Should an increase in cerebral neurochemicals following head kicks in full contact karate influence return to play?

BACKGROUND: Cerebral neurochemicals are markers of traumatic brain injury (TBI). OBJECTIVES: The aim of the study was to determine whether kicks to the head (KTH) in full contact karate significantly increased serum concentrations of protein S-100B, and neurone specific enolase (NSE). Kicks to the body (KTB) were also quantified to asses muscle tissue injury. Muscle damage was assessed by analysis of serum total creatine kinase (CK). METHODS: Twenty-four full contact karate practitioners were observed and filmed during actual competition and divided into two main groups post event: (1) Kicks to the head and body group (KTH): n = 12; mean ± SD; age, 30.4 ± 6.7 years; height, 1.74 ± 0.1 m; weight, 79.1 ± 2.1 kg; and (2): Kicks to the body group (KTB): n = 12; mean ± SD; age, 28.2 ± 6.5 years; height, 1.75 ± 0.1 m; weight, 79.2 ± 1.7 kg. The KTH group received direct kicks to the head, while group KTB received kicks and punches to the body. Blood samples were taken before and immediately post-combat for analysis of serum S-100B, NSE, CK and cardiac troponin. RESULTS: Significant increases in serum concentrations of S-100B (0.12 ± 0.17 vs. 0.37 ± 0.26, µg.L(-1)) and NSE (11.8 ± 4.1 vs. 20.2 ± 9.1 ng.mL(-1)) were encountered after combat in the KTH group and CK (123 ± 53 vs. 184 ± 103 U.L(-1)) in the KTB group (all P <0.05). CONCLUSIONS: Head kicks in full contact karate cause elevation of neurochemical markers associated with damaged brain tissue. The severity of injury is related to the early post-traumatic release of protein S-100B and NSE. The early kinetics and appearance post injury can reflect intracranial pathology, and suggest S-100B and NSE are extremely sensitive prognostic markers of TBI.

Characterisation of nickel silicide thin films by spectroscopy and microscopy techniques.

This article discusses the formation and detailed materials characterisation of nickel silicide thin films. Nickel silicide thin films have been formed by thermally reacting electron beam evaporated thin films of nickel with silicon. The nickel silicide thin films have been analysed using Auger electron spectroscopy (AES) depth profiles, secondary ion mass spectrometry (SIMS), and Rutherford backscattering spectroscopy (RBS). The AES depth profile shows a uniform NiSi film, with a composition of 49-50% nickel and 51-50% silicon. No oxygen contamination either on the surface or at the silicide-silicon interface was observed. The SIMS depth profile confirms the existence of a uniform film, with no traces of oxygen contamination. RBS results indicate a nickel silicide layer of 114 nm, with the simulated spectra in close agreement with the experimental data. Atomic force microscopy and transmission electron microscopy have been used to study the morphology of the nickel silicide thin films. The average grain size and average surface roughness of these films was found to be 30-50 and 0.67 nm, respectively. The film surface has also been studied using Kikuchi patterns obtained by electron backscatter detection.

Cardiorespiratory symptoms during pregnancy--not always pulmonary embolism.

We describe a case of sudden onset severe cardiorespiratory compromise in a parturient at 36 weeks' gestation. She received treatment for infection, pulmonary oedema and pulmonary embolism before a diagnosis of aortic dissection was made. Successful repair was undertaken following caesarean section. We discuss the difficulties of diagnosis of cardiorespiratory symptoms and the potential hazards of instituting therapy before a definitive diagnosis is reached. The value of a multidisciplinary team approach and the use of portable echocardiography in the investigation of both pulmonary embolism and cardiac disease are emphasised.

Insulin as a drug of abuse in body building.

A theoretical benefit of insulin abuse by body builders is that it is undetectable by currently available tests. A case is presented that highlights the dangers of such abuse.

Evaluation of medical rehabilitation in community based rehabilitation.

