Limited endoscopic thoracic sympathetic block for hyperhidrosis of the upper limb: reduction of compensatory sweating by clipping T4

BACKGROUND

Endoscopic thoracic sympathicotomy of T2 to T4 (ETS 2-4) has evolved into an effective treatment for severe hyperhidrosis of the upper limb. Complications such as bleeding or Horner's syndrome are rare, but side effects such as compensatory and gustatory sweating occur in 30-50% of patients. Following the Lin-Telaranta classification, we aimed to reduce these side-effects by clipping T4 solely [endoscopic thoracic sympathetic block (ESB 4)]. We present our experience and clinical results using this method, with emphasis on patients' quality of life.

METHODS

A total of 176 procedures (91 patients) were carried out in the ETS 2-4 group and 103 procedures (53 patients) in the ESB 4 group: 60.4 and 43.4% had palmar hyperhidrosis, 8.8 and 5.7% had isolated axillary, and 30.8 and 50.9% had combined manifestations, respectively. Follow-up was 22.1 months (obtained from 79.1% of patients) for the ETS 2-4 group and 7.5 months for the ESB 4 group (obtained from 88.7%).

RESULTS

The success rate was similar for both groups: 87.9 and 64.5% had completely dry limbs, 9.9 and 35.5% ( p < 0.0002) were nearly dry, and 2.1 and 0% remained wet. (ETS 2-4 vs ESB 4). Although the armpits remained slightly humid in more patients in the ESB 4 group, 100% stated full satisfaction. Complications did not differ significantly. However, compensatory sweating (55.6 vs 8.5%, p = 0.0002) and gustatory sweating (33.3 vs 2.1%, p = 0.0019) were markedly reduced (ETS 2-4 vs ESB 4). Quality of life was assessed by a hyperhidrosis index, which significantly improved in most patients.

CONCLUSIONS

ETS 2-4 and ESB 4 have similar success rates in the treatment of upper limb hyperhidrosis. The major side effects of compensatory and gustatory sweating were effectively reduced by the limited method of clipping T4, and patients' satisfaction and improvement in quality of life were remarkable.

Development of 'no-reflow' phenomenon in ischemia/reperfusion injury: failure of active vasomotility and not simply passive vasoconstriction

BACKGROUND/AIM

Local blood flow failure (no-reflow phenomenon) during ischemia/reperfusion (I/R) injury may be mediated by interstitial edema formation (passive vasoconstriction) and/or microvascular spasm (active vasoconstriction). The development of the no-reflow phenomenon in the rabbit hind limb I/R model and the influence of treatment with L-arginine and/or antioxidative vitamins were investigated.

METHODS

Untreated rabbits were compared with those treated with L-arginine (4 mg/kg/min) or antioxidative vitamins (0.4 ml/kg) alone or in combination during hind limb I/R (2.5/2 h). Interstitial edema formation and microvessel diameter alterations were measured morphometrically. Capillary blood perfusion was measured continuously with laser Doppler flowmetry.

RESULTS

I/R injury was expressed by interstitial edema formation (interstitial space increase by 80%), microvascular constriction (microvessel cross-sectional area decrease by 30%), and development of no-reflow phenomenon (blood flow reduction by 60%). Treatment with antioxidative vitamins alone or L-arginine alone reduced interstitial edema by 22 and 31%, consequently, while combined L-arginine/antioxidative vitamin treatment showed a more pronounced edema reduction by 40%. Treatment with only antioxidative vitamins failed to influence the development of no-reflow, although interstitial edema formation was reduced. L-Arginine treatment alone or in combination with antioxidative vitamins prevented microvascular constriction and preserved blood flow after reperfusion without development of no-reflow despite still apparent interstitial edema.

CONCLUSIONS

Affections of active vasomotility and not merely passive changes of external pressure (i.e., interstitial edema formation) should be considered important in the development of microvascular constriction during 'no-reflow' phenomenon.

