Functional heterogeneity of human CD34(+) cells isolated in subcompartments of the G0 /G1 phase of the cell cycle

Using simultaneous Hoechst 33342 (Hst) and Pyronin Y (PY) staining for determination of DNA and RNA content, respectively, human CD34(+) cells were isolated in subcompartments of the G0 /G1 phase of the cell cycle by flow cytometric cell sorting. In both bone marrow (BM) and mobilized peripheral blood (MPB) CD34(+) cells, primitive long-term hematopoietic culture-initiating cell (LTHC-IC) activity was higher in CD34(+) cells isolated in G0 (G0CD34(+) cells) than in those residing in G1 (G1CD34(+) cells). However, as MPB CD34(+) cells displayed a more homogeneous cell-cycle status within the G0 /G1 phase and a relative absence of cells in late G1 , DNA/RNA fractionation was less effective in segregating LTHC-IC in MPB than in BM. BM CD34(+) cells belonging to four subcompartments of increasing RNA content within the G0 /G1 phase were evaluated in functional assays. The persistence of CD34 expression in suspension culture was inversely correlated with the initial RNA content of test cells. Multipotential progenitors were present in G0 or early G1 subcompartments, while lineage-restricted granulomonocytic progenitors were more abundant in late G1 . In vitro hematopoiesis was maintained for up to 6 weeks with G0CD34(+) cells, whereas production of clonogenic progenitors was more limited in cultures initiated with G1CD34(+) cells. To test the hypothesis that primitive LTHC-ICs would reenter a state of relative quiescence after in vitro division, BM CD34(+) cells proliferating in ex vivo cultures were identified from their quiescent counterparts by a relative loss of membrane intercalating dye PKH2, and were further fractionated with Hst and PY. The same functional hierarchy was documented within the PKH2(dim) population whereby LTHC-IC frequency was higher for CD34(+) cells reselected in G0 after in vitro division than for CD34(+) cells reisolated in G1 or in S/G2 + M. However, the highest LTHC-IC frequency was found in quiescent PKH2(bright) CD34(+) cells. Together, these results support the concept that cells with distinct hematopoietic capabilities follow different pathways during the G0 /G1 phase of the cell cycle both in vivo and during ex vivo culture.

Orderly process of sequential cytokine stimulation is required for activation and maximal proliferation of primitive human bone marrow CD34+ hematopoietic progenitor cells residing in G0

Bone marrow (BM) CD34+ cells residing in the G0 phase of cell cycle may be the most suited candidates for the examination of cell cycle activation and proliferation of primitive hematopoietic progenitor cells (HPCs). We designed a double simultaneous labeling technique using both DNA and RNA staining with Hoechst 33342 and Pyronin Y, respectively, to isolate CD34+ cells residing in G0(G0CD34+). Using long-term BM cultures and limiting dilution analysis, G0CD34+ cells were found to be enriched for primitive HPCs. In vitro proliferation of G0CD34+ cells in response to sequential cytokine stimulation was examined in a two-step assay. In the first step, cells received a primary stimulation consisting of either stem cell factor (SCF), Flt3-ligand (FL), interleukin-3 (IL-3), or IL-6 for 7 days. In the second step, cells from each group were washed and split into four or more groups, each of which was cultured again for another week with one of the four primary cytokines individually, or in combination. Tracking of progeny cells was accomplished by staining cells with PKH2 on day 0 and with PKH26 on day 7. Overall examination of proliferation patterns over 2 weeks showed that cells could progress into four phases of proliferation. Phase I contained cytokine nonresponsive cells that failed to proliferate. Phase II contained cells dividing up to three times within the first 7 days. Phases III and IV consisted of cells dividing up to five divisions and greater than six divisions, respectively, by the end of the 14-day period. Regardless of the cytokine used for primary stimulation, G0CD34+ cells moved only to phase II by day 7, whereas a substantial percentage of cells incubated with SCF or FL remained in phase I. Cells cultured in SCF or FL for the entire 14-day period did not progress beyond phase III but proliferated into phase IV (with <20% of cells remaining in phases I and II) if IL-3, but not IL-6, was substituted for either cytokine on day 7. G0CD34+ cells incubated with IL-3 for 14 days proliferated the most and progressed into phase IV; however, when SCF was substituted on day 7, cells failed to proliferate into phase IV. Most intriguing was a group of cells, many of which were CD34+, detected in cultures initially stimulated with IL-3, which remained as a distinct population, mostly in G0/G1, unable to progress out of phase II regardless of the nature of the second stimulus received on day 7. A small percentage of these cells expressed cyclin E, suggesting that their proliferation arrest may have been mediated by a cyclin-related disruption in cell cycle. These results suggest that a programmed response to sequential cytokine stimulation may be part of a control mechanism required for maintenance of proliferation of primitive HPCs and that unscheduled stimulation of CD34+ cells residing in G0 may result in disruption of cell-cycle regulation.

