Complete genome sequence of an M1 strain of Streptococcus pyogenes

The 1,852,442-bp sequence of an M1 strain of Streptococcus pyogenes, a Gram-positive pathogen, has been determined and contains 1,752 predicted protein-encoding genes. Approximately one-third of these genes have no identifiable function, with the remainder falling into previously characterized categories of known microbial function. Consistent with the observation that S. pyogenes is responsible for a wider variety of human disease than any other bacterial species, more than 40 putative virulence-associated genes have been identified. Additional genes have been identified that encode proteins likely associated with microbial "molecular mimicry" of host characteristics and involved in rheumatic fever or acute glomerulonephritis. The complete or partial sequence of four different bacteriophage genomes is also present, with each containing genes for one or more previously undiscovered superantigen-like proteins. These prophage-associated genes encode at least six potential virulence factors, emphasizing the importance of bacteriophages in horizontal gene transfer and a possible mechanism for generating new strains with increased pathogenic potential.

Serotonin-, substance P- or leucine-enkephalin-containing neurons in the midbrain periaqueductal gray and nucleus raphe dorsalis send projection fibers to the central amygdaloid nucleus in the rat

By a double-labeling method combining the retrograde tracing of horseradish peroxidase and the immunocytochemical technique, serotonin-, substance P- or leucine-enkephalin-like immunoreactive neurons in the midbrain periaqueductal gray (PAG) and the nucleus raphe dorsalis (DR) of the rat were found to send projection fibers to the central amygdaloid nucleus bilaterally with an ipsilateral dominance. These PAG neurons were chiefly distributed in the ventrolateral PAG subdivision and the ventral parts of medial PAG subdivision at the middle and caudal levels of PAG.

An indirect projection from the nucleus of the solitary tract to the central nucleus of the amygdala via the parabrachial nucleus in the rat: a light and electron microscopic study

The morphological basis of how visceral information from the nucleus of the solitary tract (NTS) is relayed from the parabrachial nucleus (PBN) to the central nucleus of the amygdala (Ce) was studied at the light and electron microscopic levels using the anterograde tracer, Phaseolus vulgaris leucoagglutinin (PHA-L), kainic acid degeneration, and retrograde tracing with horseradish peroxidase (HRP). After injection of PHA-L into the caudal NTS, anterogradely labeled fibers and terminals were predominantly distributed in the external lateral (el) and central lateral (cl) subnuclei of the PBN. After injection of HRP into the Ce, retrogradely labeled neurons in PBN were mainly distributed in the same areas. In double-labeling experiments, there was a clear overlap between neuronal elements labeled with HRP and PHA-L in the el and cl. At the electron microscopic level, the PHA-L-labeled axon terminals from the NTS mainly contained spherical agranular synaptic vesicles and formed asymmetric contacts with the postsynaptic dendrites or dendritic spines in PBN. After the lesioning agent kainic acid was injected into the NTS and HRP deposited in the Ce, it was found the afferent fibers from the NTS made direct synaptic contact with the lateral PBN neurons which in turn projected to Ce. Such evidence adds to our growing knowledge of regulation of visceral function in central nervous system and would be likely helpful for understanding the important roles of the NTS, PBN and Ce in the central control of cardiovascular, respiratory and gastrointestinal functions.

Evidence of gamma-aminobutyric acidergic control over the catecholaminergic projection from the medulla oblongata to the central nucleus of the amygdala

It is known that the nucleus of the solitary tract (NTS) and the ventrolateral medulla (VLM) project to the central nucleus of the amygdala (Ce), conveying visceral information. Conversely, the Ce sends projections to the NTS and the VLM. To understand better the role of catecholamine and gamma-aminobutyric acid (GABA) in these reciprocal connections, experiments were performed by combining lectin-conjugated horseradish peroxidase (WGA-HRP) anterograde and retrograde transport with preembedding immunocytochemistry to detect tyrosine hydroxylase (TH), and postembedding immunocytochemistry to detect GABA. The light microscopic study suggested that the majority of neurons in the NTS and the VLM projecting to the Ce were TH immunoreactive (TH-IR). Most of them were located at the level of the obex. Under the electron microscope, the GABAergic and non-GABAergic terminals were found to form synaptic contacts with the TH-(IR) or Ce-projecting or TH-IR/Ce-projecting double-labelled neurons of the NTS and VLM. The GABAergic terminals mostly formed symmetrical synaptic contacts with the postsynaptic structure in which perikarya (14-19%), dendrites (79-84%), and spines (2%) were observed. Approximately 94% of the axon terminals in the NTS and 90% of those in the VLM arising from the Ce were GABAergic and appeared not to form synaptic contacts with the TH-IR or Ce-projecting neurons in these regions. The present results demonstrated that the catecholaminergic neurons of the NTS and VLM projecting to the Ce receive an extensive GABAergic innervation and that the amygdala projection to the medulla is mostly GABAergic.