Delivery of high dose VEGF plasmid using fibrin carrier does not influence its angiogenic potency

Delivery of DNA mixed with a degradable matrix carrier was supposed to improve transgene expression. Using a rabbit hind-limb ischemia model, we tested the angiogenic potency of plasmid encoding human vascular endothelial growth factor (pSG5-VEGF165) entrapped in fibrin sealant. Animals were injected intramuscularly with 500 microg of pSG5-VEGF165 or control plasmid, dissolved in saline (PBS) or fibrin glue. After 14 days, presence of delivered constructs and expression of transgene was confirmed in injected muscles of all animals. There were no significant differences in the levels of human VEGF mRNA and protein between VEGF-PBS and VEGF-fibrin groups (Mann-Whitney test). Accordingly, pSG5-VEGF165 regardless of the way of delivery, induced similar increases in capillary density within treated muscles (ANOVA). Control plasmid did not show any effects. In conclusion, injection of pSG5-VEGF165 into ischemic adductor muscle leads to synthesis of human VEGF and increases the number of capillaries. Fibrin carrier does not influence its angiogenic potential.

Ischemia/reperfusion injury of skeletal muscle: plasma taurine as a measure of tissue damage

BACKGROUND

Cell membrane rupture by oxygen-derived free radicals is a systematic feature of ischemia/reperfusion (I/R) injury. High taurine concentration gradients in skeletal muscle prompted us to evaluate whether plasma taurine levels (pTau) are a useful marker of I/R injury after different periods of ischemia.

METHODS

Rabbits were randomly assigned to either 1 or 2.5 hours of hind-limb ischemia followed by 2 hours of reperfusion (groups IR1 [n = 12] and IR2.5 [n = 13], respectively). Corresponding sham groups (SHAM1 [n = 8] and SHAM2.5 [n = 9]) were used as controls. Analyzed parameters included histomorphometry and electron microscopy of skeletal muscle biopsies, pTau, and plasma level of malondialdehyde. Skeletal muscle function was assessed 3 weeks after I/R injury.

RESULTS

No significant morphologic changes were detectable at the end of ischemia. After reperfusion, mild interstitial edema with intact muscle cell membranes developed in IR1 group; pTau was not increased. IR2.5 group, by contrast, showed severe interstitial edema formation (interfiber area increased by 112%, P <.005), microvascular constriction (microvessel area decreased by 33%, P <.0005), and damage to the muscle cell membranes that was confirmed by the increased plasma malondialdehyde. pTau was higher than in the SHAM2.5 group (P <.0005). Pronounced cell damage in IR2.5 group resulted in impaired muscle function (maximal tetanic tension was reduced 2 times, P <.005) but not in IR1 group.

CONCLUSION

Skeletal muscle tolerates 1 h/2 h but not 2.5 h/2 h of I/R, the latter resulting in interstitial edema formation, microvascular constriction, and a late muscle dysfunction. Cell membrane rupture through stimulated lipid peroxidation promotes leakage of intracellular taurine, leading to increased pTau after reperfusion and may be considered as prognostically unfavorable in terms of organ function reversibility. In the rabbit model, pTau seems to be a sensitive marker of I/R injury to skeletal muscle.

S-nitroso human serum albumin treatment reduces ischemia/reperfusion injury in skeletal muscle via nitric oxide release

BACKGROUND

Peroxynitrite generated from nitric oxide (NO) and superoxide (O2-) contributes to ischemia/reperfusion (I/R) injury. Feedback inhibition of endothelial NO synthase by NO may inhibit O2- production generated also by endothelial NO synthase at diminished local L-arginine concentrations accompanying I/R.