Almost all governments and non-governmental organisations in developing countries use a community-based rehabilitation (CBR) approach to work with disabled people. Although disabled people's organisations reject the categorisation of disability in individual terms, 'medical rehabilitation' is still regarded as an important but time limited process within rehabilitation. The paper lists measures and methods used in a comprehensive evaluation, and presents a practical method to examine the quality of medical rehabilitation. The method was developed and applied in an evaluation of service needs and service provision for disabled people in low-income communities, for the Ministry of Welfare, Government of India. The method described is a tracer approach. It assesses quality in three aspects of medical rehabilitation: (i) Technical quality, based on application of minimum technical standards for each impairment. (ii) Interpersonal quality, by observation of service sessions and interviews with service users. (iii) Management (structural) quality, by comparing the rehabilitation goals of service users and service providers. The method differs from most others in that it is process oriented, as opposed to output oriented. The method meets the challenges of providing low-cost assessment of a difficult outcome measure (the quality of medical rehabilitation), within a complex process (CBR). It is anticipated that the tracer method will be useful to the objective evaluation of disability services throughout the developing world.

Membrane dips over nuclei correlate with DNA synthesis in spreading hepatocytes.

Spreading of hepatocytes on different supports was examined using scanning electron microscopy. Positively charged Primaria plates gave a uniform morphology in 2 h. The spreading was rapid and the surface of the cells showed early prominent dips. The hepatocytes had one or two of these structures corresponding with nuclearity of the cells. The nuclear origin of the dips was confirmed after 6 h. The indentations contained solid structures the number, size, and shape of which were identical to the nucleoli seen by light microscopy. The spreading on the other supports was less uniform. Nuclear dips appeared more slowly and were less marked initially in their depths. The nuclear dipping was independent of cell density and took place under conditions under which the cells undergo phenotypic changes during culture. Individual phenotypic changes occur at different times and rates so that the initial signal for their onset cannot be determined with any certainty. However, the appearance of the dips was accompanied by DNA synthesis in the normally quiescent cells. The process stopped when the dipping was completed. The unavoidable change in nuclear morphology in spread cells may explain why maintenance of a spherical shape circumvents inappropriate DNA synthesis and maintains hepatocyte differentiation in vitro.

Utilization of amino acids in growing kidney proximal tubule cell cultures.

The growth of rat kidney proximal tubule cells was monitored continuously by the cellular incorporation of [methyl-(14)C] thymidine using scintillating microplates. The radioisotope had no effect on cell proliferation over a 5 day period, neither was it extensively converted to thymine. Leibovitz L-15 medium supplemented with bicarbonate proved a good growth medium and its high levels of carbohydrates and amino acids facilitated the appearance of intermediates in the cells' metabolism of additional radioactive amino acids. Kidney proximal tubule cells had a greater potential to process amino acids than BHK-21 cells. The utilization of amino acids by proximal tubule cells differed from that of other organs. The amino acids could be classified into three classes. Members of the first type were only used for protein synthesis (arginine, lysine, histidine and tyrosine). The second class of amino acids yielded only one or two metabolites (leucine and isoleucine), while the last type gave more than two metabolites (alanine, aspartate, glycine, methionine, proline and valine).

Early membrane depressions in hepatocytes cultured on Primaria supports.

The topography of spreading hepatocytes on positively charged Primaria plates was examined using scanning electron microscopy. The cells acquired a uniform morphology within 2 h. The spreading was rapid and the surface of the cells showed early prominent depressions or dips. The hepatocytes had either one or two of these structures which corresponded to the frequency of mononuclear and binuclear cells, respectively. The nuclear origin of the dips was strengthened after 6 h. They contained solid structures, whose number, size and shape were the same as nucleoli. The membrane dipping was independent of cell density and took place under conditions where phenotypic changes can occur. Kidney proximal tubule cells had no dips. Co-cultures of hepatocytes and kidney proximal tubule cells showed that the cell types behave differently.

Ultrastructural changes in hypothermically preserved hepatocytes.

Hypothermic preservation of hepatocytes on gelatin gels (10 degrees C) provided a stable system for investigating cold-induced changes culminating in cell death. Hepatocyte morphology remained unchanged during 9 days of preservation. Thereafter there was a progressive movement of organelles toward the center of the cell. During this process the mitochondria appeared to have a normal morphology suggesting that they are not the primary cause of the transition. When the movement was completed the mitochondria appeared aggregated and microvilli were no longer apparent on the cell surface.

Revascularization of peripheral nerve autografts and allografts.

