Improved nonclinical safety profile of a novel, highly selective inhibitor of the immunoproteasome subunit LMP7 (M3258)

M3258 is the first selective inhibitor of the immunoproteasome subunit LMP7 (Large multifunctional protease 7) in early clinical development with the potential to improve therapeutic utility in patients of multiple myeloma (MM) or other hematological malignancies. Safety pharmacology studies with M3258 did not reveal any functional impairments of the cardiovascular system in several in vitro tests employing human cardiomyocytes and cardiac ion channels (including hERG), guinea pig heart refractory period and force contraction, and rat aortic contraction as well as in cardiovascular function tests in dogs. Following single dose M3258 administration to rats, no changes were observed on respiratory function by using whole body plethysmography, nor did it change (neuro)behavioral parameters in a battery of tests. Based on pivotal 4-week toxicity studies with daily oral dosing of M3258, the identified key target organs of toxicity were limited to the lympho-hematopoietic system in rats and dogs, and to the intestine with its local lymphoid tissues in dogs only. Importantly, the stomach, nervous system, heart, lungs, and kidneys, that may be part of clinically relevant toxicities as reported for pan-proteasome inhibitors, were spared with M3258. Therefore, it is anticipated that by targeting highly selective and potent inhibition of LMP7, the resulting favorable safety profile of M3258 together with the maintained potent anti-tumor activity as previously reported in mouse MM xenograft models, may translate into an improved benefit-risk profile in MM patients.

Nonproliferative and Proliferative Lesions of the Rat and Mouse Endocrine System

The INHAND (International Harmonization of Nomenclature and Diagnostic Criteria for Lesions in Rats and Mice) Project (www.toxpath.org/inhand.asp) is a joint initiative among the Societies of Toxicological Pathology from Europe (ESTP), Great Britain (BSTP), Japan (JSTP) and North America (STP) to develop an internationally accepted nomenclature for proliferative and nonproliferative lesions in laboratory animals. The purpose of this publication is to provide a standardized nomenclature for classifying microscopic lesions observed in the endocrine organs (pituitary gland, pineal gland, thyroid gland, parathyroid glands, adrenal glands and pancreatic islets) of laboratory rats and mice, with color photomicrographs illustrating examples of the lesions. The standardized nomenclature presented in this document is also available electronically on the internet (http://www.goreni.org/). Sources of material included histopathology databases from government, academia, and industrial laboratories throughout the world. Content includes spontaneous and aging lesions as well as lesions induced by exposure to test materials. A widely accepted and utilized international harmonization of nomenclature for endocrine lesions in laboratory animals will decrease confusion among regulatory and scientific research organizations in different countries and provide a common language to increase and enrich international exchanges of information among toxicologists and pathologists.

[Promotion of breast feeding in paediatric outpatient settings]

With some data and examples it can be shown that the competence and the knowledge of paediatric doctor's assistants and paediatric nurses can and should be improved. The training courses to become a "prevention assistant" have been very positively accepted by doctor's assistants and paediatric nurses, and it seems an appropriate method to reach these aims. Prevention and especially promotion of breast feeding is possible in paediatric outpatient settings. The immediate contact between infants, parents, paediatric doctor's assistants, paediatric nurses, and doctors offers a unique opportunity to promote the health of children, mainly due to the high acceptance of regular check-ups. So why not introduce the promotion of breast feeding in paediatric outpatient settings with specially trained doctor's assistants and paediatric nurses?

