Immunocytochemical localization and immunological characterization of vitamin D-dependent calcium-binding protein in the bullfrog cerebellum

Antiserum prepared against rat renal calcium-binding protein (CaBP) was used with the unlabeled antibody peroxidase-antiperoxidase (PAP) technique to localize the 28,000 molecular weight CaBP in the cerebellum of the bullfrog, Rana catesbeiana. Whole brains of premetamorphic tadpoles and adults were fixed in Bouin's solution for 2 or 24 h and embedded in paraffin. 8-microns parasagittal sections were prepared and treated by the PAP method. Purkinje cells of the cerebellum in tadpoles and adults were specifically stained for CaBP. In the premetamorphic corpus cerebelli, the stained Purkinje cells corresponded to the precociously developed Purkinje cells described previously. In the auricular lobe region of the cerebellum mature Purkinje cells were stained. In addition, smaller stained cells were seen. The latter were presumed to be immature Purkinje cells that would mature at the time of metamorphosis. Immunoblot procedure demonstrated cross-reactivity for the ranid brains in the 28,000 molecular weight region. This immunoreactive band comigrated with the immunoreactive band observed with purified rat renal CaBP. Although the exact functional significance of CaBP is unknown at this time, our immunocytochemical and immunological findings indicate that CaBP is an excellent marker for studies of Purkinje cell maturation.     

Exploring the link between serum peroxides and angiogenesis in a bi-ethnic population from South Africa: The SAfrEIC study

BackgroundReactive oxygen species (ROS) play a fundamental role in angiogenesis, and in turn, angiogenic growth factors also affect ROS. Angiogenesis and ROS are intricately involved in vascular deterioration. Since black populations are known to have elevated oxidative stress and hypertension, we determined whether relationships exist between angiogenic growth factors and serum peroxides in Africans and Caucasians and evaluated the relationships with cardiovascular measurements.MethodsWe measured vascular endothelial growth factor-A (VEGF), angiopoietin 2 (Ang-2), and serum peroxides in Africans (N = 262) and Caucasians (N = 364) aged 20 to 70 years.ResultsAfricans displayed higher blood pressure, serum peroxide levels, VEGF, and Ang-2 (all P ≤ .002) than similarly aged Caucasians (P = .44). In multivariable adjusted analyses, Ang-2 was independently associated with serum peroxides in African men (R² = 0.31; β = 0.21; P = .014) and women (R² = 0.09; β = 0.22; P = .025); and VEGF with serum peroxides in African men (R² = 0.12; β = 0.24; P = .014), with no statistically significant associations in Caucasians. Cardiovascular measurements did not associate with serum peroxides or angiogenic factors in any subgroup.ConclusionsSignificant independent relationships exist between angiogenic growth factors and serum peroxides only in Africans who also displayed an unfavorable cardiovascular profile when compared with Caucasians. These results suggest that interplay between ROS and angiogenesis occur in African individuals that may form part of the mechanisms involved in vascular deterioration.     

Exercise blood pressure and the risk of incident cardiovascular disease (from the Framingham Heart Study)

Exaggerated systolic blood pressure (BP) augmentation with exercise has been associated with impaired endothelial function and cardiovascular risk. However, previous studies were largely restricted to men, did not evaluate diastolic BP, and focused on peak exercise measures, which are influenced by effort and fitness level. The aim of this study was to determine the association of exercise BP responses with risk of incident cardiovascular disease (CVD). BP was assessed during stage 2 of the Bruce protocol and during recovery in 3,045 Framingham Study subjects (mean age 43 years; 53% women). The association between exercise BP and CVD events during 20 years of follow-up was examined using Cox proportional hazards models. In age- and sex-adjusted analyses, exercise systolic and diastolic BP were associated with incident CVD (adjusted hazard ratios [HRs] for top quintile 1.55, 95% confidence interval [CI] 1.18 to 2.04; and 1.77, 95% CI 1.35 to 2.31, respectively, relative to the lower 4 quintiles; p <0.005). After adjustment for BP at rest and conventional risk factors, exercise diastolic BP (HR 1.41, 95% CI 1.01 to 1.95, p = 0.04), but not exercise systolic BP (HR 0.97, 95% CI 0.68 to 1.38, p = 0.86), remained a significant predictor of CVD. Similarly, in recovery responses after exercise, only diastolic BP (HR 1.53, 95% CI 1.08 to 2.18, p = 0.02) predicted incident CVD in multivariable models. In conclusion, in middle-aged adults, diastolic BP during low-intensity exercise and recovery predicted incident CVD. Our findings support the concept that dynamic BP provides incremental information to BP at rest and suggest that exercise diastolic BP may be a better predictor than exercise systolic BP in this age group.     