METHODS AND RESULTS

During hindlimb I/R (2.5 hours/2 hours), in vivo NO was monitored continuously (porphyrinic sensor), and high-energy phosphates, reduced and oxidized glutathione (chromatography), and I/R injury were measured intermittently. Rabbits receiving human serum albumin (HSA) (controls) were compared with those receiving S-nitroso human serum albumin (S-NO-HSA) beginning 30 minutes before reperfusion for 1 hour or 30 minutes before ischemia for 3.5 hours (0.1 micromol x kg(-1) x h(- 1)). The onset of ischemia led to a rapid increase of NO from its basal level (50+/-12 nmol/L) to 120+/-20 and 220+/-15 nmol/L in the control and S-NO-HSA-treated groups, respectively. In control animals, NO dropped below basal levels at the end of ischemia and to undetectable levels (<1 nmol/L) during reperfusion. In S-NO-HSA-treated animals, maximal NO levels never decreased below basal concentration and on reperfusion were 100+/-15 nmol/L (S-NO-HSA preischemia group, 175+/-15 nmol/L). NO supplementation by S-NO-HSA led to partial and in the preischemia group to total preservation of high-energy phosphates and glutathione status in reperfused muscle (eg, preischemia groups: ATP, 30.23+/-5.02 micromol/g versus control, 15.75+/-4.33 micromol/g, P<0.0005; % oxidized glutathione, 4.49+/- 1.87% versus control, 22.84+/-6.39%, P<0.0001). S-NO-HSA treatment in all groups led to protection from vasoconstriction and reduced edema formation after reperfusion (eg, preischemia groups: interfiber area, 12.94+/-1.36% versus control, 27.83+/-1.95%, P< 0.00001).

CONCLUSIONS

Long-lasting release of NO by S-NO-HSA provides significant protection of skeletal muscle from I/R injury.

Morphometric and functional results after CO(2) laser welding of nerve coaptations

BACKGROUND AND OBJECTIVE

Several reports describe nerve coaptations by laser welding in combination with stay sutures and bonding material. This study was undertaken to obtain functional and morphologic information by using a nerve coaptation technique by epineurial CO(2) laser welding only.

STUDY DESIGN/MATERIALS AND METHODS

The sciatic nerves of 24 rats were transected and epineurially coapted with the CO(2) laser at 60 mW or with microsutures as a control. Walking track analysis were carried out to evaluate the functional recovery, and the nerves were harvested for histology after 6 months of regeneration.

RESULTS

None of the 24 nerves showed dehiscence of the coaptations, and all showed good nerve fiber regeneration. Better results were obtained for the functional evaluation of the sciatic function index (P < 0.02) and the toe spread index (P < 0.04) from the laser nerve coaptations. Likewise, the morphologic evaluations of the fiber density (P < 0.04) and area fraction (P < 0.002) were better in the laser group.

CONCLUSION

CO(2) laser welded nerve coaptations are as successful as their sutured counterparts and may become a promising alternative in clinical practice.

Prostaglandin E1 reduces ischemia/reperfusion injury by normalizing nitric oxide and superoxide release

To test the effects of prostaglandin E1 on 2.5 h of ischemia followed by 2 h of reperfusion, continuous nitric oxide measurements (electrochemical) were correlated with intermittent assays of superoxide and peroxynitrite levels (chemiluminescence) and ischemia/reperfusion injury in rabbit adductor magnus muscle. Administering prostaglandin E1 (1 microg/kg) before or during ischemia/reperfusion caused normalization of the release of nitric oxide, superoxide, and peroxynitrite to slightly above preischemic levels. This pattern was dramatically different from that observed during ischemia/reperfusion alone, where nitric oxide concentration increased three times above its basal level. Normalization of constitutive nitric oxide synthase activity in the presence of prostaglandin E1 was associated with a significant reduction of superoxide and peroxynitrite production and subsequent reduction of ischemia/reperfusion injury. At 2 h of reperfusion, vasoconstriction associated with ischemia/reperfusion injury was eliminated, and edema was significantly mollified but still apparent. Prostaglandin E1 treatment does not directly inhibit constitutive nitric oxide synthase, like the inhibitor N(omega)-monomethyl-L-arginine. Some phenomenon associated with ischemia turns on endothelial constitutive nitric oxide synthase to start transforming L-arginine and oxygen into nitric oxide, but prostaglandin E1 seems to inhibit this phenomenon. Thus, essential local L-arginine pools are not depleted, and normal basal levels of essential nitric oxide are maintained, whereas cytotoxic superoxide and peroxynitrite production by L-arginine-deficient constitutive nitric oxide synthase is prevented.