Acute Hepatotoxicity: A Predictive Model Based on Focused Illumina Microarrays

Drug-induced hepatotoxicity is a major issue for drug development, and toxicogenomics has the potential to predict toxicity during early toxicity screening. A bead-based Illumina oligonucleotide microarray containing 550 liver specific genes has been developed. We have established a predictive screening system for acute hepatotoxicity by analyzing differential gene expression profiles of well-known hepatotoxic and nonhepatotoxic compounds. Low and high doses of tetracycline, carbon tetrachloride (CCL4), 1-naphthylisothiocyanate (ANIT), erythromycin estolate, acetaminophen (AAP), or chloroform as hepatotoxicants, clofibrate, theophylline, naloxone, estradiol, quinidine, or dexamethasone as nonhepatotoxic compounds, were administered as a single dose to male Sprague-Dawley rats. After 6, 24, and 72 h, livers were taken for histopathological evaluation and for analysis of gene expression alterations. All hepatotoxic compounds tested generated individual gene expression profiles. Based on leave-one-out cross-validation analysis, gene expression profiling allowed the accurate discrimination of all model compounds, 24 h after high dose treatment. Even during the regeneration phase, 72 h after treatment, CCL4, ANIT, and AAP were predicted to be hepatotoxic, and only these three compounds showed histopathological changes at this time. Furthermore, we identified 64 potential marker genes responsible for class prediction, which reflected typical hepatotoxicity responses. These genes and pathways, commonly deregulated by hepatotoxicants, may be indicative of the early characterization of hepatotoxicity and possibly predictive of later hepatotoxicity onset. Two unknown test compounds were used for prevalidating the screening test system, with both being correctly predicted. We conclude that focused gene microarrays are sufficient to classify compounds with respect to toxicity prediction.

Comparison of software tools to improve the detection of carcinogen induced changes in the rat liver proteome by analyzing SELDI-TOF-MS spectra

A common animal model of chemical hepatocarcinogenesis was used to demonstrate the potential identification of carcinogenicity related protein signatures/biomarkers. Therefore, an animal study in which rats were treated with the known liver carcinogen N-nitrosomorpholine (NNM) or the corresponding vehicle was evaluated. Histopathological investigation as well as SELDI-TOF-MS analysis was performed. SELDI-TOF-MS is an affinity-based mass spectrometry method in which subsets of proteins from biological samples are selectively adsorbed to a chemically modified surface. The proteins are subsequently analyzed with respect to their mass-charge ratios (m/z) by a time of flight (TOF) mass spectrometry (MS) approach. As data preprocessing of SELDI-TOF-MS spectra is essential, baseline correction, normalization, peak detection, and alignment of raw spectra were performed using either the Ciphergen ProteinChip Software 3.1 or functions implemented in the library PROcess of the BioConductor Project. Baseline correction and normalization algorithms of both tools lead to comparable results, whereas results after peak detection and alignment steps differed. Variability between technical and biological replicates was investigated. A linear mixed model with factors experimental group and time point was applied for each protein peak, taking into account the different correlation structure of technical and biological replicates. Alternatively, only median intensity values of technical replicates were used. Results of both models were similar and correlated well with those of the histopathological evaluation of the study. In conclusion, statistical analyses lead to comparable results, whereas parameter settings for preprocessing proved to be crucial.

Severe aortic thrombosis in the neonate--successful treatment with low-molecular-weight heparin: two case reports and review of the literature

Small- to moderate-sized aortic thrombi in the sick newborn are frequently demonstrated, however, severe aortic thrombosis is rarely encountered. We report two newborn infants presenting with signs of decreased lower limb perfusion shortly after birth. An occlusive infrarenal aortic thrombus was demonstrated in both infants by ultrasound. No predisposing condition for thrombosis could be found in the first infant; in the second, an umbilical arterial catheter was the likely cause. The infants were successfully treated with low-molecular-weight heparin. In both infants resolution of the thrombus was observed by ultrasound. No complications of treatment were encountered. The clinical spectrum of neonatal aortic thrombosis and treatment options are reviewed.

