In vitro studies on human IgD. II. IgD-secreting cells preferentially elaborate IgD, lambda molecules

The "IgD paradox" describes the unexpected finding that, despite a predominance of kappa (kappa) light (L) chains on the surface of IgD+ human B cells, the majority of monoclonal IgD proteins are of lambda (lambda) type. This potentially informative phenomenon appears to be based on a preferential association between delta (delta) heavy (H) and lambda L chains of IgD-secreting cells. The current studies analyze the phenomenon in vitro. Initial assays on tonsil "spent" supernatants showed that the higher IgD-"externalizing" cultures displayed progressively elevated IgD, lambda/kappa ratios due to parallel shifts in total IgD and IgD, lambda while IgD, kappa remained stable. The cells of the same higher-IgD cultures demonstrated that individual IgD-containing cells had a predominance of lambda chains in contrast to IgM-containing cells of the same cultures using fluorochrome-antibody double staining. Certain tonsil culture IgD-containing cells remarkably appeared to have exclusively lambda chain. These same tonsils show evidence of IgD secretion (Litwin, S. D. and Zehr, B. D., Eur. J. Immunol. 1987. 17:483); thus, these data align preferential delta-lambda chain association with IgD-secreting normal tonsil B cells in vitro and emphasize the usefulness of IgD, lambda/kappa ratio in monitoring IgD secretion. In another approach the relationship between the cellular location of IgD and the preferential delta-lambda chain association was studied using Triton X-114-partitioned cell lysates. IgD, lambda/kappa ratios were one or less in the detergent phase (membrane-enriched fraction) consistent with expected IgD, kappa predominance in membrane IgD. In contrast, the aqueous phase (intracellular-enriched fraction) of IgD-secreting cultures had 2-4 times higher supernatant IgD, lambda/kappa ratios. The restriction of high IgD, lambda/kappa ratios to intracellular fractions and supernatants of IgD-secreting cultured cells parallels the predicted distribution of secretory IgD. In sera studies, the correlation between total IgD and IgD, lambda/kappa ratio values was consistent with secreted sera IgD showing preferential lambda chain expression. It was concluded that the phenomenon of delta-lambda chain preferential association is expressed in vitro as well as in vivo; a property of normal, nonmalignant human IgD-secreting B cells; and closely related to the secretory form of IgD. In certain cultures, the delta-lambda chain preference was so striking as to imply limited heterogeneity of the IgD immune response.     

Redesigning patient care roles: a case study

Many hospitals and health care systems have reacted to changes in health care over the last 10 years through operational redesign. This article provides a graphic and detailed discussion of how one institution dealt with a core redesign issue--changing provider roles and how they affect service, quality, and cost.     

Effects of propranolol treatment on left ventricular function and intracellular calcium regulation in rats with postinfarction heart failure.

1. Chronic treatment with beta-adrenergic blocking agents can improve survival in patients with heart failure. The mechanisms underlying the beneficial effects and whether these effects are generalizable to ischaemic heart failure are unresolved. 2. We performed echocardiographic-Doppler examinations in rats (n=28) 1 and 6 weeks after myocardial infarction (MI) or sham surgery. Rats were randomized to no treatment or propranolol (500 mg/l in drinking water) after the first echocardiogram. Isometric contractions and intracellular Ca transients were recorded simultaneously in noninfarcted left ventricular (LV) papillary muscles. 3. Untreated MI rats had significant LV dilatation (10.6+/-0.4* vs 8.9+/(-0.3) mm, MI vs control), impaired systolic function (fractional shortening=11+/-2* vs 38+/-2%), and a restrictive LV diastolic filling pattern. MI rats receiving propranolol had similar LV chamber sizes (10.6+/(-0.5) mm) and systolic function (13+/(-2%). The propranolol treated animals had higher LV end-diastolic pressures (27+/-2* vs 20+/(-3 mmHg) and a more restricted LV diastolic filling pattern (increased ratio of early to late filling velocities and more rapid E wave deceleration rate). Contractility of papillary muscles from untreated MI rats was depressed (1.6+/(-0.3) vs 2.4+/(0.5 g mm(-2). In addition, Ca transients were prolonged and the inotropic response to isoproterenol was blunted. Propranolol treatment did not improve force development (1.6+/(-0.3 g mm(-2) or the duration of Ca transients during isoproterenol stimulation. 4. Chronic propranolol treatment in rats with postinfarction heart failure did not improve LV remodeling or systolic function. LV diastolic pressures and filling patterns were worsened by propranolol. Treatment also did not produce appreciable improvement in contractility, intracellular Ca regulation or beta-adrenergic responsiveness in the noninfarcted myocardium.     

A prospective study of methylenetetrahydrofolate reductase and methionine synthase gene polymorphisms, and risk of colorectal adenoma

We examined the relationship between a functional polymorphism (667C-- >T, ala-->val) of the methylenetetrahydrofolate reductase gene (MTHFR) and the risk of colorectal adenomas in the prospective Nurses' Health Study. Among 257 incident polyp cases and 713 controls, the MTHFR val/val polymorphism [relative risk (RR) = 1.35, 95% confidence interval (CI) 0.84-2.17] was not significantly associated with risk of adenomas. This lack of association was observed for both small (RR = 1.36, 95% CI 0.76-2.45) and large (RR = 1.32, 95% CI 0.66-2.66) adenomas. Furthermore, there was no significant interaction between this polymorphism and consumption of either folate, methionine or alcohol. We also examined the relationship of a newly identified polymorphism (asp919gly) of the methionine synthase gene (MS) with the risk of colorectal adenomas in the same population. The MS gly/gly polymorphism was also not significantly associated with risk of colorectal adenomas (RR = 0.66, 95% CI 0.26-1.70). These results, which need to be confirmed in other studies, suggest that the MTHFR val/val polymorphism, which has been previously inversely associated with risk of colorectal cancer, plays a role only in a late stage (adenoma-- >carcinoma) of colorectal tumorigenesis, and/or may protect against malignant transformation in the subset of benign adenomas, which may progress to malignancy.      

