56)G) of the snRNAs. We have determined the specific sequence and structural features of snRNAs for binding to the SMN complex and Sm core assembly. The minimal SMN complex-binding domain in snRNAs (except U1) is composed of an Sm site and a closely adjacent 3'stem-loop. Remarkably, the specific sequence of the stemloop is not important for SMN complex binding, but it must be located within a short distance of the 3'end of the RNA for an Sm core to assemble. This minimal snRNA-defining "snRNP code" is recognized by the SMN complex, which binds to it directly and with high affinity and assembles the Sm core. The recognition of the snRNAs is provided by Gemin5, a component of the SMN complex that directly binds the snRNP code. Gemin5 is a novel RNA-binding protein that is critical for snRNP biogenesis. Thus, the SMN complex is the identifier, as well as assembler, of the abundant class of snRNAs in cells. The function of the SMN complex, previously unanticipated because RNP biogenesis was believed to occur by self-assembly, confers stringent specificity on otherwise potentially illicit RNA-protein interactions.

Case-controlled clinical and histopathological study of conjunctivochalasis

BACKGROUND/AIMS

Conjunctivochalasis, a secondary cause of the watery eye, is frequently seen in the older age group as an elevation of the bulbar conjunctiva lying along the lateral or central lower lid margin. A prospective, interventional, case-controlled clinical and histopathological study was conducted. The relevant features of 18 patients (29 eyes) who had their conjunctivochalasis resected as part of the surgical management of their watery eye syndrome were examined. In the control group, tissue was obtained from an age matched series of 24 normal subjects undergoing routine cataract surgery.

METHODS

24 controls (24 specimens) and 18 patients (29 specimens) had conjunctival strip biopsies, taken from the usual lid margin level bulbar conjunctiva in line with the inferior limbus (controls), and the clinically apparent conjunctivochalasis (patients). These were submitted for histological study.

RESULTS

23 of 24 control sections demonstrated normal conjunctival variation. Four of 29 patient specimens demonstrated a chronic non-granulomatous conjunctivitis, while three eyes of the patient group (two patients) demonstrated features of elastosis. Of the four patients who had the inflammatory infiltrates, three had functional nasolacrimal duct obstructions (FNLDOs) and one had a primary acquired nasolacrimal duct obstruction (PANDO). Of the two patients who had elastosis, one had an FNLDO and the other had normal lacrimal drainage and was Jones 1 positive.

CONCLUSION

Six of 18 patients--that is, seven of 29 specimens of conjunctivochalasis demonstrated signs of elastosis or of chronic non-granulomatous inflammation. Clinically, patients had a spectrum of aetiologies of their watery eye syndrome.

Cure of orthopaedic infection with Scedosporium prolificans, using voriconazole plus terbinafine, without the need for radical surgery

Scedosporium prolificans infections of normal hosts usually require extensive debridement and sometimes amputation to effect cure, due to the intrinsic resistance of this species to available antifungal agents. Newer agents have not tested favourably. Variable results are obtained with voriconazole, and 100% resistance is described with echinocandins. Itraconazole and terbinafine has offered synergy against various moulds including S. prolificans. In vivo success is reported with the azole/terbinafine combination in S. apiospermum pulmonary infection and Pythium insidiosum periorbital cellulitis. We report a case of orthopaedic infection in a non-immunocompromised host with S. prolificans, in which the combinations of itraconazole/terbinafine and voriconazole/terbinafine showed synergy in vitro, and success was achieved without radical surgery, using voriconazole and terbinafine.

Sarcoplasmic reticulum Ca(2+) atpase (SERCA) 1a structurally substitutes for SERCA2a in the cardiac sarcoplasmic reticulum and increases cardiac Ca(2+) handling capacity

Ectopic expression of the sarcoplasmic reticulum (SR) Ca(2+) ATPase (SERCA) 1a pump in the mouse heart results in a 2.5-fold increase in total SERCA pump level. SERCA1a hearts show increased rates of contraction/relaxation and enhanced Ca(2+) transients; however, the cellular mechanisms underlying altered Ca(2+) handling in SERCA1a transgenic (TG) hearts are unknown. In this study, using confocal microscopy, we demonstrate that SERCA1a protein traffics to the cardiac SR and structurally substitutes for the endogenous SERCA2a isoform. SR Ca(2+) load measurements revealed that TG myocytes have significantly enhanced SR Ca(2+) load. Confocal line-scan images of field-stimulated SR Ca(2+) release showed an increased rate of Ca(2+) removal in TG myocytes. On the other hand, ryanodine receptor binding activity was decreased by approximately 30%. However, TG myocytes had a greater rate of spontaneous ryanodine receptor opening as measured by spark frequency. Whole-cell L-type Ca(2+) current density was reduced by approximately 50%, whereas the time course of inactivation was unchanged in TG myocytes. These studies provide important evidence that SERCA1a can substitute both structurally and functionally for SERCA2a in the heart and that SERCA1a overexpression can be used to enhance SR Ca(2+) transport and cardiac contractility.