RITA/Registry of Industrial Toxicology Animal data: a comparative immunohistochemical study of 77 islet cell carcinomas in Sprague-Dawley and Wistar rats using antibodies against insulin, glucagon, somatostatin and gastrin

The objective of this study was to investigate spontaneous islet cell carcinomas with particular reference to possible existing strain differences between Sprague Dawley (SD) and Wistar (W) rats in incidence and immunohistochemical staining pattern. Secondly the occurrence of somatostatin and/or gastrin-positive islet cell tumors should be tested. Islet cell adenocarcinomas (34 from SD, 43 from W-rats) were selected from the RITA-data base and company in-house data base out of an animal pool of 3915 (1681 SD, 2234 W-rats). They were untreated or sham-treated (vehicle) control animals from carcinogenicity studies and whole life-span experiments. Islet cell carcinomas occurred in a higher incidence in male rats (2.98% for SD, 3.23% for W) than in female rats (1.07% for SD, 0.63% for W). All specimens were immunohistologically stained with antibodies against insulin, glucagon, somatostatin and gastrin and, selected specimens with additional antibodies (pancreatic polypeptide, lipase, chymotrypsin, S100-protein, actin and cytokeratin). 94% (SD) and 93% (W), respectively, were insulin-positive and the mean staining intensity (on a scale ranging from 0-4) for insulin was 3.58 (SD) versus 3.37 (W). This high insulin staining incidence and intensity characterized most islet cell carcinomas as malignant insulinomas. 24% (SD) and 37% (W), respectively, were glucagon-positive. Except two tumors in W-rats with a focal strong glucagon expression, the mean staining intensity for glucagon was low (0.38 SD, 0.72 W). 38% (SD) and 44% (W), respectively, were somatostatin-positive, but except for five cases having a focal to multifocal, moderate to marked staining, only a few tumor cells were positive for somatostatin in the other cases and the mean staining intensity for somatostatin was low (0.50 SD, 0.84 W). 6% (SD) and 23% (W), respectively, were gastrin-positive, but only one case of a male Wistar rat exhibited a focal strong staining in parts of the tumor. The other cases showed only a few tumor cells which were positive for gastrin. The mean staining intensity for gastrin was low (0.06 SD, 0.35 W). In all tumors with marked glucagon, somatostatin or gastrin expression, the immunostaining for insulin was still predominating. Thus, insulin was the major hormone produced by most of the tumor cells. Five out of 77 tumors evaluated were immunohistologically negative with all applied antibodies.

CONCLUSION

This study presents the first immunohistochemical survey on spontaneous islet cell carcinomas in SD and Wistar rats stained with antibodies against the endocrine pancreas hormones insulin, glucagon, somatostatin and gastrin. No major differences in incidence or immunohistochemical staining pattern between SD and W-rats could be detected. In contrast to SD rats, Wistar rats had multihormonal coexpression in 16.3%. The multihormonal appearance of the neoplasms is well comparable with the findings in other animal species and human insulinomas. Moreover, this is the first study in rats which reports five cases with a marked co-expression of somatostatin and one case with marked focal co-expression of gastrin in malignant islet cell adenocarcinomas.

Early-infantile galactosialidosis: prenatal presentation and postnatal follow-up

Galactosialidosis (GS) is an autosomal recessive condition caused by combined deficiency of the lysosomal enzymes beta-galactosidase and alpha-neuraminidase. The combined deficiency has been found to result from a defect in protective protein/cathepsin A (PPCA), an intralysosomal protein which protects these enzymes from premature proteolytic processing. The most severe form of GS, the early-infantile form, results in early onset of edema, ascites, visceromegaly, and skeletal dysplasia. We report a case of early-infantile GS in a male infant who presented with nonimmune fetal hydrops (NIH), "coarse" facial appearance, massive fluid-filled inguinal hernias, multiple telangiectasia, and diffuse hypopigmentation; he subsequently developed visceromegaly. The diagnosis of GS was confirmed biochemically and the defect in PPCA characterized at the protein level. Examination of fetal peripheral blood smears sampled at 30 weeks gestation demonstrated vacuolation of lymphocytes, suggesting blood film examination may be a useful screening tool for cases of NIH where a metabolic disorder is suspected. Skeletal radiography at birth demonstrated punctate epiphyses of the femora, calcanei, and sacrum. We present a discussion of and differential diagnosis for this radiographic finding. To the best of our knowledge, this is the first case of early-infantile GS presenting with stippled epiphyses.

