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This study was designed to determine the organization of nociceptive inputs with different behavioral significance into spinal-brainstem circuits in the rat. Induction of Fos protein was used to localize spinal dorsal horn and hypothalamic neurons activated by noxious heating of the hind paw dorsum at rates known to preferentially activate C- or A-heat nociceptors. This was combined with retrograde transport of cholera toxin subunit B from the dorsolateral/lateral- (DL/L-) or the ventrolateral- (VL-) periaqueductal gray (PAG) in order to map the organization of A- and C-fiber input to spinal-brainstem circuits. The majority of dorsal horn heat-activated neurons were located in laminae I and II. A significantly larger proportion of C-fiber-activated neurons projected to the VL-PAG (P<0.05) compared with its DL/L-sector. In contrast, there was no columnar separation in the projections of A-fiber-activated neurons. However, a significantly greater proportion of A-fiber-activated neurons (P<0.05) were retrogradely labeled from the DL/L-PAG, when compared with C-fiber-activated neurons. A large proportion (25-50%) of A- and C-fiber-activated neurons in the lateral spinal nucleus projected to the PAG. A-fiber-activated neurons were found throughout the rostral hypothalamus but those projecting to the PAG were focused in the lateral area of the anterior hypothalamus (LAAH), from where approximately 20% projected to the VL-PAG, which was significantly more than to the DL/L PAG (P<0.05). We hypothesize that the organization of A- versus C-fiber inputs to the PAG enables the coordination of coping strategies appropriate to meet the demands imposed by these different noxious stimuli. Hypothalamic-PAG projections activated by A-fiber inputs did not reflect this level of organization and we suggest that this may relate to their role in thermoregulation as opposed to autonomic responses to particular nociceptive inputs.

Intracellular recordings were made from 21 cells in the dorsolateral periaqueductal gray matter in coronal midbrain slices. In the majority (n = 20) bath application of 5-hydroxytryptamine (30 or 150 mM) evoked either hyperpolarizing (n = 11) or depolarizing (n = 9) responses. Reconstructions of 11 neurons in the dorsolateral periaqueductal gray matter after filling with biocytin revealed a population of output neurons whose axons followed a dorsolateral trajectory towards the perimeter of the ipsilateral periaqueductal gray matter. In seven cells, the axon could be followed into the adjacent mesencephalic reticular formation. At the light microscopic level, immunostaining for 5-hydroxytryptamine revealed immunoreactive processes throughout the dorsolateral periaqueductal gray matter but no labelled somata or dendrites. Close associations (i.e. no discernible gap) were observed between serotonergic profiles and the somata and dendrites of biocytin-filled cells. At the ultrastructural level, serial sections through 21 appositions on to biocytin-filled dendrites in three slices revealed 19 true appositions (i.e. having closely parallel plasma membranes with no intervening glial cell profiles) with the biocytin-filled dendrite. Only four of the appositions (21%) showed evidence of synaptic specializations which included aggregations of synaptic vesicles, and some thickening of the apposing membrane. The dense reaction product in the biocytin-filled cells precluded identification of the ultrastructure of postsynaptic elements. However, examination of contacts between 5-hydroxytryptamine-immunoreactive profiles and unlabelled elements in material taken from the contralateral side of the periaqueductal gray matter (i.e. no biocytin present) or in material taken from perfusion-fixed whole brain, in which ultrastructural preservation was superior compared with slices, revealed a similar incidence (21% and 23%, respectively) of synaptic specializations. The data indicate that serotonergic transmission on to output neurons in the dorsolateral periaqueductal gray matter is largely mediated by non-junctional contacts, suggesting that the actions of 5-hydroxytryptamine on these cells are mediated predominantly by volume rather than wiring transmission.

