Connections of the caudal ventrolateral medullary reticular formation in the cat brainstem

 A region of the caudal ventrolateral medullary reticular formation (CVLM) participates in baroreceptor, vestibulosympathetic, and somatosympathetic reflexes; the adjacent retroambigual area is involved in generating respiratory-related activity and is essential for control of the upper airway during vocalization. However, little is known about the connections of the CVLM in the cat. In order to determine the locations of terminations of CVLM neurons, the anterograde tracers Phaseolus vulgaris leucoagglutinin and tetramethylrhodamine dextran amine were injected into this region. These injections produced a dense concentration of labeled axons throughout the lateral medullary reticular formation (lateral tegmental field), including the retrofacial nucleus and nucleus ambiguus, regions of the rostral ventrolateral medulla, the lateral and ventrolateral aspects of the hypoglossal nucleus, nucleus intercalatus, and the facial nucleus. A smaller number of labeled axons were located in the medial, lateral, and commissural subnuclei of nucleus tractus solitarius, the A5 region of the pontine reticular formation, the ventral and medial portions of the spinal and motor trigeminal nuclei, locus coeruleus, and the parabrachial nucleus. We confirmed the projection from the CVLM to both the rostral ventrolateral medulla and lateral tegmental field using retrograde tracing. Injections of biotinylated dextran amine or Fluorogold into these regions resulted in retrogradely labeled cell bodies in the CVLM. However, the neurons projecting to the lateral tegmental field were located mainly dorsal to those projecting to the rostral ventrolateral medulla, suggesting that these neurons form two groups, possibly with different inputs. Injections of retrograde tracers into the lateral tegmental field and rostral ventrolateral medulla also produced labeled cell bodies in other regions, including the medial and inferior vestibular nuclei and nucleus solitarius. These data are consistent with the view that the CVLM of the cat is a multifunctional area that regulates blood pressure, produces vocalization, affects the shape of the oral cavity, and elicits contraction of particular facial muscles. Received: 18 February 1997 / Accepted: 27 March 1997     

Congenital hypothalamic hamartoma syndrome: Nosological discussion and minimum diagnostic criteria of a possibly familial form

We report on congenital hypothalamic hamartomas, discovered at autopsy in 3 unrelated fetuses. In the first 2 patients, the tumor was associated with skeletal dysplasia only. In the third patient, it was part of a non-random congenital malformation association, suggestive of Meckel syndrome. In one family, a previous boy died soon after birth with similar craniofacial and skeletal abnormalities. As far as we know, the association between isolated skeletal dysplasia and congenital hypothalamic hamartomas has not yet been documented in the literature. Nevertheless, a spectrum of skeletal abnormalities has been described in association with congenital hypothalamic “hamartoblastoma” and a constellation of variable visceral malformations under the eponym of “Pallister-Hall syndrome” (PHS). A detailed analysis of the PHS reported cases shows that only skeletal dysplasia and oro-facial abnormalities are present constantly. They show similarities with those found in our first 2 cases. These findings prompt us to consider skeletal dysplasia and oro-facial abnormalities as common denominator and minimum criteria required to define a nosologically distinct, possibly familial entity, which we suggest calling “congenital hypothalamic hamartoma syndrome” (CHHS).     

Interactions of Respiratory and Cardiovascular Adjustments to Behavioral Stressors

The relationships among a variety of cardiovascular and respiratory measures were examined in young college males subjected to a cold pressor task, reaction-time shock avoidance task, and three levels of graded exercise. As expected, the relationships between cardiovascular (e.g., heart rate and cardiac output) and respiratory (e.g., oxygen uptake and minute ventilation) variables were tightly linear when considering rest and exercise values. However, the range of individual cardiopulmonary responses during cold pressor and reaction time was considerable, often leading to disruptions in the cardiovascular/respiratory interactions. Analyses of extreme high and low ventilation reactors during both reaction time and cold pressor revealed that the excessive ventilation responders in cold pressor showed clear signs of hyperventilation. Increases in ventilation by the high reactors during reaction time were of smaller magnitude than during cold pressor, with potential hyperventilation much less clear. Increases in minute ventilation by reactors during the cold pressor task were primarily due to large increases in tidal volume, with only modest increases in respiratory rate. For reaction time, however, the increases in ventilation by reactive individuals stemmed from rate increases with tidal volume remaining essentially unchanged.     

