The locus coeruleus, norepinephrine, and memory in newborns

Use of learned odor cues by newborn rats is critical for pup survival. Rat pups acquire approach responses to maternal odors through an associative conditioning mechanism. This learned behavioral response is accompanied by a modification of olfactory bulb neural response patterns to the learned odor. Both the behavioral and neural reponse changes involved and require norepinephrine release in the olfactory bulb. The source of this norepinephrine is the locus coeruleus. It is proposed that the unique response properties of the locus coeruleus during the early postnatal period in the rat may facilitate acquisition of these critical early memories.     

Trancranial Doppler Monitoring of Response to Therapy for Meningovascular Syphilis

Meningovascular syphilis is now quite uncommon, but there have been increasing reports in patients immunocompromised with human immunodeficiency virus. The response of syphilis affecting the central nervous system to antibiotic therapy remains a challenge. This is an even greater challenge in patients who have underlying compromise of the immune system. The authors present a 46-year-old male with recurrent stroke who was found to have cerebrospinal fluid compatible with syphilitic involvement of the central nervous system and a cerebral arteriogram, which revealed focal narrowing of the right middle cerebral artery. The baseline transcranial Doppler study demonstrated increased mean and peak flow velocity within the right middle cerebral artery. Despite a 10-day course of intravenous penicillin, with substantial improvement in the cerebrospinal fluid results, this flow velocity elevation persisted, in a remarkably consistent pattern, over a 4-month follow-up period. Thus, the involved vessel remained patent following treatment, but no clear resolution of the stenotic lesion was observed.     

Carcinosarcoma (malignant mixed tumor) of the parotid: Report of a case with a pure rhabdomyosarcoma component

Background. Carcinosarcoma or true malignant mixed tumor of the parotid gland is extremely rare, accounting for <1% of all salivary gland malignancies. Methods. A 63-year-old woman presented with a 5-cm right parotid mass which was resected with a radical parotidectomy and infratemporal fossa dissection. Results. The tumor contained two distinctive histologic patterns, that of a poorly differentiated ductal carcinoma and a pleomorphic rhabdomyosarcoma. Additionally, a residual focus of pleomorphic adenoma was present peripherally, Immunohistochemical and electron microscopic studies confirmed the skeletal muscle differentiation. Conclusions. The pattern of combined rhabdomyosarcoma and ductal carcinoma has not been previously reported and adds further evidence to the myoepithelial derivation of these tumors. © 1994 John Wiley & Sons, Inc.     

Monitoring of Neuromuscular Blockade at the P6 Acupuncture Point Reduces the Incidence of Postoperative Nausea and Vomiting

Background: Electrical stimulation of the P6 acupuncture point reduces the incidence of postoperative nausea and vomiting (PONV). Neuromuscular blockade during general anesthesia can be monitored with electrical peripheral nerve stimulation at the wrist. The authors tested the effect of neuromuscular monitoring over the P6 acupuncture point on the reduction of PONV.

Methods: In this prospective, double-blinded, randomized control trial, the authors investigated, with institutional review board approval and informed consent, 220 women undergoing elective laparoscopic surgery anesthetized with fentanyl, sevoflurane, and rocuronium. During anesthesia, neuromuscular blockade was monitored by a conventional nerve stimulator at a frequency of 1 Hz over the ulnar nerve (n = 110, control group) or over the median nerve (n = 110, P6 group) stimulating at the P6 acupuncture point at the same time. The authors evaluated the incidence of nausea and vomiting during the first 24 h.

Results: No differences in demographic and morphometric data were found between both groups. The 24-h incidence of PONV was 45% in the P6 acupuncture group versus 61% in the control group (P = 0.022). Nausea decreased from 56% in the control group to 40% in the P6 group (P = 0.022), but emesis decreased only from 28% to 23% (P = 0.439). Nausea decreased substantially during the first 6 h of the observation period (P = 0.009). Fewer subjects in the acupuncture group required ondansetron as rescue therapy (27% vs. 39%; P = 0.086).     