Projection from the ventrolateral medullary neurons containing tyrosine hydroxylase to the central amygdaloid nucleus in the rat

By using a double-labeling produce of retrograde horseradish peroxidase (HRP) tracing and the immunocytochemical localization of tyrosine hydroxylase (TH), the present study ascertained that the axonal fibers of catecholaminergic neurons in the caudal ventrolateral medulla projected to the central amygdaloid nucleus in the rat. The majority of double-labeled cells were observed primarily around the level of the obex. 92% of HRP retrogradely labeled cells contained TH-like immunoreactive (TH-IR), but only 31% of TH-IR cells was labeled with HRP.

GABAergic synapses upon neurons expressing substance P receptors in the nucleus of the solitary tract: an immunocytochemical electron microscope study in the rat

Morphological substrates for interactions between gamma-aminobutyric acid (GABA) and substance P upon neurons expressing substance P receptor (SPR) in the nucleus of the solitary tract (NST) were investigated by immunocytochemical electron microscopy. In the NST of the rat, many GABA-like immunoreactive axon terminals were in symmetric synaptic contacts with dendritic profiles; they were observed on nearly a half of the SPR-like immunoreactive dendritic profiles in the medial part of the caudal half of the NST.

[The clinical study of modified transseptal suturing after septoplasty]

Objective:To study whether modified transseptal suturing could be an alternative to packing after septoplasty. Method:We conducted a prospective randomized controlled trial. The study involved 40 patients who underwent septoplasty. Patients were randomly divided into two groups, one with anterior nasal packing and the other with modified transseptal suturing. Patients were asked to record their subjective discomfort levels on a visual analogue scale（VAS） during 48 h postoperatively. Both groups were compared for VAS, postoperative complications 2 weeks after septoplasty through nasal endoscope, the datum of rhinomanometry before surgery and 2 weeks after surgery. Result:The differences of mean postoperative VAS score between two groups were statistically significant（P<0.05）. The patients of nasal packing group experienced more discomforts than the other group. No statistically significant between two groups in terms of the datum of rhinomanometry before surgery and 2 weeks after surgery（P>0.05）. There were no bleeding, septal hematoma, nasal septum perforation and local infection in all patients 2 weeks after septoplasty. During follow-up 1 case was found with postoperative nasal adhesion, nasal vestibular swelling and fester were seen in two patients and nasal peculiar smell was found in 1 case in nasal packing group. We can find that there were a lot of blood crust in silicone ventilation tube about in 14 patients in packing group. However, the suturing group could see none of the above questions. Conclusion:Modified transseptal suturing is more simple and convenient than nasal packing. In a word, the use of modified transseptal suturing could be an alternative topacking after septoplasty.

Assessment of four sterilization techniques for meniscal allograft transplantation in rabbits

Purpose

This study aimed to compare the effects of four sterilization techniques on meniscal allograft transplantation (MAT) in rabbits.

Methods

In total, 85 medial or lateral meniscuses were obtained from 22 adult New Zealand white rabbits. These 85 meniscal allografts were seeded with Staphylococcus aureus (S. aureus) and randomly divided into five groups (n = 17): iodine group, Cobalt-60 group, glutaraldehyde group, ethylene oxide group and control group. Bacterial colonies of the allografts were determined before (n = 7) and after (n = 7) sterilization. Histological features were analyzed using haematoxylin and eosin (H&E) staining (n = 3). An additional 50 medial or lateral meniscuses were taken from 13 adult New Zealand white rabbits, and they were kept fresh-frozen (-40°C) for 1 month. Subsequently, these 50 meniscuses were randomly divided into five groups, which were treated with iodine, Cobalt-60, glutaraldehyde, ethylene oxide and normal saline, separately (n = 10), and stored at -20°C before MAT. MAT was given to the knee joints of the right hind legs of 50 adult Japanese white rabbits. After 6 weeks of MAT, the transplanted meniscal allografts were taken for biomechanical test (n = 7) and H&E staining (n = 3).

Results

The results of the bacterial count indicated that the number of S. aureus colonies was less than 1 colony-forming unit (CFU)/allograft in all five groups after sterilization, except for the control group (415 CFU/allograft). H&E staining revealed that allografts in the iodine group presented the complete structure; allografts in the Cobalt-60 and glutaraldehyde groups were preserved relatively well; and allografts in the control and ethylene oxide groups were severely destructed, especially in the ethylene oxide group. Using the transplanted allografts, the biomechanical test showed that the maximum load of allografts in each group was significantly different, with ethylene oxide effective sterilization agents being used for disinfecting meniscal grafts (iodine group: 270.71 ± 62.81 N, Cobalt-60 group: 182.14 ± 71.29 N, glutaraldehyde group: 254.29 ± 31.55 N, ethylene oxide group: 40.00 ± 22.73 N and control group: 183.14 ± 76.40) (p ≤ 0.001). H&E staining with transplanted allografts revealed that allografts in the iodine group had the most intact structure; allografts in the Cobalt-60 and glutaraldehyde groups presented a relatively intact structure; and allografts in the control and ethylene oxide groups were seriously damaged, especially in the ethylene oxide group.

Conclusion

It was found that iodine, Cobalt-60, glutaraldehyde and ethylene oxide are effective sterilization agents for disinfecting meniscal grafts. Iodine exhibited superior preservation of both the biomechanics and structural integrity of the meniscal allografts, whereas ethylene oxide caused the most severe destruction to the meniscal allografts.

Level of Evidence

Not applicable because this is an animal study.