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Biomedical subjects

C Marks

Publications and source records attributed to C Marks.

At least 37 records · Page 2Linked to original sources

Thymoma and aregenerative anemia.

Among 32 patients with thymoma treated at the Louisiana State University Medical Center, there was one patient with aregenerative anemia attributable to thymoma (an incidence of 3.3%). Despite successful surgical removal of the thymoma, there was only slight improvement of the hematologic status three years after thymectomy. The result in this patient approximates the general experience, with hematologic remission being likely in less than 20% of cases. Experience casts doubt on whether treatment with adrenocortical steroids, mediastinal irradiation, or splenectomy provides significant beneficial effects.

Anemia, Aplastic

A study of the potential pharmacokinetic interaction of lisinopril and digoxin in normal volunteers.

1. The pharmacokinetics of single oral doses of 20 mg lisinopril and 0.25 mg digoxin, given alone and together, have been studied in 12 normal young male volunteers. 2. Peak serum conc of lisinopril occurred at 6 to 8 h and were slightly higher during combined treatment. Subsequent elimination proceeded moderately rapidly in both cases, concn declining to approx. 25% of peak values in 24 h. The AUC of lisinopril was similarly slightly higher during combined treatment. 3. After lisinopril alone, urinary elimination of unchanged lisinopril was 13% dose in 72 h, and after combined therapy was 17% dose. 4. Although there were no statistically significant differences in lisinopril pharmacokinetics during single or combined treatment, serum and urinary parameters suggest that bioavailability may be enhanced slightly during combined treatment. 5. Plasma concentrations of digoxin were slightly lower and urinary excretion slightly higher during combined treatment, the mean renal clearance being 20% higher.

Adult

Blood pressure in obese adolescents: effect of weight loss.

The BP distribution of a group of 72 obese adolescents was determined both before and after weight loss. Weight loss was produced by a program of caloric restriction and behavior change alone (n = 26) or with a combination of caloric restriction, behavior change, and exercise (n = 25). It was demonstrated that obese adolescents have a BP distribution that is skewed 1 SD to the right of normal (P less than .01), and that with weight loss this distribution was no longer different from that of the general population. It was also shown that a weight loss program that incorporates exercise and caloric restriction produces the most desirable effect on BP reduction (ie, greatest decrease in resting systolic BP and greatest decrease in exercise diastolic and mean BP). Finally, it was demonstrated that obese adolescents have structural changes present in the forearm resistance vessels and that these structural changes are reversed to the greatest extent in the weight loss program that includes exercise.

Adolescent

Outpatient surgery for prolapsed lumbar disc.

A selected series of 14 patients with lumbar disc prolapse causing sciatica have been operated successfully with outpatient (daycase) surgery. Postoperative pain has been much less than expected. This form of surgery has proved very acceptable to patients and to their family doctors.

Ambulatory Surgical Procedures

Biological and technological variability of residual lung volume and the effect on body fat calculations.

Ten subjects were studied to determine within-subject variance (Swi2), and its components, biovariability (Si2) and technological error (Se2) of residual lung volume (RLV). Each subject's RLV was determined 18 times using the oxygen dilution method (O2D) over a 5-day period. Se2 was measured using a 9.0 l spirometer as a simulated subject and estimating its added space by the O2D method for 20 repeat trials. The mean +/- SD of RLV across subjects was 1.408 +/- 0.3143 l. The average Swi2 for the 18 trials was 0.0054 (Swi = +/- 0.0735 l). The variance associated with a trend effect (variance of mean trial scores, Sc2) was 0.00050 (Sc = +/- 0.0224 l). Se2 was found to be 0.00104 (Se = +/- 0.0323 l). Si2 calculated by subtracting Se2 and Sc2 from Swi2, was 0.0039 (Si = +/- 0.0621 l). It was demonstrated that body fat weight calculations can vary because of the within-subject variability in RLV. The calculated reliability of RLV across subjects was r = 0.95. It is concluded that RLV determined by the O2D method is very reliable. Moreover, biological variance accounts for 72% of Swi2 while technological variance and trend effect variance account for 19 and 9% of Swi2 respectively.