Neonatal adrenal congestion: a sonographic-pathologic correlation

We reviewed the clinical, sonographic and pathologic findings in eight neonates in whom diffuse enlargement and abnormal echogenicity of the adrenal glands was documented sonographically. Four of the patients suffered from perinatal asphyxia and two others required mechanical ventilation for other reasons. Six patients died and one suffers from severe development delay, cerebral palsy and failure to thrive. Sonographically, the glands were enlarged, their surface was smooth and there was loss of the central echogenic stripe. Diffuse sinusoidal congestion was found histologically in all five in whom autopsies were performed. These sonographic findings represent part of the spectrum of adrenal changes in neonatal asphyxia and other causes of perinatal stress, and may be associated with poor outcome because of other sequelae of asphyxia.

Lethal neonatal Menkes' disease with severe vasculopathy and fractures

A male neonate presented with an acute onset of severe intra-abdominal bleeding, haemorrhagic shock and multiple fractures leading to death on d 27. Menkes' disease was diagnosed at autopsy and confirmed by copper accumulation studies on cultured fibroblasts. Such an early onset of fatal complications in this condition has not been previously reported. New insights into the pathogenesis of Menkes' disease provided by DNA mutation analysis and difficulties in neonatal diagnosis are discussed. Menkes' disease should be considered in male infants with pathological fractures and other signs of connective tissue disease, even in the neonatal period.

Gastric-outlet obstruction induced by prostaglandin therapy in neonates

BACKGROUND

An infusion of prostaglandin E1 is widely used to maintain patency of the ductus arteriosus in neonates with congenital heart disease. After gastric-outlet obstruction was recognized in several infants who received prostaglandin E1, we studied the association between the drug and this complication.

METHODS

We evaluated all neonates who received prostaglandin E1 in our hospital between October 1, 1989, and September 30, 1991, for clinical, radiologic, or pathological evidence of acute gastric-outlet obstruction.

RESULTS

Of the 74 neonates evaluated, 65 had no signs of gastric obstruction and were considered normal; 5 had clinical and radiologic or pathological evidence of gastric obstruction consistent with the presence of antral mucosal hyperplasia. The remaining four neonates had clinical signs of gastric obstruction, but no radiologic or pathological examinations were performed. The 5 neonates with antral hyperplasia had received prostaglandin E1 for longer periods (mean [+/- SD] duration, 569 +/- 341 hours) than the 65 normal neonates (54 +/- 58 hours, P less than 0.001) or the 4 neonates with clinical signs of gastric obstruction (119 +/- 60 hours, P less than 0.05). The cumulative dose of prostaglandin E1 was higher in the neonates with antral hyperplasia (2982 +/- 1392 micrograms per kilogram of body weight) than in the normal neonates (279 +/- 270 micrograms per kilogram, P less than 0.001) or the neonates with signs of gastric obstruction (528 +/- 306 micrograms per kilogram, P less than 0.01). In two neonates with antral hyperplasia, the cessation of therapy lessened the gastric-outlet obstruction.

CONCLUSIONS

The administration of prostaglandin E1 to neonates can cause gastric-outlet obstruction due to antral hyperplasia. Neonates who receive prostaglandin E1 at recommended doses for more than 120 hours should be closely monitored for evidence of antral hyperplasia.

Corneal diameter, axial length, and intraocular pressure in premature infants

PURPOSE

Seventy premature infants 25 to 37 weeks' postconceptional age were examined during their first week of life to determine the correlation of corneal diameter, axial length, and intraocular pressure with gestational age and birth weight.

METHODS

Corneal diameter measurement was determined with corneal templates, total axial length with standardized A-scan ultrasound, and intraocular pressure with a Tonopen II tonometer.

