Search PubMed⌕ Search

Biomedical subjects

J R Snyder

Publications and source records attributed to J R Snyder.

At least 91 records · Page 5Linked to original sources
PubMed1990

Endometrial assessment by vaginal ultrasonography before endometrial sampling in patients with postmenopausal bleeding.

Endometrial sampling is the mainstay of management of the postmenopausal patient with uterine bleeding. Thirty women with postmenopausal bleeding were studied prospectively. Before endometrial sampling, a vaginal probe ultrasonographic examination was performed. Eleven patients demonstrated a thin "pencil line" endometrial echo in which the maximum anteroposterior thickness on the long axis view was less than or equal to 5 mm. All eleven patients had minimal tissue obtained on biopsy and a pathology report of "tissue insufficient for diagnosis." Seventeen patients had an echogenic endometrium greater than or equal to 6 mm. Pathology reports of their samples revealed tissue insufficient for diagnosis (two cases), proliferative endometrium (six), secretory endometrium (three), hyperplastic endometrium (three), polyp (two), and endometrial cancer (one case). Two additional patients had no endometrial echo visualized because of associated myomas. These findings suggest (1) that the absence of significant endometrial tissue (echo less than or equal to 5 mm) on vaginal ultrasonography in cases with postmenopausal bleeding is uniformly associated with tissue insufficient for diagnosis, and (2) when endometrial thickness is greater than or equal to 6 mm the histologic diagnosis should be determined in the pathology laboratory.

Adult↗
PubMed1990

Extracorporeal membrane oxygenation and cerebral blood flow velocity in newborn infants.

Doppler ultrasound was used to study cerebral hemodynamics in the pericallosal artery of 21 newborn infants undergoing extracorporeal membrane oxygenation (ECMO) for intractable respiratory failure. Cerebral blood flow velocity waveforms were obtained pre-ECMO, after every major change in cardiopulmonary bypass flow during ECMO, and post-ECMO. The mean pulsatility index (PI) pre-ECMO was slightly higher than after decannulation, secondary to hypocarbia pre-ECMO. The PI decreased significantly at high (61 to 120 ml/min.kg) cardiopulmonary bypass flows. This was associated with an increase in mean arterial pressure, but not with changes in Hct, PaO2, or PaCO2. A negative curvilinear relationship between the amount of cardiopulmonary bypass flow and PI was found. These data suggest an increase in cerebral blood flow velocity and vasodilation of the cerebral vessels at high cardiopulmonary bypass flows, and may explain the occurrence of intracranial hemorrhage in infants undergoing ECMO.

Blood Flow Velocity↗
PubMed1990

Left and right ventricular output in newborn infants undergoing extracorporeal membrane oxygenation.

Extracorporeal membrane oxygenation (ECMO) has gained a place as an alternative mode of treatment for newborn infants with life-threatening respiratory failure who do not respond to maximal conventional ventilatory support. To determine any possible changes in cardiac performance during the course of ECMO treatment, we evaluated left and right ventricular output in 10 newborn infants with pulsed Doppler ultrasound before, during, and after ECMO. Birth weight ranged from 2.5 to 4.2 kg and gestational age from 35 to 42 wk. During ECMO, left and right ventricular output decreased proportionally to the amount of bypass flow provided (r = -.82 and -.83, respectively; p less than .001), and were accompanied by a decrease in left ventricular contractility. Pulsed Doppler echocardiography provides a noninvasive method to estimate ventricular outputs during ECMO and to evaluate the response of both ventricles to volume loading during weaning from ECMO.

Apgar Score↗
PubMed1990

Oxygenation index in patients with meconium aspiration: conventional and extracorporeal membrane oxygenation therapy.