Adult

Double-blind, multicenter controlled trial comparing topical dimethyl sulfoxide and normal saline for treatment of hand ulcers in patients with systemic sclerosis.

A prospective, randomized, double-blind trial compared topical therapy with 0.85% normal saline, 2% dimethyl sulfoxide (DMSO), and 70% DMSO for treatment of digital ulcers in 84 patients with systemic sclerosis. There were no statistically significant differences among the 3 treatment groups in the improvement in the total number of open ulcers, total surface area of open ulcers, average surface area per open ulcer, number of infected ulcers, number of inflamed ulcers, or patient pain assessment. While some patients improved during the study, improvement could not be attributed to a specific treatment. Over one-quarter of the patients treated with 70% DMSO were withdrawn for significant skin toxicity.

Administration, Topical

Hepatic tumors and oral contraceptives: surgical management.

The clinical and pathological features of 14 patients with benign liver tumors are reviewed. There were two males and 12 females in this series of cases. All but one of the females had been on contraceptive steroid therapy for an average of 7.8 years. Abdominal pain was the presenting complaint in 75% of cases, a palpable abdominal mass was present in 22%, while 12.5% of the patients presented with acute hemorrhagic shock due to rupture of a liver cell adenoma. Liver cell adenomas (LCA) were found in 87.5% of the cases and a diagnosis of focal nodular hyperplasia (FNA) was made at histologic examination of the resected tumors in 12.5% of cases. Surgical resection of the liver tumors was performed successfully in 89% of the cases. Hepatic lobectomy was accomplished in four patients, hepatic segmentectomy was possible in three cases, while local wedge resection or focal excision were indicated on seven occasions. There was no operative mortality in this series, but one patient required reoperation for drainage of a complicating subphrenic abscess.

Adult

Basal metabolism of obese adolescents: age, gender and body composition effects.

Body composition (percent fat and lean body mass) and basal metabolic rates were determined in 67 obese adolescents ranging in age from 10 to 16 years (30 male, 37 female). Basal oxygen uptake was determined on rising in the morning using open-circuit spirometry with a 10-min collection period. Body composition was determined from body density measurements using the underwater weighing procedure. There were no male-female differences (except for basal VCO2 production, P less than 0.05) for any body composition or metabolic variable. The subjects' (male and female) average weight was 73 kg, height--157 cm, percent fat--40 percent, fat weight--30 kg, lean body mass--92 kg, and kcal/24 h--1535. Correlations between age, body composition and basal energy expenditure were all moderate to low (r less than or equal to 0.78). In contrast to adult data, lean body mass was not highly correlated to basal energy expenditure suggesting that perhaps there is a 'metabolic condition' of the obese adolescent modulated by excess fatness or the instability of the body cell mass. Stepwise multiple linear regression revealed that for the obese male adolescent, body surface area and percent fat, and for the obese female adolescent body surface area and body weight resulted in the best prediction of basal kcal/24 h. The standard errors of prediction were +/- 17.9 percent for the males, and +/- 14.4 percent for the females.

Adolescent

Validity of CO2-rebreathing cardiac output during rest and exercise in young adults.

To validate the CO2-rebreathing method ( Defare 's method) for estimating cardiac output in children and young adults, measurements were compared to thermodilution ( TDCO ) cardiac output in 16 subjects (age 7-19 yr) with congenital heart disease. Data were collected at rest (N = 11) and during 4-min stages of supine bicycle exercise (N = 13). Estimated arterial-venous (-v-a)CO2 content differences related linearly to the measured CO2 content difference (Y = 0. 29X + 2.47, r = 0.65, P less than 0.001). With this (v-a)CO2 difference correction for all patients (N = 16), the correlation between CO2-rebreathing cardiac output and the TDCO was r = 0.87 (SEE = +/- 1.8 l X min-1). The correlation was higher for exercise (r = 0.81) than for rest (r = 0.65). We conclude that the CO2-rebreathing method, with a (v-a)CO2 content difference adjustment, is a simple, noninvasive technique providing estimates of cardiac output in children and young adults with congenital heart disease. Individual estimates should be treated with caution, especially when used for clinical evaluations.