RESULTS

Corneal diameter and total axial length showed parallel linear increases from 6.2 mm to 9.0 mm and 12.6 mm to 16.2 mm, respectively; however, no significant correlation was found between intraocular pressure and gestational age or birth weight. The mean intraocular pressure was 10.3 mmHg (standard deviation, 3.5).

CONCLUSION

Normative values are established for corneal diameter and total axial length as they relate to birth weight and gestational age, and a mean and standard deviation for intraocular pressure in the premature newborn. These values will aid the ophthalmologist in assessing ocular dimensions in premature infants.

Induction of labor as compared with serial antenatal monitoring in post-term pregnancy. A randomized controlled trial. The Canadian Multicenter Post-term Pregnancy Trial Group

BACKGROUND

The rates of perinatal mortality and neonatal morbidity are higher for post-term pregnancies than for term pregnancies. It is not known, however, whether the induction of labor results in better outcomes than does serial fetal monitoring while awaiting spontaneous labor.

METHODS

We studied 3407 women with uncomplicated pregnancies of 41 or more weeks' duration. The women were randomly assigned to undergo induction of labor or to have serial antenatal monitoring and spontaneous labor unless there was evidence of fetal or maternal compromise, in which case labor was induced or cesarean section was performed. In the induction group, labor was induced by the intracervical application of prostaglandin E2. Serial antenatal monitoring consisted of counts of fetal kicks, nonstress tests, and assessments of amniotic-fluid volume. The outcomes we measured were the rates of perinatal mortality, neonatal morbidity, and delivery by cesarean section.

RESULTS

Among the 1701 women in the induction group, 360 (21.2 percent) underwent cesarean section, as compared with 418 (24.5 percent) of the 1706 women in the monitoring group (P = 0.03). This difference resulted from a lower rate of cesarean section performed because of fetal distress among the women in the induction group (5.7 percent vs. 8.3 percent, P = 0.003). When two infants with lethal congenital anomalies were excluded, there were no perinatal deaths in the induction group and two stillbirths in the monitoring group (P not significant). The frequency of neonatal morbidity was similar in the two groups.

CONCLUSIONS

In post-term pregnancy, the induction of labor results in a lower rate of cesarean section than serial antenatal monitoring; the rates of perinatal mortality and neonatal morbidity are similar with the two approaches to management.

[Abilities and requirements profile of rheumatic patients, basis for suitability assessment as an interdisciplinary task in vocational rehabilitation]

Vocational rehabilitation service provision is always required when current job tasks can no longer be carried out due to disease-related performance restrictions. For social service agencies and employment offices as well as the rehabilitation facilities to intervene, information is needed on the remaining abilities, in order to be able to match future job requirements accordingly. Chronic rheumatic diseases gain increasing importance due to their high incidence and chronic progression; their impact on the capacity for work is considerable, with little attention however so far paid by the rehabilitation community. For 30 rheumatic patients of working age, abilities profiles have therefore been prepared and requirements profiles been established for their current job tasks, based on the methodological concept of Ertomis-Stiftung which had been supplemented by certain items important from an industrial medical angle. The findings show that the rheumatic person experiences limitations in all movement functions, and that lifting and carrying in particular are not possible. A major request is inclusion of a dynamic assessment criterion in the abilities profiles, as the person with a rheumatic disease in principle is capable of carrying out all movements, not however at the speed required to perform the job tasks.

[The occurrence of tumors in large bears (Ursidae)--a literature review and six case descriptions]

Histological findings on two Malayan sun bears and four sloth bears show that malignant neoplasms play an important role in tropic bears. Further, most of the tumors originated from the hepatic and biliary tract. Our results were compared with other investigations on zoo animals during the last 70 years revealing that malignant neoplasms are the most common ones in bears of the family Ursidae. Accordingly to our results, sloth and Malayan sun bears seem to have a disposition to develop malignant neoplasms of the hepatic and biliary tract, but within other species only polar bears seem to suffer predominantly from such neoplasia. The reason for this phenomenon could be an alimentary intake of carcinogens. Furthermore, Malayan sun bears show very often neoplasms of the thyroid gland as it is also observed in other carnivora.

