Oxygen metabolism and oxygenation of the newborn

The premature infant is to some extent protected from hypoxia, however defense against hyperoxia is poorly developed. The optimal assessment of oxygenation is to measure oxygen delivery and extraction. At the bedside PaO₂ and SpO₂ are approximations of oxygenation at the tissue level. After birth asphyxia it is crucial to know whether or not to give oxygen supplementation, when, how much, and for how long. Oxygen saturation targets in the delivery room have been studied, but the optimal targets might still be unknown because factors like gender and delayed cord clamping influence saturation levels. However, SpO₂ > 80% at 5 min of age is associated with favorable long term outcome in preterm babies. Immature infants most often need oxygen supplementation beyond the delivery room. Predefined saturation levels, and narrow alarm limits together with the total oxygen exposure may impact on development of oxygen related diseases like ROP and BPD. Hyperoxia is a strong trigger for genetic and epigenetic changes, contributing to the development of these conditions and perhaps lifelong changes.

Effects of Probiotic Supplementation on the Gut Microbiota and Antibiotic Resistome Development in Preterm Infants

Objectives: In 2014 probiotic supplementation (Lactobacillus acidophilus and Bifidobacterium longum subspecies infantis; Infloran^Ⓡ) was introduced as standard of care to prevent necrotizing enterocolitis (NEC) in extremely preterm infants in Norway. We aimed to evaluate the influence of probiotics and antibiotic therapy on the developing gut microbiota and antibiotic resistome in extremely preterm infants, and to compare with very preterm infants and term infants not given probiotics. Study design: A prospective, observational multicenter study in six tertiary-care neonatal units. We enrolled 76 infants; 31 probiotic-supplemented extremely preterm infants <28 weeks gestation, 35 very preterm infants 28-31 weeks gestation not given probiotics and 10 healthy full-term control infants. Taxonomic composition and collection of antibiotic resistance genes (resistome) in fecal samples, collected at 7 and 28 days and 4 months age, were analyzed using shotgun-metagenome sequencing. Results: Median (IQR) birth weight was 835 (680-945) g and 1,290 (1,150-1,445) g in preterm infants exposed and not exposed to probiotics, respectively. Two extremely preterm infants receiving probiotic developed NEC requiring surgery. At 7 days of age we found higher median relative abundance of Bifidobacterium in probiotic supplemented infants (64.7%) compared to non-supplemented preterm infants (0.0%) and term control infants (43.9%). Lactobacillus was only detected in small amounts in all groups, but the relative abundance increased up to 4 months. Extremely preterm infants receiving probiotics had also much higher antibiotic exposure, still overall microbial diversity and resistome was not different than in more mature infants at 4 weeks and 4 months. Conclusion: Probiotic supplementation may induce colonization resistance and alleviate harmful effects of antibiotics on the gut microbiota and antibiotic resistome. Clinical Trial Registration: Clinicaltrials.gov: NCT02197468. https://clinicaltrials.gov/ct2/show/NCT02197468.

Resuscitation of newborn piglets. short-term influence of FiO2 on matrix metalloproteinases, caspase-3 and BDNF

BACKGROUND

Perinatal hypoxia-ischemia is a major cause of mortality and cerebral morbidity, and using oxygen during newborn resuscitation may further harm the brain. The aim was to examine how supplementary oxygen used for newborn resuscitation would influence early brain tissue injury, cell death and repair processes and the regulation of genes related to apoptosis, neurodegeneration and neuroprotection.

METHODS AND FINDINGS

Anesthetized newborn piglets were subjected to global hypoxia and then randomly assigned to resuscitation with 21%, 40% or 100% O(2) for 30 min and followed for 9 h. An additional group received 100% O(2) for 30 min without preceding hypoxia. The left hemisphere was used for histopathology and immunohistochemistry and the right hemisphere was used for in situ zymography in the corpus striatum; gene expression and the activity of various relevant biofactors were measured in the frontal cortex. There was an increase in the net matrix metalloproteinase gelatinolytic activity in the corpus striatum from piglets resuscitated with 100% oxygen vs. 21%. Hematoxylin-eosin (HE) staining revealed no significant changes. Nine hours after oxygen-assisted resuscitation, caspase-3 expression and activity was increased by 30-40% in the 100% O(2) group (n = 9/10) vs. the 21% O(2) group (n = 10; p<0.04), whereas brain-derived neurotrophic factor (BDNF) activity was decreased by 65% p<0.03.

