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Biomedical subjects

J Sapp

Publications and source records attributed to J Sapp.

17 recordsLinked to original sources
PubMed2001

Electrophysiology and anatomic characterization of an epicardial accessory pathway.

Pericardial access permitted epicardial catheter mapping and ablation of a rapidly conducting posteroseptal accessory pathway (AP) that had failed repeated ablation attempts. Transient block was achieved at the site of an AP potential. The AP was visible at surgery and resected. Histologic examination revealed cells typical of specialized cardiac conduction tissue. The location, size, and presence of conduction tissue likely account for failure of catheter ablation and resistance to drug therapy.

Atrioventricular Node↗
PubMed2001

Ulnar artery thrombosis: a 6-year experience.

Thrombosis of the ulnar artery can be a cause of significant morbidity. Most often a consequence of blunt trauma to the hypothenar eminence of the hand, it may be attributable to one traumatic event or to repetitive insults. Surgery is often required. We reviewed the presentation and diagnosis of ulnar artery thrombosis and evaluated the effectiveness of treatment by ulnar artery excision with interposition vein grafting. Retrospective chart analysis from 1989 to 1995 at the Medical Center of Central Georgia showed that nine patients (eight male, one female) were treated for ulnar artery thrombosis. Three had associated ulnar artery aneurysms. Eight of the nine were treated with artery excision and interposition vein grafting. Four also received stellate ganglion blocks before surgery. One was treated with stellate ganglion blocks alone. All patients had symptomatic relief and resolution of physical findings. We conclude that ulnar artery thrombosis can be managed with ulnar artery excision and interposition vein grafting when conservative measures fail.

Adolescent↗
PubMed1998

Freewheeling centrioles.

The century-old controversy over the reproduction and function of the centriole is examined to elucidate the conceptual and methodological issues that have made it so resistant to closure. The study of centrioles is situated in two distinct eras punctuated by the deployment of the electron microscope. From the late 19th century to the mid-20th century, centrioles were defined largely in functional terms- as self-reproducing 'central bodies' playing a directive role in mitosis. During this period, when their structure remained unknown, their universal presence in all cells was ambiguous, and their reality was seriously debated. A conceptual switch occurred after the mid-1950s. When the centriole was made visible under the electron microscope, it was defined in terms of its characteristic cart-wheel structure, but its function and manner of reproduction have remained enigmatic. The controversy over the nature of centrioles illustrates the dynamic interplay of techniques, theories, and background assumptions in the production of scientific knowledge. It also highlights the difficulties biologists face in coming to grips with problems of cell structure and intracellular morphogenesis.

Animals↗
PubMed1997

Jean Brachet, l'hérédité générale and the origins of molecular embryology.

Jean Brachet's research on microsomes and the role of RNA in protein synthesis during the 1940s and 50s is placed in the context of embryological views about the role of the cytoplasm in development, and plasmagene theory based on studies of non-Mendelian inheritance in microorganisms. I show how Brachet's subsequent conception of messenger RNA evolved in the context of his conceptions of the relations between plasmagenes and nuclear genes. His theorizing on cytoplasmic organelles and viruses is further situated in the bio-political controversy over the inheritance of acquired characteristics during the Lysenko controversy.

Animals↗
PubMed1995

Incidence and hospital stay for cardiac and pulmonary complications after abdominal surgery.

OBJECTIVE: Internists frequently evaluate preoperative cardiopulmonary risk and co-manage cardiac and pulmonary complications, but the comparative incidence and clinical importance of these complications are not clearly delineated. This study evaluated incidence and length of stay for both cardiac and pulmonary complications after elective laparotomy. DESIGN: Nested case-control. SETTING: University-affiliated Department of Veterans Affairs Hospital. PATIENTS: Computerized registry of all 2,291 patients undergoing elective abdominal operations from 1982 to 1991. MEASUREMENT AND MAIN RESULTS: Strategy for ascertainment and verification of complications was systematic and explicit. The charts of all 116 patients identified by the registry as having complications and 412 (19%) randomly selected from 2,175 remaining patients were reviewed to verify presence or absence of cardiac or pulmonary complications, using explicit criteria and independent abstraction of pre- and postoperative components of charts. From these 528 validated cases and controls (23% of the cohort), 96 cases and 96 controls were matched by operation type and age within ten years. Hospital and intensive care unit stays were significantly longer (p < 0.0001) for the cases than for the controls (24.1 vs 10.3 and 5.6 vs 1.5 days, respectively). All 19 deaths occurred among the cases. Among the cases, pulmonary complications occurred significantly more often than cardiac complications (p < 0.00001) and were associated with significantly longer hospital stays (22.7 vs 10.4 days, p = 0.001). Combined cardiopulmonary complications occurred among 28% of the cases. Misclassification-corrected incidence rates for the entire cohort were 9.6% (95% CI 7.2-12.0) for pulmonary and 5.7% (95% CI 3.6-7.7) for cardiac complications. CONCLUSIONS: For noncardiac surgery, previous research has focused on cardiac risk. In this study, pulmonary complications were more frequent, were associated with longer hospital stay, and occurred in combination with cardiac complications in a substantial proportion of cases. These results suggest that further research is needed to fully characterize the clinical epidemiology of postoperative cardiac and pulmonary complications and better guide preoperative risk assessment.