The timing and mechanisms of peripheral nerve revascularization were investigated using a 2-cm sciatic nerve graft model in 58 rats. Epineurial perfusion was consistently established by 48 hours and endoneurial perfusion by 72 hours. The pattern of endoneurial perfusion was "all-or-none"--either all or none of the vessels in a fascicle exhibited blood flow. Conventional allografts exhibited similar revascularization dynamics and patterns. Capping the ends of the autograft with Silastic significantly delayed revascularization; no flow was observed at 4 days, and only a peripheral rim of perfused fascicular vessels was observed at 7 days. These patterns suggested that the primary method of revascularization in the conventional graft was longitudinal inosculation; no evidence of peripheral neovascularization or dependence on the graft bed as a source of revascularization was observed. The introduction of a major histocompatibility complex barrier between the grafted tissue and the recipient animal did not alter the timing or the mechanics of blood flow reestablishment.

Decreased intracellular proteolysis correlates with the maintenance of a specific isoenzyme of cytochrome P-450.

The rates of intracellular protein degradation, of identically labelled populations of proteins, were compared in hepatocytes cultured at 37 degrees (on an adsorbed collagen layer) and in cells preserved on gelatin gels at 10 degrees C. The half-lives of the long-lived proteins were 35.4+/-8.6 h (N=4) and 692.9+/-216.9 h (N=4) respectively. Proteolysis was substantially decreased at 10 degrees C but the rate of decrease remained constant. Hepatocytes rapidly removed resorufin from the culture medium. The resorufin was not being conjugated or accumulated within the cells. Dicumarol, a potent inhibitor of quinone oxidoreductase, at high concentration (500 microm ) caused only a 72% decrease in the utilization of resorufin. The microsomal detoxifying enzyme, cytochrome P-450 1A1 remained at a constant level in the preserved hepatocyte monolayers. The results of this study strongly favour storing hepatocytes at 10 degrees C rather than at 4 degrees or 37 degrees C.

Hydrogen peroxide in human urine: implications for antioxidant defense and redox regulation.

The presence of hydrogen peroxide, at levels sometimes exceeding 100 microM, in human urine samples was established by three different assay methods: 2-oxoglutarate decarboxylation and the ferrous oxidation-xylenol orange (FOX) assay and an oxygen electrode. Detected levels of H(2)O(2) were decreased by addition of superoxide dismutase. We conclude that urine contains autooxidizable molecules that, upon exposure to 21% O(2), undergo rapid superoxide-dependent autooxidation reactions to generate H(2)O(2). The exposure of human tissues to hydrogen peroxide may be greater than is commonly supposed, which has implications in relation to the proposed role of this species in cell signaling.

Peripheral nerve revascularization: histomorphometric study of small- and large-caliber grafts.

The revascularization of nerve grafts was investigated using histologic and morphometric techniques. Small-diameter nerve grafts (sciatic in the rat and sural in adult ewes) were studied, as was a large-diameter peroneal nerve graft in the ewe. Ninety-six hours after sciatic nerve engraftment, rats were injected with an intravascular fluorescent tracer. Evans blue albumin (EBA). Specimens were observed for the number of vessels perfused. Analysis showed no difference in vascular pattern between the grafted nerves and their control nerves, suggesting that spontaneous revascularization had occurred to establish a vascular tree essentially identical to the native nerve. Sural and peroneal nerve grafts were evaluated in adult ewes at 7 or 40 days post-nerve grafting. Similar to the rat sciatic nerve, the small-diameter sural nerve grafts were completely revascularized, with an equal number of perfused vessels at both time periods, with respect to control specimens. In contrast, the larger-caliber peroneal nerve grafts were not perfused at 7 days, and very poorly perfused at 40 days. This correlated with scant neural regeneration at 40 days. The finding suggests that small-diameter nerve grafts spontaneously revascularize, and revascularization using microvascular techniques is not necessary. In contrast, the larger-diameter nerve graft did not revascularize well. Such a large-diameter nerve graft would provide a suitable model to investigate the potential merits of a vascularized nerve graft.

Regeneration across cold preserved peripheral nerve allografts.