CONCLUSIONS

The use of 100% oxygen for resuscitation resulted in increased potentially harmful proteolytic activities and attenuated BDNF activity when compared with 21%. Although there were no significant changes in short term cell loss, hyperoxia seems to cause an early imbalance between neuroprotective and neurotoxic mechanisms that might compromise the final pathological outcome.

13q33.2 deletion: a rare cause of ambiguous genitalia in a male newborn with growth restriction

13q deletion is a rare cause of ambiguous genitalia in the male newborn, and can be associated with mental retardation of varying degree, retinoblastoma, and malformations of the brain, eye, genitourinary and gastrointestinal tract, depending on the level of the deletion. We present a male neonate with ambiguous genitalia and IUGR with a 13q33.2 deletion, and a paternal balanced translocation. Microarray analysis found the genes involved to be on chromosome 13 in the region 102989254bp-109214509bp. This deletion encompasses the EFNB2 gene, which has been implicated in genital malformations in 13q deletion cases.

CONCLUSIONS

We find a link between haploinsufficiency of the EFNB2 gene and the presence of ambiguous genitalia and hypospadia in patients with a 13q.33 deletion. This work emphasizes the importance of early diagnosis of this condition due to the link with mental retardation and the need for follow up and management.

Resuscitation of hypoxic newborn piglets with supplementary oxygen induces dose-dependent increase in matrix metalloproteinase-activity and down-regulates vital genes

The optimal oxygen concentration for newborn resuscitation is still discussed. Oxygen administration during reoxygenation may induce short- and long-term pathologic changes via oxidative stress and has been associated to later childhood cancer. The aim was to study changes in oxidative stress-associated markers in liver and lung tissue of newborn pigs after acute hypoxia followed by reoxygenation for 30 min with 21, 40, or 100% oxygen compared with room air or to ventilation with 100% oxygen without preceding hypoxia. Nine hours after resuscitation, we found a dose-dependent increase in the matrix metalloproteinase gelatinase activity in liver tissue related to percentage oxygen supply by resuscitation (100% versus 21%; p = 0.002) pointing at more extensive tissue damage. Receiving 100% oxygen for 30 min without preceding hypoxia decreased the expression of VEGFR2 and TGFBR3 mRNA in liver tissue, but not in lung tissue. MMP-, VEGF-, and TGFbeta-superfamily are vital for the development, growth, and functional integrity of most tissues and our data rise concern about both short- and long-term consequences of even a brief hyperoxic exposure.

Resuscitation with 21 or 100% oxygen in hypoxic nicotine-pretreated newborn piglets: possible neuroprotective effects of nicotine

BACKGROUND

Perinatal asphyxia is a major concern in perinatal medicine. Resuscitation and ways to prevent and minimize adverse outcomes after perinatal asphyxia are subject to extensive research.

OBJECTIVES

In this study we hypothesized that, prior to hypoxia, intravenously administered nicotine might have an effect on how newborn piglets tolerate hypoxia, with regard to the time and degree of damage inflicted, due to its suggested neuroprotective abilities, and further that resuscitation with 21 compared with 100% oxygen in nicotine-pretreated animals would cause less cerebral damage.

METHODS

Thirty anesthetized newborn piglets were randomized to either hypoxia or control groups, and pretreatment with either saline or nicotine. In addition, the nicotine/hypoxia group was randomized to resuscitation with either 21 or 100% oxygen for 15 min following hypoxia.

RESULTS

We found significantly more necrosis in the striatum and cortex combined (p = 0.036), and in the striatum alone (p = 0.026), in the animals pretreated with nicotine and resuscitated with 100% when compared to 21% oxygen. There was no significant difference in the cerebellum. We also found significantly increased tolerance to hypoxia as measured by the time interval that the animals endured hypoxia: 103.8 +/- 28.2 min in the nicotine-pretreated animals vs. 66.5 +/- 19.5 min in the saline-pretreated animals (p = 0.035).