Outcome of Transplantation Using Organs From Donors Infected or Colonized With Carbapenem‐Resistant Gram‐Negative Bacteria

Donor‐derived infections due to multidrug‐resistant bacteria are a growing problem in solid organ transplantation, and optimal management options are not clear. In a 2‐year period, 30/214 (14%) recipients received an organ from 18/170 (10.5%) deceased donors with infection or colonization caused by a carbapenem‐resistant gram‐negative bacteria that was unknown at the time of transplantation. Among them, 14/30 recipients (47%) received a transplant from a donor with bacteremia or with infection/colonization of the transplanted organ and were considered at high risk of donor‐derived infection transmission. The remaining 16/30 (53%) recipients received an organ from a nonbacteremic donor with colonization of a nontransplanted organ and were considered at low risk of infection transmission. Proven transmission occurred in 4 of the 14 high‐risk recipients because donor infection was either not recognized, underestimated, or not communicated. These recipients received late, short or inappropriate posttransplant antibiotic therapy. Transmission did not occur in high‐risk recipients who received appropriate and prompt antibiotic therapy for at least 7 days. The safe use of organs from donors with multidrug‐resistant bacteria requires intra‐ and inter‐institutional communication to allow appropriate management and prompt treatment of recipients in order to avoid transmission of infection.     

Golgi studies on Purkinje cell development in the frog during spontaneous metamorphosis. I. General pattern of development.

The development of Purkinje cells was studied in the bullfrog from prometamorphic tadpoles to 10-week-old postmetamorphic froglets by the Golgi-Kopsch method. In this species, the rate of Purkinje cell development is unusually slow and proceeds in two waves. The first wave of development begins prior to the establishment of the external granular layer (EGL), and proceeds slowly for two to three months during the formation of the EGL; then accelerating as metamorphosis is being completed, the cells reach near-adult dimensions a month later. Even prior to the formation of the EGL these cells are already present in the stage of dendritic orientation and flattening which, however, varies from the norm. The second wave of Purkinje cell development begins during metamorphosis and proceeds at a more rapid pace until two months after metamorphosis, at which time they appear to have reached adult dimensions. In these cells the development of the apical dendrite does not always coincide with the stellate stage but may proceed directly to the stage of dendritic orientation and flattening which, in accordance with the norm, is towards the pia and in the sagittal plane. Many variations are present in the dendritic trees and orientation of the dendritic branches of Purkinje cells throughout their development. These variations are similar to those seen in mammals, however, since the frog cerebellum consists of a simple plate, they cannot be attributed to a Cartesian transformation of dendrites to accomodate the curvatures of a folial pattern. Similarly, since these morphological variations occur in the course of normal development they cannot be attributed to a reaction to, or recovery from, injury during development.     

Brain damage after neonatal tetanus in a rural Kenyan hospital

OBJECTIVE: Neonatal tetanus (NNT) is an important cause of mortality in resource poor countries, particularly sub-Saharan Africa. There are no reports of the long-term outcome of children who survive NNT in African hospitals. DESIGN: In a retrospective study of children discharged from Kilifi District Hospital (KDH), Kenya with NNT, each child was linked with a comparative child (CC) in the community matched for age, sex and locality. PARTICIPANTS: A total of 123 patients were admitted with NNT between 1992 and 1996, of whom 68% died. Twenty-three (59%) of the 39 survivors were traced in the community, 10 had moved away, six had died. OUTCOME MEASURES: NNT survivors underwent a neurological and developmental examination and a questionnaire was administered to the parents about the behaviour of the child. A verbal autopsy was used to determine the cause of death in children who had died after discharge. RESULTS: The head circumference of NNT survivors was significantly smaller than that of CC (P=0.037); eight children had microcephaly compared with one CC (P=0.011). NNT survivors had more problems with hand-eye co-ordination tasks (P=0.035), a lower summated developmental score (P=0.023) and more mild neurological abnormalities (P=0.008) than CC. Parents of NNT survivors reported more behavioural problems (P=0.02) than parents of CC. CONCLUSIONS: Children who survive NNT have evidence of brain damage that manifests as microcephaly, mild neurological abnormalities, developmental impairment - particularly fine motor difficulties - and behaviour problems.     

Calcium-binding protein (28,000 Mr calbindin-D28k) in kidneys of the bullfrog Rana catesbeiana during metamorphosis

A protein of approximately 28,000 relative molecular mass (Mr) cross-reacting with antiserum against the 28,000-Mr rat renal calcium-binding protein (calbindin-D28k) has been localized in the kidney of a salientian amphibian, Rana catesbeiana. Cells reactive for calbindin-D28k were found in the distal tubule at all stages of metamorphosis by the unlabeled antibody peroxidase-antiperoxidase technique. Adult kidneys appeared to have more calbindin-D28k-positive cells. The renal corpuscle, neck, and proximal tubule were negative. An immunoreactive 28,000-Mr band that comigrated with the band of calbindin-D28k was visualized by the immunoblot technique. The finding of the 28,000-Mr calbindin-D in the anamniotic kidney demonstrates that this calcium-binding protein (CaBP) is phylogenetically older than our previous studies of higher vertebrates had revealed (Rhoten et al., 1985). Although the function of calbindin-D28k in the distal nephron is unknown, this CaBP can now be presumed to have functional significance in the mesonephric as well as the metanephric kidney.