Acute Immobilization Stress and Intraventricular Injection of CRF Suppress Naloxone-Induced LH Release in Ovariectomized Estrogen-Primed Rats

The present study was undertaken to evaluate the role and possible interaction of the endogenous opioid peptide (EOP) and corticotropin-releasing factor (CRF) in the acute stress-induced suppression of gonadotropin secretion in ovariectomized estrogen-primed rats. An intravenous (i.v.) injection of naloxone (10 or 20  mg/kg), an EOP antagonist, significantly elevated serum luteinizing hormone (LH) levels within 10  min in non-stressed animals. The naloxone-induced LH release was completely eliminated when tested 30  min after the onset of acute immobilization. In a subsequent study, it was found that suppression of the naloxone-induced LH release occurred as early as 5  min after the stress onset, and was still evident 60  min after the end of a 30-min period of immobilization. The effect of naloxone was restored 3  h after liberation of the animal from the 30-min immobilization. An intraventricular (i.c.v.) injection of CRF (1 or 5  μg) also significantly suppressed, in a dose-related manner, the effect of a subsequent i.v. injection of naloxone. However, an i.c.v. injection of α -helical CRF(9-41) (25 or 50  μg), a CRF antagonist, prior to immobilization, could not interfere with the suppressive effect of stress on naloxone-induced LH release. These results suggest that both acute immobilization stress and CRF can inhibit the LH secretory activity without mediation by EOP neurons. However, the stress-related suppression may involve non-CRF mechanism(s).     

Benign schwannoma of the pancreas

Reported cases of intrapancreatic schwannomas have recently increased in the literature. However, none of these cases were diagnosed clearly as schwannoma preoperatively. We herein describe the clinicopathologic findings of a solitary benign schwannoma occurring in the head of the pancreas. Additionally, the differential diagnosis versus other cystic- and solid-appearing pancreatic masses is briefly discussed.     

The efficacy and safety of laparoscopic nephrectomy in patients with three or more comorbidities

OBJECTIVES: Laparoscopic surgery for kidney treatment is a common procedure. However, the efficacy of this procedure in patients with several comorbidities has not been well investigated. We conducted a retrospective comparison of results of laparoscopic surgery between patients with several comorbidities and patients with no comorbidity to access the efficacy and safety of this procedure. METHODS: The subjects were 20 patients with three or more comorbidities (group A) and 46 patients with less than three comorbidities (group B). These 66 patients were 48 men and 18 women with a mean age of 62.3 years (age range, 24-83 years). The data from these two groups were compared for American Society of Anesthesiology (ASA) physical status score, previous surgical history, duration of surgery, estimated blood loss, tumor size, complications during and after surgery, conversion rates, time to oral intake, and length of hospital stay. RESULTS: The initial ASA score and age were significantly higher for the patients with comorbidities (P < 0.0001, P = 0.0008, respectively). All other variables before, during, and after surgery were similar for both laparoscopic groups. However, the incidence of atelectasis of laparoscopy was higher than that of open surgery. CONCLUSIONS: Laparoscopic nephrectomy for patients with comorbidities is safe and minimally invasive. Further investigation to prevent atelectasis is necessary.     

Effect of nasal continuous positive airway pressure treatment on plasma adrenomedullin levels in patients with obstructive sleep apnea syndrome: roles of nocturnal hypoxia and oxidant stress.

Obstructive sleep apnea syndrome (OSAS) is recognized as one of the risk factors of hypertension and cardiovascular disorders. In the current study, we hypothesized that the hypoxic stress and oxidative stress caused by obstructive sleep apnea would increase circulating adrenomedullin (ADM) levels in untreated OSAS patients as compared to an age and body mass index (BMI)-matched control group and an age-matched, but normal-BMI control group. We further hypothesized that nasal continuous positive airway pressure (nCPAP) treatment may decrease OSAS-induced hypoxic stress, oxidative stress and ADM levels. To examine these hypotheses, we measured circulating ADM and reactive oxygen species (ROS) from leukocytes before and after nCPAP therapy in OSAS patients. The circulating levels of ADM and amount of ROS in untreated OSAS patients were significantly greater than those in the controls. No differences in ADM levels were found between the increased-BMI controls and normal-BMI controls. We observed that nCPAP treatment decreased sleep apneas, nocturnal oxyhemoglobin desaturation, the circulating ADM, and ROS production by leukocytes in OSAS patients. The ADM levels were associated with the magnitude of oxyhemoglobin desaturation rather than the number of sleep apneas. These observations suggest that nCPAP therapy could reduce OSAS-induced nocturnal hypoxemia, generation of ROS, and ADM in patients with OSAS.     

