Increased mechanical fragility and intravascular lysis of erythrocytes in cats fed a propylene glycol-containing diet

The mechanism responsible for the decreased red blood cell (RBC) lifespan associated with feeding propylene glycol (PG)-containing diets was investigated to understand better how Heinz body-contained RBC are destroyed. Three cats were fed a diet containing 12% PG for 14 days and three other cats served as control. The experimental group developed reticulocytosis and increased Heinz body numbers. Red blood cell membrane immunoglobulih G (IgG) concentration and phagocytosis of RBC by peritoneal macrophages were lower in the PG group compared to the control group suggesting that neither IgG nor non-IgG-mediated phagocytosis was responsible for the RBC destruction. Osmotic fragility, rate of RBC proteolysis and mild mechanical fragility test results were not statistically different from controls. However, when RBC from cats fed PG were exposed to severe mechanical stress, their fragility were increased 2.2–2.8 times. Additionally, haptoglobin concentrations were decreased in the PG group. These data suggest that intravascular lysis may be involved in the pathogenesis of PG-induced RBC destruction.     

Ethnicity, pressor reactivity, and children's blood pressure. Five years of observations.

During the 5 years of this investigation, resting blood pressure and pressor reactivity were measured in 292 white children and 46 black children in 1987, 1988, 1989, and 1991. In 1987, all children were in the third grade; in 1991, the children were in the seventh grade. Reactivity was assessed with a standardized psychological stressor, a television video game. Children displayed significant stability of absolute blood pressure and heart rate reactivity between grades 3 and 7. At all examinations, black children demonstrated blood pressure reactivity that was significantly greater in magnitude (both absolute level and change from resting measurements) than that of white children. Black children exhibited significantly greater heart rate reactivity only when defined as change from the resting measurements; absolute levels of heart rate reactivity were comparable for blacks and whites. For black children, blood pressure reactivity in 1987 was the strongest predictor of resting blood pressure (both systolic and diastolic) in 1991. Among white children, resting blood pressure was the strongest predictor of future resting blood pressure. Further research is needed to determine if ethnic differences in children's pressor reactivity are associated with ethnic differences in the prevalence of hypertension.     

Lack of age-related differences in temporal lobe volume of very healthy adults.

PURPOSETo evaluate age-related differences in temporal and supratemporal brain regions in carefully selected, very healthy men 19 to 92 years of age.METHODSMR quantification of brain regions used image segmentation into cerebrospinal fluid and brain matter based on nonlinear modeling of pixel intensity distributions.RESULTSThere was a significant age-related decrease (approximately 1% per decade) of posterior frontal lobe volume, but not of temporal lobe volume. The mean volume of the right temporal lobe was significantly greater than the left, and this relation did not change with age.CONCLUSIONIn very healthy aging, the volume of the temporal lobes remains constant over the age range of human life.     

Space time clustering of births in SIDS: do perinatal infections play a role?

The aetiology of sudden infant death syndrome (SIDS) remains uncertain; many causal pathways have been proposed. In this paper we have examined firstly the variation in the risk of SIDS with age, month of death and month of birth; and secondly the space time clustering of SIDS deaths, and, separately, space time clustering of their births. Data were obtained from the Office of Populations, Censuses and Surveys on all certified SIDS deaths in the period; children were assigned grid references for the address of birth and of death. Data on number of births were abstracted from published material. A log-linear modelling technique was used to investigate the separate effects of age, month of death and month of birth on the risk of SIDS. The Knox method was used to investigate space time clustering of deaths and of births of children who died of SIDS. Separate, statistically significant effects were found for age, month of death and month of birth. There was minor space time clustering of SIDS births and deaths at large time and space intervals, and a marked space time clustering of births in short space time intervals in the first quarter of the year. The finding of an effect of month of birth on the risk of SIDS, and of space time clustering of births suggest that a perinatal hazard--possibly of infectious origin--may play a role in the aetiology of SIDS.     

Herniated disc with radiculopathy following cervical manipulation: nonsurgical management.

