Influence of kynurenines in pathogenesis of cataract formation in tryptophan-deficient regimen in Wistar rats.

L-Tryptophan (Trp) is an essential amino acid and its deficiency is involved in various pathologies. In this present investigation an attempt was made to study the role of tryptophan and its metabolites in cataract formation in wistar rats. Rats were divided and maintained in 3 groups, Group A--control; Group B--marginal-tryptophan and Group C--Tryptophan-deficient diet for 3 months. Slit lamp microscope observations indicated lenticular opacities in Group-C (tryptophan-deficient) rats. In the rats that were maintained on tryptophan deficient diet, a decrease in protein content, kynurenines, reduced glutathione (GSH), glutathione peroxidase (GPx), glutathione-s-tranferase (GSTs) and tryptophan-fluorescence intensities and an increase in lipid peroxidation indicative of oxidative stress have been observed. The above changes were normalized in the rats on supplementation of 0.05% tryptophan (Group-B) in their diets. These results suggest that tryptophan-deficiency in the diet leads to an overall significant decrease in kynurenines and levels of antioxidant enzymes (except SOD) in ocular tissue with a concomitant lenticular opacification. The results suggest that diet with adequate tryptophan has protective influence and is of immense benefit in mitigating the changes that may otherwise contribute to the lenticular opacities.

Effect of quercetin on galactose-induced hyperglycaemic oxidative stress in hepatic and neuronal tissues of Wistar rats.

In recent times there has been great demand for natural products that have possible preventive action against diabetes and its secondary complications. Keeping this in mind, this study was undertaken to investigate the influence of the flavonoid, quercetin, on oxidative stress markers and the antioxidant defence system of hepatic and neuronal tissues from galactose-induced hyperglycaemic rats. Weanling male Wistar rats were treated with 30% galactose in AIN 93 diet (group B, n=8) to induce hyperglycaemia. Control rats received normal Stock AIN 93 diet (group A, n=8). The third set of rats received group B diet with quercetin at 400 mg/100 g diet (group C, n=8). Glucose levels and body weights were measured on a weekly basis for four weeks to monitor the hyperglycaemia induced by galactose feeding. Parameters involved in the pathogenesis of galactose-induced hyperglycaemia, which included organosomatic index, protein content, antioxidant enzymes superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px), tryptophan fluorescence, content of protein carbonyls, prooxidant malonaldehyde (MDA) and glutathione (GSH) in hepatic and neuronal tissues were determined at the end of the fourth week. The study suggest that quercetin counters the pro-oxidant effects of galactose-induced hyperglycaemic stress, as there was a significant reversal of changes with respect to body weights, organosomatic index of hepatic and neuronal tissues, lipid peroxidation, protein carbonyl content, reduced glutathione and activities of antioxidant enzymes. In addition, treatment with quercetin appears to reduce the osmotic stress induced by hyperglycaemia, as assessed by polyol pathway enzyme aldose reductase. These results imply that inclusion of quercetin in the diet controls, to some extent, galactose-induced hyperglycaemia and its attendant complications.

Behavioral, morphological and physiological shift in the rats administered with tryptophan deficient regimen.

Protein-restriction or deficiency is associated with many pathological disorders. We have made an attempt to study the effect of marginal tryptophan deficiency and supplementation of adequate tryptophan on the activity of antioxidant enzymes in the liver and neuronal tissue of rats. Marginal tryptophan deficiency was created in the animals (group-C) by feeding them with diet consisting of casein (6%) and gelatin (12%). Control animals (group-A) received 20% casein in their diet. Another set of animals (group-B) received the marginal tryptophan deficient diet with 0.05% tryptophan. We have observed a decrease in body weight and organ development in the deficient animals. However, a protective mechanism has been observed in the tryptophan deficient animals that received 0.05% tryptophan. Biochemical studies have shown a decrease in protein content, reduced glutathione (GSH) levels, activities of catalase, glutathione-s-tranferase (GSTs) and tryptophan-fluorescence in tryptophan deficient rats. There is an increase in lipid peroxidation and AGE-fluorescence suggesting the oxidative stress due to tryptophan deficiency. However, in deficient rats that received 0.05% tryptophan in diet there was an increase in protein content, glutathione levels, catalase, glutathione-s-tranferase (GSTs) levels, tryptophan-fluorescence and inhibition in AGE-fluorescence and lipid peroxidation. Our findings suggest that adequate tryptophan administration to tryptophan deficient animals has a protective influence as revealed in the activity levels of antioxidant enzymes in relation to deficient animals.

