Evaluation of handheld Raman spectrometers for the detection of intact explosives

The detection of intact explosives in the field provides a unique challenge for investigators, considering the sensitive and dangerous nature of these samples. Handheld Raman instruments have grown in popularity for the analysis of unknown samples in the field, combining speed of data collection and reliability with a size that allows for the instruments to be field portable. Handheld Raman instruments are used commonly in the field, and yet there is very little research on the detection capabilities of these instruments, specifically for explosive compounds. The present study aimed to evaluate the detection capabilities of two handheld Raman spectrometers, the Rigaku ResQ-CQL and the Field Forensics HandyRam™, using explosives analytical standards, including 2,4,6-trinitrotoluene (TNT), nitromethane (NM), ammonium nitrate (AN) and smokeless powder components such as diphenylamine (DPA), ethyl centralite (EC), and methyl centralite (MC). The spectrometers were evaluated on their sensitivity, the repeatability of the data, and the performance of the internal library when available. In addition, an interference study with glass and plastic containers was also performed. Finally, authentic intact explosive samples, including TNT flakes, a mixture of ammonium nitrate and fuel oil (ANFO), smokeless powder and nitromethane were analyzed to evaluate the developed method and test the detection capabilities of the spectrometers with authentic samples. Spectra were reproducible for all the analytes across both instruments, with regards to the peak location and the intensity. Spectra obtained with the Rigaku ResQ-CQL displayed better resolution for all analytes, including the authentic samples. In addition, its wider scan range allowed for the detection of more detailed peaks below 400 cm-1. Identifying the detection capabilities of these handheld instruments can therefore help guide investigators on how to best utilize them in the field.

Electron activated dissociation - a complementary fragmentation technique to collision-induced dissociation for metabolite identification of synthetic cathinone positional isomers

Over the last decade, a remarkable number of new psychoactive substances (NPS) have emerged onto the drug market, resulting in serious threats to both public health and society. Despite their abundance and potential toxicity, there is little information available on their metabolism, a crucial piece of information for clinical and forensic purposes. NPS metabolism can be studied using in vitro models, such as liver microsomes, cytosol, hepatocytes, etc. The tentative structural elucidation of metabolites of NPS formed using in vitro models is typically carried out using liquid chromatography combined with high-resolution tandem mass spectrometry (LC-HRMS2) with collision-induced dissociation (CID) as a fragmentation method. However, the thermally-excited ions produced with CID may not be sufficient for unambiguous identification of metabolites or their complete characterization. Electron-activated dissociation (EAD), a relatively new fragmentation approach that can be used to fragment singly-charged ions, may provide complementary structural information that can be used to further improve the confidence in metabolite identification. The aim of this study was to compare CID and EAD as fragmentation methods for the characterization and identification of synthetic cathinone positional isomers and their metabolites. The in vitro metabolism of 2-methylethcathinone (2-MEC), 3-methylethcathinone (3-MEC) and 4-methylethcathinone (4-MEC) was investigated with both CID and EAD methods using LC-HRMS2. Four, seven and six metabolites were tentatively identified for the metabolism of 2-MEC, 3-MEC and 4-MEC, respectively. Here, the metabolism of 3-MEC and 2-MEC is reported for the first time. The EAD product ion mass spectra showed different fragmentation patterns compared to CID, where unique and abundant product ions were observed in EAD but not in CID. More importantly, certain EAD exclusive product ions play a significant role in structural elucidation of some metabolites. These results highlight the important role that EAD fragmentation can play in metabolite identification workflows, by providing additional fragmentation data compared with CID and, thus, enhancing the confidence in structural elucidation of drug metabolites.

The differentiation of N-butyl pentylone isomers using GC-EI-MS and NMR

Forensic laboratories are faced with an ever-expanding seized drug landscape including the increasing prevalence of novel psychoactive substances (NPS), such as synthetic cathinones, that have varying potencies and scheduling. This study demonstrates a combined gas chromatography-electron ionization-mass spectrometry (GC-EI-MS) and nuclear magnetic resonance (NMR) spectroscopy approach for the differentiation of N-butyl pentylone isomers based on distinct retention times, characteristic EI mass spectra, and NMR characterization. Retention time reproducibility was assessed from 60 replicate measurements for each isomer over the course of a month. In addition, the effect of the mass spectrometer tune and the stability of an identified characteristic ion ratio using spectral data from ± 1 scan on either side of the peak apex were also statistically assessed using Welch's ANOVA testing. The presence of diastereomers for N-sec-butyl pentylone was identified using the developed GC-EI-MS method, which was confirmed using one-dimensional and two-dimensional NMR spectroscopy. The retention time reproducibility of the chromatographic method was ± 0.076% or less over the course of a month. An identified characteristic ion ratio between the abundance of the fragment ion at m/z 128 and the fragment ion at m/z 72 enabled the differentiation of the four N-butyl pentylone isomers, even when accounting for the effect of the mass spectrometer tune and mass spectral scans used to calculate the characteristic ion ratio. The 95% confidence interval mean abundance ratio of the fragment ions at m/z 128 and m/z 72 was 17.14 ± 0.14 for N-butyl pentylone, 6.44 ± 0.05 for N-isobutyl pentylone, 3.38 ± 0.02 for N-sec-butyl pentylone, and 0.75 ± 0.01 for N-tert-butyl pentylone. These results highlight the capabilities of a combined GC-EI-MS and NMR approach for the differentiation and characterization of synthetic cathinone isomers.