The use of the alveolar-arterial oxygen difference P(A-a)O2 and the oxygenation index (mean airway pressure [Paw] FIO2 x 100/PaO2) have been proposed for selecting infants who will require extracorporeal membrane oxygenation (ECMO) therapy. However, the use of the oxygenation index (OI) in conjunction with Paw in an exclusive population of patients with meconium aspiration syndrome (MAS) has not been reported. Fourteen patients born in our facility and managed with conventional therapy and five infants treated with ECMO were enrolled in the study. All patients had clinical and x-ray evidence of MAS. Infants who received conventional treatment required mechanical ventilation greater than 48 h, FIO2 1.0, and were under the care and supervision of one neonatologist. Management was directed to minimize barotrauma by avoidance of routine hyperventilation, use of lower Paw, and sufficient expiratory time. One patient died before ECMO and 13 infants survived. Six survivors had an OI greater than 25 (three had an OI greater than 40), six had a Paw greater than or equal to 12 cm H2O (12 to 15 cm H2O in five infants) and six patients had a P(A-a)O2 greater than or equal to 610 torr. One surviving infant was transferred for ECMO therapy (OI 67, Paw 20 cm H2O). The five patients treated with ECMO survived (OI 48 to 92, Paw 20 to 29.5 cm H2O P(A-a)O2 627 to 650 torr). One patient in each group developed chronic lung disease with evidence of resting tachypnea. Our findings indicate that an OI greater than 40 in association with a Paw greater than or equal to 20 cm H2O may be helpful in predicting which infants with MAS need ECMO, whereas patients requiring a Paw less than or equal to 15 cm H2O can be managed with conventional therapy. An OI greater than or equal to 25 but less than 40 is not associated with high mortality in these patients. The predictive value of Paw of 16 to 20 cm H2O and the duration of an OI greater than 40 in patients with MAS need further investigation.

Airway Resistance↗
PubMed1990

Traumatic disruption of the suspensory apparatus in foals.

Traumatic disruption of the suspensory apparatus is a catastrophic injury in the horse. Although this injury has been described in the adult, little information is available in the foal. This paper describes 3 foals with metacarpophalangeal joint instability caused by traumatic disruption of the suspensory apparatus. Two foals had biaxial proximal sesamoid fractures in a single forelimb, and 1 foal had avulsion of the distal sesamoidean ligaments in 1 forelimb plus biaxial proximal sesamoid fractures in the other forelimb. The foals with single forelimb involvement were managed with splints, and the foal with bilateral disruption of the suspensory apparatus was euthanatized. Both treated foals resumed natural exercise at pasture. Both continue to be pasture sound 2 and 3 years after injury and are to be used for breeding. Management of disruption of the suspensory apparatus causing metacarpophalangeal joint instability using external support was effective for salvage of these 2 valuable foals for breeding.

Animals↗
PubMed1989

Strangulating volvulus of the ascending colon in horses.

Of 57 horses with strangulating volvulus of the ascending colon, 42 were mares (including 21 postparturient mares), 8 were stallions, and 7 were geldings. Volvulus occurred most frequently in the summer (n = 24) and spring (n = 17). Pain was evaluated as severe in 41 horses, moderate in 9, and mild in 4. The abdominal fluid from 30 horses varied from clear yellow in 19 horses, to cloudy yellow in 3 horses, and serosanguineous in 8 horses. Protein content and nucleated cell count in the abdominal fluid were 2.5 +/- 1 g/dl and 1,000 +/- 900 microliters, respectively. Fifty horses had greater than or equal to 360 degrees volvulus and 7 had a 270 degrees volvulus, with 49 occurring in a counterclockwise direction. The site of volvulus in all horses was at the mesenteric attachment of the colon, except for a 360 degrees volvulus at the sternal and diaphragmatic flexures in 1 horse. Survival rates for horses with a greater than or equal to 360 degrees and a 270 degrees volvulus were 36% and 71%, respectively. The difference in survival rates reflected the severe vascular occlusion in the colon of horses with greater than or equal to 360 degrees volvulus. In nonsurvivors, hemorrhage in the submucosa and lamina propria (P less than 0.005) and edema in the submucosa (P less than 0.01) were greater than those in survivors. In nonsurvivors, greater than 97% of the superficial epithelium was lost. In horses that survived, only 60% of the cells were lost or degenerated.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1989

The pathophysiology of intestinal damage: effects of luminal distention and ischemia.