Cumulative antioxidant defense against oxidative challenge in galactose-induced cataractogenesis in Wistar rats.

Natural dietary ingredients are known for their antioxidant activity. Of such, curcumin, the active principle of turmeric, at 0.01% in the diet proved as pro-oxidative in galactose-induced cataract in vivo. The purpose of this study was to investigate the effect of vitamin E (VE), a well-known antioxidant, in combination with curcumin on the onset and maturation of galactose induced cataract. Periodic slit-lamp microscope examination indicated that in combination with vitamin-E, 0.01% curcumin (G-IV) delayed the onset and maturation of galactose-induced cataract. Biochemical analyses revealed that combined treatment of 0.01% curcumin and vitamin-E diet exhibited an efficient antioxidant effect, as it inhibited lipid peroxidation and contributed to a distinct rise in reduced glutathione content. The results indicate that natural dietary ingredients are effective in combination rather than the individual administration as they are complementing each other in reducing the risk of galactose induced cataract.

Protective effect of curcumin during selenium induced toxicity on dehydrogenases in hepatic tissue.

Selenium administration resulted in a marked decrease in the activity levels of the liver succinate dehydrogenase, malate dehydrogenase, and lactate dehydrogenase while pyruvate dehydrogenase increased significantly (P<0.001) in the wistar rat. The degree of decrease of these enzymes was significantly less (P<0.001) when rats were treated with curcumin, a natural constituent Curcuma longa. Curcumin seems to prevent oxidative damage mediated through selenium and protect the dehydrogenases possibly through its anti-oxidative property.

The inhibitory effect of Isoflavones isolated from Caesalpinia pulcherrima on aldose reductase in STZ induced diabetic rats.

Increased aldose reductase activity has been implicated in the development of retinopathy due to accumulation of intracellular sugar alcohol, i.e., sorbitol. In this study, the compounds isolated from the Caesalpinia pulcherrima, have been examined for its inhibitory effects on aldose reductase (AR), which plays a major role in diabetic retinopathy. 3,6,7,4',5'-Pentamethoxy-5,3'-dihydroxyflavone (Compound 2) has shown significant inhibition of rat retina AR with an IC50 value of 16.24±0.046µM in a non-competitive manner. Molecular docking study results are steady with the pattern of AR inhibition by Compound 2 and its specificity. The supplementation of Compound 2 suppresses sorbitol accumulation in retina by decreased AR activity in STZ induced diabetic rat in dose dependent manner. Besides this, rats fed with Compound 2 have shown improved levels of antioxidant enzymes. This study revealed that Compound 2 has pharmacologically active component with a potential to inhibit rat retina AR and affecting the delaying process of diabetic retinopathy in STZ induced diabetic rats.

A simple noninvasive technique of measuring intracranial pressure in the newborn.

A noninvasive approach to measuring intracranial pressure in newborns based on optical principles and devoid of electrical hazards is described. This monitoring technique can be used to detail subtle changes in measurements in ill newborns and to predict hydrocephalus. The mean anterior fontanel pressure in normal infants was 10.14 +/- 0.39 cm H2O. Increased pressure was noted in sick neonates and in infants with hydrocephalus. Good correlation was noted between anterior fontanel pressure and CSF pressure. Pediatrics, 59:957-961, 1977, INTRACRANIAL PRESSURE, ANTERIOR FONTANEL PRESSURE, HYDROCEPHALUS, MONITORING DEVICE.