This case report compares the pancreatic output with different feeding regimes in a patient who underwent a partial pancreatectomy for carcinoma of the ampulla of Vater. A postoperative secretin stimulation test demonstrated significant pancreatic reserve. There was no difference in pancreatic exocrine secretion when the patient was fed jejunally with a polymeric immune-enhancing formula or supported with two different formulations of total parenteral nutrition. This result suggests that jejunal infusion of a polymeric immune-enhancing formula may be safe to administer in patients with acute pancreatitis.

Objective: To review the literature on transcutaneous bilirubinometry so that its exact role in the prevention of kernicterus or bilirubin encephalopathy could be determined., Design and Methods: Literature searches were done in Medline and Current Contents., Results: It is estimated that about 50% of newborns have an episode of jaundice in the first few days of life. Six percent of newborns may develop hyperbilirubinemia (> 220 mumol/L), which can potentially cause bilirubin encephalopathy or kernicterus, a severe neonatal disease. In the past, serum bilirubin (SB) has been the preferred method of detecting hyperbilirubinemia in newborns. The ordering of SB in neonates is based on visual evaluation by either physicians or nursing staff. Skin puncture collection of blood exposes the neonate to trauma and risk of infection. A noninvasive device for predicting serum bilirubin levels in newborns diminishes the need to do skin punctures. One such device that has been very extensively studied is the Minolta AirShields Jaundice Meter. It is a portable light-weight instrument that uses reflectance measurements on the skin to determine the amount of yellow color present in the skin, namely transcutaneous bilirubin (TcB). Although the TcB measurements correlate well with serum bilirubin (SB) levels, they cannot accurately predict serum bilirubin because of error related to a variety of factors., Conclusions: TcB cannot be used directly to make decisions about transfusions or phototherapy in neonates. It is a good tool for screening neonates to determine when a laboratory measurement of serum bilirubin is needed. Such a practice requires careful selection of the decision level so that false-negative TcB values do not prevent appropriate serum bilirubin tests from being done.

Objective: To determine what the clinical impact would be of implementing a jaundice meter for use in a busy neonatal service as an adjunctive screening tool for hyperbilirubinemia., Design and Methods: Test utilization data was collected for a 6-month period to determine how neonatal bilirubin was utilized in this hospital. The jaundice meter was evaluated in a study population of healthy term infants. The performance characteristics of the meter and the test utilization data were used to predict the clinical impact a meter could have on screening for hyperbilirubinemia., Results: Utilization data indicated that about 60% of all single bilirubin neonatal testing (i.e., bilirubin only ordered) was done by normal nurseries. A jaundice meter cutoff decision reading of 17 was shown to have a sensitivity of 100% and a specificity of 68% for hyperbilirubinemia (> 260 mumol/L) in a study population of healthy term infants. From this data, it was estimated that use of a jaundice meter could eliminate 43% of the single (i.e., not combined with other tests) bilirubin tests done on healthy term neonates with no prior exposure to phototherapy. This constitutes an overall 20% reduction in bilirubin testing in normal nurseries when testing done on babies exposed to phototherapy and combined bilirubin testing are taken into consideration. Additionally, it was shown that there would be an improvement of 9% in the prediction of hyperbilirubinemia without loss of 100% sensitivity., Conclusion: Use of a jaundice meter in normal nurseries as an adjunctive screening tool enhances patient care by reducing the overall blood procurement rate in normal nurseries by 20% and increasing screening efficiency for significant hyperbilirubinemia by 5%.

The distribution in the human uterus of the enzyme cyclooxygenase,, involved in prostaglandin synthesis, was studied using the peroxidase-antiperoxidase immunohistochemical technique. Specific staining was observe only during the luteal phase of the menstrual cycle It was found that cyclooxygenase was localised in the surface and glandular epithelium of the endometrium but could not be demonstrated in the endometrial stroma, myometrium or blood vessels The location of specific staining for cyclooxygenase and its variation during the menstrual cycle was the same regardless of the amount of menstrual blood loss. Tissue samples obtained from early pregnant and postmenopausal patients failed to exhibit any specific staining.