Motion-induced sickness following bilateral ablation of area postrema in squirrel monkeys

Using squirrel monkeys as experimental subjects, we reexamined the disputed role of the area postrema (AP) in motion-induced vomiting. After anesthetization, the obex and rhomboid fossa were exposed surgically, and the AP was ablated by thermal coagulation using either a battery cautery or a CO2 microsurgical laser. Sham operations were performed on another sample of monkeys. Two or more weeks after surgery, all animals were given 10 daily 2-hour horizontal rotations at 30 rpm. Every monkey in both the lesions and sham samples vomited on two or more test days. While the vomiting characteristics were modified following ablation of AP, its function is not indispensible for the development of motion sickness in horizontally-rotated squirrel monkeys.     

The effect of age and activity on arterial oxygen pressure and arterial oxygen saturation in hospitalized patients

In order to obtain adequate normal values for arterial blood gas values, the effect of aging and activity was investigated by cross-sectional selection in an in-patient population of 108 patients aged between 20 and 90 years. The patients were free of pulmonary, cardiac and metabolic disease. Smoking and obesity were tolerated up to specified limits. Arterial blood was obtained during standardised resting and active states. The results show a clinically important and highly significant (p less than 0.001) decline of the oxygen tension (PaO2) with age and also a considerable effect of minor activity (p less than 0.01) on blood gas values. However, the relationship of both oxygen tension and oxygen saturation with age is not a linear function as suggested in previous studies. For the interpretation of arterial oxygen tension values or to define hypoxaemia, only normal values related to age and activity should be used. In the elderly, low levels of PaO2 are encountered regularly. Determination of the oxygen saturation may be helpful, especially in differentiating between a normal and a pathological state.     

Calcium transport and phospholamban in sarcoplasmic reticulum of ischemic myocardium

The present study was designed to examine the relation between the loss of Ca2+ uptake activity and the change of protein phosphorylation in sarcoplasmic reticulum from ischemic myocardium. Ischemic (0.5, 1 and 2 h duration) and non-ischemic tissue samples were taken from the coronary-ligated porcine left ventricle and sarcoplasmic reticulum fractions were isolated. The membranes were tested for Ca2+ uptake and ATPase activities and phosphorylation of phospholamban. The in vitro 32P incorporation into phospholamban in the presence of cAMP plus the catalytic subunit of cyclic AMP dependent protein kinase became markedly reduced depending on the duration of ischemia. The activities of the Ca2+ pump (Ca2+ uptake and ATPase) were also decreased. The 32P incorporation into the myofibrillar component troponin I, which is also a specific substrate for catalytic subunit, was not affected by ischemia. The reduction of the Ca2+ pump activity correlated with the reduction of 32P incorporation into phospholamban. It is postulated that the ischemia induced inactivation of the Ca2+ pump is not only a consequence of specific loss of enzyme activity, but it is also caused by altered characteristics of phospholamban.     

Effect of cimetidine on wound healing in rats

Cimetidine, an H-2 antagonist, is one of the most commonly prescribed drugs and is used in the management of peptic ulcer disease and prevention of stress ulcerations following major trauma or operations. It has been shown that histamine has a stimulatory effect on wound healing which is believed to be mediated through H-2 receptors. We hypothesized that cimetidine would have an inhibitory effect on wound healing. Fifty-two adult rats were divided into two groups: Group A was placed on a standard chow and Group B was given chow supplemented with cimetidine (300 mg/Kg diet), a dose equivalent to that clinically used in man and effective in inhibiting gastric hypersecretion in the rat. Ten days later, all rats underwent a dorsal skin incision under pentobarbital anesthesia and implantation of a polyvinyl alcohol sponge subcutaneously. Animals were maintained on their respective diets. Rats were killed with ether five and ten days postoperatively, the wounds were excised and breaking strength measured. Sponge hydroxyproline content was measured. No significant difference in breaking strength or sponge hydroxyproline content was found between the two groups. We thus conclude that cimetidine has no effect on wound healing in rats when used in doses equivalent to the clinical dose in man.Supported in part by Army Medical Research and Development Command Contract DADA-17-82-C-2091 to the Albert Einstein College of Medicine, and the Department of Surgery Research Fund.     

Cerebrovascular changes in a rat model of moderate closed-head injury

We have developed and tested a rat (Wistar) model of moderate concussion. Concussion is produced by controlled and repeatable mechanical fixed, closed-head injury. Moderate concussion in this model is characterized by 4 to 10 minutes of unconsciousness, absence of skull fractures or brain contusions, and few, if any, acute neurologic symptoms. By 2 hours postinjury, the subsequent trauma is further characterized by regional and global increases in cerebrovascular permeability and decreases in cerebral blood flow. Such changes are accompanied by brain swelling and two phases of elevated intracranial pressure; one lasting about 5 hours with a peak of about 10 mmHg, the other lasting more than 3 days postinjury with a peak of about 30 mmHg. Regional neurohistologic damage detected between 3 and 4 days postinjury correlates for the most part with earlier changes in regional permeability and blood flow. Significant morphologic changes which are characterized by patchy neuronal degeneration can be found in numerous forebrain locations, particularly in the frontal (coup) and entorhinal (contre coup) cortices. These observations have important parallels in human head trauma and suggest that this reliable physiological model may be a useful, relatively simple and inexpensive tool for investigating the mechanisms and therapeutics of head trauma.     

