Mitochondrial complex I subunit deficiency promotes pancreatic α-cell proliferation

OBJECTIVE

There is strong evidence that mitochondrial DNA mutations and mitochondrial dysfunction play a role in diabetes pathogenesis. The homozygous knock-in mtDNA mutator mouse is a model of premature aging due to the accumulation of mitochondrial DNA mutations. We used this mouse model to investigate the relationship between mitochondrial subunit expression and pancreatic islet cell composition.

METHODS

Quadruple immunofluorescence was used to quantify mitochondrial subunit expression (complex I and IV) and cell composition in pancreatic islets from mitochondrial DNA mutator mice (PolgAmut/mut) and control C57BL/6 mice at 12 and 44 weeks of age.

RESULTS

Mitochondrial complex I subunit expression was decreased in islets from 12 week PolgAmut/mut mice. This complex I deficiency persisted with age and was associated with decreased insulin staining intensity at 44 weeks. Complex I deficiency was greater in α-cells compared with β-cells in islets from 44 week PolgAmut/mut mice. Islet cell composition was normal in 12 week PolgAmut/mut mice, but the β: α cell ratio was decreased in islets from 44 week PolgAmut/mut mice. This was due to an increase in α-cell number linked to an increase in α-cell proliferation.

CONCLUSION

Complex I deficiency promotes α-cell proliferation and alters islet cell composition.

A Bioreactor Technology for Modeling Fibrosis in Human and Rodent Precision-Cut Liver Slices

Precision cut liver slices (PCLSs) retain the structure and cellular composition of the native liver and represent an improved system to study liver fibrosis compared to two-dimensional mono- or co-cultures. The aim of this study was to develop a bioreactor system to increase the healthy life span of PCLSs and model fibrogenesis. PCLSs were generated from normal rat or human liver, or fibrotic rat liver, and cultured in our bioreactor. PCLS function was quantified by albumin enzyme-linked immunosorbent assay (ELISA). Fibrosis was induced in PCLSs by transforming growth factor beta 1 (TGFβ1) and platelet-derived growth factor (PDGFββ) stimulation ± therapy. Fibrosis was assessed by gene expression, picrosirius red, and α-smooth muscle actin staining, hydroxyproline assay, and soluble ELISAs. Bioreactor-cultured PCLSs are viable, maintaining tissue structure, metabolic activity, and stable albumin secretion for up to 6 days under normoxic culture conditions. Conversely, standard static transwell-cultured PCLSs rapidly deteriorate, and albumin secretion is significantly impaired by 48 hours. TGFβ1/PDGFββ stimulation of rat or human PCLSs induced fibrogenic gene expression, release of extracellular matrix proteins, activation of hepatic myofibroblasts, and histological fibrosis. Fibrogenesis slowly progresses over 6 days in cultured fibrotic rat PCLSs without exogenous challenge. Activin receptor-like kinase 5 (Alk5) inhibitor (Alk5i), nintedanib, and obeticholic acid therapy limited fibrogenesis in TGFβ1/PDGFββ-stimulated PCLSs, and Alk5i blunted progression of fibrosis in fibrotic PCLS. Conclusion: We describe a bioreactor technology that maintains functional PCLS cultures for 6 days. Bioreactor-cultured PCLSs can be successfully used to model fibrogenesis and demonstrate efficacy of antifibrotic therapies.

Congenital scoliosis in a neonate: can a neonatologist ignore it?

The frequency of diagnosis of congenital scoliosis in the neonatal period is expected to rise given the increasing survival of high risk neonates in the surfactant era and their frequent exposure to x rays. Considering its significant long term implications a neonatologist cannot afford to ignore the diagnosis of congenital scoliosis in a neonate as close surveillance, early detection, and treatment may prevent/minimise the wide spectrum of potentially serious deformities that can affect the developing spine. The review provides general guidelines to help the neonatologists in counselling the parents and in planning the multidisciplinary follow up for management of congenital scoliosis.

Realtime fetal ultrasound by telemedicine in Queensland. A successful venture?

