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Biomedical subjects

J D Stone

Publications and source records attributed to J D Stone.

31 records · Page 2Linked to original sources
PubMed1992

Sex differences in central cholinergic and angiotensinergic control of vasopressin release.

In conscious, unrestrained rats, the intracerebroventricular injection of the cholinergic agonist, carbachol, or angiotensin II resulted in the transient stimulation of vasopressin secretion, elevation of mean arterial blood pressure, and reduction of heart rate. After the injection of carbachol (25 ng) into a lateral cerebral ventricle, the plasma vasopressin concentration in male rats was increased to twice that of female rats in each phase of the estrous cycle; mean arterial blood pressure was elevated more in males than females, whereas heart rate fell to the same extent in both sexes. In contrast, the increase in the plasma vasopressin concentration of males after the injection of angiotensin II (20 ng) was one-half that of females, and the hypertensive and bradycardic responses were similar in both sexes. Phase of the female estrous cycle had no effect on the responses to either agent. These findings indicate that central cholinergic and angiotensinergic mechanisms controlling vasopressin release are influenced differently by gender. The role of the gonadal steroid hormones in these mechanisms remains to be determined.

Angiotensin II↗
PubMed1991

Sex differences in central adrenoreceptor-mediated vasopressin response to hemorrhage.

Hemorrhage-induced changes in the plasma vasopressin concentration and mean arterial blood pressure (MABP) were studied in conscious rats of both sexes with and without central alpha 1-adrenoreceptor blockade. Rats were subjected to two sequential hemorrhages (H1 and H2), each 0.8% of body weight after an intracerebroventricular injection of the alpha 1-adrenoreceptor antagonist corynanthine or of vehicle. H1 stimulated vasopressin secretion more in proestrous females than in males; there were no significant sex-related differences in responses to H2. Corynanthine pretreatment attenuated the vasopressin response to H2 in males, potentiated this response in proestrous females, but had no effect in estrous females. MABP decreased after H1 in all female groups and in corynanthine-pretreated males. After H2, all groups were hypotensive to the same extent. These data indicate that central alpha 1-adrenoreceptor-mediated pathways participate in vasopressin and blood pressure responses to hemorrhage, but their role is complex and is dependent on gender and on the phase of the estrous cycle.

Animals↗
PubMed1989

Sex differences in central adrenergic control of vasopressin release.

Central adrenoreceptor-mediated regulation of vasopressin secretion and cardiovascular function was studied in male rats and female rats in specific estrous cycle phases. In conscious, unrestrained rats with intracerebroventricular (icv) cannulas and femoral artery and vein catheters, plasma arginine vasopressin concentration (PAVP), mean arterial blood pressure (MABP), and heart rate (HR) were determined before and 5 and 15 min after icv injection of 10 micrograms norepinephrine or 50 micrograms phenylephrine. Norepinephrine (icv) increased PAVP in proestrus and metestrus four and three times (P less than 0.01 and 0.05, respectively) more than in males. Norepinephrine induced similar MABP elevations (P less than 0.01) in males and females in all cycle phases; HR decreased only in proestrus, estrus, and metestrus (P less than 0.01). The increase in PAVP after icv phenylephrine was four and three times greater in proestrous and diestrous females (P less than 0.01 and 0.05, respectively) than in males. The proestrous MABP rise was three times that in males (P less than 0.05); HR decreased similarly in diestrus, proestrus, and males. These results suggest gonadal steroid hormones influence adrenoreceptor-mediated control of vasopressin secretion, MABP, and HR.

Animals↗
PubMed1982

Stress and depression: a test of the buffering model of social support.

The buffering model of social support states that effective social support networks lessen the adverse psychological consequences of stress. Among a large community sample (N = 1,000) of Los Angeles County adults interviewed in 1979, life-event losses and perceived strain were positively related to depressive symptomatology, while close relationships and perceived support were negatively related to these symptoms. In all models tested, these effects were found to be direct effects, not interaction effects as predicted by the buffering model. The effects of stress on depressive symptomatology were similar among those with low and high levels of social support. Social support, instead of merely protecting an individual against the negative impact of stress, may itself be important in ameliorating depressive symptoms. Moreover, assuming that lack of perceived or actual social support is not just a manifestation of depression itself, our findings support the corollary that the lack of social support contributes to the creation of depressive symptoms.

Adult↗
PubMed1982

Racial/ethnic differences in access to health care: further comments on the use-disability ratio.

Indicators of access to health care generally fall into one of two broad groups. The first group of indicators focuses on factors responsible for differential rates of use and often are assessed through reports of patient satisfaction. The second group of indicators focuses more specifically on actual rates of use, and therefore represents a more objective measure of access. One of the most widely used objective indicators of access is the use-disability ratio. This article illustrates some problems in using this ratio in health services research and some strategies one might adopt to minimize these problems. The data reported below were obtained from an analysis of racial/ethnic differences in use of services that was conducted as part of the 1979 Los Angeles Health Survey (N = 1003). Our findings suggest that 1) blacks had greater access to health care than either white/Anglos or Hispanics, particularly for respiratory and musculo-skeletal problems, and 2) the use-disability ratio should be used cautiously, since it is sensitive to subgroup differences in the chronicity and cause of the disability

California↗
PubMed1980

Single-stage reconstruction of mandibular and soft tissue defects using a free osteocutaneous groin flap.