Histomorphology of rabbit thigh muscles: establishment of standard control values

The thigh muscles of New Zealand White (NZW) rabbits are frequently used in experimental surgery, particularly for evaluation after reinnervation or ischaemia. Although histomorphometric analyses are regularly performed, morphological data for untreated thigh muscles in previously unoperated animals are not available. Specimens from the rectus femoris (RF), vastus medialis (VM) and adductor magnus (AM) muscles from both thighs were harvested in 7 untreated rabbits and were processed for histomorphometric evaluation. The right RF and VM were harvested in a further 5 rabbit hindlimbs after experimental denervation and reinnervation of the contralateral RF and subsequently processed for histomorphometric analysis. Muscle fibre type distribution, diameter and connective tissue content were evaluated on serial transverse cryosections reacted for ATPase and NADH tetrazolium reductase activity and statistical analysis was performed. In all untreated animals RF revealed the highest proportion of type I muscle fibres (right: 8.4+/-4%, left: 11.4+/-4.9%), whereas VM showed the highest percentage of IIa fibres (right: 31.9+/-5.5%, left: 28.3+/-7.8%) and AM the highest proportion of IIb/d fibres (right: 80.5+/-8.6%, left: 84.4+/-6.3%). Fibre type distribution and diameter in rabbits after contralateral experimental operations revealed a statistically significant difference from the data obtained in bilaterally untreated animals. Knowledge of the morphology of untreated muscles is fundamental to the understanding of changes induced by intervention to the ipsi and/or contralateral thigh muscles.

Multivitamin administration before ischemia reduces ischemia-reperfusion injury in rabbit skeletal muscle

This study investigated the effect of a multivitamin preparation administered before ischemia or before reperfusion, on ischemia-reperfusion (I/R) injury of skeletal muscle. An in vivo hindlimb skeletal muscle I/R model (2.5 h/2 h) was carried out on adult New Zealand white rabbits. Animals used as I/R models were treated with a multivitamin preparation (0.4 ml/kg bw i.v. bolus), containing alpha-tocopherol, ascorbic acid, retinol, vitamin B complex, 30 min before starting ischemia (group MV(isc)) or 5 min before reperfusion (group MV(rep)) and compared to animals with I/R without treatment (group IR) and sham operated animals (group SHAM). Interstitial edema (muscle interfiber area, %MIFA) and changes in microvessel size (microvessel cross sectional area, MVCSA, microm(2)) were measured. Plasma malondialdehyde concentrations (MDA-TBA, nmol/ml) served as a measure of lipid peroxidation. After 2h of reperfusion, ischemia-reperfusion developed a significant microvascular constriction and an interstitial edema (IR, vs SHAM;P<< 0.01), but administration of antioxidative vitamins before the onset of ischemia reduced microvascular constriction and edema formation (P<< 0.05 vs IR group). In a similar manner, administration of vitamins before ischemia lowered plasma MDA-TBA levels as compared to the untreated group during reperfusion (p<< 0. 05). In animals treated with vitamins before reperfusion, the biochemical and morphological results showed no differences as compared to the untreated group. Antioxidative treatment with a multivitamin preparation exerted a beneficial effect on I/R injury of skeletal muscle when the aforementioned vitamins were administered before ischemia but not before the onset of reperfusion.

Morphology and histochemistry of myogelosis

Myogelosis is a common diagnosis in the case of chronic pain conditions, especially in the region of the pectoral girdle musculature, the glutei muscles, and the erector spinae muscle. Although such indurative areas continue to be palpable even on the cadaver, few studies concerning the morphological substrate of these areas have been undertaken. Selected biopsies as well as larger tissue samples were taken from 11 corpses and prepared for histological study. Following staining, the frozen sections were examined morphometrically. A histologically constant, significant morphological alteration was found in the areas of concern. The spaces between the individual muscle fibers of healthy muscle tissue appear relatively wide, the endomysium of the myogelotic area are clearly narrowed. Split fibers, ragged red fibers, Type II fiber atrophy, and fibers with a moth-eaten appearance have been detected. The morphometry shows considerable increase in thickness of the affected muscle fibers, suggestive of a pathological, local hypertrophy. The changes described may well represent a fixed condition, so that it should not be surprising that myogelosis therapy is difficult and protracted.

[Effect of transplant length on functional and morphologic outcome of nerve transplantation--an experimental study]

BACKGROUND

The present study was done in order to clarify whether the sometimes poor results after the use of long grafts for nerve reconstruction are due to the length of the graft itself or due to the concomitant big defect in the soft tissues necessitating the use of long grafts.