We have established a realtime fetal tele-ultrasound consultation service in Queensland, which has been integrated into our routine clinical practice. The service, which uses ISDN transmission at 384 kbit/s, allows patients in Townsville to be examined by subspecialists in Brisbane, 1500 km away. For the 90 tele-ultrasound consultations performed for the first 71 patients, 90% of the babies have been delivered, and outcome data have been received on all the pregnancies. All significant anomalies and diagnoses have been confirmed. The referring clinicians would have physically referred 24 of the 71 patients to Brisbane in the absence of telemedicine. A crude cost-benefit calculation suggests that the tele-ultrasound service resulted in a net saving of A$6340, and at the same time enabled almost four times the number of consultations to be carried out.

Permissive hypercapnia in neonates: the case of the good, the bad, and the ugly

Advances in neonatology have resulted in an increase in the absolute number of survivors with chronic lung disease (CLD), though its overall incidence has not changed. Though the single most important high-risk factor for CLD is prematurity, the focus of attention has recently changed over to minimizing the impact of other two risk factors: baro/volutrauma related to mechanical ventilation, and oxygen toxicity. Permissive hypercapnia (PHC) or controlled ventilation is a strategy that minimizes baro/volutrauma by allowing relatively high levels of arterial CO(2), provided the arterial pH does not fall below a preset minimal value. The benefits of PHC are primarily mediated by the reduction of lung stretch that occurs when tidal volumes are minimized. PHC can be a deliberate choice to restrict ventilation in order to avoid overdistention, while application of high airway pressures and large tidal volumes would permit normocapnia, or relative hypocapnia (PaCO(2), < or = 25-30 mmHg), but may result in CLD and be harmful to the developing lung. The current concept that PaCO(2) levels of 45-55 mmHg in high-risk neonates are "safe" and "well tolerated" is based on limited data. Further prospective trials are needed to study the definition, safety and efficacy of PHC in ventilated preterm and term neonates. However, designing disease/gestational-postnatal age-specific clinical trials of PHC will be difficult in neonates, given the diverse pathophysiology of their diseases and the various ventilatory modes/variables currently available. The potential benefits and adverse effects of PHC are reviewed, and its relationship to current ventilatory strategies like synchronized mechanical ventilation and high-frequency ventilation in high-risk neonates is briefly discussed.

Postnatal changes in maternal and neonatal plasma antioxidant vitamins and the influence of smoking

OBJECTIVE

To study the postnatal changes in the plasma concentrations of fat soluble antioxidant vitamins and malondialdehyde (MDA) in mothers and their newborns and their relation to smoking.

DESIGN

Prospective cohort study.

SETTING

Tertiary perinatal centre.

SUBJECTS

Eighteen non-smoking and 14 smoking mothers and 33 infants.

MAIN OUTCOME MEASURES

Plasma concentrations of vitamins E, A, and beta-carotene and MDA were measured in mothers and infants at delivery and on day 4 post partum.

RESULTS

Neonatal plasma levels of vitamins E, A, and beta-carotene were significantly lower than maternal levels both at delivery and on day 4 in both groups. There was a significant postnatal increase in plasma vitamin E levels in smoking mothers and neonates of both groups. A significant postnatal increase in maternal, but not neonatal, plasma vitamin A was noted in both groups. Cord plasma vitamin E levels were significantly lower in infants of smoking mothers (mean 4.7 v 6.5 micromol/l, p = 0.041). Plasma MDA was paradoxically lower in smoking mothers at delivery (3.19 v 4.01 micromol/l, p = 0.03) and on day 4 (1.37 v 3.29 micromol/l, p = 0.005) and in infants of the smoking group on day 4 (2.18 v 3.12 micromol/l, p = 0.014). Also, there was a significant postnatal fall in plasma MDA levels on day 4 in mothers and infants in the smoking group.

CONCLUSIONS

The postnatal changes in plasma vitamin E were more pronounced in the smoking group. The postnatal changes in plasma vitamins A and beta-carotene were similar in both groups. The rapid decline in plasma MDA in smoking mothers and their infants suggests withdrawal of oxidative stress from smoking around delivery. This coincided with the increase in plasma vitamin E.

Maternal awareness of sudden infant death syndrome in North Queensland, Australia: an analysis of infant care practices

OBJECTIVES

To assess awareness of sudden infant death syndrome (SIDS) and risk reducing recommendations in a sample of mothers in North Queensland, Australia, and to examine their infant care practices.

METHOD

Interviews conducted with 195 women using a standardized questionnaire between October 1997 and January 1998.