In vitro metabolism of cathinone positional isomers: does sex matter?

Synthetic cathinones, one of the most prevalent categories of new psychoactive substances, have been posing a serious threat to public health. Methylmethcathinones (MMCs), notably 3-MMC, have seen an alarming increase in their use in the last decade. The metabolism and toxicology of a large majority of synthetic cathinones, including 3-MMC and 2-MMC, remain unknown. Traditionally, male-derived liver materials have been used as in vitro metabolic incubations to investigate the metabolism of xenobiotics, including MMCs. Therefore, little is known about the metabolism in female-derived in vitro models and the potential sex-specific differences in biotransformation. In this study, the metabolism of 2-MMC, 3-MMC, and 4-MMC was investigated using female rat and human liver microsomal incubations, as well as male rat and human liver microsomal incubations. A total of 25 phase I metabolites of MMCs were detected and tentatively identified using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Seven sex-specific metabolites were detected exclusively using pooled male rat liver microsomal incubations. In addition, the metabolites generated from the sex-dependent in vitro metabolic incubations that were present in both male and female rat liver microsomal incubations showed differences in relative abundance. Yet, neither sex-specific metabolites nor significant differences in relative abundance were observed from pooled human liver microsomal incubations. This is the first study to report the phase I metabolic pathways of MMCs using in vitro metabolic incubations for both male and female liver microsomes, and the relative abundance of the metabolites observed from each sex.

Expert Algorithm for Substance Identification Using Mass Spectrometry: Application to the Identification of Cocaine on Different Instruments Using Binary Classification Models

This is the second of two manuscripts describing how general linear modeling (GLM) of a selection of the most abundant normalized fragment ion abundances of replicate mass spectra from one laboratory can be used in conjunction with binary classifiers to enable specific and selective identifications with reportable error rates of spectra from other laboratories. Here, the proof-of-concept uses a training set of 128 replicate cocaine spectra from one crime laboratory as the basis of GLM modeling. GLM models for the 20 most abundant fragments of cocaine were then applied to 175 additional test/validation cocaine spectra collected in more than a dozen crime laboratories and 716 known negative spectra, which included 10 spectra of three diastereomers of cocaine. Spectral similarity and dissimilarity between the measured and predicted abundances were assessed using a variety of conventional measures, including the mean absolute residual and NIST's spectral similarity score. For each spectral measure, GLM predictions were compared to the traditional exemplar approach, which used the average of the cocaine training set as the consensus spectrum for comparisons. In unsupervised models, EASI provided better than a 95% true positive rate for cocaine with a 0% false positive rate. A supervised binary logistic regression model provided 100% accuracy and no errors using EASI-predicted abundances of only four peaks at m/z 152, 198, 272, and 303. Regardless of the measure of spectral similarity, error rates for identifications using EASI were superior to the traditional exemplar/consensus approach. As a supervised binary classifier, EASI was more reliable than using Mahalanobis distances.

Expert Algorithm for Substance Identification Using Mass Spectrometry: Statistical Foundations in Unimolecular Reaction Rate Theory

This study aims to resolve one of the longest-standing problems in mass spectrometry, which is how to accurately identify an organic substance from its mass spectrum when a spectrum of the suspected substance has not been analyzed contemporaneously on the same instrument. Part one of this two-part report describes how Rice-Ramsperger-Kassel-Marcus (RRKM) theory predicts that many branching ratios in replicate electron-ionization mass spectra will provide approximately linear correlations when analysis conditions change within or between instruments. Here, proof-of-concept general linear modeling is based on the 20 most abundant fragments in a database of 128 training spectra of cocaine collected over 6 months in an operational crime laboratory. The statistical validity of the approach is confirmed through both analysis of variance (ANOVA) of the regression models and assessment of the distributions of the residuals of the models. General linear modeling models typically explain more than 90% of the variance in normalized abundances. When the linear models from the training set are applied to 175 additional known positive cocaine spectra from more than 20 different laboratories, the linear models enabled ion abundances to be predicted with an accuracy of <2% relative to the base peak, even though the measured abundances vary by more than 30%. The same models were also applied to 716 known negative spectra, including the diastereomers of cocaine: allococaine, pseudococaine, and pseudoallococaine, and the residual errors were larger for the known negatives than for known positives. The second part of the manuscript describes how general linear regression modeling can serve as the basis for binary classification and reliable identification of cocaine from its diastereomers and all other known negatives.

