Proximal rectus femoris release surgery is not effective in normalizing hip and pelvic variables during gait in children with cerebral palsy

The purpose of this study was to determine the efficacy of the proximal rectus femoris release to treat hip flexor contractures and hip and pelvic gait deviations in children with spastic cerebral palsy. This study was a retrospective repeated-measures analysis of data collected on two matched groups of patients, those with and without proximal rectus femoris release surgery, seen in our Motion Analysis Laboratory. Proximal rectus release surgery did not improve hip extension, did not decrease anterior pelvic tilt, and did not improve temporal-distance measures of gait in children with cerebral palsy. A multivariate measure, the Hip Flexor Index, was also unchanged. The group of patients without any hip flexor surgery was not different from the rectus femoris release group on hip or pelvic variables before or after surgery. The findings of this study offer no evidence that the proximal rectus femoris release is successful in achieving desired gait outcomes at the hip and pelvis in children with cerebral palsy.     

Regional localization of the murine Duchenne muscular dystrophy gene on the mouse X chromosome

The murine locus corresponding to the human Duchenne/Becker muscular dystrophy (DMD) gene has been regionally mapped on the mouse X chromosome by hybridizing DNA from interspecies mouse crosses with a cDNA clone for the mouse Dmd gene. The results demonstrate that the relative organization of genes on the murine and human X chromosomes is more divergent than has previously been postulated. Furthermore, the mouse Dmd gene maps to a similar region of the X chromosome as does the mouse muscular dystrophy mutation mdx, providing further evidence that the mdx mutant may be a murine equivalent of human DMD. However, Southern analysis of portions of the mouse Dmd gene has not yet revealed any differences between mdx and wild-type mice.     

Computed tomography evaluation of the sacroiliac joints in Crohn disease

Computed tomography (CT) was used in a prospective study of the sacroiliac joints in 86 patients with Crohn disease to determine the type and frequency of sacroiliac joint abnormalities present in this population. The CT findings were correlated with review of the clinical history in 64 patients. Computed tomography demonstrated changes of sacroiliitis in 29% of the study group. This high prevalence of sacroiliac joint abnormality was found even in those under 30 years of age. It exceeds the 11–19% previously reported from plain film examination, reflecting the greater sensitivity of CT. In the subgroup of 64 patients studied clinically, 19 (30%) had abnormal sacroiliac joints on CT, but only 2 (3%) reported symptoms related to the sacroiliac joints.     

Minimally invasive vein harvest and wound healing using the SaphLITE Retractor System

BACKGROUND: In response to reported wound complication rates of 19% to 43% for traditional saphenous vein harvest, several minimally invasive vein harvest (MIVH) techniques have been developed. The purpose of this investigation is to determine the effectiveness of one such MIVH technology, the Genzyme SaphLITE Retractor System (Genzyme Biosurgery, Cambridge, MA). METHODS: Since May 2000, saphenectomy was undertaken in 305 coronary artery bypass graft (CABG) patients using SaphLITE in a prospective, nonrandomized trial at three centers. Patients were assessed for wound healing (ASEPSIS tool) and incisional pain (numeric scale) through the postoperative visit. Harvest times, incision lengths, and vein lengths were recorded. RESULTS: ASEPSIS indicated satisfactory healing in 96.0%. Infection rate was 1.3% with four patients requiring antibiotics and debridement of one incision. Of hospitalized patients, 85.4% had no or minimal affected leg pain. Additional mean data include: harvest time 43.4 +/- 17.6 minutes, incision number 3.0 +/- 1.2, incision length 2.9 +/- 1.4 cm, and vein length 46.0 +/- 15.2 cm. CONCLUSIONS: SaphLITE provides an effective alternative to traditional saphenous vein harvest, with improved wound healing, decreased pain, and acceptable harvest times.     

Mutations affecting the structure of hypoxanthine: guanine phosphoribosyltransferase in cultured Chinese hamster cells

14 Clones resistant to 8-azaguanine, isolated from mutagenically treated cultured cells from Chinese hamsters, were tested for loss of enzymic and immunological activities of hypoxanthine: guanine phosphoribosyltransferase. Three of the clones had no enzymic activity but reacted strongly with antiserum prepared against the enzyme (CRM(+)), indicating the presence of a defective enzyme protein, probably caused by a mutation in its structural gene. The other 11 mutants had little or no enzymic or immunologic activity. Revertant clones with positive enzymic and crossreacting immunologic activities were derived from both classes of mutants. The antiserum has been used for rapid purification of the phosphoribosyltransferase from Chinese hamster cells by immunoadsorbant affinity chromatography.     

Dysregulation of collagen production in diabetes following recurrent skin injury: Contribution to the development of a chronic wound

Recurrent injury has been implicated in the development of chronic diabetic wounds. We have developed a chronic diabetic wound model based upon recurrent injury in diabetic mice. We hypothesized that dysregulation of collagen production at both the mRNA and microRNA levels contributes to the development of chronic diabetic wounds. To test this, both diabetic and nondiabetic mice were made to undergo recurrent injury. Real‐time PCR for TGF‐β1, SMAD‐3, Col1α1, Col3α1, microRNA‐25, and microRNA‐29a and Western blot for collagen I and III were performed 7 days following each injury. Diabetic wounds displayed decreased collagen at all time points. This was associated with dysregulated collagen production at both the gene and microRNA levels at all time points. Following the final injury, however, diabetic collagen production significantly improved. This appeared to be due to a substantial decrease in both microRNAs as well as an increase in the expression of collagen pathway genes. That dysregulated collagen production progressed throughout the course of wounding suggests that this is one factor contributing to the development of chronic diabetic wounds. Future studies using this model will allow for the determination of other factors that may also contribute to the development and/or persistence of chronic diabetic wounds.     