RESULTS

191 questionnaires analyzed; 134 (70.2%) Caucasian and 57 (29.8%) indigenous women. Four women with previous SIDS experience were excluded from the analysis. Eight (4.2%) had never heard of SIDS. Twenty-nine (15.2%) had heard of SIDS and 154 (80.6%) had heard of SIDS and could list risk recommendations to reduce its incidence. Multivariate analysis identified ethnicity as the only significant predictor of maternal knowledge. Indigenous mothers knew less about SIDS: adjusted odds ratio (OR) = 5.4; 95% confidence interval (CI) = [2.1-14.0]. Avoidance of prone sleeping was the most frequently identified recommendation (n = 132), with no smoking in pregnancy (n = 48) and breastfeeding (n = 40) identified least frequently. There were 80.2% of mothers who put their infant in non-prone positions to sleep. Only 48 (25%) women identified smoking in pregnancy, and 93 (48.6%) smoking in the infant's environment as risk factors. Indigenous women were more likely to smoke in their pregnancy (P = 0.004), bed share with their infant (P = 0.0001), and have smokers in the home.

CONCLUSION

There is a high level of awareness of SIDS and the main associated risk factor of infant prone sleeping, but the link between SIDS and smoking requires further emphasis. Future campaigns should ensure the SIDS message is delivered more effectively to the indigenous communities.

Unusual presentation of neonatal Behcets disease

Intrauterine growth retardation and neonatal transient mucocutaneous lesions ("transient Behcet syndrome") have been reported in pregnancies complicated by Behcets disease (BD). Neonatal neurological manifestations have not been reported in such pregnancies. Vascular and neurological involvement is known to worsen the prognosis in adults with BD. The clinical course and outcome of a 34-weeks' gestation neonate born to a mother with BD is reported. Progressive recovery from minimal respiratory distress syndrome was followed by catastrophic presentation on 6th day of life with generalized seizures. Cranial ultrasound revealed multiple hyperechoic lesions in the frontal, parietal, and periventricular regions with a few surrounded by a ring of reduced echogenicity suggesting haemorrhage into ischemic areas. Death occurred after withdrawal of life support on Day 9, after extensive discussions with parents in view of the progressive deterioration in the neonates' general condition and the cranial ultrasound findings. Strong family history of BD, clinical course, and laboratory results (no evidence of disseminated intravascular coagulation, normal levels of protein C and S, absence of factor V Leiden and anticardiolipin antibodies) suggested neurological manifestations of BD as the most probable diagnosis.

An in vitro study of the efficacy of rifampicin and minocycline coated umbilical venous catheters

The use of antibiotic coated catheters has been proposed as a means of reducing catheter related sepsis. In this study, an in vitro comparison of bacterial colonisation rates was made between uncoated umbilical venous catheters and catheters coated with rifampicin and minocycline. The following parameters were determined; the direct antimicrobial effect of coated and uncoated catheter segments against a range of organisms associated with line sepsis, the assessment of the decline in antimicrobial activity in coated catheters immersed in plasma and the inhibitory efficacy of the catheters to colonisation over a 28-day period. Minocycline and rifampicin coated umbilical catheters showed a superior inhibitory effect and prevented colonisation with the commoner line-related organisms, when compared with uncoated catheters. The inhibitory effect declined after 14 days in the human plasma. Resistance to colonisation in vitro may not extend beyond 21 days.

Clinical value of real-time tertiary fetal ultrasound consultation by telemedicine: preliminary evaluation