Hyperplasia of somatostatin and pancreatic polypeptide immunoreactive cells in dogs with idiopathic atrophy of the exocrine pancreas

The pancreatic tissue from 25 dogs with idiopathic atrophy of the exocrine pancreas, and from 6 control dogs, was studied histologically and immunohistometrically. Cells producing insulin (B), glucagon (A), somatostatin (D), and pancreatic polypeptide (PP) were identified using specific antisera and the ABC technique. Histometrical quantitation revealed differences in the distribution of these cell types between the right and left pancreatic lobe. Initial stages of atrophy showed little changes concerning the relative proportions of the four cell types examined. In more advanced stages of atrophy, however, there was significant increase in the percentage of the D cells in the cell population of the left lobe. B and A cells showed no significant changes. In final stages, only tiny tissue spots were considered a secondary and regenerative phenomenon, but an endocrine dysregulation cannot be excluded. Atrophy accompanied by diabetes mellitus and a lack of B cells seem to be due to a deficiency of insulin.

Cerebral blood-flow velocity patterns in post-hemorrhagic ventricular dilation

To evaluate the effect of ventricular dilation (VD) on cerebral hemodynamics, serial cerebral bloodflow velocity patterns from the anterior and middle cerebral, and circle of Willis arteries were examined by range-gated, pulsed Doppler sonography in premature infants developing post-hemorrhagic VD. Nine infants (25 to 30 weeks gestation) without a patent ductus arteriosus were studied until resolution of VD. Forty-nine cranial sonograms from all nine infants were reviewed independently and grouped cross-sectionally into mild, moderate and severe VD prior to shunt. The corresponding pulsatility index (PI) showed a consistent trend of increase with VD in all three studied vessels. In six infants, absent or reversed diastolic flow was observed at the height of VD. Four of these infants required V-P shunt. Immediate fall in PI occurred in all three vessels. Serial measurement of PI during VD reflects global changes in cerebrovascular resistance. Results confirmed PI could be a useful index in monitoring cerebral hemodynamic changes.

Regional cerebral blood flow velocity patterns in newborn infants

Using range-gated pulsed Doppler sonography, cerebral blood flow velocity (CBFV) waveforms from the anterior cerebral artery (ACA), middle cerebral artery (MCA) and circle of Willis artery (CW) were examined in a total of 34 newborn infants. We compared the pulsatility index (PI) from the three cerebral arteries sampled in 10 term and 10 preterm (29 +/- 2 weeks) newborn infants without a history of perinatal asphyxia or intracranial pathology. The Pl in the ACA ranged from 0.60 to 1.03. There were no significant differences in Pl between the three vessels by paired comparisons. The Pl of the MCA differed from that of the ACA by 0.00 +/- 0.05. The variation coefficient (CV) was 7%. For CW with ACA, the difference was 0.00 +/- 0.04 and CV was 6%. Both intra- and interexaminer variation in Pl measurements were studied in another 14 infants. The variation coefficients were 5-8% for all three cerebral arteries. We showed that CBFV waveform patterns were similar in regional cerebral arteries, with Pl being a consistent CBFV index. In normal cerebral circulation, the intervessel Pl differences were within observer variations. Deviation from this may suggest abnormal regional cerebral haemodynamics.

Impact of delayed development in premature infants on mother-infant interaction: a prospective investigation

We examined events that precede a diagnosis of developmental delay by comparing 16 very low birth weight premature infants whose condition was diagnosed as developmental delay at 18 months corrected age with 16 matched developmentally normal infants. All infants were observed with their mothers during maternal visits to the nursery and during home visits 1, 3, 6, and 9 months after discharge. The mothers' reactions to their infants were rated at these times. All the children were followed up at a neonatal clinic, and detailed clinic records were used to document the time when a physician first suspected a delay and when this delay was first mentioned to the mother. The results indicate that parents had usually been told of their child's handicap by the time the child was 6 to 9 months old; yet mothers of the delayed children changed the interaction with their children as early as 1 month after discharge from hospital. These mothers initially touched, smiled at, and talked to their developmentally delayed infants significantly more often, but by 9 months they did so much less often than mothers of nondelayed children. The degree of change in mothers' behavior was related to their psychosocial background, with better-adjusted mothers showing the most change. We conclude that mothers' statements about their infants are usually valid and that physicians may share their potential concerns about infants more freely.