Cholinesterases and peanut agglutinin binding related to cell proliferation and axonal growth in embryonic chick limbs

Embryonic cholinesterases are assigned important functions during morphogenesis. Here we describe the expression of butyrylcholinesterase and acetylcholinesterase, and the binding of peanut agglutinin, and relate the results to mitotic activity in chick wing and leg buds from embryonic day 4 to embryonic day 9. During early stages, butyrylcholinesterase is elevated in cells under the apical ectodermal ridge and around invading motoraxons, while acetylcholinesterase is found in the chondrogenic core, on motoraxons and along the ectoderm. Peanut agglutinin binds to the apical ectodermal ridge and most prominently to the chondrogenic core. Measurements of thymidine incorporation and enzyme activities were consistent with our histological findings. Butyrylcholinesterase is concentrated near proliferative zones and periods, while acetylcholinesterase is associated with low proliferative activity. At late stages of limb development, acetylcholinesterase is concentrated in muscles and nonexistent within bones, while butyrylcholinesterase shows an inverse pattern. Thus, as in other systems, in limb formation butyrylcholinesterase is a transmitotic marker preceding differentiation, acetylcholinesterase is found on navigating axons, while peanut agglutinin appears in non-invaded regions. These data suggest roles for cholinesterases as positive regulators and peanut-agglutinin-binding proteins as negative regulators of neural differentiation.     

Biometric measurements in fetuses of different race and gender.

Sonographic fetal biometric measurements on 6082 low-risk patients were compared in the second and third trimesters of pregnancy with respect to fetal race and gender. Ultrasonic measurements were obtained from fetuses of women participating in the Routine Antenatal Diagnostic Imaging with Ultrasound Study (RADIUS), who underwent both an early sonographic evaluation between 15 and 22 weeks' gestation and a later scan between 31 and 35 weeks' gestation. In the 16-21-week scans, male fetuses had significantly larger biparietal diameter measurements compared to female fetuses (estimated difference 0.852 mm, 95% CI 0.737-0.967). There was only minimal difference in biparietal diameter between Black and White fetuses. Femur length was similar in both female and male fetuses, but longer in Black compared to White fetuses (estimated difference 0.808 mm, 95% CI 0.539-1.078).During the 31-35-week scans, male fetuses continued to have larger biparietal diameter measurements compared to female fetuses (estimated difference 1.22 mm, 95% CI 1.04-1.40), and femur lengths were persistently longer in Black compared to White fetuses (estimated difference 0.563 mm, 95% CI 0.234-0.893).Further investigation is necessary to evaluate the effect of these slight differences in morphometric fetal measurements between races and genders, so that we can determine how best to use them for optimizing prenatal care.     

Spatial and temporal pattern of purkinje cell degeneration in shaker mutant rats with hereditary cerebellar ataxia

Temporal-spatial patterns of surviving Purkinje cells were studied quantitatively in a rat mutant (shaker) with differential hereditary cerebellar ataxia and Purkinje cell degeneration. Shaker rat mutants are characterized behaviorally as mild if they are ataxic or as strong if they have ataxia and tremor. Purkinje cells degenerate in both mild and strong shaker mutants, but the temporal and spatial patterns of cell death are strikingly different. In mild shaker mutants, Purkinje cell death is temporally restricted, with 31-46% of the Purkinje cells in lobules I-IX dying by 3 months of age. Very few Purkinje cells degenerate after this age. Purkinje cell death is spatially random. In lobules I-IX, every second, third, or fourth Purkinje cell degenerates. Purkinje cells in lobule X do not degenerate. In strong shaker mutants, Purkinje cell degeneration is temporally protracted and spatially restricted. By 3 months of age, most Purkinje cells in lobules I-VIa, -b, and -d, and -d have degenerated. Numerous Purkinje cells in the paravermis of lobules VIIb-VIII have also degenerated. Surviving Purkinje cells in the vermis and lateral hemisphere of lobules VIIb-VIII are aligned in parasagittally oriented stripes or transversely oriented bands. Purkinje cells continue to degenerate in localized areas of the posterior lobe such that, by 18 months of age, surviving Purkinje cells are limited primarily to lobules VIc, VIIa, IXd, and X. Quantitative analysis indicates that none of the Purkinje cells in these lobules degenerate.