Subtle Cardiovascular Abnormalities in Prader-Willi Syndrome Might Begin in Young Adulthood

Objective Patients with Prader-Willi syndrome (PWS) are known to have a high mortality rate. However, little is known about the exact reason for this, particularly in adults, because so few reports have been published. The present study examined cardiovascular abnormalities to determine the cause of death in adults with PWS. Methods From September 2017 to April 2019, a total of 18 adults with PWS, and, no history of cardiovascular diseases, were enrolled. We investigated the levels of the cardiovascular biomarkers: high-sensitivity C-reactive protein (hs-CRP) and troponin T (TnT). To estimate the cardiac function, we measured the left ventricular ejection fraction (LVEF), global longitudinal systolic strain (GLS) of the left ventricle, ratio of peak early mitral filling velocity (E) to early diastolic mitral annular velocity (E/e' ratio), mitral annular plane systolic excursion (MAPSE) and tricuspid annular plane systolic excursion (TAPSE) using standard and tissue Doppler echocardiography. Results The mean patient age was 28±9 years old. There were 11 men, and the mean body mass index was 45.1 kg/m². Dyslipidemia (82%), diabetes mellitus (82%) and hypertension (83%) were commonly found as comorbidities. Most patients had elevated levels of hs-CRP (mean 1.007±0.538 mg/dL). The LVEF (mean 61%±5%) showed normal values, while the GLS (mean 15.0%±3.0%) was decreased. The TAPSE was mildly reduced (mean 16±3 mm). Conclusion These results suggest that subtle cardiovascular abnormalities have already begun in young adults with PWS. We need to manage obesity and the resultant obesity-related disorders in order to prevent heart failure and coronary atherosclerosis in PWS patients.

Effects of losartan on blood pressure and humoral factors in a patient who suffered from anaphylactoid reactions when treated with ACE inhibitors during LDL apheresis

In a patient who was taking an angiotensin-converting-enzyme inhibitor, low-density lipoprotein (LDL) apheresis with dextran-sulfate cellulose provoked hypotension accompanied by lacrimation and blurred vision. Hypotension was eliminated by changing the anticoagulant from heparin to a protease inhibitor, nafamostat mesilate. A study was undertaken to clarify whether an antagonist of angiotensin type 1-receptor, losartan, could be safely used in the same patient during LDL apheresis treatment. Blood pressure and humoral factors were compared between the apheresis sessions with losartan and those without. Although angiotensin II and bradykinin plasma levels during LDL apheresis were significantly greater with losartan than without, blood pressure reduction by losartan was mild and unpleasant symptoms were not induced. Losartan was thus safely used for this patient during treatment by LDL apheresis. The greater rise in bradykinin levels during apheresis with losartan might be ascribable to angiotensin type 2-receptor stimulation.

Immunohistochemical demonstration of nerve fibers in the synovial fold of the human cervical facet joint

The role of the intra-articular synovial fold as a source of facet joint pain is unclear, because the nature of nociceptive innervation in lumbar synovial folds is controversial, and there have been no such studies in cervical synovial folds. The present study aimed to demonstrate the presence of nerve fibers including nociceptive fibers in synovial folds of human cervical facet joints using immunohistochemistry. Synovial folds of cervical facet joints removed from patients undergoing cervical spine laminoplasty were analyzed immunohistochemically using antibodies to protein gene product 9.5, beta III-tubulin, substance P and calcitonin gene-related peptide. Many nerve fibers immunoreactive for protein gene product 9.5 and beta III-tubulin were demonstrated both around blood vessels and as free fibers in the stroma of the synovial fold. Also. immunostaining showed the presence of free nerve fibers immunoreactive for substance P and calcitonin gene-related peptide in the stroma. The presence of putative nociceptive fibers in cervical synovial folds supports a possible role for these structures as a source of cervical facet joint pain.

Types of synovial fold in the cervical facet joint

Few detailed studies of synovial folds of cervical facet joints exist at the moment. This study was performed to provide anatomical data for each synovial fold in the cervical facet joints, using 20 cervical spines from C2 to C7 for dissection. Anatomic evaluation of the synovial folds included the gross morphology, in three dimensions, and the histology. Also, degenerative changes of the lower facet surface on which synovial folds occurred were evaluated. On the basis of gross morphology and histological composition, three types of synovial folds were identified. Type-1 synovial folds, shaped like a crescent, consisted principally of adipose tissue. Type-2 synovial folds had an apical region made up of dense fibrous tissue, with the base and middle region consisting of adipose tissue. In type-2 folds, the size and shape varied, including some elliptic-shaped synovial folds projecting well into the joint cavity. Type-3 synovial folds were thin with ragged free borders, and were formed exclusively of fibrous tissue. This study shows the variable appearance of synovial folds. Speculation was raised that the articular facet impingement of a large synovial fold and the subluxation of a smaller structure may play a possible role in the pathology of some disorders of the neck.

Analysis and comparison of reflex times and electromyograms of cervical muscles under impact loading using surface and fine-wire electroces

Myoelectric signals [electromyograms (EMGs)] can be collected using either surface or fine-wire electrodes. Application of the latter results in higher-frequency contents of EMG. In the field of impact biomechanics, surface electrodes are more often utilized than fine-wire ones. However, the removal of motion artefacts from EMG recorded under transient loads requires application of high-pass filters with relatively high cutoff frequencies, which may eliminate a significant part of the surface EMG power spectra. Therefore, in the current study, both surface and fine-wire electrodes were utilized to record the EMG of cervical muscles under conditions simulating a rear-end car collision at low speed. The results indicated that application of high-pass filtering at 50 Hz can be necessary to remove motion artefacts from the EMG collected under such conditions. Such filtering resulted in a higher decrease in amplitude of the surface EMG than that of the fine-wire one. However, the reflex times obtained here were not significantly affected by the type of the electrodes utilized to collect EMG.

