Glomerular cell replication and cell loss through apoptosis in experimental diabetes mellitus

AIM: To evaluate changes in the glomerular cell balance between replication and apoptosis in experimental diabetes mellitus (DM) in relation to morphometric data. METHODS: Adult Sprague-Dowley rats with streptozotocin-induced DM and controls of the same age and strain were sacrificed 4 and 8 weeks and 6 months after disease onset. Cell replication was demonstrated with MIB-5, and apoptosis with the terminal uridine nick end labeling technique. Glomerular size and glomerular cell population were estimated morphologically. RESULTS: Diabetic and control rats showed irrelevant MIB-5 positivity at all time points. Glomerular apoptosis was minimal in rats with 4 and 8 weeks of DM and in controls. Rats with 6 months of DM showed significantly higher glomerular apoptosis values than controls (2.49 +/- 0.25 vs. 0.65 +/- 0.16%; p < 0.001). The mean cell count per glomerular profile was significantly lower in these diabetic rats (64.02 +/- 1.93 vs. 78.27 +/- 0.99; p < 0.001), a change that correlated with that in apoptosis. The glomerular cell density was further decreased in diabetic rats because of the diabetic increase in mean glomerular volume (1.598 vs. 0.927 10(6) microm). CONCLUSIONS: Apoptosis is associated with loss of glomerular cells in rats with long-term, streptozotocin-induced DM and - to a considerably lower degree - in controls of the same age and strain. These changes could be relevant to glomerulosclerosis associated with long-term, streptozotocin-induced DM.     

alpha-Melanocyte-stimulating hormone protects the allograft in experimental heart transplantation

BACKGROUND: With the increasing need for organ transplantation and the use of "marginal" organs, novel approaches are sought to increase the efficiency and survival of transplanted tissue. We tested the idea that treatment with the anti-inflammatory peptide, alpha-melanocyte-stimulating hormone (alpha-MSH), an endogenous hormone that does not cause marked immunosuppression but does reduce reperfusion injury, may protect allografts and prolong their survival. METHODS: Donor cardiac grafts (Brown Norway) were transplanted heterotopically into the abdomen of recipient (Lewis) rats. Treatments consisted of intraperitoneal injections of Nle DPhe -alpha-MSH (NDP-alpha-MSH) or saline from the time of transplantation until sacrifice or spontaneous rejection. Allografts were removed on day 1, day 4, or at the time of rejection and examined for histopathology and expression of molecules prominent in reperfusion injury, transplant rejection, and apoptosis. RESULTS: NDP-alpha-MSH treatment caused a significant increase in allograft survival and a marked decrease in leukocyte infiltration. Expression of molecules such as endothelin 1, chemokines, and adhesion molecules, which are involved in allograft rejection, was significantly inhibited in NDP-alpha-MSH-treated rats. CONCLUSIONS: The results indicate that protection of the allograft from early injury with alpha-MSH can postpone rejection. Addition of this early protection with the peptide to usual treatment with immunosuppressive agents may, therefore, improve success of organ transplants.     

Fracture risk is increased in patients with GH deficiency or untreated prolactinomas--a case-control study

OBJECTIVE: The pituitary secretes many hormones of significance to bone turnover and thus skeletal integrity. The aim of this study was to examine fracture risk in patients with pituitary disorders with special reference to GH deficiency and hyperprolactinaemia. DESIGN: Case-control study. MEASUREMENTS: Fracture occurrence. PATIENTS: A self-administered questionnaire was issued to 537 consecutive patients with pituitary disorders excluding Cushing's disease. A total of 426 (79%) returned the questionnaire and 422 of these could be analysed. Each respondent was compared to three age- and gender-matched control respondents to the same questionnaire drawn randomly from the background population. RESULTS: The patients had a mean age of 51.4 +/- 14.8 years. One hundred and eight patients had acromegaly, 86 had prolactinomas, 136 had non-functioning pituitary adenomas (NFPA), 23 had craniopharyngiomas, and 73 had other types of pituitary disorders. For the total group the fracture risk was not elevated either before or after confirmed diagnosis compared to controls. However, among the patients with prolactinomas, the fracture risk was significantly increased before (relative risk, RR = 1.6, 95% CI: 1.1--2.3) but not after diagnosis. In patients with NFPA, fracture risk was borderline significantly elevated following diagnosis (RR = 1.6, 95% CI: 1.0--2.6). Patients with subnormal stimulated peak GH values suggestive of GH deficiency had a significantly higher risk of fractures after diagnosis than patients who had normal stimulated peak GH values (odds ratio, OR = 4.90, 95% CI: 1.10--21.88). CONCLUSIONS: Untreated prolactinomas were associated with a significant increase in fracture risk. Growth hormone deficiency was also associated with a higher fracture risk.     