CONCLUSION

Nicotine enhances newborn piglets' ability to endure hypoxia, and resuscitation with 21% oxygen inflicts less necrosis than 100% oxygen. The potential neuroprotective effects of nicotine in the newborn brain should be further investigated.

Resuscitation of hypoxic newborn piglets with oxygen induces a dose-dependent increase in markers of oxidation

Newborn resuscitation with pure oxygen may be associated with long-term detrimental effects. Due to the change in attitude toward use of less oxygen upon resuscitation, there is a need to study effects of intermediate hyperoxia. The aim was to study dose-response correlation between inspiratory fraction of oxygen used for resuscitation and urinary markers of oxidative damage to DNA and amino acids. Hypoxemia was induced in newborn piglets following a standardized model; they were resuscitated for 15 min with either 21%, 40%, 60% or 100% oxygen and observed for 1 h. Urine samples were collected. Urinary elimination of 8-hydroxy-2'-deoxyguanosine (8-oxo-dG), 2'deoxyguanosine (2dG), ortho-tyrosine (o-Tyr) and phenylalanine (Phe) were determined by HPLC and tandem mass spectrometry (HPLC-MS/MS). Quotient of 8-oxo-dG/2dG and o-Tyr/Phe ratios were significantly and dose-dependant higher in piglets resuscitated with supplementary oxygen. 8-oxodG/dG: Mean (SD) 5.76 (1.81) versus 22.44 (12.55) p < 0.01 and o-Tyr/Phe: 19.07 (10.7) versus 148.7 (59.8)for 21% versus 100%, p < 0.001. Hypoxia and subsequent resuscitation for 15 min with graded inspiratory fraction of oxygen causes increased oxidative stress and a dose-dependant oxidation of DNA and Phenylalanine. The increase in the hydroxyl attack may lead to a pro-oxidative status and risk for genetic instability.

Skeletal size and bone mineral content in Turner's syndrome: relation to karyotype, estrogen treatment, physical fitness, and bone turnover

Bone mineral content (BMC), bone mineral density, and metacarpal dimensions were studied in 50 women with Turner's syndrome aged 21-45 years in relation to karyotype, estrogen treatment, physical fitness, and biochemical markers of bone turnover. No differences were found between the 25 women with karyotype 45.X and women with other karyotypes. Forty-six women had received estrogen. Significant partial correlations were found between bone mineral density of the forearm and duration of estrogen treatment and physical fitness. BMC of the lumbar spine corrected for vertebral height (BMC(C)spine) was directly correlated with duration of estrogen treatment and height, marginally correlated with physical fitness, and inversely correlated with age. Outer metacarpal width was positively correlated with duration of estrogen treatment, age at initiation of therapy, and body weight. The diameter of medullary space showed negative correlation with physical fitness and height, and positive correlation with age at initiation of estrogen treatment. Cortical thickness was positively correlated with duration of estrogen treatment, physical fitness, and height. No convincing effects of estrogen could be demonstrated in women below the age of 30. Above the age of 30, all bone mineral measurements were markedly elevated in women treated for longer than the average of this age group. BMC(C)spine was inversely correlated with biochemical markers of bone formation. Our results demonstrate that estrogen treatment and physical fitness are important determinants of bone mineral status in Turner's syndrome and add to the evidence that estrogen treatment increases BMC in Turner's syndrome.

[Percutaneous embolization of vascular abnormalities]

In six male patients, percutaneous embolisation of symptom-producing vascular anomalies was performed with spirals or small particles. After a total of ten treatments, symptom-free states were obtained in half of the patients and definite improvement in the remainder. The results are so promising that this method of treatment will be continued.

[Percutaneous transluminal angioplasty of the brachiocephalic arteries]

The results of eight percutaneous transluminal angioplastic (PTA) interventions in seven patients on the brachiocephalic arteries are presented. The occlusions and stenoses were dilated up to the normal lumen. The subjective symptoms disappeared in all of the patients and, similarly, the pulse and blood pressure in the arm were normalized. No complications were registered.

