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Biomedical subjects

K Sankaran

Publications and source records attributed to K Sankaran.

At least 73 records · Page 4Linked to original sources
PubMed1987

An evaluation of gentamicin dosing according to renal function in neonates with suspected sepsis.

Aminoglycoside antibiotics are frequently used for the treatment of suspected and confirmed sepsis in the newborn patient. In an attempt to evaluate gentamicin dosing based on serum creatinine concentrations, two groups of neonates were studied (infants less than 34 weeks n = 8 and greater than 34 weeks n = 14). The dosing interval was adjusted per protocol depending on the serum creatinine concentrations. Analysis of the results indicate reasonable therapeutic serum gentamicin trough and peak concentrations in most infants.

Bacterial Infections↗
PubMed1986

Crystallization and preliminary data of Indian buffalo erythrocyte carbonic anhydrase.

The most abundant anhydrase isoenzyme from the erythrocyte of Indian buffalo has been purified using affinity gel and DEAE-cellulose ion-exchange columns and single crystals suitable for X-ray diffraction studies have been obtained. The unit cell dimensions are a = 46.8 A, b = 104.5 A, c = 60.4 A, beta = 91.2 degrees and the space group is P2(1), with two molecules per asymmetric unit.

Animals↗
PubMed1986

Physiologic changes induced by endotracheal instillation and suctioning in critically ill preterm infants with and without sedation.

Endotracheal instillation and subsequent suctioning produces fluctuations of intracranial pressure (ICP), mean arterial pressure (MAP), and cerebral perfusion pressure (CPP) in sick preterm infants. In an attempt to observe if these fluctuations could be minimized using sedation, we studied a group of seven sick mechanically ventilated preterm infants with and without sedation. Continuous monitoring of ICP, MAP, heart rate, CPP, and arterial oxygen tension (PaO2) were obtained. The statistical analysis of the data revealed significant blunting of fluctuations of MAP, ICP, and CPP with sedation.

Blood Pressure↗
PubMed1986

Cerebrospinal fluid and plasma beta-endorphin concentrations in prolonged infant apnea (near-miss sudden infant death syndrome).

Elaboration of beta-endorphins (beta-ED) is implicated in the modulation of respiratory control in infants. Therefore, beta-ED concentrations were measured in paired samples of CSF and plasma in three groups of infants. Group 1 and group 3 were used as controls. Group 2 infants suffered prolonged apnea of infancy (near-miss sudden infant death syndrome) and were successfully resuscitated. Age and weight (mean +/- SEM) in groups 1, 2 and 3 were 8.5 +/- 3 months and 7.2 +/- 1.4 kg, 3.8 +/- 0.7 months and 5.2 +/- 0.6 kg, and 3.4 +/- 0.9 months and 3.4 +/- 0.7 kg, respectively. CSF beta-ED concentrations were found to be significantly elevated in group 2, 67.8 +/- 4.7 pg/ml, when compared to group 1, 29.8 +/- 3.1 pg/ml, and group 3, 46.5 +/- 7.2 pg/ml (p less than 0.01). No correlation was observed with plasma and CSF concentrations in all three groups. beta-ED may play a role in the pathophysiology of prolonged infant apnea (near-miss sudden infant death syndrome).

Apnea↗
PubMed1985

Congenital tracheal occlusion in neonates--a minireview.

Congenital tracheal occlusion, though seemingly rare, is generally fatal if not attended to immediately. A high index of suspicion should help to make the diagnosis in a neonate when there are respiratory distress at birth and no audible cry and an endotracheal tube cannot be advanced beyond the vocal cords. We present our experience with cases of congenital tracheal obstruction due to various causes during a period of four years.

Female↗
PubMed1984

Plasma beta-endorphin concentration in infants with apneic spells.

In an attempt to determine whether plasma beta-endorphin (beta-ED) concentrations correlate with occurrence of apnea in preterm infants, measurements were made in three groups of infants. The control group consisted of 11 infants with a mean (+/- SEM) gestational age of 30.5 +/- 0.8 weeks, a mean (+/- SEM) birthweight of 1650 +/- 180 g, and a mean (+/- SEM) postnatal age of 1.3 +/- 0.5 days. Eight infants with apnea, bradycardia, and associated hypotension had a mean (+/- SEM) gestational age, birthweight and postnatal age of 30 +/- 0.9 weeks, 1165 +/- 90 g, and 7.8 +/- 1.9 days, respectively. The third group consisted of eight infants experiencing apnea alone without bradycardia and had a mean (+/- SEM) gestational age, birthweight, and postnatal age of 31 +/- 0.8 weeks, 1380 +/- 125 g, and 2.6 +/- 0.9 days, respectively. The last two groups of infants suffered varying degrees of apnea, but differed in their severity. The plasma endorphin concentrations (+/- SEM) were 26.9 +/- 2, 68.0 +/- 9.0, and 39.6 +/- 2.0 pg/ml, respectively, for the previously described three groups. Significant elevation in beta-ED concentration was observed in the severely apneic infants with bradycardia when compared to the other two groups. The association of increased plasma beta-ED release with severe apneic spells may suggest that these endogenous opiates play a role in the pathophysiology of apnea of prematurity.