Rate of knee cartilage loss after partial meniscectomy

OBJECTIVE: Surgical removal of the meniscus of the knee is thought to be a risk factor for later appearance of knee osteoarthritis (OA). We examined whether there is a difference in cartilage loss in those who undergo a partial meniscectomy compared to healthy controls. METHODS: Eight patients who underwent a meniscectomy (5 partial medial, 3 partial lateral) and 13 controls with normal knee radiographs and magnetic resonance imaging (MRI) had an MRI at baseline and at a mean 28.6 +/- 7.6 months followup. Articular cartilage volumes were determined by processing images acquired in the sagittal plane using T1 weighted fat saturation MRI on an independent work station. RESULTS: The mean +/- SD of percentage rates of cartilage loss from baseline volume were 4.1 +/- 2.8% per year for the meniscectomy subjects and -2.3 +/- 3.0% per year for the controls (difference 6.5% per year, 95% CI 3.7-9.3% per year; p < 0.001). After adjustment for age, body mass index, and sex the difference increased slightly to 6.9% per year (95% CI 3.4-10.3%; p = 0.001). CONCLUSION: This study suggests that significant rates of cartilage loss are seen in subjects post partial meniscectomy compared with healthy controls. This may be a useful model in which to examine therapies to prevent OA.     

Kidney immune cell infiltration and oxidative stress contribute to prenatally programmed hypertension

BACKGROUND: Prenatal environment has been shown to modify adult blood pressure profile, but the underlying mechanisms are not well understood. The role of renal immune cell infiltration, oxidative stress, and nitric oxide bioavailability in the pathogenesis was investigated. METHODS: Adult hypertension in rat offspring was induced by maternal low protein diet. Oxidative stress was determined by quantitative immunoblotting for nitrotyrosine, and T-cell and macrophage content by immunostaining, in offspring kidneys before and after the onset of hypertension. Nitric oxide metabolites (NOx) were measured in 24-hour urines. A group of offspring was treated with the immunosuppressive drug mycophenolate mofetil (MMF) to reduce inflammation, or with the superoxide dismutase mimetic Tempol to reduce oxidative stress, for a 3-week period before the onset of hypertension. RESULTS: During the prehypertensive stage, at 4 weeks of age, the low protein diet pups exhibited an increase in kidney nitrotyrosine content and in number of immune cells, both of which persisted in untreated animals after hypertension was established, at 8 weeks of age. Urine NOx was increased at 4 weeks and unchanged at 8 weeks of age. Both MMF and Tempol treatment prevented the immune cell infiltration, the increase in kidney nitrotyrosine abundance, and the development of hypertension. The effect on blood pressure persisted throughout the 4- to 10-week observation period after discontinuation of the treatments. CONCLUSION: Renal oxidative stress and infiltrating immune cells may play a pathogenetic role in prenatally programmed hypertension. Nitric oxide bioavailability does not appear impaired.     

Correlation of magnetic resonance imaging and pathologic size of infiltrating lobular carcinoma of the breast

BACKGROUND: Determining the extent of infiltrating lobular carcinoma (ILCA) in the breast is difficult. This study was designed to determine if the size of ILCA on magnetic resonance imaging (MRI) correlated with final pathology. METHODS: Retrospective study of patients between 1998 and 2004, who were evaluated for extent of ILCA prior to definitive treatment, was conducted. Demographic data and radiology and pathology results were obtained. Spearman correlation coefficient was used. RESULTS: Twenty-nine patients (median age 62 years) had MRI of breast. Fourteen patients (48%) had contralateral MRIs; 13 (45%) normal; 1 (8%) prompted core biopsy; 6 of 13 patients underwent contralateral mastectomies, which were benign. The distribution of tumor size was: T1 = 15 (52%); T2 = 7 (24%); T3 = 5 (17%); T4 = 2 (7%). Spearman correlation coefficient between tumor size on ultrasound and MRI with pathology was .19 (P = .5) and .88 (P < .001), respectively. CONCLUSION: MRI provided superior correlation between tumor size and pathology.     

bla(SHV) Genes in Klebsiella pneumoniae: different allele distributions are associated with different promoters within individual isolates

Extended-spectrum β-lactamases (ESBLs) emerge by point mutation from non-extended-spectrum precursors. The aims of this study were to reveal the basis for variations in resistance levels found in a collection of 21 Klebsiella pneumoniae clinical isolates from Brisbane, Australia. Previous studies have shown that 20 of these isolates possess bla_SHV-11, bla_SHV-2a, and/or bla_SHV-12, and there is an association between the copy numbers of the ESBL-encoding genes and resistance levels. In this study, a real-time PCR method for interrogating the polymorphic sites at codons 238 and 240 was developed, and this confirmed the relationship between mutant gene copy numbers and resistance levels. The bla_SHV promoter region was cloned from one of the ESBL-expressing isolates, and this showed that bla_SHV genes exist downstream of two different promoters within this single isolate. These promoters have both been reported previously, and they differ by virtue of the presence or absence of an IS26 insertion. The bla_SHV copy numbers in cis with the different promoters were measured, and the copy number of the IS26 promoter was correlated with resistance levels. Cloning and analysis of PCR products showed that different bla_SHV variants existed in cis with individual promoters in individual isolates but that mutant genes were more abundant downstream of the IS26 promoter. There were no ESBL-positive isolates without this promoter. It was concluded that bla_SHV in cis with the IS26 promoter is located on an amplifiable replicon, and the presence of the IS26 insertion may facilitate the acquisition of an ESBL-positive phenotype.