Congenital fetal abnormalities are major causes of perinatal mortality and morbidity. The performance of ultrasound in the diagnosis and assessment of fetal anomalies varies enormously between tertiary referral centers and general units. Telemedicine offers a chance for tertiary realtime ultrasound consultations using standard telephone lines for remote sites. Preliminary investigations by our group have shown that real-time transmission of fetal ultrasound images over long distances via telephone (integrated systems digital network [ISDN]) lines is technically feasible. A live link of up to 2 Mb/s was established between Mater Mothers Hospital in Brisbane and Kirwan Hospital for Women in Townsville, which are 1,500 km apart. The objective of the current study was to evaluate the clinical value of a tertiary teleultrasound consultation service. Patients requiring tertiary ultrasound consultations were recruited from North Queensland. Clinicians from the referral site established an initial diagnosis and management plan. Using standard ISDN lines, the real-time ultrasound images were transmitted to the maternal fetal medicine subspecialists in Brisbane. The ultrasound examination was completed under the direction of the subspecialist. The subspecialist explained the findings to the patient at the end of the session, and discussed the diagnosis and management plans with the clinicians involved. Any diagnosis and management variations were classified into minor and major upon agreement by the two teams of clinicians involved. The clinicians and patients in Townsville rated the value of the consultation, and the subspecialists rated the confidence of their diagnoses on five-point scales. Pregnancy outcomes were obtained and the data analyzed. Over a 3-month period, 24 teleultrasound consultations were carried out. The indications for referral were: assessment of growth restriction/fetal wellbeing in the third trimester (6); detailed assessment for high-risk patients (5); evaluation of markers for anomalies (5); isolated fetal anomalies (1); and complex fetal problems such as twin/twin transfusion, multiple anomalies, etc. (7). Overall, the consultations resulted in some modifications to the clinical diagnosis in 45.8% of the cases, and modifications to the management plan in 33.3% of the cases (about half of which were minor variations). The clinicians rated the teleconsultations highly (mean rating 4.7, SD 0.44). The patients also rated the consultations highly, and were comfortable that their privacy and confidentiality were maintained during the consultation. The subspecialists were confident in making their diagnoses by telemedicine (mean score for confidence 4.2, SD 0.43). All the pregnancies have now been completed, with all antenatal diagnoses confirmed to be correct postnatally. Tertiary real-time ultrasound consultation by telemedicine is not only technically feasible, it is welcomed by the clinicians and patients involved. It also contributes to diagnostic and management differences. Larger scale clinical trials are needed to evaluate the true benefits and costs involved. The social benefits in bridging the healthcare gap between the country and the city, and in enabling patients in remote areas to stay close to their family under times of stress is well recognized by all involved.

Hypertension-hyponatremia syndrome in neonates: case report and review of literature

Hypertension hyponatremia syndrome occurred in a 32-week male neonate following septicemic shock on Day 9. The systolic blood pressure rose from 60 to 85 mmHg as the serum sodium dropped from 136 to 121 mmol/L associated with natriuresis, polyuria, and dehydration. Convulsions occurred at a systolic blood pressure of 102 mmHg. Investigations for hypertension revealed hyper-reninemia without cardio/renovascular or neuroendocrine abnormalities. Salt supplementation and antihypertensive therapy with captopril led to resolution of natriuresis and hyponatremia. Review of literature revealed associated renovascular pathology in all neonatal cases of the syndrome reported so far. Renal ischemia from possible renal microthrombi may have been the triggering event in our case. Decline in renin levels during follow-up favors this hypothesis.

Congenital varicella syndrome in the absence of cutaneous lesions

A case of congenital varicella syndrome characterized by intrauterine growth retardation, ocular and neurologic abnormalities, but no cutaneous lesions is reported. This case highlights the risk of embryopathy from varicella infection during pregnancy in non-immune women.

Minimum requirements for remote realtime fetal tele-ultrasound consultation

We studied the transmission bandwidth required for accurate diagnoses when performing realtime fetal tele-ultrasound consultations. The study was divided into three phases. In phase I, three experienced clinicians evaluated the quality of ultrasound images transmitted at various bandwidths (internally looped back within Brisbane) using eight commercially available codecs at random. The two codecs that performed best proceeded to phase 2, in which a realtime video-link of up to 2 Mbit/s was set up between Brisbane and Townsville (1,500 km apart). Testing with a standard video-tape was performed at seven different bandwidths selected at random, with four clinicians (who were blinded to the equipment and bandwidths used). The optimum line rates for transmission were determined, and testing was then performed using these line rates for fetuses with various anomalies (phase 3). The results showed significant differences in performance according to bandwidths used, but not according to observers. Bandwidths were grouped into three levels. At level I (256 kbit/s) the performance was significantly worse than at level II (384, 512 or 768 kbit/s), which was in turn worse than that at level III (1, 1.5 or 2 Mbit/s). However, within each level, performance at one bandwidth was not significantly different from that at the others. The most cost-effective transmission rates therefore appeared to be 384 kbit/s and 1 Mbit/s. Further testing with fetuses affected by various anomalies confirmed that the majority could be diagnosed using a 384 kbit/s link, with slight improvement in evaluation when the bandwidth was increased to 1 Mbit/s.