Effect of pneumothorax-induced systemic blood pressure alterations on the cerebral circulation in newborn dogs

Pneumothorax has been associated with intraventricular hemorrhage in premature infants, although the mechanism for this relationship is not clear. Because alterations in cerebral blood flow are believed to be important in the pathogenesis of intraventricular hemorrhage, the effect of induced pneumothorax and subsequent evacuation on the cerebral circulation in 16 newborn dogs was evaluated. Continuous Doppler ultrasound was used to monitor changes in cerebral blood velocity. Pneumothorax was induced by slow infusion (5 cc/kg/min) or rapid infusion (5 to 10 seconds) of air to reduce mean arterial blood pressure to half of base-line levels. Both methods of pneumothorax induction resulted in significant elevations of central venous pressure and intrapleural pressure, whereas mean arterial blood pressure and cerebral blood velocity decreased significantly. In each group, the pneumothorax was evacuated either by slow withdrawal of air (10 cc/kg/min) or as rapidly as possible. Rapid evacuation of air resulted in an immediate increase in mean arterial blood pressure and cerebral blood velocity to supranormal levels. Slow evacuation led to a more gradual normalization of mean arterial blood pressure and cerebral blood velocity. It is suggested that the precipitous increases in mean arterial blood pressure and cerebral blood velocity following rapid evacuation of a tension pneumothorax may account for the observed association between pneumothorax and intraventricular hemorrhage in premature infants.

Regional cerebral blood flow, cerebral blood velocity, and pulsatility index in newborn dogs

A technique employing a Doppler ultrasound probe to measure cerebral blood velocity was used to study the cerebral circulation continuously in 30 newborn mongrel dogs. Utilizing a transfontanelle approach, the probe was maintained in fixed position throughout a given experiment. In 20 animals, changes in systolic, diastolic, and mean cerebral blood velocity during hypo- and hypercarbia were directly correlated (P less than 0.01) with changes in regional cerebral blood flow (rCBF) determined in 12 regions of the brain by the [14C]iodoantipyrine autoradiography technique. In an additional 10 dogs, multiple determinations of systolic, diastolic, and mean blood velocity were made over a wide range of PaCO2 values and found to be directly related to the PaCO2 (P less than 0.001). These data suggest that changes in cerebral blood velocity are closely related to changes in cerebral blood flow. We also calculated the pulsatility index (PI) from the peak systolic and end diastolic velocities and found a poor, but direct (r = 0.28, P less than 0.05) relationship between the PI and PaCO2 rather than the indirect relationship, which has been suggested in published clinical studies. We conclude that the Doppler technique may be valuable in monitoring dynamic events of the neonatal cerebral circulation if a constant probe position is maintained. Our results suggest, however, that the PI is not a reliable index of cerebral vascular resistance.

Blood-brain barrier permeability to lactic acid in the newborn dog: lactate as a cerebral metabolic fuel