In vivo presynaptic and postsynaptic striatal dopamine functions in idiopathic normal pressure hydrocephalus.

Differentiation of impaired gait seen in idiopathic normal pressure hydrocephalus (iNPH) from parkinsonian gait is sometimes a great challenge and important for future medication in the clinical setting. To investigate dopaminergic contribution to its pathophysiology, two aspects of the trans-synaptic dopamine functions in the striatal region in eight iNPH patients na?ve to dopaminergic drugs were examined using positron emission tomography with a presynaptic marker [11C]CFT ([11C]2-beta-carbomethoxy-3beta-(4-fluorophenyl) tropane) that binds to dopamine transporter and a postsynaptic marker [11C]raclopride that binds to D2 receptor. Quantitative values of binding potentials (BPs) for [11C]CFT and [11C]raclopride were compared between patients and eight age-matched healthy subjects. The BPs and magnetic resonance imaging-based morphometric measures in iNPH were used for correlation analyses between the magnitude of binding of these in vivo markers and clinical severity of the patients. Analysis of variance showed significant reduction in [11C]raclopride binding in the putamen and nucleus accumbens (P<0.05, corrected for multiple comparison) and unchanged striatal [11C]CFT binding in iNPH. The dorsal putamen [11C]raclopride binding correlated negatively with gait severity (r=0.720, P<0.05), and the nucleus accumbens [11C]raclopride binding correlated positively with emotional recognition score (r=0.727, P<0.05) in the disease group. No significant relationship was observed between BPs and morphometric measures. The current result of the postsynaptic D2 receptor reduction along with preserved presynaptic activity in the nigrostriatal dopaminergic system reflects a pathophysiology of iNPH. Postsynaptic D2 receptor hypoactivity in the dorsal putamen may predict the severity of gait impairment in iNPH.     

The effect of myocardial preservation technique on supraventricular tachycardia following aortic valve replacement

We studied 100 patients who underwent an isolated aortic valve replacement (AVR) between 1974 and 1991. The patients were divided into the following two groups and compared: group A, which consisted of 40 patients operated on before 1978 who underwent continuous left coronary perfusion with blood; and group B, which consisted of 60 patients operated on after 1979 in whom St. Thomas solution was used in combination with topical cardiac cooling. Moreover, we divided the group B patients into two subgroups: group Bl, who underwent AVR before 1986 during which we administered St. Thomas solution with ice slush every 30 min; and group B2, who had AVR after 1986 in which we used St. Thomas solution with a cold saline (4°C) solution and treated with a small amount of slushed ice every 15 min. The incidence of supraventricular tachycardias was 15% in group A, 50% in group BI, and 15% in group B2. The severity of preoperative New York Heart Association (NYHA) functional class, the type of valve lesions, cardiothoracic ratio, left ventricular function, aortic clamp time, bypass time, and use of drugs did not correlate with the incidence of supraventricular tachycardias in either group A or B. In group B2 patients, we paid a lot of attention to cooling the right atrium as well as the left ventricle by immersing the whole heart using a 4°C saline solution, which led to a remarkable reduction of the incidence of supraventricular tachycardia. This fact indicates that right atrial preservation is one of the most important factors for reducing the incidence of supraventricular tachycardia.     

A sheep survived for 48 days with the biventricular bypass type total artificial heart

A biventricular bypass type total artificial heart (BVB-TAH) utilizing two pusher-plate pumps was developed and implanted in a sheep for 48 days with excellent results. A Hall effect sensor was utilized to operate each pump independently with a full stroke at variable rates (VR). With this system, the animal's hemodynamics was kept physiologically, and all metabolic parameters except hemoglobin and hematocrit returned to normal three weeks after implantation. However, signs of infection appeared on the forty-second day, and consequently the animal fell into a state of shock. Even at that time the BVB-TAH maintained circulation by increasing pumping rate automatically. On the forty-eighth day, the animal could not stand and suffered from anuria; the experiment was then terminated after 1,140 h pumping. At autopsy, there was an enlarged heart with an atrophic change, 1,900 ml of pleural effusion, and 3,100ml of ascites fluid. Blood culture taken on the forty-seventh day yielded Acinetobacter calcoaceticus. The BVB-TAH operated in an independent VR mode maintained entire circulation, and has a capability of substituting the native heart function in any situation.