Clinical significance of monitoring anterior fontanel pressure in sick neonates and infants.

The intracranial pressure was monitored via the anterior fontanel, using a noninvasive technique, in 78 acutely ill, 39 normal term, and 6 normal preterm infants. In normal term and preterm infants the anterior fontanel pressure (AFP) was 10.2 +/- 0.4 and 9.5 +/- 0.8 cm H2O, respectively. Infants with hyaline membrane disease had elevated pressure (13.3 +/- 0.6 cm H2O), which was higher than that of normal preterm infants. Following an episode of intracranial hemorrhage in four infants, the AFP increased to 26.2 +/- 2.5 cm H2O. Elevated pressure was noted in infants with meconium aspiration syndrome (24.1 +/- 1.8 cm H2O); the pressure decreased during the phase of recovery (15.6 +/- 3.5 cm H2O). Elevated pressure was noted in infants with meningitis and hydrocephalus. Repeated measurements helped to diagnose shunt obstruction in an infant with hydrocephalus.

Early and late surfactant treatments in baboon model of hyaline membrane disease.

Because the issue of optimal time for artificial surfactant therapy for hyaline membrane disease has not been established, the effects of treatment with a reconstituted bovine surfactant (surfactant TA) were compared at two time periods in a hyaline membrane disease model in a premature baboon. The baboons were delivered by cesarean section at 75% of gestation (139.5 +/- 1.5 days, mean +/- SD). One group was treated with surfactant TA within ten minutes after birth (ultraearly), another group was treated at two hours of age (late) and a third (comparison group) did not receive the surfactant. Both treatment groups had significantly higher compliance and ratio of arterial to alveolar Po2 ratio and lower mean airway pressure and oxygen requirement (Fio2) than the comparison group. At autopsy, the largest residual volume and hysteresis in pulmonary pressure-volume curves were noted in the ultraearly group, intermediate values were found in the late group, and least values were found in the comparison group. These data indicate that early surfactant therapy for hyaline membrane disease results in greater improvement in lung mechanics than delaying treatment, even for two hours. Delivery room treatment with surfactant of infants at risk for hyaline membrane disease is perhaps better than therapy for established hyaline membrane disease.

Centronuclear myopathy in the newborn period causing severe respiratory distress.

Centronuclear myopathy can be classified into four clinical varieties based on age, severity at onset, and rapidity of progress. In the severe form with involvement of respiratory muscles at birth, the progress is rapid and fatal before 3 years of age. The case described in this report illustrates rapid progression of muscle paralysis and death in a neonate. However, in a majority of cases the disease is either moderately severe or mild with the affected individuals confined to wheel chair by adolescence or early adult life. Diagnosis of the disease is based on appropriate muscle histopathology and electron microscopic studies.

Circle of Willis blood velocity and flow direction after common carotid artery ligation for neonatal extracorporeal membrane oxygenation.

The velocity and direction of blood flow in the circle of Willis arteries were measured in three infants who underwent right common carotid artery ligation for extracorporeal membrane oxygenation treatment. Within 15 minutes of common carotid artery ligation, blood flow was detected in one infant's right middle cerebral artery; however, the velocity was reduced to 50% of the preextracorporeal membrane oxygenation level. The velocity remained 50% to 70% lower than normal during the 88 hours of extracorporeal membrane oxygenation therapy. In the other two infants, the velocity changes were less severe. By 2 to 10 weeks after weaning from extracorporeal membrane oxygenation, the velocities in the left cerebral arteries were increased to 116% to 217% of the corresponding right cerebral vessels. Following common carotid artery ligation, a retrograde direction of flow was noted in the first (A1) segment of the right anterior cerebral artery and in the right posterior communicating artery, whereas the direction of flow was normal in the corresponding vessels on the left. After common carotid artery ligation, the vertebrobasilar and the contralateral internal carotid systems appear to be the main sources of reperfusion of the right cerebral hemisphere via the circle of Willis. Furthermore, because of the known variants of the circle anatomy, a noninvasive pulsed Doppler method could be used to evaluate the flow patterns in the circle of Willis arteries, both before and after common carotid artery ligation for extracorporeal membrane oxygenation.