Effects of resistance training on bone mineral content and density in adolescent females

Postmenarcheal adolescent girls performed resistance training (RT) for 26 weeks, which consisted of 4 sets of 13 exercises of varying and progressive intensity performed 3 times weekly on hydraulic resistance machines. Bone mineral was assessed by dual photon absorptiometry. Resistance training resulted in significant increases (pre-post) in biceps curl (21.4%), triceps press (21.5%), knee extension (25.1%), knee flexion (52.8%), and squat press (21.5%) strength. There were no significant differences between RT and control (C) groups initially, and no significant effects of training (pre-post) for total body (TB) or lumbar spine (LS) bone mineral content (BMC) or bone mineral density (BMD). The largest increases in LS bone mineral occurred during the first 13 weeks, and although not significant, the increases in LS BMC (g) (3.9 vs. 5.9%), LS BMC (g.cm-1) (2.6 vs. 5.9%), LS areal BMD (g.cm-2) (1.48 vs. 4.75%), and LS bone mineral apparent density (BMAD, g.cm-3) (0.47 vs. 4.13%) were greater in the RT compared with the C group during this period. In conclusion, resistance training resulted in a trend towards a transient increase in LS bone mineral during the first 13 weeks, but despite significant strength gains, there were no significant changes in TB or LS bone mineral after 26 weeks of training.

Changing hospital practices to increase the duration of breastfeeding

OBJECTIVE

To change the breastfeeding policy in a university teaching hospital in accord with the Ten Steps to Successful Breastfeeding of the United Nations Children's Fund and World Health Organization and to assess the impact of hospital practices on the duration of breastfeeding.

METHODS

One hundred ninety-two and 392 postpartum women in a maternity ward were interviewed in 1990 and 1993, respectively, regarding how they were feeding their infants and feeding practices in the hospital. Between these two periods, the hospital infant-feeding policy was reviewed and revised in accord with the Ten Steps. Two hundred seventy of the mothers interviewed in 1993 were interviewed again when their infants were 4 months old regarding the duration of full and partial breastfeeding.

RESULTS

By 1993, more newborns were put to the breast in the first hour of life (63.2% vs 24.8%); fewer breastfed infants were fed foods other than breast milk (27.9% vs 46.7%); and more mothers received breastfeeding guidance from hospital staff (81.9% vs 61.3%). The duration of breastfeeding in 1993 was longer for women who did not receive formula in the hospital, who were not given discharge packs containing formula and/or coupons, and who roomed-in more than 60% of the time. These associations persisted after controlling for confounding.

CONCLUSION

Infant-feeding policies and practices are amenable to change, and policies such as the Baby-Friendly Hospital Initiative may contribute to an increase in the duration of breastfeeding.

Composing our future: a retrospective and forecast of a specialty practice's achievements in a best practice

This article documents the practice's achievements resulting from the planning efforts and suggests that several key factors, such as establishing and communicating a practice direction and empowering and valuing people, resulted in the physicians' successful planning.

Guidelines for physician training in advanced cardiac procedures: the importance of case mix

In recent years, guidelines have been issued for the standardization of physician training in various advanced cardiac procedures. One area that is often neglected by guidelines committees is the need for an adequate case mix during physician training. Case mix refers to the variety of patients and diseases that the trainee is exposed to during the course of learning a new procedure. Although physicians may perform the requisite number of procedures during their training, if the case mix is inadequate, the physician's competence in performing the procedure and interpreting its results may be inadequate as well.