METHODS

In 22 rabbits, the saphenous nerve was used as a nerve graft. Animals were separated into three groups with different lengths of the grafts, namely 3 cm (group 1), 5 cm (group 2) and 7 cm (group 3). In one hindlimb, the proximal end of the graft was coapted to the motor nerve branch of vastus medialis. In a second step, the distal end of the graft was coapted to the nerve branch of rectus femoris. After a total period of 15 months the maximum tetanic tensions in the reinnervated rectus femoris and in the contralateral untreated muscle were determined. Biopsies of the graft and the motor branch distal to the graft were taken in order to count the number of regenerated myelinated nerve fibers.

RESULTS

The average maximum tetanic tension in the rectus femoris muscle reinnervated by the 3 cm long graft was 27.2 N; in group 2 the force amounted to 20.4 N. In group 3, the maximum force was 17.6 N, which meant an average loss of 29% compared to the contralateral untreated muscle. In accordance with the functional results, the mean number of regenerated myelinated fibres in the rectus femoris motor branch decreased from 1683 in group 1 to 1136 in group 3.

CONCLUSIONS

The results show that the length of the graft influences the results after nerve grafting to a certain extent, but a combination of other factors like concomitant soft tissue injury and destroyed target organs may also be responsible for some of the poor results after the clinical use of long nerve grafts.

Bioflavonoid quercetin scavenges superoxide and increases nitric oxide concentration in ischaemia-reperfusion injury: an experimental study

BACKGROUND

L-Arginine-depleted environments accompanying ischaemia-reperfusion enhance superoxide production, leading to the formation of reactive oxygen species and a concomitant reduction in basal nitric oxide levels. The bioflavonoid quercetin may prevent these undesirable effects by scavenging superoxide.

METHODS

Untreated rabbits were compared with those infused with quercetin (5 mg/kg for 2 min) during hindlimb ischaemia (2.5 h) and reperfusion (2 h). In both groups, nitric oxide concentration was measured (porphyrinic microsensor) in the femoral artery wall. Microvasculature changes (morphometry) and superoxide concentration (chemiluminescence) were measured intermittently in biopsies.

RESULTS

Approximately 6 min into the period of ischaemia a rapid increase in nitric oxide level from a mean(s.e.m.) basal level of 50(20) to 450(30) nmol/l was observed. In untreated animals, nitric oxide concentration dropped to an undetectable level (less than 1 nmol/l) during reperfusion. In quercetin-treated animals, the decrease in nitric oxide concentration was slower, such that substantial amounts (60(20) nmol/l) accumulated during reperfusion. In biopsies after ischaemia-reperfusion maximal calcium ionophore A23187-stimulated nitric oxide concentration increased (25-30 per cent) in the presence of quercetin, while the superoxide concentration decreased.

CONCLUSION

Quercetin treatment mollified ischaemia-reperfusion injury to skeletal muscle by scavenging destructive superoxide and enhancing the cytoprotective nitric oxide concentration.

The impact of a muscle target organ on nerve grafts with different lengths--a histomorphological analysis

The present study was done in order to evaluate the influence of a target muscle on the regenerative processes in long nerve grafts. In 21 rabbits the saphenous nerve was used as a nerve graft and coapted to the cut motor nerve of vastus medialis. The animals were separated into three groups with different graft lengths, namely 3, 5, and 7 cm. In a second stage the distal end of the graft (Graft.dist.) was coapted to the motor branch of rectus femoris. Cross sections of the normal vastus nerve and the Graft.dist. before and 7 months after the connection to rectus femoris were analyzed histomorphometrically. Before coaptation to the target organ mean fiber number in the Graft.dist. of the 3-cm-long grafts was 3380 and decreased to 2413 in the 7-cm-long grafts. Seven months after coaptation the results showed a statistically significant decrease of fibers in the Graft.dist. of group two and three and a distinct decrease of the fibers in group one. Summarizing, in a two-stage nerve grafting procedure the reinnervation of the muscle target organ leads to a down-regulation of fibers in the distal end of short and long nerve grafts.