Comparison of in-source collision-induced dissociation and beam-type collision-induced dissociation of emerging synthetic drugs using a high-resolution quadrupole time-of-flight mass spectrometer

In-source collision-induced dissociation (CID) is commonly used with single-stage high-resolution mass spectrometers to gather both a molecular formula and structural information through the collisional activation of analytes with residual background gas in the source region of the mass spectrometer. However, unlike tandem mass spectrometry, in-source CID does not involve an isolation step prior to collisional activation leading to a product ion spectrum composed of fragment ions from any analyte present during the activation event. This work provides the first comparison of in-source CID and beam-type CID spectra of emerging synthetic drugs on the same instrument to understand the fragmentation differences between the two techniques and to contribute to the scientific foundations of in-source CID. Electrospray ionization-quadrupole time-of-flight (ESI-Q-TOF) mass spectrometry was used to generate product ion spectra from in-source CID and beam-type CID for a series of well-characterized fentanyl analogs and synthetic cathinones. A comparison between the fragmentation patterns and relative ion abundances for each technique was performed over a range of fragmentor offset voltages for in-source CID and a range of collision energies for beam-type CID. The results indicate that large fragmentor potentials for in-source CID tend to favor higher energy fragmentation pathways that result in both kinetically favored pathways and consecutive neutral losses, both of which produce more abundant lower mass product ions relative to beam-type CID. Although conditions can be found in which in-source CID and beam-type CID provide similar overall spectra, the in-source CID spectra tend to contain elevated noise and additional chemical background peaks relative to beam-type CID.

Anaesthetic Considerations in Facial Reconstruction for Down'S Syndrome

Sixty-three patients with Down's syndrome underwent facial reconstructive surgery under general anaesthesia in order to improve their acceptability and potential for functioning effectively in society. Preoperatively, one-third of the patients had respiratory illnesses, 11 (17.5%) had cardiac anomalies, and 5 (7.9%) had endocrinological abnormalities. Anaesthesia was based on spontaneous ventilation of halothane and N2O in oxygen via an endotracheal tube with appropriate monitoring. Only one patient had an intraoperative complication, an episode of ventricular dysrhythmia, but postoperatively 9 patients required nasopharyngeal airways or endotracheal intubation in order to maintain a patent upper airway. The anaesthetic considerations for facial reconstructive surgery in Down's syndrome are discussed.

Hematuria from arteriovesical fistula: unusual presentation of ruptured iliac artery aneurysm

Iliac artery aneurysm rupture can be rapidly fatal if not diagnosed immediately. These aneurysms usually present in patients with other aneurysmal diseases of the aortoiliac arterial system. If not diagnosed and surgically repaired, iliac artery aneurysms can proceed to expand and ultimately rupture, usually presenting with back, flank, or abdominal pain and, possibly, signs of systemic shock. We present an unusual case report of a common iliac artery aneurysm rupture presenting as gross hematuria due to an arteriovesical fistula. Only three other cases of arteriovesical fistulae have been reported previously. Unlike the case presented, all three of these cases involved trauma or surgical instrumentation or manipulation of the bladder.

Endogenous synthesis of arginine plays an important role in maintaining arginine homeostasis in postweaning growing pigs

This study was conducted to determine whether endogenous synthesis of arginine plays a role in regulating arginine homeostasis in postweaning pigs. Pigs were fed a sorghum-based diet containing 0. 98% arginine and were used for studies at 75 d of age (28.4 kg body weight). Mitochondria were prepared from the jejunum and other major tissues for measuring the activities of Delta1-pyrroline-5-carboxylate (P5C) synthase and proline oxidase (enzymes catalyzing P5C synthesis from glutamate and proline, respectively) and of ornithine aminotransferase (OAT) (the enzyme catalyzing the interconversion of P5C into ornithine). For metabolic studies, jejunal enterocytes were incubated at 37 degrees C for 30 min in Krebs-Henseleit bicarbonate buffer containing 2 mmol/L L-glutamine, 2 mmol/L L-[U-14C]proline, and 0-200 micromol/L gabaculine (an inhibitor of OAT). The activities of P5C synthase, proline oxidase and OAT were greatest in enterocytes among all of the tissues studied. Incubation of enterocytes with gabaculine resulted in decreases (P < 0.05) in the synthesis of ornithine and citrulline from glutamine and proline. When gabaculine was orally administered to pigs (0.83 mg/kg body weight) to inhibit intestinal synthesis of citrulline from glutamine and proline, plasma concentrations of citrulline (-26%) and arginine (-22%) decreased (P < 0.05), whereas those of alanine (+21%), ornithine (+17%), proline (+107%), taurine (+56%) and branched-chain amino acids (+21-40%) increased (P < 0.05). On the basis of dietary arginine intake and estimated arginine utilization, the endogenous synthesis of arginine in the 28-kg pig provided >/=50.2% of total daily arginine requirement. Taken together, our results suggest an important role for endogenous synthesis of arginine in regulating arginine homeostasis in postweaning growing pigs, as previously shown in neonatal pigs.