Peripheral blood flows during colorectal distension in anaesthetised dogs

Distension of the descending colon elicits reflex cardiovascular responses, including increases in heart rate and arterial blood pressure. To study the relative contribution of vasoconstriction in individual vascular beds to this reflex response, experiments were performed on seven dogs anaesthetised with chloralose and instrumented with electromagnetic flowmeters around the superior mesenteric, the left renal and the left external iliac arteries. The colorectal portion of the intestine was distended at constant pressure (36.6 mm Hg, 4.9 kPa mean; range 25–50 mm Hg, 3.3–6.7 kPa) with warm Ringer solution for periods of 2 min. After a set of control distensions, the experiments were performed whilst the reflex rise in arterial pressure was prevented by removal of blood from the arterial tree. In control distensions arterial pressure increased by 11.3±1.5 mm Hg, 1.51±0.12 kPa (mean±SEM). In distensions at constant arterial pressure, peripheral blood flows were altered to different extents in the three territories studied: vascular resistance increased by 30.8±5.6% (P<0.01) in the mesenteric, by 4.1±1.5% (P<0.03) in the renal, and by 15.2±6.8% (NS) in the external iliac bed. We conclude that colorectal distension may reflect activation of a function-specific pathway of the sympathetic nervous system, which leads to much greater vasoconstriction in the splanchnic circulation than in renal or musculocutaneous circulations.     

Cardiovascular ‘reactivity’ to graded splanchnic nerve stimulation in spontaneously hypertensive and normotensive control rats

Cardiovascular ‘reactivity’ to graded splanchnic nerve stimulations was compared in adult spontaneously hypertensive rats (SHR) and normotensive controls (NCR), during abolished adrenal medullary secretion and neurogenic cardiac control and depressed reflex vascular adjustments. Arterial pressure, heart rate and cardiac output were measured, and total peripheral resistance (TPR) and stroke volume (SV) computed before, during and after nerve stimulation. The neurogenic resistance increases in the major gastrointestinal-renal-hepatic circuits expressed themselves as TPR elevations, which were much accentuated in SHR. This reflects an increased w/r₁ of SHR resistance vessels rather than any altered effector sensitivity, since the responses were particularly accentuated at high discharge rates when noradrenaline junction concentrations approach maximal levels. The splanchnic capacitance responses expressed themselves as SV increases, being the most relevant aspect of capacitance control. SV increased less in SHR, mainly reflecting the reduced diastolic compliance of the hypertrophied SHR left ventricle and the consequent rightward shift of its Frank-Starling curve. The results indicate that an elevated resistance may well be maintained by a normal sympathetic discharge in established SHR hypertension. There seems, however, to be an increasing need for accentuated discharge to the capacitance side to maintain proper cardiac filling of the hypertrophied left ventricle.     

Genomic imprinting and uniparental disomy in Angelman and Prader-Willi syndromes: A review

Although Angelman (AS) and Prader-Willi (PWS) syndromes are human genetic disorders with distinctly different developmental and neurobehavioural phenotypes, they both have abnormalities in inheritance of chromosome 15q11–q13. Whether AS or PWS arises depends on the parental origin of a deletion or uniparental disomy (the inheritance of 2 copies of a genetic locus from only one parent) for 15q11–q13. Normal development requires a genetic contribution for this genetic region from both a male and female parent. The dependence on parental origin implies that genes in human 15q11–q13 have distinct functions depending upon epigenetic, parent-of-origin differences, known as genomic imprinting. Here, I review the role of uniparental disomy and genomic imprinting in the pathogenesis of AS and PWS, and briefly discuss phenotype-genotype correlations using candidate genes and mouse models, in particular for hypopigmentation. © 1993 Wiley-Liss, Inc.     