Bovine surfactant (surfactant TA) therapy in immature baboons with hyaline membrane disease.

As a prelude to clinical trials with a bovine surfactant (surfactant TA), in human infants with hyaline membrane disease, pulmonary and hemodynamic changes following its instillation in premature baboons were investigated. Baboons, delivered by cesarean section at 141 +/- 3.5 days (mean +/- SD, 77% gestation), were provided with intensive care. At 2 hours of age in one group (n = 10), 100 mg/kg of surfactant TA (reconstituted bovine surfactant, Tokyo Tanabe Co., Tokyo) was instilled into the lungs. Sequential measurements and monitoring of pulmonary and hemodynamic variables were carried out in these ten baboons and in a control group of five baboons for 16 hours, at which time the experiments were electively terminated. At birth, the pulmonary compliance, findings of chest radiographs, ratio of arterial PO2 to alveolar PO2, and respirator variables needed to maintain normal blood gas and acid base status were identical in both groups and indicative of severe hyaline membrane disease. Following surfactant instillation, the treated group demonstrated a rapid increase in PO2 with significantly improved ratio of arterial PO2 to alveolar PO2 (from a mean +/- SD pretreatment value of 0.21 +/- 0.11 to 0.45 +/- 0.11 by 16 hours). Pulmonary compliance improved similarly (from pretreatment value of 0.18 +/- 0.06 mL/cm H2O/kg to 0.27 +/- 0.09 mL/cm H2O/kg). Significant reduction in respirator support variables could be achieved in all treated animals; however, in the control animals, the pulmonary status worsened as evidenced by increasing mean airway pressure and respirator variables to keep normal blood gas and acid base status, thus worsening compliance. At autopsy, pulmonary pressure-volume curves were significantly different with large hysteresis obtained in the surfactant-treated group. Although no deleterious effect on hemodynamics was noted in surfactant TA-treated animals, a large patent ductus arteriosus was demonstrated by aortography. Increased lung blood flow, probably due to a large patent ductus arteriosus flow, was demonstrated by radiolabeled microsphere technique. The physiologic significance and clinical relevance of these findings in premature baboons treated with surfactant TA are discussed.

Interruption of patent ductus arteriosus in premature infants with respiratory distress syndrome.

In infants with respiratory distress syndrome (RDS) hypoxemia inhibits closure of the patent ductus arteriosus (PDA), resulting in increased pulmonary blood flow with subsequent increased hypoxemia. In an attempt to interrupt this cycle 42 consecutive premature infants with RDS and PDA, weighing between 550 and 2,000 gm (average, 1,383 gm) and with an average gestational age of 31 weeks, were arbitrarily treated either medically (13 patients) or by interruption of the PDA (20 patients). Eleven patients who were initially treated medically could not be weaned from the respirator and later underwent operation. There were no operative or anesthetic deaths; late survival was 65% (20 patients). The last 31 patients were randomly divided into operative and nonoperative groups. Preliminary results revealed no significant differences in late survival between the two groups. Since the operative risk is minimal, further investigative efforts are indicated to settle this issue.

Intravenous morphine attenuates pain induced changes in skin blood flow in newborn infants.