[Nerve coaptation using CO2 milliwatt laser]

The technique of laser tissue welding with a low-output CO2 laser has become popular due to the minimal amount of nerve tissue damage caused. The purpose of this study was to ascertain the efficacy of nerve coaptation by laser tissue welding in comparison to micro-sutures. In a first series of 15 rats, peripheral nerves were transsected. 24 nerves were coaptated by laser welding (LW) with different parameters in order to evaluate the optimal laser settings. For comparison, six nerves were coapted (NS) with four 10/0 nylon sutures. Finally, the nerves were removed and the tensile strength of the different coaptations determined. The best results of the laser welds were obtained at laser settings of 40 to 60 mW in the continuous mode resulting in a tensile strength of 9.5 +/- 2.2 g. The tensile strength was 39.3 +/- 7.3 g for the sutured coaptation. In a second series, one sciatic nerve was coapted in thirteen rats by laser welding (LW) (60 mW, cont. mode) and in eleven rats using four 10/0 nylon sutures (NS). After six months, the Sciatic Function Index (SFI) was evaluated and the nerves were harvested for histological examination of transverse and longitudinal sections. All animals showed good regeneration and none of the 24 nerve coaptations showed dehiscence. The SFI was for the NS-group -94 +/- 23 and for the LW-group -77 +/- 20. The mean number of myelinated nerve fibres (NS 10,170 +/- 2512 vs. LW 11,902 +/- 1649) and the fibre diameter (NS 4.30 +/- 0.14 um vs. LW 4.02 +/- 0.59 microns) of the nerves distal to the coaptation were similar in both groups and showed no statistical difference. We conclude that nerve coaptation by CO2-laser welds are as successful as the 10/0 nylon sutures in the animal model. Improvements of welding techniques may in the future reduce nerve damage even further and so yield even better functional results.

The influence of the graft length on the functional and morphological result after nerve grafting: an experimental study in rabbits

Clinical experience shows that the results after the use of long nerve grafts for reconstruction are sometimes poor. Nevertheless several authors have stressed that the concomitant big defect in the soft tissues necessitating the use of long grafts is the reason for some of the failures. In 22 rabbits the saphenous nerve was used as a nerve graft. Animals were separated into 3 groups with different lengths of the grafts, namely 3 cm (group 1), 5 cm (group 2) and 7 cm (group 3). In the left hindlimb the proximal end of the graft was coapted to the cut motor nerve branch of vastus medialis. In a second stage the distal end of the graft was coapted to the nerve branch of rectus femoris. After a total period of 15 months the maximum tetanic tension in the reinnervated rectus femoris and in the contralateral unoperated muscle was determined. Biopsies of the graft and the motor branch distal to the graft were taken in order to count the number of regenerated myelinated nerve fibers. The average maximum tetanic tension in the rectus femoris muscle reinnervated by the 3 cm long graft was 27.2 N, in group 2 the force was 20.5 N. In group 3 the maximum force was 17.6 N, which meant an average loss of 29% compared to the contralateral unoperated muscle. The mean number of regenerated myelinated fibres distal to the graft in the rectus femoris motor branch was 1683 in group 1 and decreased to 1137 in group 3. The results show that the length of the graft influences the results after nerve grafting to a certain extent, but a combination of other factors like concomitant soft tissue injury and destroyed target organs may also be responsible for some of the poor results after the clinical use of long nerve grafts.

[Comparative studies of morphometric and functional results following reconstruction of motor nerves]

In order to determine the value of a reconstructive procedure in the peripheral nerve, experimental studies often evaluate the number and the diameter of myelinated nerve fibers as a parameter for the quality of regeneration. This study addresses the correlation between the number of fibers in a peripheral motor nerve after microsurgical reconstruction and the functional result, expressed as the force of the reinnervated muscle. In a total number of 24 sheep, the motor branch to the rectus femoris muscle was severed. The muscle was reinnervated either by direct neurorrhaphy or by nerve grafting, performed in three different ways (free grafting to the ipsilateral muscle, free grafting to the contralateral muscle, vascularized grafting to the ipsilateral muscle). In the final experiments, the muscle force in the reinnervated muscle was determined by supramaximal electrical stimulation. Number and diameter of myelinated nerve fibers were evaluated by computer-assisted morphometric analysis. Regression analysis of morphometric data and the muscle forces was calculated. No correlation was found between fiber numbers in the nerve graft and the maximal force. However, a positive correlation between the number of myelinated fibers in the motor branch distal to the site of coaptation and the functional result was observed in some cases. The diameter of myelinated fibers had no influence on the functional outcome.