Microvascular reconstruction of the mandible and soft tissues using the composite groin flap is ideal in selected patients. No other available bone so closely approximates the mandible in both thickness and curvature as does the iliac crest. The soft tissues are available for reconstruction and may allow the surgeon to avoid a second flap, except in cases where both lining and cover are needed. The deep circumflex artery is of generous size, usually 2 to 2.5 mm in diameter, allowing greater reliability in the microvascular anastomoses. The flap has a fairly long vascular predicle, 6 to 8 cm. The ability of this flap to withstand irradiation and infection because of its blood supply permits early institution of postoperative radiotherapy and prevents bone loss due to small intraoral wound dehisicence or total flap loss. Although the donor site requires extensive dissection, it can be closed primarily, eliminating the need for skin grafts or other flaps. As further experience is gained with this flap, both the functional and cosmetic results should be improved. In patients undergoing resection of the remaining portion of the mandible, the symphysis or the anterior portion of the mandible, a procedure of this type should be done primarily to prevent deformity and to minimize disability for the patient.

Aged↗
PubMed1979

Annoyance response of nonsmokers to cigarette smoke.

In three experiments, nonsmoking subjects rated their annoyance by task environments while either exposed or not exposed to ambient tobacco smoke. In Exps. 1 and 2 subjects rated annoyance with the environment while exposed to three intensities of noise, and in Exp. 3 subjects rated annoyance while performing multiplication problems under conditions of high and low task motivation. The source of the ambient smoke in Exp. 1 was a smoke pump. For Exps. 2 and 3, the source of the smoke was confederate subjects. No differences in annoyance were obtained in Exps. 1 and 2 as a function of exposure to smoke. Exp. 3 showed that nonsmokers' annoyance to a task environment is dependent upon task motivation and exposure to ambient smoke. In Exp. 3 nonsmokers exposed to smoke were more annoyed than those not exposed under low motivating conditions. When nonsmokers were highly motivated in the task environment those exposed to smoke were significantly less annoyed than those not exposed.

Adolescent↗
PubMed1975

Information processing and estimation of short time intervals.

Duration estimates were assessed by the method of reproduction with filled reproduction intervals. Mental arithmetic, reading and mirror-image drawing were used in pairs as initial and/or reproduction tasks. All nine possible pairs of tasks were used in a 9 X 5 X 5 mixed design with five Ss per task pair and five interruption intervals for each initial task. Results indicated that, when arithmetic was used as the initial task, Ss underestimated the duration of the initial interval. When arithmetic was used as the reproduction task, Ss overestimated the duration of the initial interval. A significant correlation was obtained between arithmetic outputs and the lengths of the duration estimates. Results are interpreted as supportive of Burnside's (1971) interpretation of Ornstein's (1969) storage-size hypothesis.

Humans↗
PubMedDate not supplied

Assessment of posterior cruciate ligament graft performance using robotic technology.

We used the information on in situ forces provided by robotics to compare two methods of posterior cruciate ligament graft fixation. Twenty porcine knees were studied using robotic technology to determine and repeat intact, deficient, and reconstructed knee motion under 110 N of posterior tibial loading at 30 degrees, 60 degrees, and 90 degrees of knee flexion. Reconstruction was performed using a bone-patellar tendon-bone graft with the distal end of the graft placed in the posterolateral aspect of the posterior cruciate ligament tibial insertion. Specimens were separated into two groups based on the femoral fixation site: the proximal or anterior aspect of the femoral insertion. Repetition of knee motion allowed measurement of the force in the intact posterior cruciate ligament and graft using the principle of superposition. The forces in the graft and the intact ligament provided additional information to evaluate graft performance. Force in the intact posterior cruciate ligament was significantly greater at 90 degrees than at 30 degrees and 60 degrees of knee flexion. The forces in both graft types were significantly lower than those of the posterior cruciate ligament, but the force in the anteriorly placed graft was significantly greater at 90 degrees than at 30 degrees and 60 degrees of knee flexion, similar to the intact posterior cruciate ligament. Thus, the anteriorly placed graft had a more physiologic increase in tension with knee flexion, when the joint provided less restraint.

Animals↗
PubMedDate not supplied

Carbamazepine hypersensitivity reaction.

Carbamazepine is an anticonvulsant that is being used more frequently in the treatment of various psychiatric disorders. The drug has been associated with serious adverse reactions that appear to have an immunological pathogenesis. A case report describing a patient suffering an adverse reaction to carbamazepine is presented, to illustrate the various body systems typically affected in the apparent hypersensitivity reaction. The importance of laboratory and patient monitoring during the initial 3 months of carbamazepine therapy is reinforced.

Adult↗