Ullrich-Turner syndrome with a small ring X chromosome and presence of mental retardation

Since some patients with Ullrich-Turner syndrome (UTS) have mental retardation, we reviewed our experience to look for a high-risk subgroup. Among 190 UTS and gonadal dysgenesis patients with X chromosome abnormalities, 12 had mental retardation. All of the six (100%) with a small ring X were educable (EMI) or trainable mentally impaired (TMI) with more severe delay than expected in UTS. Among the 184 with other X abnormalities, only 6 had similar delays (2 from postnatal catastrophes), for a frequency of 3.3% mental retardation among those without a small ring X; only 2.2% of these had unexplained mental retardation. Polymerase chain reaction studies showed no Y-derived material in the 2 patients who were evaluated, and in situ hybridization confirmed X origin of the ring in the 6 subjects who were evaluated. We describe the phenotype of the 6 individuals with a small ring X, and an additional 2 patients with a small ring X who were identified outside the survey. The subjects with a small ring X comprised a clinically distinct subgroup which had EMI/TMI and shorter stature than expected in UTS. Seizures and a head circumference <10th centile were observed in half of the patients with a small ring X, and strabismus, epicanthus, and single palmar creases were present in more than half. A “triangular” face in childhood, pigmentary dysplasia, sacral dimple, and heart defects were also common. Neck webbing appeared to be less frequent than in 45, X. We hypothesize that the high risk of mental retardation in this form of the UTS results from lack of lyonization of the ring X due to loss of the X inactivation center. Excluding those with a small ring X, mental retardation is not significantly increased in patients with UTS. © 1992 Wiley-Liss, Inc.     

Heart rate reactivity and heart period variability throughout the first year after heart transplantation

Heart rate reactivity to mental stress is substantially blunted early after heart transplantation, suggesting that the loss of neural modulation limits the cardiovascular response to mental stress. We tested whether reactivity to mental stress recovers during the first year after heart transplantation. Hemodynamic and respiratory responses to mental arithmetic challenge were studied in 20 heart transplant recipients 3, 6, and 12 months after surgery. A normal comparison group was studied at equivalent intervals. Heart rate reactivity to mental arithmetic was significantly reduced in the cardiac transplant group compared to the normal subjects. This effect persisted up to 1 year after transplantation. Heart period variability in the heart transplant recipients was minimal in all three-test sessions. The findings suggest that no functional reinnervation or other compensatory adaptation occurs up to 1 year after heart transplantation.     

胎盘生长因子在妊娠期高血压疾病胎盘组织中的定位及定量分析

目的探讨胎盘生长因子(placental growth factor,PLGF)在妊娠期高血压疾病胎盘中定位及定量表达。方法选择妊娠期高血压疾病患者46例,其中子痫前期重度23例,子痫1例;慢性高血压并发子痫前期1例,选择同期正常妊娠妇女20例作为对照组。采用免疫组织化学染色法和免疫印迹(Western blot)方法检测两组患者胎盘PLC蛋白定位及定量表达。结果 (1)免疫组织化学染色发现PLGF蛋白在妊娠期高血压疾病组及正常妊娠组胎盘中分布范围基本一致, 主要分布在绒毛合体滋养细胞和间质细胞的胞浆,部分血管合体膜上也有PLGF阳性染色。(2)Western blot方法检测妊娠期高血压疾病组子痫前期轻、重度胎盘绒毛PLGF蛋白表达低于正常妊娠组(0.3±0.4 vs 0．6±0．4、0．2±0．5 vs 0．6± 0．4),差异有统计学意义(P<0．01);妊娠期高血压患者胎盘中PLGF蛋白的表迭为0．5±0．6,与对照组比较,差异无显著性(P>0．05)。结论胎盘PLGF蛋白表达异常在妊娠期高血压疾病发病中可能具有重要的作用。     

Preprocessor Adapts Cardiovascular Signals to a Minicomputer

A laboratory-developed analog signal processor, driven by a conventional polygraph recorder and associated signal conditioning devices, provides automatic heart beat-by-heart beat preprocessing of various cardiovascular functions for input to a laboratory-type minicomputer. The technique of preprocessing individual functions, integrated with the minicomputer system which includes an A/D converter and teletype as input-output peripherals, provides a low-cost data acquisition and reduction system for the on-line computation and analysis of cardiovascular functions in experimental research applications. Such preprocessing more efficiently uses the minicomputer's memory to handle large amounts of information since the digitized data is in the form of one data sample, per function, per heart beat. Preprocessing analog data provides a low density data format and simplified software programs that are ideally suited for the utilization of a minicomputer in this on-line application.