In a previous study we found that pain and discomfort caused a marked increase in skin blood flow in newborn infants, and that skin blood flow decreased after morphine. In this study we tested morphine effect on the skin blood flow response to pain more systematically. Skin blood flow was measured using a laser Doppler technique during 19 percutaneous central venous catheter placements in 18 infants, 10 of whom received intravenous morphine premedication. The mean +/- SD baseline skin blood flow was similar between the two groups: 22.5 +/- 9.5 ml 100 g-1 min-1 in the morphine group, and 23.7 +/- 8.0 ml 100 g-1 min-1 in the no-morphine group, respectively (p = n.s.). During PCVC placement in the morphine treated group, skin blood flow remained low with minimal variability. The mean value was 22.6 +/- 7.7 ml 100 g-1 min-1 (p = n.s. compared to baseline). In 7/9 infants not treated with morphine skin blood flow increased dramatically during PCVC placement, while in two it did not. But the mean skin blood flow in this group of 9 infants during PCVC placement was 45.3 +/- 34 ml 100 g-1 min-1, an overall change of 97% increase from the baseline. This was statistically significant compared with the baseline and the morphine group value during PCVC insertion (p < 0.04). During the 45 min time period after PCVC placement, skin blood flow values between groups again were similar. We conclude that morphine pretreatment for PCVC placement minimizes pain-associated increases in skin blood flow. The issue of whether skin blood flow changes could serve as measures of adequate analgesia needs to be evaluated with further studies.

Cranial Doppler applications in neonatal critical care.

Although Doppler methods have been validated, it must be stressed that, at their best, Doppler results reflect qualitative circulatory changes, and suggest the direction of change. Because the large conduit arteries may also be controlling changes in flow volume, a direct extrapolation of the numeric findings from Doppler studies may lead to incorrect conclusions. Doppler methods have not made their way into routine neonatal critical care until now, but several studies have concluded that Doppler-derived information can be used as adjunct to clinical management in cases with shock, asphyxia, brain death, vascular malformations, and increased intracranial pressure. As with any physiologic variable, serial measurements may be of greater value than a single measurement. The Doppler techniques already are powerful investigative tools, but with continued improvements in technology, they hold promise of becoming important adjuncts in the monitoring of cerebral hemodynamics in perinatal-neonatal critical care units.

Low cerebral perfusion pressure: an indicator of poor prognosis in asphyxiated term infants.

To establish the value of monitoring cerebral perfusion pressure (CPP) as an index for outcome in acutely ill neonates, blood pressure and intracranial pressure (ICP) were monitored in 44 sick newborn infants. ICP was measured via the fontanel using a noninvasive technique. The results indicate that CPP was similar in preterm hyaline membrane disease infants with intracranial bleed and in those without bleed. In term asphyxiated infants, CPP correlated with outcome; 86% of those with low CPP either died or developed cerebral palsy and 75% of those with normal CPP were neurologically normal. We feel that low CPP in asphyxiated term infants must be viewed with concern.

Effect of acute hypovolemic hypotension on cerebral metabolism in newborn piglets.

To evaluate the temporal changes in cerebral energy metabolism in shock during the perinatal period, we studied cerebral blood flow (CBF) and other metabolic variables in newborn piglets subjected an acute hypovolemic hypotension (HVH). By 30 minutes following HVH, the cardiac output dropped 64%, but the CBF was maintained. Serum glucose rose 110% baseline, resulting in an increase in brain glucose delivery. Cerebral metabolic rate of glucose also increased 246%, while that of oxygen remained unaffected. Further, at 30 minutes of HVH, systemic arterial lactate levels increased 250%, but cerebrospinal fluid (CSF) lactate levels remained in the normal range. By contrast, at 60 minutes following HVH, the CBF dropped 60%, the cerebral metabolic rate for glucose dropped 45%, and that of oxygen 43% of the respective baseline values. A profound systemic lactatemia was noted (500% baseline value), with a concomitant rise in the CSF lactate levels to 190% baseline value. These findings suggest that post-hemorrhagic hypovolemia can be divided into two arbitrary, but distinct phases: 1) An initial phase of relative compensation lasting approximately 30 minutes, during which time the brain utilization of metabolic substrates is well preserved. 2) A later phase of decompensation by 60 minutes of HVH, during which time the CBF as well as brain utilization of metabolic substrates drop significantly. By this time a loss of blood-CSF or brain-CSF barrier for lactate can be seen. The findings of this study may have important implications in the treatment of hemorrhagic shock in the perinatal period.