Influence of seat characteristics on occupant motion in low-speed rear impacts

To analyze the effect of the seat characteristics on dummy motions and human volunteer motions, sled tests simulating low-speed rear impacts were conducted with some seats which had different characteristics. Volunteer's cervical vertebral motions were photographed with an X-ray cineradiographic system at a speed of 90 frames/s as well as the visible motions of dummy's and volunteer's were recorded. Although the tests were conducted under limited conditions, the results indicated the relationship between the occupant's visible motions, which are assumed to be closely related to the whiplash injury mechanism, and seat characteristics. It should be noted that the volunteer sled tests were discussed and approved by the Tsukuba University Ethics Committee and the volunteer submitted his informed consent in writing in line with the Helsinki Declaration.

Motion analysis of cervical vertebrae during whiplash loading

STUDY DESIGN

The motion of each cervical vertebra during simulated rear-end car collisions was analyzed.

OBJECTIVES

To clarify the mechanism of zygapophysial joint injury during whiplash loading.

SUMMARY OF BACKGROUND DATA

The zygapophysial joint is the suspected origin of neck pain after rear-end car collision. However, no studies have been conducted on the mechanisms of zygapophysial joint injuries.

METHODS

Ten healthy male volunteers participated in this study. Subjects sat on a sled that glided backward on inclined rails and crashed into a damper at 4 km/kr. The motion of the cervical spine was recorded using cineradiography. Each vertebra's rotational angle and the instantaneous axes of rotation of the C5-C6 motion segments were quantified. These measurements implemented the template method.

RESULTS

There were three distinct patterns of cervical spine motion after impact. In the flexion-extension group, C6 rotated backward before the upper vertebrae in the early phase; thus, the cervical spine showed a flexion position (initial flexion). After C6 reached its maximum rotational angle, C5 was induced to extend. As upper motion segments went into flexion, and the lower segments into extension, the cervical spine took an S-shaped position. In this position, the C5-C6 motion segments showed an open-book motion with an upward-shifted instantaneous axis of rotation.

CONCLUSIONS

The cervical spine is forced to move from the lower vertebrae during rear-end collisions. This motion completely differs from normal extension motion and is probably related to the injury mechanism.

Structural gene and complete amino acid sequence of Vibrio alginolyticus collagenase

The DNA encoding the collagenase of Vibrio alginolyticus was cloned, and its complete nucleotide sequence was determined. When the cloned gene was ligated to pUC18, the Escherichia coli expression vector, bacteria carrying the gene exhibited both collagenase antigen and collagenase activity. The open reading frame from the ATG initiation codon was 2442 bp in length for the collagenase structural gene. The amino acid sequence, deduced from the nucleotide sequence, revealed that the mature collagenase consists of 739 amino acids with an Mr of 81875. The amino acid sequences of 20 polypeptide fragments were completely identical with the deduced amino acid sequences of the collagenase gene. The amino acid composition predicted from the DNA sequence was similar to the chemically determined composition of purified collagenase reported previously. The analyses of both the DNA and amino acid sequences of the collagenase gene were rigorously performed, but we could not detect any significant sequence similarity to other collagenases.

Detection of elastase production in Escherichia coli with the elastase structural gene from several non-elastase-producing strains of Pseudomonas aeruginosa

The elastase structural gene from Pseudomonas aeruginosa IFO 3455 has been cloned and sequenced. Using this gene as a probe, we cloned the DNA fragments (pEL3080R, pEL10, and pEL103R) of the elastase gene from non-elastase-producing strains (P. aeruginosa IFO 3080, N-10, and PA103 respectively). These three Pseudomonas strains showed no detectable levels of elastase antigenicity by Western blotting (immunoblotting) or by elastase activity. When elastase structural genes about 8 kb in length were cloned into pUC18, an Escherichia coli expression vector, we were able to detect both elastase antigenicity and elastolytic activity in two bacterial clones (E. coli pEL10 and E. coli pEL103R). However, neither elastolytic activity nor elastase antigenicity was detected in the E. coli pEL3080R clone, although elastase mRNA was observed. The partial restriction map determined with several restriction enzymes of these three structural genes corresponded to that of P. aeruginosa IFO 3455. We sequenced the three DNA segments of the elastase gene from non-elastase-producing strains and compared the sequences with those from the elastase-producing P. aeruginosa strains IFO 3455 and PAO1. In P. aeruginosa N-10 and PA103, the sequences were almost identical to those from elastase-producing strains, except for several nucleotide differences. These minor differences may reflect a microheterogeneity of the elastase gene. These results suggest that two of the non-elastase-producing strains have the normal elastase structural gene and that elastase production is repressed by regulation of this gene expression in P. aeruginosa. Possible reasons for the lack of expression in these two strains are offered in this paper. In P. aeruginosa IFO 3080, the sequence had a 1-base deletion in the coding region, which should have caused a frameshift variation in the amino acid sequence. At present, we have no explanation for the abnormal posttransciptional behavior of this strain.