Correlates and determinants of bone mineral content and density in healthy adolescent girls

The relationships between whole-body and lumbar spine bone mineral content and density, and measures of chronologic age, body composition, physical activity, cardiorespiratory and strength fitness, gynecologic attributes, sexual maturity, and endocrine status were studied in 35 healthy menarcheal girls (14-18 years of age). Body mass (0.464 < r < 0.704), growth hormone (-0.34 < r < -0.42), and one-repetition maximum double-leg press strength (0.343 < r < 0.467) were significantly (p < 0.05) correlated with each of the five bone mineral measures. Multiple regression analysis indicated that body mass accounted for the largest significant proportion of the explained variance (30.2-68.2%) in each of the five bone mineral measures. Age at first menses accounted for a smaller but still significant proportion of the variance in whole-body bone mineral content (4.05%) and lumbar spine bone mineral content (8.06%). Growth hormone entered the regression model as an important predictor of whole-body bone mineral content, accounting for 3.51% of the explained variance in this variable. Age, cardiorespiratory fitness, level of habitual activity, and strength did not contribute significantly to the explained variance in any of the bone mineral measures. Body mass appears to be the single most important determinant of bone mineral among females during this developmental period.

Portal venous system after portosystemic shunts or endoscopic sclerotherapy: evaluation with Doppler sonography

We sought to determine the usefulness of duplex Doppler sonography in the assessment of blood flow and clot formation in the portal vein in 44 patients with portal hypertension and bleeding esophageal varices who had undergone either endoscopic sclerotherapy (28 cases) or portosystemic shunt procedures (16 cases). The main, left, and right portal veins (collectively referred to as intrahepatic portal veins), superior mesenteric vein, splenic vein, and shunt were assessed for flow direction, presence of thrombi, and collaterals. Patent shunts were visualized in 12 (75%) of the 16 cases. Clot was detected in 27 (69%) of 39 intrahepatic portal veins in patients with end-to-side shunts, in six (67%) of nine intrahepatic portal veins in patients with distal splenorenal shunts, and in five (5%) of 92 intrahepatic portal veins in patients who had had endoscopic sclerotherapy. Flow in the main portal vein was hepatopetal in two (15%) of 13 patients with patent shunts (one end-to-side portacaval shunt and one distal splenorenal shunt). Flow in the main portal vein was hepatopetal in 26 (93%) of 28 patients who had had endoscopic sclerotherapy. Our data suggest endoscopic sclerotherapy preserves antegrade portal flow and results in fewer portal vein clots than surgical portosystemic shunts do. Patterns of thrombosis and flow direction vary unpredictably from patient to patient. Shunt patency should not be inferred without direct visualization of the shunt.

Developing a model for the study of quality of life in elderly patients with chronic disease: use of hypertension as an example

The concept of quality of life (QOL) is multidimensional and complex, especially in regard to chronic disease and old age. The purpose of this study was to explore QOL in a population of elderly patients with hypertension and to suggest a technique for model building. The specific purpose of the study was to test the viability of a model for understanding how the treatment of hypertension affects QOL. Indicators of QOL and determinants of QOL were measured in a group of patients aged 60 years or older with hypertension. Correlation coefficients confirmed the hypothesized model. The confirmed model thus can be used to study other chronic diseases and to assess the QOL effects of treatment of chronic diseases.

Inpatient capillary glucose monitoring: a useful adjunct to the management of diabetes in community hospitals

Nursing personnel in two rural hospitals were taught to measure capillary blood glucose with a reflectance meter. Reflectance meter readings correlated well with laboratory blood glucose on all hospital units (R = .977 to .944) and were clinically useful. Measurements on a designated diabetes unit showed the closest correlation to laboratory measurements (P less than or equal to .001). Capillary blood glucose measurements are a feasible alternative to urine glucose testing in community hospitals.

Anterior Knee Pain in a 29-Year-Old Woman

A group of experts from the University of California, San Diego, School of Medicine, met to discuss a case. This case conference is part of a series featuring a variety of sports medicine topics.

Clinical associations of Norwalk-like virus in the stools of children

From among 1,360 stool specimens examined during the 19-month period from March 1982 to September 1983, small round-structured viruses, morphologically indistinguishable from the Norwalk agent, were detected by electron microscopy in 42 specimens from 28 children. Diarrhoea was mild, and vomiting, although frequently observed, was not an invariable feature. Mild pyrexia occurred in three patients. Many cases occurred some time after admission to the ward; this and other features suggested a hospital-acquired infection. These cases in particular tended to have other viral infectious agents detected at the same time. Persistent diarrhoea occurred in only three cases; one with preexisting gastrointestinal pathology, and two with a combined Norwalk-like agent, astrovirus, and rotavirus infection.