BACKGROUND CONTEXT: Spinal manipulation applied to the cervical spine is a relatively safe and effective treatment for neck pain and headache. However, complications of this form of treatment have been reported and these can at times be disabling and on rare occasions can be devastating. A postmanipulation complication being treated with a different form of manipulation has not previously been reported. PURPOSE: To report a case of a patient who was treated with manipulation and who developed neck, scapular, and arm pain and arm numbness after the sixth visit, which was later attributed to three herniated discs. The patient was subsequently treated with a nonsurgical approach that included, but was not limited to, a different form of manipulation with apparent resolution of the problem. STUDY DESIGN/SETTING: The patient was a 38-year-old banker who began seeing a chiropractic physician for treatment that included cervical manipulation. On the sixth visit, he developed pain immediately after treatment which became severe and was accompanied by numbness in his arm. He saw a neurosurgeon who recommended surgery, but was subsequently seen by a different chiropractic physician and was treated nonsurgically. METHODS: The patient was found to have clinical signs of radiculopathy, including motor loss. Magnetic resonance imaging revealed disc herniations at C3-C4, C4-C5, and C5-C6. RESULTS: The patient was treated by the author with an alternate approach that included non-high-velocity, low-amplitude manipulation and exercise with resolution of the problem. CONCLUSION: This paper reports a case of a patient with radiculopathy secondary to multilevel disc herniations that appeared to be precipitated by cervical manipulation and who was treated nonsurgically with resolution of the problem. It is doubtful that the manipulation actually caused the disc herniations, but it is possible that it caused preexisting asymptomatic disc herniations to become symptomatic. Consideration should be given to nonsurgical referral of patients who have postmanipulative complications but do not need immediate surgery.     

A prospective randomized trial of laparoscopic versus open appendectomy.

BACKGROUND. Laparoscopic appendectomy is feasible, but whether it confers any advantage to patients with acute appendicitis is not known. We performed a randomized controlled trial to compare results of laparoscopic and open appendectomy in patients with signs and symptoms suggesting acute appendicitis who were seen by one surgical team. METHODS. Sixty-two consecutive patients were randomized, 30 to laparoscopy and 32 to a classical open appendectomy. Postoperative recovery, complications, and return to normal activities were compared in the two groups. RESULTS. The laparoscopy group were discharged earlier (2.5 vs 3.8 days, p less than 0.01). Postoperative complications were more frequent after open appendectomy. Follow-up showed less pain, shorter bed stay at home, and faster return to work and sport after laparoscopic appendectomy. CONCLUSIONS. This prospective randomized study shows that laparoscopic appendectomy is superior to open appendectomy in terms of hospital stay, postoperative complications, and return to normal activities and is recommended as the approach of choice in the management of acute appendicitis.     

Differential Contractile Response of Cultured Microvascular Pericytes to Vasoactive Agents

Objective: Microvascular pericytes may contract in two different ways: In the first, a circumferential or radial mechanical force applied at right angles to the long axis of the vessel may constrict the underlying vessel affecting blood flow and transmural pressure. Retraction and elongation of pericyte processes may also occur tangentially and at right angles to the vessel axis and alter microvessel permeability by changing the amount of ablumenal surface covered or the openness of interendothelial junctions. In this study, cultured pericytes were utilized as a model experimental system to determine if vasoactive stimulation changes their shape in a manner consistent with this hypothesis. Methods: Pericytes cultured from isolated rate capillaries were subjected to angiotensin II and histamine. Their response was monitored by measuring the area of nonyielding substrate covered by the pericytes and the manner in which their shape changed. Shape changes were quantified by calculating the surface area: perimeter perimeter ratios. Results: Histamine significantly reduced surface area covered and the surface area: perimeter ratio. The pericyte processes retracted, resulting in elongated, spindle-shaped cells. These effects were nullified by the H₁ blocker diphenhydramine suggesting a receptor-specific response. Angiotensin II also elicited contraction and reduced surface area, but the cells contracted laterally and longitudinally. The surface area: perimeter ratios also decreased. Conclusions: These results indicate that pericytes are capable of two types of contractile responses in culture, depending on the specific vasoactive stimulus.     