L-arginine treatment alters the kinetics of nitric oxide and superoxide release and reduces ischemia/reperfusion injury in skeletal muscle

BACKGROUND

Constitutive nitric oxide synthase (cNOS) may produce species involved in ischemia/reperfusion (I/R) injury: NO in the presence of sufficient L-arginine and superoxide at the diminished local L-arginine concentration accompanying I/R.

METHODS AND RESULTS

During hindlimb I/R (2.5 hours/2 hours), in vivo NO was continuously monitored (porphyrinic sensor), and L-arginine (chromatography), superoxide (chemiluminescence), and I/R injury were measured intermittently. Normal rabbits were compared with those infused with L-arginine 4 mg x kg(-1) x min(-1) for 1 hour. In both groups, approximately 6 minutes into ischemia, a rapid increase of NO from its basal level of 50+/-17 to 115+/-7 nmol/L, P<.005 (microvessels), was observed. In animals not treated with L-arginine, NO dropped below basal to undetectable levels (<1 nmol/L) during reperfusion. In animals treated with L-arginine, the decrease of NO was slower, such that substantial amounts accumulated during reperfusion (25 nmol/L). Decreased NO during I/R was accompanied by increased superoxide, which during reperfusion reached 50 nmol/L without or 23 nmol/L with L-arginine treatment. Calcium-dependent cNOS was a major source of superoxide release (inhibited 70% by L-NMMA and 25% by L-NAME) during I/R.

CONCLUSIONS

L-Arginine treatment decreased superoxide generation by cNOS while increasing NO accumulation, leading to protection from constriction (microvessel area, 17.77+/-0.95 versus 11.66+/-2.21 microm2 untreated, P<.0005) and reduction of edema after reperfusion (interfiber area, 16.56+/-2.13% versus 27.68+/-7.70% untreated, P<.005).

Hypertrophy and transformation of muscle fibers in paraplegic patients

Transcutaneous electrical stimulation of the quadriceps femoris muscle was applied in 14 paraplegic patients (10 spastic patients with spinal cord lesions and 4 patients with conus-cauda lesions with denervation atrophy). In both the spastic and the denervated group, the vastus lateralis muscle was biopsied and computed tomography (CT) images of the entire upper leg were made both at the onset and termination of the 8-month training period. The stimulation was carried out twice a day for 20 min. The increase in muscle tissue was significant in the CT images. The biopsies showed that the fiber diameter of both fiber types increased during the training period in the spastic group from 47 to 67 microns and in the denervated group from 22 to 38 microns. In both groups, the differences were significant between the first and second biopsies. Both groups showed a marked Type 2 fiber predominance. The histological and CT findings correlated with the clinical improvement of muscle function.

Effect of the CO2 milliwatt laser on neuroma formation in rats

BACKGROUND AND OBJECTIVE

The purpose of this study was to determine whether the milliwatt laser can suppress neuroma formation at the end of a divided nerve.

STUDY DESIGN/MATERIALS AND METHODS

The peripheral nerves of eight rats were transected with microscissors and the cross-sectional area of their proximal ends was irradiated using the CO2 milliwatt laser. The power ranges used were similar to those applied to weld neural tissue.

RESULTS

None of the eight irradiated nerve ends formed a neuromatous bulb and only one of them regenerated into the surrounding tissues. Histologically, these nerve ends did not show the disorganized picture of classic neuromas. On morphometric measurements, they contained less connective tissue than the control nerve ends (P < 0.001) and their nerve fibers were larger in diameter (P < 0.001) and better myelinated (P < 0.001).

CONCLUSION

These findings in rats show that the CO2 milliwatt laser has the ability to suppress neuroma formation at the end of a divided nerve.