Local administration of antibiotics with an implantable osmotic pump

A totally implantable drug pump was evaluated as a delivery system in the treatment of osteomyelitis. Gentamicin levels in rabbit serum and bone obtained by systemic administration are compared with levels in rabbit serum and bone obtained by local administration via an implantable drug pump. Systemic administration gave mean gentamicin bone levels ranging from less than 1 microgram/gm to 3.6 micrograms/gm, while drug pump administration gave bone levels ranging from 10.8 micrograms/gm to 64.0 micrograms/gm (micrograms = microgram, or 10(-6) gram). To evaluate the drug pump as a mode of therapy, acute staphylococcal osteomyelitis was induced in ten rabbits. Drug pumps filled with amikacin were inserted in five of the infected animals. Three of these were culture-negative at one week. One had a scant growth of Staphylococcus from the pump, and one had scant growth from the pump and the wound. Clinically, none of these five rabbits appeared infected at seven days. The remaining five rabbits were all culture-positive, with heavy growths of staphylococci from their wounds, and clinically, all appeared grossly infected at seven days. These data demonstrate that high local and low systemic levels of antibiotics can be achieved with an implantable drug pump and that this method can sterilize an infected musculoskeletal wound. Therefore, antibiotic administration via an implantable drug pump is an important potential mode of therapy in the treatment of osteomyelitis.

Jejunal intubation via gastrostomy catheters in pediatric patients

We describe a technique wherein an endotracheal tube is used as a sheath for a feeding tube, which has been placed through the wall of a gastrostomy catheter, to allow selective intubation of the duodenum.

A new surgical approach to fractures of the lateral tibial plateau

We are reporting on a previously undescribed surgical approach and postoperative protocol for the treatment of fractures of the lateral tibial plateau in which there is a split pattern and depression of the articular surface. In this approach the anterior horn of the lateral meniscus is incised and detached so that the split fragment can be opened like a book. Detachment and incision of the anterior horn minimizes the need to free the lateral meniscus from its tibial attachment. The postoperative protocol includes continuous passive motion followed by non-weight-bearing in a toe-to-groin plaster cast for three months. Our preliminary results have been encouraging, and arthroscopic examination in the seven knees so studied indicated a healed fracture, restoration of the tibial articular surface, and a healed lateral meniscus.

Posterior fracture-dislocation of the distal part of the fibula. Mechanism and staging of injury

The Bosworth fracture, a fixed posterior fracture-dislocation of the distal part of the fibula due to external rotation of the supinated foot, is a rare injury. In this report we review the literature, present two new cases, and describe our cadaver studies, showing that the initial stages of the injury are identical to those of a Maisonneuve fracture. The final stages that are unique to this fracture-dislocation are the posterior dislocation and fracture of the fibula and the fracture of the medial malleolus or rupture of the deltoid ligament. The objectives of treatment are reduction of the dislocation, repair and stabilization of the tibiofibular syndesmosis, and restoration of the ankle mortise to its anatomical position.

Enzyme-linked immunosorbent assay for the detection of human rotavirus in stools

A simple method for the detection of human rotavirus in stools is described, using a double antibody sandwich enzyme-linked immunosorbent assay. Polysterene microtitre plates were used as solid phase. Four capture antibodies were tried, bovine, egg-derived, guinea pig and monoclonal antibody to rotavirus. Both bovine and egg-derived antirotavirus labelled with horseradish peroxidase were used as the detecting antibodies. The results obtained were compared with a commercially available ELISA, Rotazyme (Abbott Laboratories), and also with the direct detection of rotavirus by electron microscopy. Bovine antibody was found to be an unsuitable capture antibody due to non-specific false positive reactions.