Impaired estrogen-induced uterine insulin-like growth factor-I gene expression in the streptozotocin diabetic rat

Summary Circulating somatomedin-C/insulin-like growth factor-I levels are low in the diabetic rat and unresponsive to exogenous growth hormone. However, the nature of this defect in growth hormone action remains unclear and there is little data on insulin-like growth factor-I gene expression in response to other stimuli and in non-hepatic tissues where insulin-like growth factor-I may have important paracrine and/or autocrine actions. We have previously shown that 17-beta estradiol stimulates uterine insulin-like growth factor-I expression in the ovariectomised rat. In this report uterine and hepatic insulin-like growth factor-I gene expression have been examined in the streptozotocin-diabetic rat. Serum insulin-like growth factor-I concentrations were significantly reduced in diabetic rats compared to normal rats (0.72±0.08 vs 1.23±0.05U/ml, p<0.0005) and hepatic insulin-like growth factor-I mRNA abundance was similarly reduced in diabetic rats to 49±5% of that seen in non-diabetic intact rats (p<0.005). In contrast, uterine insulin-like growth factor-I mRNA abundance was not significantly reduced in diabetic rats compared to control rats (76±12%, p = NS). Although both diabetic and non-diabetic rats demonstrated a significant increase in uterine wet weight following a single injection of 17-beta estradiol the increase in uterine insulinlike growth factor-I expression was significantly less marked in diabetic rats. Acute administration of insulin together with estradiol had no significant effect on serum insulin-like growth factor-I concentrations or hepatic insulin-like growth factor-I mRNA abundance; however, the uterine insulin-like growth factor-I response was significantly (p<0.01) augmented. The observations reported here demonstrate that hepatic insulin-like growth factor-I gene expression is markedly reduced in the diabetic rat and that the estradiol-induced uterine insulin-like growth factor-I response is significantly diminished, consistent with the hypothesis that there is a defect in insulin-like growth factor-I gene activation in the diabetic rat.     

Arteriosclerosis obliterans in a rabbit model.

RATIONALE AND OBJECTIVES. The authors induced atherosclerotic occlusions in a rabbit model, using and comparing different experimental methods. METHODS. Lesions were induced in 40 femoral arteries in 20 rabbits. Four combinations of lesion induction methods were used: 1) drying of the endothelium with carbon dioxide gas; 2) gas-drying of the artery plus mechanical injury; 3) gas-drying plus induced thrombosis of the treated segment using thrombin; and 4) gas-drying, mechanical injury, and induced thrombosis. All rabbits were fed a high-fat, high-cholesterol diet for 1 to 2 months after lesion induction. RESULTS. Seventeen rabbits were available for follow-up. Sixty-eight percent (13 of 19) of femoral arteries treated with thrombin-induced thrombosis demonstrated atherosclerotic occlusions, compared with 27% of those that did not receive this treatment (4 of 15; P < .01). CONCLUSIONS. Thrombin-induced thrombotic occlusion of a segment of artery which has been de-endothelialized, followed by a high-fat, high cholesterol diet, results in a higher yield of experimental occlusive atherosclerosis in rabbits than is achievable by other methods.     

Cytomegalovirus Disease in High-Risk Transplant Recipients Despite Ganciclovir or Valganciclovir Prophylaxis

The clinical patterns and predictors of cytomegalovirus (CMV) disease in kidney and/or pancreas transplant patients on ganciclovir (1.0 g po t.i.d.) or valganciclovir (450 mg po q.d.) prophylaxis were studied. This is a retrospective analysis of 129 transplant recipients. Median follow up was 12 months (range, 6-18 months). The overall incidence of CMV disease at 1-year post-transplant was 14% (4% tissue-invasive, 10% noninvasive). Seventeen of 18 patients were diagnosed with CMV after completion of 3 months' prophylaxis (median 8 weeks, range, 2-28 weeks). Induction treatment with thymoglobulin, and Donor +/Recipient - CMV status were the strongest predictors for the development of CMV disease. Cytomegalovirus incidence was not different between patients treated with ganciclovir or valganciclovir (15 vs. 17%, respectively). Valganciclovir (450 mg q.d.) is as effective as oral ganciclovir in CMV prophylaxis. High-risk individuals might require higher doses or longer duration of valganciclovir treatment.