Apnea↗
PubMed1984

Hypoxic-ischemic encephalopathy: cerebrovascular carbon dioxide reactivity in neonates.

Using noninvasive measurement of cranial blood flow, we previously demonstrated that full-term asphyxiated neonates have decreased cerebral perfusion that can persist up to 5 days of age. In an attempt to test their postischemic cerebrovascular CO2 reactivity, we measured cranial blood flow in ten asphyxiated term (39 +/- 0.8 weeks and 3078 K 400 gm) infants with and without inhaled carbon dioxide (3 percent). The end tidal CO2 (PaCO2) increased significantly, from 28.8 +/- 1.0 mm Hg to 32.3 +/- 2.0 mm Hg after CO2 inhalation (p less than 0.01), whereas the cranial blood flow showed no significant change (38.5 +/- 5.0 ml/min/100 gm brain weight to 37.6 +/- 6.0 ml/min/100 gm brain weight). We conclude that term infants with hypoxic-ischemic encephalopathy have low cranial blood flow at 3 days of age. Their cerebrovascular response to inhaled CO2 is variable and suggests some impairment.

Asphyxia Neonatorum↗
PubMed1984

Plasma beta-endorphin concentrations in neonates associated with acute stress.

Plasma beta-endorphin concentrations were measured in two groups of neonates. The control group (group 1) consisted of 20 infants with a mean gestational age of 31.5 +/- 0.6 weeks and a mean birth weight of 1,720 +/- 135 g. Blood samples were collected at a mean postnatal age of 1.0 +/- 0.3 days. Group 2 consisted of 23 infants with clinical evidence of acute illness and associated significant stress who had a mean gestational age of 33.2 +/- 1.1 weeks and a mean birth weight of 2,075 +/- 225 g. Their blood samples were collected at a mean postnatal age of 3.4 +/- 1.3 days. The mean beta-endorphin concentration in group 1 was 27.8 +/- 6 pg/ml and 63.9 +/- 4.2 pg/ml in group 2 (p less than 0.05). No correlation was observed for gestation or birth weight and beta-endorphin concentrations in group 1; however, in group 2 a positive correlation was seen for gestational age and plasma beta-endorphin concentrations (r = 0.4411) suggesting an increased release of plasma beta-endorphin with increasing gestation when faced with significant clinical stress.

Acute Disease↗
PubMed1984

Hypoxic-ischemic encephalopathy and plasma beta-endorphin.

In an attempt to determine whether hypoxic-ischemic encephalopathy in and of itself or its associated pathologic conditions lead to increased concentrations of plasma beta-endorphin (beta-ED), measurements were made in three groups of term infants. Group 1 (control) consisted of 8 infants with a mean gestation of 38.6 +/- (SE) 0.4 weeks, a mean birth weight of 3,420 +/- 150 g, and a mean postnatal age of 1.4 +/- 0.7 days. Group 2 consisted of 10 infants with a mean gestational age, birth weight and postnatal age of 40.1 +/- 0.5 weeks, 3,310 +/- 80 g and 3,9 +/- 1.1 days, and group 3 included 6 infants with a mean gestational age, birth weight and postnatal age of 40.4 +/- 1 weeks, 3,650 +/- 310 g, and 2.8 +/- 1 days, respectively. The group 2 and 3 infants suffered clinical and neurological evidence of hypoxic-ischemic brain injury from perinatal asphyxia; however, the infants in group 2 suffered additional problems such as meconium aspiration, persistent fetal circulation with ongoing hypoxemia as measured by transcutaneous or umbilical arterial oxygen monitoring. The group 3 infants were normoxemic after resuscitation. The mean plasma beta-ED concentrations were 19 +/- (SE) 2.7, 103 +/- 35.7 and 25 +/- 4.5 pg/ml in groups 1, 2 and 3, respectively. A significant elevation of plasma beta-ED concentration was observed in group 2 when compared to groups 1 and 3. The association of increased plasma beta-ED concentration in infants with hypoxic-ischemic encephalopathy associated with ongoing hypoxemia suggests that hypoxemia may act as a strong stimulus for plasma beta-ED release in term infants.

Asphyxia Neonatorum↗
PubMed1984

Genetic resistance of mice to persistent infection with Mycobacterium lepraemurium in vitro: association with macrophage bactericidal responsiveness to lymphokines and dissociation from production of hydrogen peroxide by macrophages.

Peritoneal and splenic adherent macrophages (SAC) from M. lepraemurium susceptible (C3H/HeJ) and resistant (C57B1/6J) mice were studied for their abilities to generate H2O2 in vitro. Unexpectedly, SAC from the susceptible C3H/HeJ strain produced more H2O2 than those of the resistant C57BL/6J. In vivo sensitization with M. bovis (BCG), or C. parvum increased production of H2O2 by SAC from both strains, whereas in vivo sensitization with M. lepraemurium enhanced H2O2 production only in the C3H/HeJ susceptible strains. In vitro addition of a crude lymphokine enhanced H2O2 production by C3H/HeJ SAC more than by C57BL/6J SAC. In vitro addition of M. lepraemurium caused an inhibition of H2O2 production by SAC from both strains but the inhibition was greater for the resistant C57BL/6J strain. M. lepraemurium phagocytosed in vitro by untreated peritoneal macrophages of both mouse strains were morphologically altered to the same extent. However, the addition of lymphokine dramatically increased the degree of bacterial lysis in only the C57BL/6J strain. These results, support the view that H2O2 plays a limited, if any, role in the protection of the host from M. lepraemurium and may even contribute to susceptibility by inhibiting the host's immune response.