Gestational magnesium deficiency is deleterious to fetal outcome

A number of recent epidemiological findings have implicated magnesium as being essential to fetal well-being. Few studies, however, have examined the relationship between maternal requirements for dietary magnesium and subsequent mortality and morbidity in offspring. The present study uses a rodent model of dietary-induced hypomagnesemia to investigate the effects of magnesium deficiency prior to and during gestation on neonatal morbidity and mortality. Magnesium deficiency during gestation significantly increased neonatal mortality and morbidity. Such increases were associated with a reduced free magnesium concentration in both maternal and offspring blood and an increased incidence of periventricular hemorrhage and edema in newborn pups as observed by magnetic resonance imaging and histology. Animals fed a magnesium-deficient diet before mating but given magnesium supplementation during gestation did not demonstrate a significant change in neonatal mortality and morbidity when compared to control animals. The significant improvement in fetal outcome with dietary magnesium supports the concept of magnesium supplementation during pregnancy.

Improved oxygenation following adenosine infusion in persistent pulmonary hypertension of the newborn

Six consecutive cases of persistent pulmonary hypertension of the newborn (PPHN) were treated with adenosine following failure of conventional therapy, excluding inhaled nitric oxide. A rise in arterial PO2 >20 mm Hg occurred in 5 of 6 cases within 30 min of commencing adenosine infusion. Individual maximal increases in PaO2 ranged from 31 to 131 mm Hg. Three neonates survived and 3 died. Amongst deaths, intensive support was withdrawn in a preterm neonate due to severe arthrogryposis/pulmonary hypoplasia. Of the remaining 2, the improvement in oxygenation persisted until death occurred from causes unrelated to adenosine. Side effects related to adenosine (bradycardia, hypotension, prolonged bleeding time) did not occur. Due to its ease of availability, administration and extremely short half-life, adenosine may be an important therapeutic option in PPHN.

Telemedicine in neonatology: lessons from North Queensland

Using videoconferencing technology, educational programs in neonatology were provided for staff at rural hospitals. The technology was also used to reunite babies with their families and its usefulness in long-distance diagnosis was assessed. Eighty-two educational sessions were delivered over a 9 month period and, despite problems with technology, operation and presentation, were considered worthwhile by the audiences. Family reunions were very successful. Neonatal diagnosis was impossible at the narrow bandwidth used (128 kilobits/s). Valuable lessons were learned regarding optimum use of this medium.

Meconium thorax: a case report and review of literature

A case is presented in which extension of meconium peritonitis through muscular defects in the diaphragm lead to intrathoracic calcifications diagnosed sonographically at 23 weeks of gestation. There were three diaphragmatic defects, two small ones corresponded to foramina of Morgagni and one large posterior defect that did not correspond to the foramen of Bochdelak. There were three additional muscular defects: one in the rectus abdominus and two, bilaterally, in the loins. Despite long-standing fetal ascites and fresh intraperitoneal meconium at laparotomy, postoperative progress was uneventful. The baby did not have other dysmorphic features except for a single palmar crease, the chromosomes were normal, and the baby did not have cystic fibrosis. Follow-up examination at 10 months showed a thriving infant with mild hypotonia and developmental delay, but no respiratory or gastrointestinal problems.

A novel method for isolating and quantifying urine pathogens collected from gel-based diapers

BACKGROUND

Given that children often present to physicians with a wet gel-based diaper, a method for using this diaper for a urine specimen was studied.

METHODS

A blinded clinical laboratory trial was conducted in the microbiology laboratory. The sampling technique involved the use of oval gynecologic forceps as a template and sterile scissors to cut out samples of diapers. Each diaper sample was then vortexed in 20 mL of sterile saline and the supernatant quantitatively cultured. Diaper sample supernatant cultures with simulated infected urines (suspensions of Escherichia coli) were used.

RESULTS

Weight measurements of the diaper samples soaked with 20 mL or more of saline yielded reproducible results (0.703 g; 95% confidence interval [CI], 0.52 to 0.88 g). Culture results (colony-forming units per liter [CFU/L] of supernatant) from diapers soaked with 25 mL of various concentrations of E coli (10(6), 10(7), 10(8), 10(9) CFU/L) showed excellent correlation with the inoculum used, and no effect of a 2-hour delay in culturing the wet diapers.

CONCLUSIONS

Our technique provides accurate and reliable estimates of bacterial concentrations in the usual range for infected urine from gel-based diapers soaked with solutions of E coli. Further evaluation of clinical implementation is needed.