Quality of life outcomes after brachytherapy for early stage prostate cancer

PURPOSE: We compare general and disease specific health related quality of life in men undergoing brachytherapy for early stage prostate cancer to those undergoing radical prostatectomy and age matched healthy controls. MATERIALS AND METHODS: Cohorts consisted of 48 men treated with brachytherapy with and without pretreatment external beam radiation therapy (brachytherapy group), 74 who underwent radical prostatectomy (prostatectomy group) and age matched healthy controls from the literature. The RAND 36-item general health survey, University of California Los Angeles Prostate Cancer Index, American Urological Association symptom index, validated Cancer Interference with Life and Family Scales, and sociodemographic and co-morbidity questionnaires were completed 3 to 17 months after treatment. RESULTS: General health related quality of life did not differ greatly among the 3 groups. Urinary function (leakage) was worse in the brachytherapy group than in controls but better than in the prostatectomy group. Brachytherapy group patients had more irritative urinary symptoms and worse bowel function than controls. Sexual function and bother were worse in prostatectomy and brachytherapy groups than in healthy controls. Physical function, bodily pain, urinary function, and bother and American Urological Association symptom index scores improved with time after brachytherapy. Patients who underwent brachytherapy after external beam radiation performed worse in all general and disease specific health related quality of life domains compared to those who did not undergo pretreatment radiation therapy. CONCLUSIONS: At an average of 7.5 months after treatment the general health related quality of life of patients undergoing brachytherapy with and without pretreatment external beam radiation was similar to age matched controls, although urinary, bowel and sexual problems were reported. These problems appeared to improve during the first year after treatment. Much of the impairment in disease specific health related quality of life among patients undergoing brachytherapy may be attributed to pretreatment radiation.     

Hand-assisted laparoscopic surgery (HALS) with the HandPort system: initial experience with 68 patients

OBJECTIVE: To evaluate the feasibility and potential benefits of hand-assisted laparoscopic surgery with the HandPort System, a new device. SUMMARY BACKGROUND DATA: In hand-assisted laparoscopic surgery, the surgeon inserts a hand into the abdomen while pneumoperitoneum is maintained. The hand assists laparoscopic instruments and is helpful in complex laparoscopic cases. METHODS: A prospective nonrandomized study was initiated with the participation of 10 laparoscopic surgical centers. Surgeons were free to test the device in any situation where they expected a potential advantage over conventional laparoscopy. RESULTS: Sixty-eight patients were entered in the study. Operations included colorectal procedures (sigmoidectomy, right colectomy, resection rectopexy), splenectomy for splenomegaly, living-related donor nephrectomy, gastric banding for morbid obesity, partial gastrectomy, and various other procedures. Mean incision size for the HandPort was 7.4 cm. Most surgeons (78%) preferred to insert their nondominant hand into the abdomen. Pneumoperitoneum was generally maintained at 14 mmHg, and only one patient required conversion to open surgery as a result of an unmanageable air leak. Hand fatigue during surgery was noted in 20.6%. CONCLUSIONS: The hand-assisted technique appeared to be useful in minimally invasive colorectal surgery, splenectomy for splenomegaly, living-related donor nephrectomy, and procedures considered too complex for a laparoscopic approach. This approach provides excellent means to explore, to retract safely, and to apply immediate hemostasis when needed. Although the data presented here reflect the authors' initial experience, they compare favorably with series of similar procedures performed purely laparoscopically.     

Patients at risk for low systemic oxygen delivery after the Norwood procedure

Background. Identification of patients at risk for inadequate systemic oxygen delivery following the Norwood procedure could allow for application of more intensive monitoring, provide for earlier intervention of decreased cardiac output, and result in improved outcome.

Methods and Results. Superior vena cava saturation (SvO₂) and arteriovenous oxygen content difference were prospectively monitored as indicators of systemic oxygen delivery and recorded hourly for the first 48 hours in 29 of 33 consecutive patients following the Norwood procedure. Risk factors were evaluated using multiple linear regression to determine their impact on SvO₂ and arteriovenous oxygen content difference. Age less than 8 days, weight less than 2.5 kg, aortic atresia, and prolonged cardiopulmonary bypass time were risk factors for low SvO₂ and wide arteriovenous oxygen content difference (p < 0.05). Phenoxybenzamine and increasing time after operation were associated with higher SvO₂ and narrower arteriovenous oxygen content difference (p < 0.05). Thirty-day survival was 97% and hospital survival was 94%. The earliest death occurred on postoperative day 20. Survival to bidirectional cavopulmonary shunt was 77%. Preoperative mechanical ventilation was the only risk factor identified for late death.

Conclusions. Aortic atresia, low weight, younger age, and prolonged cardiopulmonary bypass, previously identified risk factors for mortality, were associated with decreased SvO₂ and narrower arteriovenous oxygen content difference in the early postoperative period. The impact of this hemodynamic vulnerability on mortality was minimized by continuous SvO₂ monitoring.     

The evolution of lung cancer screening

In the 1970s, four trials failed to demonstrate any mortality reduction using a combination of chest X-ray (CXR) and/or sputum cytology. The recent early lung cancer action project (ELCAP) demonstrated that modern screening is capable of detecting Stage I lung cancers. Bronchial epithelial changes leading up to cancers are now being understood to include histologic changes and genetic alterations. Emerging molecular markers detected in sputum and serum show promise in the future of lung cancer screening.