Pre-mRNA splicing imprints mRNA in the nucleus with a novel RNA-binding protein that persists in the cytoplasm

We describe a novel RNA binding protein, Y14, a predominantly nuclear nucleocytoplasmic shuttling protein. Interestingly, Y14 associates preferentially with mRNAs produced by splicing but not with pre-mRNAs, introns, or mRNAs produced from intronless cDNAs. Y14 associates with both nuclear mRNAs and newly exported cytoplasmic mRNAs. Splicing of a single intron is sufficient for Y14 association. Y14-containing nuclear complexes are different from general hnRNP complexes. They contain hnRNP proteins and several unique proteins including the mRNA export factor TAP. Thus, Y14 defines novel intermediates in the pathway of gene expression, postsplicing nuclear preexport mRNPs, and newly exported cytoplasmic mRNPs, whose composition is established by splicing. These findings suggest that pre-mRNA splicing imprints mRNA with a unique set of proteins that persists in the cytoplasm and thereby communicates the history of the transcript.

Positive association between an estrogen receptor gene polymorphism and Parkinson's disease with dementia

Parkinson's disease (PD) is a common cause of dementia in the elderly. Dementia in Alzheimer's disease (AD) and PD share common biologic and clinical features. The estrogen receptor (ER) gene is one of the susceptibility genes for AD. In order to test the hypothesis that the overlap between AD and PD may have a genetic basis, we determined ER gene polymorphisms in 13 PD patients with dementia (PDD) (age +/- SD; 71.9 +/- 5.5 years), 71 PD patients without dementia (PDND) (68.4 +/- 7.5 years), 86 AD patients (76.8 +/- 8.0 years) and 51 control subjects (CTL) (74.9 +/- 6.9 years). ER genotypes were classified as a P or p allele on the basis of a Pvu II-RFLP, and X and x on the basis of a Xba I-RFLP. The frequency of the P allele in the PDD group as well as the AD group was higher than that in CTL. There was no significant difference in the distribution of the P allele between CTL and PDND. There were no significant differences in the distribution of the X allele among the PDD, PDND and CTL groups, whereas a higher incidence was found in AD. We conclude that the ER gene may be a common susceptibility gene for dementia in PD as well as AD.

[Anaerobic threshold as determined by gas metabolic parameters]

In order to demonstrate the possibility of evaluating anaerobic threshold (AT) by gas exchange parameters, treadmill exercise tests were made by 1-min increment protocol in 25 healthy young men. Ten parameters of gas exchange were collected when AT was reached. The analysis showed that correlation between VO2 and VE (r = 0.8004) or VCO2 (r = 0.9743) are high. While correlation between VO2 and RQ (r = 0.4491) or HR (r = 0.4666) are significantly lower. So the accuracy of VE and VCO2 is higher than that HR or RQ for the determination of AT.

The nephrotoxicity of fractionated components of Aipysurus laevis venom

Six major venom fractions were obtained when crude Aipysurus laevis (Olive sea snake) venom was fractionated by standard HPLC techniques. Subcutaneous doses of between 9.5-20.3 micrograms venom/kg body weight were injected into male Quackenbush mice, showing that all six fractions of A. laevis venom are nephrotoxic, producing renal lesions within 24 hrs and lasting for up to three months. It is postulated that each fraction contains a nephrotoxic component, suggesting a core or common biochemical structure, the nature of which is to yet to be determined; and those from different fractions may act synergistically. The resulting renal lesions are no different from those seen in our previous whole venom study, but the severity is less and shorter in duration. A significant difference is that after fraction injection, the kidneys returned to normality after two months, with minor segmental glomerulosclerosis being the only remaining stigma of the previous damage. This is contrary to the whole venom-induced tubulo-interstitial nephritis with cystic changes seen after three months of envenomation. All fractions also increase the granularity of the juxtaglomerular cells, for reasons unknown.