Hospitalization for psychiatric illness under Medicare, 1985

National and state-level data on Medicare-covered hospital discharges after treatment for psychiatric illness in 1985 were analyzed to determine the distribution of cases among various types of psychiatric and general hospitals. In most states, 80 to 90 percent of Medicare patients with psychiatric conditions received care in a setting that provided specialized treatment for psychiatric illness. However, the distribution of discharges among public and private psychiatric hospitals and general hospitals with psychiatric units varied substantially among states. Between 1984, the first year of Medicare's prospective payment system, and 1985, the number of discharges decreased overall, and a shift toward treatment in specialized psychiatric facilities and toward settings exempt from the prospective payment system was apparent.     

Childbirth Experiences in Australia of Women Born in Turkey,Vietnam, and Australia

ABSTRACT: Background: Migrant women constitute a growing proportion of the childbearing population in many high‐income countries. The aim of this study was to investigate experiences of childbirth, including recollection of pain and use of pain relief, in women born in Vietnam, Turkey, and Australia who gave birth in Victoria, Australia. Methods: One hundred Vietnamese‐born and 100 Turkish‐born women were compared with 100 Australian‐born women who gave birth in the same metropolitan hospital during the same time period. Only women who had a normal vaginal birth and gave birth to a healthy baby were included. They were interviewed between 24 hours after the birth and hospital discharge. Results: Vietnamese women used less pain relief, reported more pain, and described childbirth overall more negatively than Australian women, while also reporting less anxiety, more confidence, and less panic during labor. Turkish women's responses were more similar to those of Australian women, but they were slightly more satisfied with childbirth overall despite recollecting more pain, and were also more likely to perceive time normally. Turkish women used a similar amount of pharmacological pain relief as Australian women, but used more relaxation and breathing techniques. Conclusions: This study showed that women's responses to childbirth are associated with cultural background. Midwives and other caregivers should be particularly sensitive in assessing Vietnamese women's pain during labor. (BIRTH 32:4 December 2005)     

Tumor necrosis factor-alpha mediates acid aspiration-induced systemic organ injury.

Acid aspiration-induced systemic organ injury is mediated by the sequestration of activated neutrophils (PMN). In other settings cytokines have been shown to increase neutrophil-endothelial adhesion, a requisite for injury. This study tests whether the systemic leukosequestration and permeability following localized aspiration is mediated by tumor necrosis factor (TNF)-alpha-induced synthesis of an adhesion protein. Anesthetized rats underwent tracheostomy and insertion of a fine-bore cannula into the anterior segment of the left lung. This was followed by the instillation of either 0.1 mL 0.1 N HCI (n = 18) or 0.1 mL saline in control rats (n = 18). Localized aspiration induced generalized pulmonary leukosequestration with 95 PMN/10 high-power fields (HPF) in the aspirated lung and 46 PMN/10 HPF in the nonaspirated lung, higher than control values of 7 PMN/10 HPF and 5 PMN/10 HPF in saline- and nonsaline-aspirated sides, respectively (p less than 0.05). The leukosequestration was associated with permeability edema shown by increased protein concentrations in bronchoalveolar lavage (BAL) of 3900 micrograms/mL in the aspirated and 2680 micrograms/mL in the nonaspirated side, higher than saline with 482 micrograms/mL and 411 micrograms/mL, respectively (p less than 0.05). There was generalized pulmonary edema following aspiration measured by increase in wet-to-dry weight ratios (w/d) of 6.6 in the aspirated and 5.1 in the nonaspirated lung, higher than control values of 3.5 and 3.4, respectively (p less than 0.05). Localized aspiration led to systemic leukosequestration documented by increases in myeloperoxidase activity (units/g tissue) of 2.2 and 1.7 in heart and kidney, higher than control values of 0.3 and 0.4, respectively (p less than 0.05). This event was associated with edema of these organs with w/d ratios of 4.6 and 4.3, relative to control values of 3.0 and 3.4 (p less than 0.05). Treatment of animals (n = 18) 20 minutes after aspiration with anti-TNF-alpha antiserum (rabbit anti-murine) but not normal rabbit serum (n = 18) reduced lung leukosequestration in the aspirated and nonaspirated segments (61 and 32 PMN/10HPF), BAL protein concentration (1490 and 840 micrograms/mL), and w/d ratio (4.3 and 3.7) (all p less than 0.05). In the heart and kidney there were reductions in myeloperoxidase activity (0.7 and 0.6) and w/d ratio (3.5 and 3.6) (both p less than 0.05). Treatment of rabbits (n = 18) with the protein synthesis inhibitor cycloheximide, 0.2 mg/kg/hr was as effective as TNF-alpha antiserum in modifying aspiration injury.(ABSTRACT TRUNCATED AT 400 WORDS)