Adolescent

The parasacral approach to the rectum.

The posterior parasacral approach to the rectum is well-suited to several benign conditions and may occasionally be indicated in malignant rectal disorder. The York Mason modification of the Kraske procedure permits preservation of the sphincters and preservation of anal continence. The procedure is recommended as part of a surgeon's repertoire in operations on the rectum.

Adult

Overwhelming postsplenectomy sepsis in childhood.

Three hundred ninety-three splenectomies were performed within the Charity Hospital system during the decade from 1969 through 1979. This number included 56 operations in children under 16 years of age, which formed the basis of this report of the risk of infection in young splenectomized patients and provided guidelines for the role of splenectomy under emergency and elective conditions. Eight episodes of serious infection were documented in four patients. There was only one case of overwhelming postsplenectomy infection which resulted in death, for a mortality rate of 1.8 percent (1 of 56 children) for death due to overwhelming postsplenectomy sepsis. It is emphasized, however, that the development of serious postsplenectomy sepsis in our series resulted in a 25 percent mortality rate. The risk of postsplenectomy sepsis is much greater in those individuals who are immunologically compromised, such as those who undergo staging splenectomy for Hodgkin's disease. If splenectomy is indicated for a hematologic disorder, it is wise to defer operation for as long as possible, especially if the acute episodes are self-limiting or mild. Rather than the promiscuous use of polyvalent serum and antibiotic therapy after splenectomy in children, it is recommended that parents be advised to bring the child to the hospital anytime an illness or fever develops that might require an immediate loading dose of an appropriate antibiotic. The role of subtotal splenectomy or hemisplenectomy merits consideration in staging Hodgkin's disease. Preoperative study of certain immunologic parameters may provide guidelines as to the proportion of individuals who may be vulnerable to overwhelming sepsis after splenectomy.

Adolescent

Extracranial carotid artery injury. Current surgical management.

Fifty patients were treated for extracranial carotid artery trauma during the period from 1954 through 1981. The overall mortality rate was 20 percent. Primary repair was achieved in 38 patients (76 percent) with a mortality of 7.8 percent, and ligation was performed in six patients (12 percent) with a 50 percent mortality. The left carotid system was injured more frequently than the right; hemorrhage from an isolated carotid injury was readily controlled by digital pressure. Associated injuries affected the prognosis adversely. Significant neurologic deficits were present in 12 patients on first admission but the presence of neurologic deficit or coma did not serve as a contraindication to arterial repair and restoration of cerebrovascular continuity. Arteriography was not utilized once the clinical diagnosis of carotid arterial injury was made, but it was utilized when the proximity of the cervical injury provided the only suggestive evidence that vascular damage may have occurred. The presence of significant shock, coma, or neurologic deficit represent adverse prognostic features but do not contraindicate carotid repair. Profuse bleeding from a carotid injury or the presence of severe posthemorrhagic shock require urgent surgery. If control of bleeding is difficult to achieve, then ligation is preferred to suture repair.

Adolescent

Thermostable erythrocyte rosettes in chronic renal failure and allograft rejection.