Evaluation of the modified Visuwell Strep-A enzyme immunoassay for detection of group-A Streptococcus from throat swabs

The modified Visuwell Strep-A enzyme immunoassay (EIA) was compared with culture for detection of group-A Streptococcus from throat swabs. Throat swabs in modified Stuarts medium obtained after culture at two institutions were tested in Visuwell. Cumulative results were n = 417, sensitivity 87.8%, specificity 89.9% predictive value positive (PVP) 67.9%, predictive value negative (PVN) 96.8%, and accuracy 89.5%. At another site, swabs were delivered to the laboratory without transport medium, cultured, and subsequently tested by Visuwell (n = 202, sensitivity 79.6%, specificity 84.5%, PVP 65.2%, PVN 91.9%, accuracy 83.2%). When 1+ culture-positive specimens were considered negative, the sensitivity and PVN increased from 79.6% to 90.2% and 91.9% to 97.1% respectively. Overall performance of the modified Visuwell was comparable with that of the initial assay for throat swabs transported with or without modified Stuarts medium. Cross reaction with organisms other than group-A Streptococcus normally found in the oropharynx was negligible in Visuwell and the limit of detection of group-A Streptococcus was 5 x 10(4) colony-forming units.

Comparison of Visuwell enzyme immunoassay to culture for detection of group A Streptococcus in throat swab specimens

A microwell enzyme immunoassay (Visuwell) for direct detection of Group A streptococcal antigen from throat swab specimens has been developed. It incorporates urease conjugated antibody as the detector and is easily interpreted by a yellow to purple color change. Throat specimens obtained on rayon-tipped swabs were transported moist in modified Stuarts medium and cultured before being tested in Visuwell (n = 585, prevalence 17.1%, sensitivity 88%, specificity 92.4%, predictive value positive 70.4%, predictive value negative 97.4%, and accuracy 91.6%). In instances of discrepancy between culture and Visuwell, throat swab extracts were tested in a latex agglutination test. In 21 of 37 instances of Visuwell-positive, culture-negative specimens, latex agglutination was positive. Throat specimens obtained using double rayon swabs and transported to the laboratory dry had one swab cultured and the other tested in Visuwell (n = 280, prevalence 20.4%, sensitivity 75.4%, specificity 88.3%, predictive value positive 62.3%, predictive value negative 93.4%, and accuracy 85.7%). When 1+ culture positive specimens were considered negative, a sensitivity of 97.6% was obtained. In 14 of 26 instances of Visuwell-positive, culture-negative specimens, latex agglutination was positive. Cross-reaction with organisms other than Group A Streptococcus found in the oropharynx was negligible in Visuwell. Limit of detection of Group A streptococcal antigen was equivalent for Visuwell and latex agglutination.

Comparative in-vitro activity of erythromycin, vancomycin and pristinamycin

We have studied the in-vitro activity of erythromycin, vancomycin and pristinamycin against 1,006 clinical isolates comprising streptococci, staphylococci, Neisseria gonorrhoeae, Haemophilus influenzae and anaerobes. In-vitro studies show pristinamycin to inhibit staphylococci and streptococci, including erythromycin highly-resistant organisms, at a concentration of less than or equal to 0.78 mg/l. Although pristinamycin's mean MIC for streptococci is higher than that of erythromycin, pristinamycin is bactericidal, whereas erythromycin is bacteristatic against Streptococcus agalactiae and oral streptococci. Enterococci were less uniformly susceptible to pristinamycin: 58 of the 94 Enterococcus faecalis tested were resistant (MIC greater than or equal to 3.12 mg/l). 14 of the 15 isolates of Enterococcus faecium were inhibited by less than or equal to 1.56 mg/l pristinamycin. Pristinamycin showed poor activity against Haemophilus influenzae (mode MIC 1.56 and MIC90 of 3.12 mg/l) but all except two of the 100 Neisseria gonorrhoeae tested were inhibited by less than or equal to 0.78 mg/l pristinamycin. Pristinamycin inhibited all nine Clostridium spp. at less than or equal to 0.39 mg/l and 38 of 40 strains of anaerobic gram-positive cocci at less than or equal to 0.78 mg/l. It was less effective against the Bacteroides fragilis group: (MIC90 3.12 mg/l). Pristinamycin had poor bactericidal activity against the anaerobes tested.

Fetal intravascular transfusion for severe erythroblastosis: effects on haematology and survival

Since February 1984, 8 fetuses (including a set of hydropic twins) with severe erythroblasts in the second trimester have received intravascular transfusions guided by ultrasound. These transfusions were associated with a decreasing fetal reticulocytosis, a decreasing proportion of circulating fetal haemoglobin and a decreasing mean fetal red corpuscular volume. All infants were born alive at an average of 5.5 weeks after the first transfusion; 3 infants died, including the hydropic twins and another with lethal congenital anomalies. All 5 survivors required simple transfusions for up to 54 days after birth because of prolonged bone marrow suppression. In severe erythroblastosis in the second trimester, direct intravascular transfusion using ultrasound guidance promises to improve fetal outcome.