Animals↗
PubMed1984

Time-wise sequential analysis of gastric aspirate for occult blood and pH in sick preterm infants.

Improvements in both care and technology have led to the survival of more low birthweight infants. Initially, these infants are not fed orally and are placed on parenteral nutrition. In an attempt to evaluate sequential time-wise changes in gastric pH and occult blood loss, evaluation of gastric pH and tests for the presence of blood in the gastric aspirate were carried out in two groups of infants. Group 1 consisted of seven cases, three males and four females, with a mean +/- SE gestation of 29.9 +/- 0.8 weeks and a birthweight of 1410 +/- 190 g. Group 2 consisted of nine cases, three males and six females, with a mean +/- gestation of 28.6 +/- 0.84 weeks and a birthweight of 940 +/- 120 g. Gastric contents were sampled through indwelling orogastric tubes every 4-6 h daily for the first seven days in Group 1 and 14 days in Group 2. Infants in Group 1 were spontaneously breathing with mild hyaline membrane disease (HMD) whereas Group 2 infants had severe HMD requiring ventilation. Results indicate that critically ill preterm infants (Group 2) had significantly lower pH when compared to Group 1 (p less than 0.015). Progressive decrease in pH was observed in both groups (P less than 0.001). The association of occult gastric blood loss with decreasing pH was examined using pooled data from both groups of neonates. During the times when bleeding occurred, the mean +/- SE gastric pH level was 2 +/- 0.1.(ABSTRACT TRUNCATED AT 250 WORDS)

Female↗
PubMed1983

Studies on the size and shape of rabbit intestinal glucoamylase-maltase complex.

Rabbit intestinal glucoamylase-maltase was examined in detail with respect to its molecular weight, sedimentation, diffusion and viscosity. It is a large asymmetrical molecule, with a molecular weight of 750 000-760 000. Its appearance under the electron microscope supports the idea that it is a long string (62.0 nm) consisting of eight beads of diameter 6.0 nm each and a surface-to-surface interbead distance of approx. 2.0 nm. The shape of the enzyme derived from its hydrodynamic behaviour by using the string-of-spherical-beads model originally proposed by Kuhn [(1932) Z. Phys. Chem. Abt. A 161, 1-32] and later modified by Shulman [(1953) J. Am. Chem. Soc. 75, 5846-5852] fits moderately well with the electron-microscopic picture. The beads might represent about six subunits, and the absence of sulphur from the enzyme and the inability to dissociate the enzyme by conventional methods indicate the possibility of unusual covalent cross-linking between the subunits and between the beads.

Animals↗
PubMed1983

Cranial volume and occipito-frontal circumference in neonates.

Occipitofrontal head circumference (OFC), using tape, and calibrated scale and cranial volumes, using styrofoam plastic cast, were measured in nine preterm and 13 term infants. Term infants had a mean +/- S.E. gestation of 40 +/- 0.2 wk and a mean +/- S.E. birth weight of 3461 +/- 108 g. Preterm infants had a mean +/- S.E. gestation of 30.5 +/- 1.4 wk and a mean +/- S.E. birth weight of 1596 +/- 211 g. Five sequential measurements were made on term infants and nine such measurements were done on preterm infants at specified time intervals. The values of cranial volume were compared with previously published results in term infants. Brain weight and cranial volumes were also compared in 10 preterm infants and seven term infants who died of non-intracranial pathology. To determine if this method is reproducible, it was tested using 50 paired measurements and was found to be within 3%. There was a significant decrease in cranial volume in term and preterm infants with time. Term infants reached the control value at 64 h of age and preterm infants reached the control value at 160 h of age. Preterm infants showed a significant decrease in OFC but term infants did not. The rate of change was not significantly different in either group.(ABSTRACT TRUNCATED AT 250 WORDS)

Brain↗
PubMed1983

Tracheal atresia, proximal esophageal atresia, and distal tracheoesophageal fistula: report of two cases and review of literature.

Two cases with unusual primitive foregut anomalies are described. Both children, born within 24 hours of each other, had complete tracheal atresia, proximal esophageal atresia, and distal tracheoesophageal fistula along with some minor anomalies; both needed immediate tracheostomy for adequate ventilation. At 15 months of age, both patients are thriving and developing normally with the exception of their speech. A review of the literature revealed no other survivors with this condition. Diagnosis of tracheal atresia should be kept in mind when a newborn infant exhibits respiratory distress without an audible cry associated with failure to advance the endotracheal tube beyond the vocal cords. An immediate tracheostomy can be lifesaving in these children.

Diagnosis, Differential↗