Efficacy of transferrin determination in human sera in the diagnosis of iron deficiency

Apparently healthy persons (n = 425) as well as 264 patients characterized by an iron concentration in serum < 7.2 mumol/l were examined. A latent iron deficiency was defined as a concentration of ferritin < 20 micrograms/l (males) and < 15 micrograms/l (females), without anaemia; manifest iron deficiency defined by an additional presence of hypochromic microcytic anaemia. Fifty-nine of 425 (= 14%) apparently healthy persons showed a latent iron deficiency. In the remaining 366 we established the following reference intervals for the concentration of transferrin in serum [mumol/l]: 25.2-45.3 (males), 29.1-54.5 (females, < or = 25 years of age) and 25.3-48.6 (females, > 25 years of age). Eight of 59 (= 14%) apparently healthy persons with latent iron deficiency had a transferrin concentration above the reference interval. Sixty-one of 264 (= 23%) patients with an iron concentration < 7.2 mumol/l showed a ferritin concentration < 20 micrograms/l (males) and < 15 micrograms/l (females). Thirty-eight of these 61 patients (= 62%) had a manifest iron deficiency. In 18 of these 38 patients (= 47%) the transferrin concentration was increased. For our 264 patients we determined the diagnostic validity of an increased transferrin concentration for diagnosis of iron deficiency, assuming an iron deficiency if the concentration of ferritin remained below the discrimination values mentioned above: The diagnostic sensitivity was 36%, the diagnostic specificity 97%, the predictive value of the positive test result 79% and the predictive value of the negative test result 83%.(ABSTRACT TRUNCATED AT 250 WORDS)

Regenerative potential of abdominal vagal nerves in rats

After truncal vagotomy, impaired gastric emptying may represent a serious complication. This led us to study the feasibility of a reinnervation of the antrum by microsurgical vagorrhaphy and vagoplasty. Sixty-four rats were randomly assigned to undergo either 1) no operation (control), 2) laparotomy and vagal dissection (sham operation), 3) truncal abdominal vagotomy with nerve segment resection, 4) truncal vagotomy followed by vagorrhaphy, or 5) vagal resection extending to the nerve of Latarjet followed by grafting of the gap using the resected vagal segment (vagoplasty). Six months after surgery, vagal regeneration was assessed by morphometry of the anterior vagus and the antral wall and by recording the gastric emptying of a radiolabeled meal, the contractile response to electrical stimulation of the cervical vagi, and basal and insulin-stimulated acid secretion. After truncal vagotomy, there was a marked degeneration of vagal fibers and no evidence of spontaneous reinnervation. After vagorrhaphy, a recovery of gastric secretory and motor functions as well as morphological data indicated vagal regeneration. After vagoplasty, a partial recovery of gastric motor functions and the morphological appearance suggested a partial vagal reinnervation.

[Relations between donor nerve size and degree of neurotization in the nerve transplant--an experimental study]

The present study was undertaken to investigate whether the number of myelinated fibers in a sensory nerve used as an autograft influences the result of nerve fiber regeneration in the graft. In 30 rabbits, the left saphenous nerve was used as an autograft. It was coapted to the motor branch to the rectus femoris muscle. Biopsies from both ends of the graft were taken. Animals were separated into four investigation groups, which were reexamined 3, 6, 9 and 12 months after the grafting procedure. Biopsies for histological and morphometric examination were again taken from the proximal and the distal part of the grafts. Thus, the number of myelinated nerve fibers in the different specimens could be obtained by computer-assisted image analysis. At the proximal end of the original saphenous nerve, the number of fibers varied between 1032 and 3100 (mean 2145). Corresponding data obtained from the distal end ranged from 1044 to 3084 myelinated nerve fibers (mean 1724). Fiber numbers in the proximal and distal parts of the grafts before and after regeneration were correlated to each other. In the whole population of specimens (correlation coefficient +/-0) as well as in the experimental subgroups, the quantitative success of neurotization in the grafts did not depend to a high degree upon the fiber numbers in the original saphenous nerve. The correlation coefficient for the proximal part of the graft exceeded 0.5 to only three and twelve months after grafting, but did not reach a level of statistical significance. In the distal part of the graft, the coefficient for a linear correlation was always less than 0.45.