[Comparison of 2 non-ionic radiographic contrast agents in intravenous subtraction angiography]

A prospective randomised comparison was undertaken of iopromide and iopamidol in intravenous digital subtraction angiography. This revealed that the two contrast agents produced pictures of similar quality. A slightly increased number of side effects in patients with cardio-pulmonary disease was demonstrated in the investigation and a slightly increased number of side effects after injection of iopamidol.

[Bone changes following long-term isotretinoin (Roaccutane) treatment]

The case is presented of a 33-year-old man treated with Roaccutane for two years on account of severe acne conglobata. X-ray examination after two years showed pronounced hyperostoses with bridging in the thoracic spine and hyperostoses and beginning bridging in the cervical spine. Furthermore, small exostoses were found on the hands and feet. X-ray control of patients treated for more than six months with Roaccutane is recommended.

[Preoperative evaluation of arteriosclerotic symptoms in the lower extremities by means of intravenous digital subtraction angiography]

Intravenous DSA was performed in 106 patients with symptoms of arterial insufficiency in the lower extremities, requiring treatment according to preceding clinical examination. The examinations were carried out using a 36.5 cm (14 in.) intensifier and a 5.5 F pigtail catheter located centrally. 71% of the examinations were carried out on out-patients. No complications were observed. In 96% of the cases, the intravenous DSA provided sufficient information to make decisions about treatment.

Renal parenchymal appearance on 123iodine-hippurate renoscintigrams and excretory urograms

In 61 patients with vesicoureteral reflux renal scar formation was diagnosed by excretory urography and 123iodine-hippurate scintigrams. Scar formation on the nephrograms was detected in the upper, middle and lower zones of the kidneys on tomography exposures. Scintigraphic detection of scars was performed on the computerized uptake of the parenchymal phase. Maximal time elapse between the 2 investigations was 1 year. Excretory urography revealed 37 kidneys with a total of 74 regional scars. On scintigraphy 57 kidneys were judged to have 102 scars. There were 281 regions judged to be identical on the scintigram and the nephrogram. A true positive ratio (sensitivity) of 0.46 and a true negative ratio (specificity) of 0.90 were noted for the excretory urogram, compared to a sensitivity of 0.64 and a specificity of 0.81 for renography. The study confirms an over-representation of scars judged from scintigrams, which calls for further investigation of scar formation detection.

[Wilms' tumor and neuroblastoma--diagnosis and differential diagnosis]

The radiological results of the urographic findings of 39 children with Wilms' tumours and 20 children with neuroblastomas were analysed respectively. In most cases an exact diagnosis could be achieved by means of the intravenous pyelography with differentiation between the two malignant tumours. Only in a few cases the investigation had to be supplemented with a retrograde pyelography or an angiography. Of great value was the detection of calcifications, the evaluation of the outline and size of the kidneys, decreased function of the affected kidney and filling defects of the calyceal groups and displacement of the renal pelvis.

[Extraskeletal calcification in chronic renal failure during hemodialysis and after renal transplantation (author's transl)]

The frequency of calcifications in vessels and soft tissue was 39% in 184 patients with chronic renal failure. Non-dialyzed patients and dialyzed patients at the start of dialysis treatment had most frequently calcifications of the aorta and larger vessels. Renal transplant recipients, who developed osteonecrosis or spontaneous fractures after transplantation, showed at the time of transplantation a higher frequency of calcifications compared to renal transplant recipients, who did not develop these complications. The frequency of calcifications increased with increasing age not only in the aorta, but also in the other vessels. In nondialyzed patients and in dialyzed patients at the start of dialysis treatment the calcifications were more commonly found in women and in renal transplant recipients in men. In all groups of patients a significant, higher frequency of calcifications was found in patients with radiologic evidence of bone resorption compared to patients without resorptive bone changes. Before and during chronic hemodialysis and following renal transplantation the frequency of calcifications increased. Calcification was most pronounced in the larger vessels in nondialyzed and dialyzed patients and in small vessels in renal transplant recipients. Increase in frequency of calcifications occurred slowly in nondialyzed patients and in renal transplant recipients, whereas an accelerated increase occurred in the first 15 months of the dialysis period in hemodialyzed patients.