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Biomedical subjects

J K Simon

Publications and source records attributed to J K Simon.

11 recordsLinked to original sources
PubMed1992

Improved detection of cytomegalovirus viremia in AIDS patients using shell vial and indirect immunoperoxidase methodologies.

One hundred twelve peripheral blood specimens were tested for the presence of cytomegalovirus (CMV) by the tube culture indirect immunoperoxidase (TC-IPA) procedure, the shell vial assay [shell vials were pre- and postinoculation treated with medium containing 2 of 10% fetal bovine serum (FBS) or 100 micrograms% cortisol] (SV-IFA), and conventional (MRC-5) tube cultures (TC-CPE). CMV was detected in 25 (22%) of the 112 specimens tested by at least one of these methods. The detection/isolation of CMV among the 25 positive specimens in shell vials maintained with 2% FBS, 100 micrograms% cortisol + 2% FBS, and 10% FBS was 36, 44, and 52%, respectively. Detection/isolation of the virus from blood by TC-IPA and TC-CPE was 52% and 76%, respectively. A significantly greater CMV detection rate occurred using TC-CPE compared to SV-IFA treated with medium supplemented with an FBS concentration of 2% (P = .0132), but not medium containing the higher serum supplement or the glucocorticoid (P greater than .05). Differences in the identification of a CMV viremia were observed by IPA, SV-IFA, and TC-CPE methodologies on a patient-to-patient basis, denoting the necessity of incorporating each methodology into the CMV screening panel. Demographic analysis of 82 AIDS patients showed a CMV viremia prevalence of 9% (2/28) in intravenous drug users, 57% (27/47) in homosexual patients, and 22% (2/9) in heterosexual and transfusion patients. Overnight (24 hr) storage of whole blood at 4 or 24 degrees C, respectively, reduced CMV recovery by 40% and 65%, when tested by TC-CPE.(ABSTRACT TRUNCATED AT 250 WORDS)

AIDS-Related Opportunistic Infections↗
PubMed1991

Effect of renal denervation on plasma renin activity after aortic baroreceptor deafferentation.

Renal nerves are thought to play an important role in cardiovascular regulation under both normotensive and hypertensive conditions. In the present study the effect of renal denervation on the changes in plasma renin activity (PRA) after aortic baroreceptor deafferentation (tADN) were investigated in the rat. Bilateral renal denervation did not alter arterial pressure (AP, 100 +/- 4 mmHg; 1 mmHg = 133.32 Pa), heart rate (HR, 363 +/- 12 bpm), or PRA (2.9 +/- 0.6 ng.mL-1.h-1) compared with the respective sham renal denervation values of 106 +/- 3 mmHg (AP), 385 +/- 13 bpm (HR), and 3.3 +/- 0.7 ng.mL-1.h-1 (PRA). On the other hand, bilateral tADN resulted in significant increases in AP, HR, and PRA. One and 3 days after tADN, AP was 130 +/- 4 and 127 +/- 6 mmHg, HR was 461 +/- 15 and 463 +/- 20 bpm, and PRA was 9.1 +/- 3.0 and 11.9 +/- 4.5 ng.mL-1.h-1, respectively. Renal denervation before tADN prevented the increases in AP and PRA, but it did not affect the increase in HR. These data indicate that renal denervation does not alter basal PRA in normotensive animals but prevents the increased renin release observed in neurogenic hypertension. These data suggest that the increased PRA may be one of several factors that contributes to the elevated AP after tADN.

Animals↗
PubMed1989

Reorganization/diversification: six years later.

Hospital efforts in diversification strategies have met with mixed reviews. After a slow beginning and some difficult learning experiences, this hospital organization found a successful approach.

Hospital Administration↗
PubMed1989

Contribution of afferent renal nerves to the metabolic activity of central structures involved in the control of the circulation.