The feasibility of peripheral nerve allograft pretreatment utilizing cold storage (5 degrees C in the University of Wisconsin Cold Storage Solution) or freeze-thawing to prevent rejection was investigated. Regeneration across cold-stored (3 or 5 weeks) or freeze-thawed (FT), 3.0-cm sciatic nerve allografts were compared to fresh auto- and allografts in an inbred rat model. At 16-week post-engraftment, only FT allografts appeared similar to autografts on gross inspection; FT grafts were neither shrunken nor adherent to the surrounding tissue as seen in the other allograft groups. Qualitatively, the pattern of regeneration in the graft segments of the fresh allograft and to a lesser extent of pretreated allografts was inferior to that of autografts as evidenced by a disruption in the perineurium, more extrafascicular axons, smaller and fewer myelinated axons, increased intrafascicular collagen deposition, and the persistence of perineurial cell compartmentation and perivascular infiltrates. Distal to these grafts, the regeneration became more homogenous between groups, although areas of ongoing Wallerian degeneration, new regeneration as well as compartmentation, were more prevalent in fresh and pretreated allografts. Although the number of myelinated fibres was equivalent to autografts, the fibre diameters, the number of large diameter fibres, and the G-ratio were significantly decreased in the allograft groups, which, in part, accounted for the significant decrease in conduction velocity in the 3-week stored and fresh allograft, and the slight decrease in the 5-week stored and FT allograft groups. There was a small return in the Sciatic Function Index towards normal, but no consistent differences between groups were found. Prolonged cold storage and freeze-thawing of nerve allografts resulted in regeneration that was better than fresh allografts, but inferior to autografts. With the concomitant use of host immunosuppression or other immunotherapies, these storage techniques can provide a means of transporting nerve allografts between medical centres and for converting urgent into elective procedures.

The effects of postoperative continuous passive motion on peripheral nerve repair and regeneration. An experimental investigation in rabbits.

The effects of continuous passive motion (CPM) on nerve regeneration following nerve repair were investigated. In 26 rabbits, the medial popliteal nerve was transected and microsurgically repaired. Half of the animals were treated with cast immobilization and the rest with 70 degrees arc CPM. Both treatments were discontinued on day 14. After sacrifice on day 100, no animal showed separation at the suture line. Mean nerve conduction velocity was slightly slower in the CPM than in the immobilization group. Mean fibre density was also slightly less in the CPM group but the difference was not significant. Mean fibre diameters, fibre diameter distributions, and soleus-muscle wet weights were similar in the two groups.

Cold preserved nerve allografts: changes in basement membrane, viability, immunogenicity, and regeneration.

Rat sciatic nerve graft segments were harvested and pretreated by either placement in the University of Wisconsin Cold Storage Solution at 5 degrees C and storage from 1 to 26 weeks, or repeatedly freezing (-40 degrees C) and thawing (20 degrees C). Following pretreatment, grafts were transplanted as either syngeneic or allogeneic nerve grafts. Storage and freeze-thawing did not affect the Schwann cell basal lamina or laminin distribution of the peripheral nerve. Graft cell viability decreased with increasing time of storage, with some viable cells detectable even after 3 weeks of storage. Freeze-thawed grafts were not viable. Increasing time of storage led to decreasing immune response and graft rejection, but improved regeneration. Freeze-thawed and 26-week stored allografts were nonimmunogenic and rejection was not seen, but regeneration was delayed compared to autografts. Graft storage may become a useful adjunct to clinical nerve allografting to permit elective scheduling of surgery, provide greater time for preoperative tissue testing, and possibly blunt the immune response.

Differences between contractions of fast and slow muscles after nerve grafting.

The nature of reinnervation of fast- and slow-twitch skeletal muscles, as assessed by contractile characteristics, was determined in a rat sciatic-nerve graft model. The isometric contractile function of the fast-twitch plantaris and slow-twitch soleus muscles from hindlimbs of adult male Lewis rats (225 to 250 g) was assessed at 16 weeks after sciatic-nerve grafting. A 3-cm interposition sciatic-nerve graft was performed in the following groups: fresh syngeneic (n = 10), fresh allogeneic (n = 11), 3-week stored allogeneic (n = 9), and freeze-thawed allogeneic (n = 9). A control group consisted of 8 normal unoperated rats. Contractile properties were assessed by stimulating the muscles indirectly via the sciatic nerve. At 16 weeks, soleus and plantaris muscle masses were 40 and 52 percent of controls, while their respective absolute tetanic forces (N) were less than 65 and 45 percent of controls. Analysis of time-dependent contractile parameters showed that the soleus/plantaris ratios for time to peak tension (TTP) and maximum rate of force development (df/dt) were not significantly altered following grafting. However, the ratio for half relaxation time (1/2RT) was significantly reduced from 4.44 +/- 0.62 toward a value of 1 following grafting. In this study, the authors found that, when fast and slow muscles were reinnervated from a common nerve, maintenance of differences in rate of force development supported selective reinnervation, while loss of differences in time of force relaxation supported random reinnervation.