Animal models for the study of perinatal hypoxic-ischemic encephalopathy: a critical analysis.

We critically evaluated various design features from 292 animal studies related to perinatal hypoxic-ischemic encephalopathy (HIE). Rodents were the most frequently used animals in HIE research (26%), followed by piglets (23%) and sheep (22%). Asphyxia with or without ischemia was the most predominant method of producing experimental brain damage, but there were significant variations in specific details, particularly regarding the method and duration of brain insult. In 71% (207/292) of studies the CNS outcomes were tested within 24 h of experimental insult and in 29% (85/292) they were tested 24 h or more after the insult. Acute CNS metabolic end-points were assessed in 82-100% of all studies. In 90% of studies the chronological age of the animal was equivalent to that of human term newborn infant. However, in only 23% (67/292) were clinical neurological, developmental or behavioral outcomes evaluated, and in only 26% (76/292) was neuropathology assessed. While no single animal model was found to be ideal for all HIE research, some models were distinctly superior to others, depending upon the specific research question. The fetal sheep, newborn lamb and piglet models are well suited for the study of acute and subacute metabolic and physiologic endpoints, whereas the rodent and primate models could be used for long-term neurological and behavioral outcome experiments as well. We also feel that standardizing the study design features, including an HI insult method that produces consistent and predictable brain damage is urgently needed. Studies in neuro-ethology should explore how well brains of various animals compare with that of the newborn human infant. There is also a need for developing animal models that mimic clinical entities in which long-term neuro-developmental and behavioral outcomes can be assessed.

Skin blood flow changes during routine nursery procedures.

OBJECTIVE: The objective of this study was to establish that changes in skin blood flow could serve as an index of pain and discomfort in newborn infants. METHODS: Skin blood flow changes during intensive care procedures and during morphine administration were measured in a group of newborn infants using a laser Doppler technique. Heart rate, respiratory rate and oxygen saturation were also measured. Changes in skin blood flow and physiologic variables that occurred during procedures were analyzed and compared among procedures. RESULTS: Measurements were made during 145 procedures in 15 infants 2-32 days old with birth weights of 500-2900 g and gestational ages of 23-37 weeks. Ten of the infants were receiving mechanical ventilation. Skin blood flow increased 27-134% during lancet puncture of the heel, physical handling, standard suctioning and chest physiotherapy, and there were no changes during closed system suctioning. Skin blood flow decreased 35% by 20 min after intravenous morphine. Changes seen in heart rate, respiratory rate and oxygen saturation were generally minimal. CONCLUSIONS: We conclude that laser Doppler skin blood flow changes could be an index of neonatal pain and discomfort; even noninvasive handling procedures are associated with increases in skin blood flow; and changes in skin blood flow may be more useful than conventional physiologic variables in assessing the response to intensive care nursery procedure.

Improving handwashing habits in the newborn nurseries.

In five separate sessions over a 13-month period, the authors monitored the handwashing habits of doctors, nurses, and other healthcare professionals in the nursery. Compliance rates regarding three specific items related to handwashing prophylaxis were noted by a group of observers without the knowledge of the subjects involved. Good handwashing prophylaxis was carried out by the doctors only 37.5% prior to handling infants, and 29.2% after contact with inanimate objects, whereas for these items the nurses complied 53.9% and 29.2%, respectively. Wrist ornaments were removed prior to handwashing in 72.7% and 75.3% of contacts. The data for other healthcare professionals were generally similar. The information from this study was used for educational purposes, which seemed to have had an impact on handwashing habits. The compliance rates during the later part of the study for the first two items combined improved from 28.4% to 62.6% (p less than 0.001). The authors conclude that in the newborn units, the compliance with handwashing is generally poor. They believe that with continued monitoring and educational efforts, it may be possible to improve habits regarding handwashing prophylaxis.