The arteriovenous difference (A-V) method was utilized to assess the permeability of the blood-brain barrier to lactic acid in paralyzed and artificially ventilated newborn dogs. A femoral artery and the sagittal sinus were cannulated to sample arterial and cerebral venous blood simultaneously for measurements of glucose and lactate during normoglycemia, normoglycemia and hyperlactatemia insulin-induced hypoglycemia, or hypoglycemia and hyperlactatemia. During normoglycemia, arterial lactate concentrations remained less than 2 mmoles/liter for up to 2 h; mean A-V lactate was essentially zero. Arterial lactate increased up to 8 mmoles/liter during intravenous infusion of neutralized 10 mM L-lactic acid. During hyperlactatemia, the A-V lactate was directly proportional to the arterial concentration of the metabolite, a finding which is consistent with transport into brain either by simple diffusion or via a carrier with saturability greater than 8 simple diffusion or via a carrier with saturability greater than 8 mmoles/liter. During hypoglycemia (mean arterial glucose=27 mg/dl), A-V glucose was reduced by 71% with a significant increase in A-V lactate at an arterial lactate level of 1.3 mmoles/liter. Hyperlactatemia combined with hypoglycemia resulted in A-V lactate which was 2-3 fold greater than during normoglycemia at similar arterial lactate concentrations. Brain/blood lactate ratios declined by 83% during hypoglycemia compared with normoglycemic ratios, indicating that, once in brain, lactic acid was actively consumed for oxidative processes. These experimental observations may have clinical relevance in newborn human infants when concentrations of lactate in blood often approach or even exceed those of glucose.

Ventricular dimensions of the brain in premature and full-term infants

A total of 120 computed tomographic scans of the brain in premature and full-term infants were reviewed. Of these, 28 were judged to exhibit normal ventricular dimensions, and the bifrontal, bicaudate, and bioccipital indices of the lateral ventricles were determined. The bifrontal and bicaudate indices followed a Gaussian distribution, with mean values of 0.28 +/- 0.07 (SD) and 0.15 +/- 0.03 (SD), respectively, whereas the bioccipital index was uniform in its distribution (range, 0.13 to 0.26). For comparison, corresponding indices were determined in scans of ten infants with clinical evidence of hydrocephalus. Based on these data, guidelines are suggested to distinguish normal and abnormal ventricular dimensions in newborn infants.

Neonatal sepsis due to group G streptococci

Two cases of neonatal septicaemia due to group G streptococci (Streptococcus canis) are described. In one patient, infection coexisted with transient neonatal hyperthyroidism, while, in the other, concomitant group G streptococcal septicaemia and endometritis in the mother was seen. Group G streptococci are rare causes of infection, especially in the paediatric age group. Bacteria were identified by serological and biochemical methods. Both neonates responded well to penicillin therapy, but the maternal infection required combination therapy with penicillin G, gentamicin, and chloramphenicol. The literature on systemic group G streptococcal infection is briefly reviewed. With increasing use of serotyping in the identification of beta-haemolytic streptococci, non-group A organisms will probably be identified more frequently from neonatal and other infections.

Cerebral oxidative metabolism in perinatal post-hemorrhagic hydrocephalus

Survivors of perinatal intraventricular hemorrhage often develop a distinct clinical syndrome characterized by hydrocephalus and biochemical abnormalities in cerebrospinal fluid. The authors investigated six neonates with post-hemorrhagic obstructive hydrocephalus in order to identify cerebral metabolic disturbances responsible for the hypoglycorrhachia observed in this disorder. Lactic acid concentraions and lactate/pyruvate ratios in ventricular fluid were significantly elevated in infants with post-hemorrhagic hydrocephalus compared with the values in five with congenital (non-hemorrhagic) obstructive hydrocephalus. Comparable degrees of ventricular dilatation and intracranial hypertension were present in the two groups. There is evidence that neither residual cellular elements in ventricular fluid nor a disrupted blood-CSF barrier can fully explain the observed alterations in ventricular-fluid glucose, lactate or lactate/pyruvate ratios. It is suggested that when periventricular hemorrhage occurs, the associated cerebral ischemia leads to focal anaerobic glycolysis and increased glucose requirement. With inadequate cerebral glucose glycolysis and increased glucose requirement. With inadequate cerebral glucose delivery from the blood, glucose diffuses into the brain from the ventricular fluid, resulting in hypoglycorrhachia. Cerebral lactic acid production is enhanced, which accumulates in ventricular fluid in the presence of ventricular obstruction.