Abdomen↗
PubMed1993

Dopamine D2 receptor density estimates in schizophrenia: a positron emission tomography study with 11C-N-methylspiperone.

Positron emission tomography (PET) with 11C-N-methylspiperone as the radioligand was carried out in 25 chronic schizophrenic patients to determine dopamine D2 receptor density estimates in the corpus striatum. The sample included 18 neuroleptic-naive and 7 neuroleptic-free patients. Dopamine D2 receptor density estimates (Bmax) were obtained using a two-scan/four-compartment model. The Bmax estimates for the entire group (33.39 +/- 3.43 pmole/g) were significantly elevated when compared with estimates for the control group (Bmax = 15.63 +/- 2.38). The Bmax values for the entire group of schizophrenic patients showed a significant decline as a function of age. The Bmax values were significantly related to duration of illness (y = 13.2 + 10.3795x - 0.7931x2; r = 0.48). Thirteen patients and seven control subjects were added to our original publication sample (Wong et al., 1986c). The patients' Bmax values, when adjusted for age and sex effects, were significantly different compared with those of control subjects. Clinical data from the entire group were compared with published data from other research groups that have estimated dopamine D2 receptor density using different radioligands and different methods of data analysis. Comparisons of the clinical characteristics of the published studies show significant differences in patient populations, suggesting that discrepancies among published studies may reflect, in part, heterogeneity among groups of schizophrenic patients. The D2 receptor abnormality described in this study may be a late manifestation of disease, and the implications of this observation are discussed.

Adult↗
PubMed1991

Physostigmine in Alzheimer's disease: effects on cognitive functioning, cerebral glucose metabolism analyzed by positron emission tomography and cerebral blood flow analyzed by single photon emission tomography.

The effect of acute, intravenous administration of physostigmine on measures of brain activity and cognitive functioning were investigated in 14 patients with Alzheimer's disease. Regional cerebral glucose metabolism was assessed using (18F)-fluoro-2-deoxy-D-glucose and positron emission tomography, and cerebral blood flow was assessed using 123I-iodoamphetamine single photon emission tomography. Although physostigmine enhanced cerebral blood flow in most patients, only one patient showed significant clinical improvement. This patient, however, also showed a very pronounced improvement in cerebral glucose metabolism. It is concluded that these preliminary findings hold considerable promise for our appreciation of the pathophysiology of dementing illness as well as our understanding of centrally acting compounds of interest in Alzheimer's disease.

Aged↗
PubMed1980

Simultaneous combination radiotherapy and multidrug chemotherapy for stage III and stage IV squamous cell carcinoma of the head and neck.

Combined simultaneous radiotherapy and multidrug chemotherapy have been utilized in an attempt to eradicate or shrink tumors of the head and neck area in advanced stages to allow subsequent surgical extirpation. Thirty-six patients (1 stage II; 11 stage III; 24 stage IV; 1 unknown primary) were treated with simultaneous radiotherapy and fractionalized doses of bleomycin, adriamycin, and 5-fluorouracil. Thirty of 36 patients completed the treatment schedule. Twenty-nine of 30 (97%) had a 75% or greater response to treatment; 20/30 (66%) had 100% response; 9/30 (30%) had 75% response; and 1/30 had 50% response. Of the 30 patients completing the regimen, 19/30 (63%) are alive three to 27 months later, and 12 (40%) of these have no evidence of disease. Six patients died within four months of initiation of therapy, mostly from complications of their disease. This treatment regimen appears effective in the control of locoregional disease or to produce enough shrinkage of tumor to allow subsequent surgical extirpation.

Adult↗