Clinical associations of stool astrovirus in childhood

From among 1,248 stool specimens examined during the 2-year period, February 1979 to February 1981, astrovirus was detected by electron microscopy in 42 specimens from 28 children. Diarrhoea was an invariable clinical feature; vomiting occurred in 18 children, abdominal pain in 7, and mild dehydration in 5. Fourteen of the children with acute diarrhoea were admitted directly to the gastroenteritis unit. The other 14 children developed their acute diarrhoea sometime after hospital admission. Although the excretion of astrovirus was associated with mild gastroenteritis, the presence of other enteric pathogens in 16 of the 28 children limited the degree to which the clinical symptoms could be attributed to astrovirus alone. Transient monosaccharide intolerance lasting 1 to 2 days occurred in 18 children, and cow's milk protein intolerance requiring milk elimination for several months was a sequel in 3 children.

Mutagenicity of nitrosated cimetidines

Dinitrosocimetidine and mononitrosocimetidine were tested in a series of short term assay systems. Both compounds were mutagenic in the absence of rat liver microsomes. The dinitrosocimetidine produced higher mutagenic or clastogenic effects at concentrations that were 50 to 500 times lower than the concentrations at which the mononitrosocimetidine produces its maximum effects. The most sensitive short term assay system was the Chinese hamster ovary cell culture system. Dinitrosocimetidine caused sister chromatid exchanges at a concentration of 10(-8) M and chromosome aberrations at 10(-7) M in this system. Dinitrosocimetidine had moderate activity in the bacterial short term assay systems. In the Ames test, strain TA 100 was the most sensitive. The compound was of lower activity in the E. coli WP-2 and the E. coli rec- systems.

The Pennsylvania hemophilia program 1973-1978

In Pennsylvania, the prevalence of hemophilia is one per 10,000 males. Factor VIII deficiency is five times more frequent than Factor IX deficiency, and 34% of the patients have no relatives affected with the disease. The mean age is 23 years old, and 50% of the patients are less than 20 years old. Approximately one-third of the patients with Factor VIII deficiency and one fourth of the patients with Factor IX deficiency have levels of less than 0.01 mu/ml. By clinical criteria, 55% of those with Factor VIII deficiency are severe compared to 45% of those with Factor IX deficiency. Factor VIII-deficient patients are treated an average of 18 times per year compared to ten times per year for patients with Factor IX deficiency. Hemarthroses account for 70% of the hemorrhages treated and for 40% of the concentrate usage. Home therapy patients use an average of 45,950 Factor VIII units per year at a cost of ø170 per patient and their use accounts for 60% of the total Factor VIII usage of 1.7 million units. Less than five days per patient per year are lost from school or work because of bleeding, and patients are hospitalized for bleeding an average of only two to three days per patient year. Adverse immediate reactions to therapy are infrequent. Five percent of patients have persistence of the hepatitis B virus, and 7.5% have inhibitors. The mortality rate is 0.04% per year, with half of the deaths being hemophilia-related.

Heparin pretreatment suppresses norepinephrine concentrations in dogs in endotoxic shock

Mongrel dogs were treated intravenously with either 1000 units of beef-lung heparin per kilogram of body weight or with isotonic saline, before intravenous administration of E. coli endotoxin. We found significant differences in circulating norepinephrine concentrations between a heparin-pretreatment group (1.89 +/- 0.39 microgram/liter) and the control group (9.83 +/- 4.64 microgram/liter), but none with respect to epinephrine. Systolic blood pressures at 360 min were also significantly (P less than 0.05) different, 148 +/- 6 mmHg as compared with 118 +/- 13.4 mmHg. Evidently heparin pretreatment can decrease circulating norepinephrine concentrations in the endotoxic state and changes in circulating catecholamine concentrations can affect physiological variables.

Heparin pretreatment suppresses norepinephrine concentrations in dogs in endotoxic shock

Mongrel dogs were treated intravenously with either 1000 units of beef-lung heparin per kilogram of body weight or with isotonic saline, before intravenous administration of E. coli endotoxin. We found significant differences in circulating norepinephrine concentrations between a heparin-pretreatment group (1.89 +/- 0.39 microgram/liter) and the control group (9.83 +/- 4.64 microgram/liter), but none with respect to epinephrine. Systolic blood pressures at 360 min were also significantly (P less than 0.05) different, 148 +/- 6 mmHg as compared with 118 +/- 13.4 mmHg. Evidently heparin pretreatment can decrease circulating norepinephrine concentrations in the endotoxic state and changes in circulating catecholamine concentrations can affect physiological variables.