Intestinal edema, luminal distention, and ischemia are common pathologic processes involved in producing the intestinal damage found during surgical exploration for acute abdominal disorders in the horse. The severity of intestinal edema depends on the degree of altered intravascular forces and changes in capillary permeability. Capillary hydrostatic pressure rises as the less pliable venules and veins become occluded during intestinal obstruction. Concurrently, the production of various endogenous products that damage the vascular wall leads to increases in capillary permeability and protein exudation, causing fluid movement into the interstitium and consequent tissue edema. The information presently available indicates that luminal distention does not produce the morphologic damage observed during natural conditions. However, slight intestinal edema was observed with experimental distention of the equine small intestine. Although the effects of increased luminal pressure appear minor, in the overall scheme of intestine damage, many processes are occurring together, and the luminal distention may be additive in the production of intestinal damage. The intestinal damage occurring during natural obstructions is most likely related to both the severity of the ischemia and the subsequent reperfusion injury. Experimentally, an ischemic insult produces a consistent sequence of mucosal alterations to both the equine small and large intestine. Severity of ischemia may be the limiting factor in determining the clinical outcome in cases in which the ischemic insult is irreversible; however, if the intestinal tissue survives the ischemia, the reperfusion injury may substantially increase the damage, producing an irreversible injury. The proposed mechanisms responsible for the reperfusion injury include the presence of highly reactive cytotoxic oxygen radicals. The intestinal epithelium and vascular endothelium are both capable of producing these unstable compounds. Secondly, the influx and activation of neutrophils may also release oxygen radicals. During experimental ischemia, neutrophils gradually move to the affected area; however, during reperfusion their numbers dramatically increase and may play a significant role in producing intestinal damage. Therapy for intestinal damage involves first determining the viability of the affected intestine. All nonviable bowel should be resected and viable intestine anastomosed. The care and maintenance of intestine of questionable viability are presently based on therapy in humans and experimental information concerning the pathophysiologic mechanisms of intestinal ischemia.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1989

Microvascular circulation of the ascending colon in horses.

Microvascular circulation of the ascending colon in healthy horses was studied using microangiography, light microscopy, and scanning electron microscopy. The pelvic flexure with 30 cm of ventral and dorsal colon attached was removed from 14 adult horses immediately after horses were euthanatized. The lumen was flushed with warm water, and this section of the ascending colon was placed in a 37-C bath of isotonic NaCl. In sections from 8 horses, colic vessels were perfused with a radio-opaque medium for microangiography. After angiographic evaluation, tissue sections were prepared for light microscopic observation, using standard histologic methods. In sections from 6 horses, injection replicas were made by perfusing the vessels with 2 types of plastics. The results of microangiography, light microscopy, and scanning electron microscopy of vascular replicas were correlated, providing a comprehensive documentation of the microvasculature of the ascending colon at the pelvic flexure. Arteries branched from mesenteric colic vessels approximately every 2 cm toward the colonic tissue. Immediately after branching, arterial vessels formed an anastomotic plexus, the colonic rete. However, each branch from the colic vessel eventually continued into the colonic tissue. A second set of vessels originated from the colonic tissue. A second set of vessels originated from the colonic rete and supplied the mesenteric lymph nodes. Arterial vessels penetrated the tunica muscularis into the submucosa 3 to 4 cm toward the antimesenteric border forming a submucosal vascular network. From the submucosal arterioles, branching took place at right angles to supply the mucosal capillaries. Capillaries surrounded the colonic glands and anastomosed at the luminal surface, forming a superficial luminal honeycomb-appearing vascular plexus.(ABSTRACT TRUNCATED AT 250 WORDS)

Angiography↗
PubMed1989

The postmenopausal cystic adnexal mass: the potential role of ultrasound in conservative management.

Often ovarian cancer does not present clinically until the advanced stages. In the past, the presence of any cystic adnexal enlargement in postmenopausal women was an indication for surgical exploration. The ultrasound scans of 42 postmenopausal women with simple adnexal cysts were reviewed. We included only patients who were available for follow-up and who had cysts that were less than or equal to 5 cm in maximum diameter, unilocular (ie, without septations or solid components), and without ascites. Of these patients, 26 underwent prompt surgical exploration. All exhibited benign histopathology. In 16 patients, serial sonographic surveillance was performed every 3-6 months. Two of these patients had exploratory laparotomy at 6 and 9 months of observation; the first operation, for increasing size and septation, demonstrated a cystadenofibroma, and the second, for increasing pain, demonstrated a degenerating myoma. The remaining 14 patients were followed from 10-73 months without any change in size or character of the cyst. Small (less than 5 cm), unilocular postmenopausal cysts had a low incidence of malignant disease (0%) in this series of 28 surgical specimens. Therefore, serial ultrasound follow-up without surgical intervention may play a role in the clinical management of such patients.

Adnexal Diseases↗
PubMed1989

Protection against clinical endotoxemia in horses by using plasma containing antibody to an Rc mutant E. coli (J5).