Afferent renal nerves (ARN) are thought to be an important link in the pathogenesis of hypertension because of their influence on neuronal circuits involved in the control of arterial pressure and body fluid homeostasis. However, the central neural pathways involved in mediating ARN information have not been completely elucidated. In the present study, regions of the brainstem and forebrain, whose metabolic activity was altered after renal denervation, were functionally identified using hexokinase histochemistry in the rat. No differences in arterial pressure or heart rate were observed in either the 3-day or 13-day ARN-transected (tARN) animals compared with the respective sham ARN-transected (sARN) groups. Significant increases in the hexokinase reaction product were seen in the parvocellular component of the paraventricular nucleus of the hypothalamus, the supraoptic nucleus, the arcuate nucleus, the subfornical organ, the median preoptic nucleus, and the medial nucleus of the amygdala in both the 3-day and 13-day tARN animals. The bed nucleus of the stria terminalis was observed to have a significant decrease in hexokinase activity in the tARN groups, as were the caudal and medial aspects of the nucleus of the solitary tract. In the 3-day tARN group only, a significant decrease in hexokinase activity was observed in the region of the brainstem containing the A5 cell group, compared with sARN animals. The magnocellular component of the paraventricular nucleus of the hypothalamus and the lateral hypothalamus was seen to have increased hexokinase activity in the 13-day tARN animals only.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1989

Renal denervation alters forebrain hexokinase activity in neurogenic hypertensive rats.

The effect of afferent renal nerve transection (tARN) on the metabolic activity of forebrain structures the activity of which was altered after aortic depressor nerve transection (tADN) was studied using the hexokinase (HK) histochemical method in the rat. In tADN-sham (s) ARN rats, increases in HK activity were observed in the medial septum (MS), median preoptic nucleus (MnPO), subfornical organ, supraoptic nucleus, nucleus circularis (Nc), magnocellular, and dorsal and medial (mpPVH) parvocellular components of paraventricular nucleus, the anterior, lateral, and dorsomedial (DMH) hypothalamus, and in the central and medial nuclei of the amygdala. In addition, a decrease in HK activity was seen in the dorsal arcuate nucleus (dArc). Similarly, increases in HK activity were seen in sADN-tARN rats in all the above structures except MS, Nc, and DMH, where no changes were observed, and dArc, where an increase in HK activity was noted. The bed nucleus of the stria terminalis, lateral preoptic nucleus (POA), and ventral (v) Arc also showed elevated HK activity. In contrast, the increased HK activity after either tADN or tARN alone was returned to levels not different from sADN-sARN rats in all structures in the tADN-tARN rats, except MnPO, mpPVH, and dArc, where the level of HK activity was only attenuated, and MS, POA, and vArc, where it remained elevated. These data suggest that similar forebrain structure are associated with the hypertension after tADN and are involved in the integration of ARN information and that these sites of interaction are involved in the maintenance and the reversal of the neurogenic hypertension.(ABSTRACT TRUNCATED AT 250 WORDS)

Afferent Pathways↗
PubMed1989

Afferent renal nerve effects on plasma vasopressin and oxytocin in conscious rats.

Experiments were done in conscious, unrestrained, baroreceptor-intact rats to investigate the effects of afferent renal nerve (ARN) stimulation on circulating levels of arginine vasopressin (AVP) and oxytocin (OXY). Electrical stimulation of ARN elicited a rise in arterial pressure (AP) of 12 +/- 2 mmHg and no significant change in heart rate (HR). Plasma concentrations of AVP and OXY measured by radioimmunoassay were significantly increased immediately after the stimulation period. AVP increased from control levels of 1.89 +/- 0.72 to 4.59 +/- 1.19 pg/ml after stimulation of ARN and OXY increased from 4.3 +/- 0.35 to 10.0 +/- 1.00 pg/ml. AVP remained significantly elevated at 1 h after stimulation and gradually returned to control levels by 3 h after stimulation. On the other hand, OXY values were at control levels at 1 h after stimulation. Stimulation of ARN, after cutting ARN proximal to the stimulating electrode, and sham ARN stimulation did not alter AP, HR, or plasma levels of AVP and OXY. Plasma osmolality was not altered during the experiments. These data demonstrate that, in the conscious rat, afferent information from the kidney alters the release of AVP and OXY from the neurohypophysis and suggests that ARNs are important components of a neuronal circuit that modulates differentially the release of these hormones, which function in the homeostatic regulation of AP and fluid balance.

Afferent Pathways↗