Multimodal imaging enables early detection and characterization of changes in tumor permeability of brain metastases

Our goal was to develop strategies to quantify the accumulation of model therapeutics in small brain metastases using multimodal imaging, in order to enhance the potential for successful treatment. Human melanoma cells were injected into the left cardiac ventricle of immunodeficient mice. Bioluminescent, MR and PET imaging were applied to evaluate the limits of detection and potential for contrast agent extravasation in small brain metastases. A pharmacokinetic model was applied to estimate vascular permeability. Bioluminescent imaging after injecting d-luciferin (molecular weight (MW) 320 D) suggested that tumor cell extravasation had already occurred at week 1, which was confirmed by histology. 7 T T1w MRI at week 4 was able to detect non-leaky 100 μm sized lesions and leaky tumors with diameters down to 200 μm after contrast injection at week 5. PET imaging showed that ¹⁸F-FLT (MW 244 Da) accumulated in the brain at week 4. Gadolinium-based MRI tracers (MW 559 Da and 2.066 kDa) extravasated after 5 weeks (tumor diameter 600 μm), and the lower MW agent cleared more rapidly from the tumor (mean apparent permeabilities 2.27 × 10^− 5 cm/s versus 1.12 × 10^− 5 cm/s). PET imaging further demonstrated tumor permeability to ⁶⁴Cu-BSA (MW 65.55 kDa) at week 6 (tumor diameter 700 μm). In conclusion, high field T1w MRI without contrast may improve the detection limit of small brain metastases, allowing for earlier diagnosis of patients, although the smallest lesions detected with T1w MRI were permeable only to d-luciferin and the amphipathic small molecule ¹⁸F-FLT. Different-sized MR and PET contrast agents demonstrated the gradual increase in leakiness of the blood tumor barrier during metastatic progression, which could guide clinicians in choosing tailored treatment strategies.     

Antibody evolution to SARS-CoV-2 after single-dose Ad26.COV2.S vaccine in humans

The single-dose Ad.26.COV.2 (Janssen) vaccine elicits lower levels of neutralizing antibodies and shows more limited efficacy in protection against infection than either of the two available mRNA vaccines. In addition, Ad.26.COV.2 has been less effective in protection against severe disease during the Omicron surge. Here, we examined the memory B cell response to single-dose Ad.26.COV.2 vaccination. Compared with mRNA vaccines, Ad.26.COV.2 recipients had significantly lower numbers of RBD-specific memory B cells 1.5 or 6 mo after vaccination. Despite the lower numbers, the overall quality of the memory B cell responses appears to be similar, such that memory antibodies elicited by both vaccine types show comparable neutralizing potency against SARS-CoV-2 Wuhan-Hu-1, Delta, and Omicron BA.1 variants. The data help explain why boosting Ad.26.COV.2 vaccine recipients with mRNA vaccines is effective and why the Ad26.COV2.S vaccine can maintain some protective efficacy against severe disease during the Omicron surge.     

Cytochrome P450 epoxygenase-derived epoxyeicosatrienoic acids contribute to insulin sensitivity in mice and in humans

Aims/hypothesis

Insulin resistance is frequently associated with hypertension and type 2 diabetes. The cytochrome P450 (CYP) arachidonic acid epoxygenases (CYP2C, CYP2J) and their epoxyeicosatrienoic acid (EET) products lower blood pressure and may also improve glucose homeostasis. However, the direct contribution of endogenous EET production on insulin sensitivity has not been previously investigated. In this study, we tested the hypothesis that endogenous CYP2C-derived EETs alter insulin sensitivity by analysing mice lacking CYP2C44, a major EET producing enzyme, and by testing the association of plasma EETs with insulin sensitivity in humans.

Methods

We assessed insulin sensitivity in wild-type (WT) and Cyp2c44 ^?/? mice using hyperinsulinaemic–euglycaemic clamps and isolated skeletal muscle. Insulin secretory function was assessed using hyperglycaemic clamps and isolated islets. Vascular function was tested in isolated perfused mesenteric vessels. Insulin sensitivity and secretion were assessed in humans using frequently sampled intravenous glucose tolerance tests and plasma EETs were measured by mass spectrometry.

Results

Cyp2c44 ^?/? mice showed decreased glucose tolerance (639 ± 39.5 vs 808 ± 37.7 mmol/l × min for glucose tolerance tests, p = 0.004) and insulin sensitivity compared with WT controls (hyperinsulinaemic clamp glucose infusion rate average during terminal 30 min 0.22 ± 0.02 vs 0.33 ± 0.01 mmol kg^?1 min^?1 in WT and Cyp2c44 ^?/? mice respectively, p = 0.003). Although glucose uptake was diminished in Cyp2c44 ^?/? mice in vivo (gastrocnemius R_g 16.4 ± 2.0 vs 6.2 ± 1.7 μmol 100 g^?1 min^?1, p < 0.01) insulin-stimulated glucose uptake was unchanged ex vivo in isolated skeletal muscle. Capillary density was similar but vascular K_ATP-induced relaxation was impaired in isolated Cyp2c44 ^?/? vessels (maximal response 39.3 ± 6.5% of control, p < 0.001), suggesting that impaired vascular reactivity produces impaired insulin sensitivity in vivo. Similarly, plasma EETs positively correlated with insulin sensitivity in human participants.

Conclusions/interpretation

CYP2C-derived EETs contribute to insulin sensitivity in mice and in humans. Interventions to increase circulating EETs in humans could provide a novel approach to improve insulin sensitivity and treat hypertension.