Rejection of an allograft usually is preceded by activation of T lymphocytes, in which state such cells may be identified by their ability to form thermostable rosettes with sheep erythrocytes (TE-R). The objective of the present work, therefore, was to determine whether or not enumeration of TE-R in the peripheral blood was of any value in the diagnosis of rejection. The results showed no significant differences between TE-R (mean +/- SEM) in normal subjects (9.9 +/- 1.3; n = 25), renal allograft recipients without rejections (13.5 +/- 1.7; n = 5) and in patients who suffered from acute tubular necrosis in the posttransplant period (12.4 +/- 2.5; n = 8). In contrast, recipients who had rejection episodes showed a marked rise in TE-R levels (43.0 +/- 4.0; n = 11) about two to seven days prior to the diagnosis of rejection by clinical and chemical criteria. Furthermore, TE-R remained high if the rejection episodes turned out to be irreversible after therapy (42.2 +/- 3.7) but fell if the episodes were reversible (19.9 +/- 3.2). TE-R values were elevated in patients with chronic renal failure on maintenance hemodialysis (45.7 +/- 4.9; n = 23). Neither acute dialytic runs or acute infections altered TE-R values. In conclusion, those results show that enumeration of TE-R may be helpful in the early diagnosis of allograft rejection, before clinical and chemical stigmata are apparent.

Erythrocytes

Immunobiological determinants in organ transplantation.

The most important development in determining successful organ transplantation has been the improved understanding of the immune response and the interactions between antigens, antibody, immune complexes, complement component, lymphocytes and macrophages. The initiation and termination of an immune response, whether cellular or humoral depends upon cellular interaction between subsets of the lymphocyte cell series and macrophages. An equilibrium between helper and suppressor T cells determines protection of the host from non-self tissue invasion, infection and neoplasia. The role of mediators, immunosuppressants, hybridomas and recombitant DNA technology are briefly considered. The relative importance of tissue typing and blood transfusion in preventing allograft rejection is considered and the role of immunological monitoring in allograft transplantation is reviewed.

B-Lymphocytes

Asymmetric release of estrone and estradiol derived from labeled precursors in perfused human placentas.

Human placentas were perfused in vitro through fetal vessels of a single cotyledon with a solution of tritiated androstenedione (A) or tritiated testosterone in oxygenated Krebs-Ringer bicarbonate buffer containing glucose. The same buffer, without labeled steroids, was used to perfuse the maternal side of the placenta. Fractions of unrecycled "fetal" and "maternal" perfusates were collected to estimate the steady-state rates of output into each perfusate of labeled estrone (E1) and estradiol (E2), formed by aromatization of the perfused androgens. An unequal distribution of the two estrogens was observed, i.e., a significantly larger proportion of E2 than of E1 was released to the maternal perfusate. Addition of unlabeled A or ethinyl estradiol (10(-5)M) to the fetal perfusion buffer resulted in a redistribution of the E2 output toward the fetal perfusate. These in vitro results are similar to the findings of Walsh and McCarthy, who detected by tracer experiments an unequality in the in vivo fetomaternal distribution of the output of placentally produced E1 and E2 in rhesus monkeys. These results also support the possibility of the existence of saturable specific E2 carriers in the syncytiotrophoblast, postulated by the same authors to explain their findings. However, an extrasyncytial conversion of E2 to E1 could also account for the disproportion in the relative output of the estrogens toward mother and fetus. The perfusion system used in these studies may be useful for the elucidation of factors determining the relative rates of placental secretion of steroids toward mother and fetus.

Androstenedione

Current management of paragangliomas.

Since 1948, 33 paragangliomas in 32 patients were seen and studied at Charity Hospital. Tumors of the head and neck comprised the bulk of recorded instances, with only five paragangliomas being noted below the diaphragm. The most frequent symptoms correlated closely with tumor location and were related to local mass effect. Angiography remains an important diagnostic study for tumors of the head and neck with computed tomography scanning becoming increasingly important in large paragangliomas of the jugular region. Paragangliomas of the retroperitoneal space can be successfully located by a computed tomography scan, although a new radionuclide scan may prove to be more specific in the future. Tumors of the urinary bladder and retroperitoneal space are commonly endocrine functional and have a greater metastatic potential than do paragangliomas in other locations. Over-all, total excision is possible with complete recovery in most instances. Prolonged follow-up study is recommended, however, as local recurrences and distant metastases may present years after the initial diagnosis.

Adult