Thirty-two horses with clinicopathologic evidence of endotoxic shock were randomly selected for a double-blind trial of hyperimmune lipopolysaccharide (LPS) core antigen plasma. Horses were suffering from acute toxic enteritis (n = 15), 360 degrees volvulus of the large colon (n = 9), proximal jejunitis/duodenitis (n = 6), or strangulating obstruction of the small intestine (n = 2). Plasma was harvested from suitable equine plasma donors (preimmune plasma) and horses were immunized with a whole-cell bacterin of an Rc mutant E. coli (J5). Plasma was again harvested from these horses when IgG ELISA titers recognizing LPS core antigen were greater than 1:32,000. All horses included in the trial received either preimmune or hyperimmune plasma in addition to traditional therapy (fluids, antimicrobials, antiinflammatory agents, etc.) as dictated by the attending clinician. The mortality rate in the group of horses receiving hyperimmune plasma was 13%; in the control group receiving preimmune plasma, the mortality rate was 47% (P = .045). Horses receiving J5 hyperimmune plasma had a significantly improved clinical appearance 48 hours after plasma administration (P less than .05) and a shorter period to recovery than control horses (P = .069).

Animals↗
PubMed1989

Utilization of allied health personnel in HMOs.

Health Maintenance Organizations (HMOs) have become a significant component of the health care delivery system and thus provide employment opportunities for allied health professionals. This study investigated the utilization of selected allied health services and personnel in a national sample of HMO settings. Significant utilization of allied health services were reported both through provision of services in-house and through contractual arrangements. Smaller HMOs tended to use several allied health services in-house, while larger HMOs used both in-house and contractual services. Younger HMOs tended to utilize contractual arrangements while older HMOs utilized in-house services. Staff and group HMOs tended to have the highest utilization of health manpower with the larger, older HMOs employing more of those personnel.

Allied Health Personnel↗
PubMed1988

Furanose ring anomerization: a kinetic study of the 5-deoxypentoses and 5-O-methylpentoses.

The anomerization of 5-deoxy-L-pentoses (1-4) and 5-O-methyl-D-pentoses (5-8) in aqueous solution has been studied by 13C saturation-transfer n.m.r. (s.t.-n.m.r.) spectroscopy, using compounds substituted with 13C at the anomeric carbon atom. Unidirectional rate-constants of ring-opening (k open) and ring-closing (k close) have been obtained for these compounds under identical solution conditions (50mM acetate buffer, pH 4.0 at 60 degrees), and have been compared to those measured for the D-tetroses (9 and 10) and the four D-pentose 5-phosphates (11-14). Based on these comparisons, several correlations between furanose structure and reactivity have been revealed, and models have been proposed to explain the observed kinetic behavior of compounds (1-10). The effect of exocyclic structure on acid-catalyzed rate-constants was also examined by comparing the behavior of 5-deoxy-L-(1-13C)-lyxose and 5-O-methyl-D-(1-13C)lyxose. Some consideration has been given to identifying the factors (enthalpic and entropic) that may play roles in determining the effect of structure on anomerization reactivity.

Chemical Phenomena↗
PubMed1988

Assessment of visual function in patients with age-related macular degeneration and low visual acuity.

The visual function of 100 eyes with low visual acuity of 100 patients with age-related macular degeneration was examined using measurements of visual acuity, peak contrast sensitivity, and the ability to read, to tell time, and to distinguish colors, products, and facial expressions. Visual acuity and peak contrast sensitivity were correlated (r = .62); however, a range of peak contrast sensitivities was observed at each level of acuity. When considered individually, visual acuity and peak contrast sensitivity were related to the ability to perform each of the tasks. When multivariate methods were applied, both visual acuity and peak contrast sensitivity contributed independently to the ability to read and tell time. Among patients with the same contrast sensitivity, visual acuity had little or no relationship to the ability to identify colors, products, and faces.

Aged↗
PubMed1988

An analysis of inservice education practices for hospital laboratory personnel.

Inservice education is a form of continuing professional education provided by the health care employer at the worksite. The purposes of this study were to describe current inservice practices in clinical laboratories and to explore laboratory managers' perceptions of the job impact and cost-worthiness of specific inservice education activities. A written survey was mailed to 237 hospitals in Ohio to gather data. Results of the study (61% usable return) were analyzed using descriptive statistics. Notable findings include: Most laboratories do not have an inservice budget; most important for cost worthiness and job impact are new employee orientation, policy and procedure discussions, and instruction on instrumentation. The report discusses ratings of several inservice activities in terms of their value for improving employees' knowledge, skills, and attitudes.

Cost-Benefit Analysis↗