Recombinant leech antiplatelet protein prevents collagen-mediated platelet aggregation but not collagen graft thrombosis in baboons

Leech antiplatelet protein (LAPP) is a specific inhibitor of collagen-induced human platelet aggregation and adhesion to collagen under static conditions. Recombinant LAPP (rLAPP) and L-366,763 (acetylated-Cys-Asn-Pro-Arg-Gly-Asp-Cys-NH2), a peptidyl fibrinogen receptor antagonist, were evaluated in an anesthetized baboon thrombosis model using a collagen-coated graft segment of an arteriovenous shunt to elicit thrombus formation. Animals were randomized to receive systemic intravenous administration of rLAPP (100 micrograms.kg-1 x min-1; n = 5), L-366,763 (8.5 micrograms.kg-1 x min-1; n = 3), or saline (n = 3). Despite complete and selective inhibition of type I collagen-induced ex vivo aggregation of platelets, rLAPP had no significant effect on the rate or the extent of 111-In-labeled platelet deposition onto the collagen graft and no effect on template bleeding time. In contrast, L-366,763 completely prevented platelet deposition, maintained blood flow, and significantly prolonged bleeding time at the dosage that inhibited ex vivo aggregation in response to all agonists studied. In this study, the absence of an antithrombotic benefit of rLAPP contrasted sharply with the efficacy of the fibrinogen receptor antagonist. These results demonstrate that specific inhibition of collagen-mediated platelet aggregation alone is not sufficient to prevent platelet-dependent thrombosis in this baboon model.

Arterial reconstruction of vessels in the foot and ankle

OBJECTIVE

This study demonstrated that arterial reconstruction of vessels of the foot and ankle can preserve the majority of ischemic extremities with extensive tibial and peroneal occlusive disease and patent pedal arteries.

SUMMARY BACKGROUND DATA

There are successful reports of bypass procedures to the ankle and foot, but despite this, these procedures have not gained widespread acceptance among surgeons performing infra-inguinal revascularization. Primary amputation is often offered for such patients. For this reason, the authors have reviewed their experience with bypasses to the foot and ankle.

METHODS

A retrospective review was done of 75 arterial bypasses (5 bilateral), done since 1985, to the ankle and foot in 70 patients (38 males and 32 females). Fifty-four (77%) of the patients were diabetic. The age ranged from 55 to 95 years. Twenty-six (37%) were older than 80 years. The patients were selected for operative intervention because of severe tibioperoneal occlusive disease with ischemic rest pain or gangrene of the foot. Digital subtraction arteriography facilitated visualization of distal vessels. Operative principles included regional anesthesia, autogenous graft material, short bypass, non-traumatic vessel occlusion, selective operative arteriography, tension free ankle and foot skin closure, and concomitant conservative debridement of infected devitalized tissue. Incomplete pedal arch did not influence decision for operation. Indications for operation were: gangrene, 42 (56%); non-healing ulcer, 21 (28%); and rest pain, 12 (16%). Graft material was in situ greater saphenous vein, 40 (53%); translocated greater saphenous vein, 19 (25%); reversed greater saphenous vein, 11 (15%); and arm vein, lesser saphenous vein or vein patch, 5 (7%). Donor artery was popliteal, 30 (41%); common femoral, 26 (35%); and superficial femoral, 17 (23%). Recipient vessel was dorsalis pedis, 43 (57%); posterior tibial, 18 (24%); distal anterior tibial, 9 (12%); and distal peroneal, plantar or tibial endarterectomy, 5 (7%).

RESULTS

There were four (5.7%) deaths and three (4.2%) graft failures within 30 days. Early graft failure led to transmetatarsal amputation (1), below knee amputation (1), and conversion of graft to femoral (1), popliteal bypass graft with limb salvage (1). In one patient, significant tissue necrosis with infection necessitated a below knee amputation within 30 days, despite a patent graft. Long-term follow-up revealed 10 graft failures, 4 major amputations, 3 graft revisions, and 15 deaths. Cumulative primary and secondary patency was 79.0% and 81.6% at 36 months. Limb salvage was 87.5% at 36 months.

CONCLUSIONS

These results support an aggressive approach to limb salvage in patients with threatened limb loss, unreconstructable tibio-peroneal occlusive disease, and patent pedal arteries. Bypasses to the ankle and foot will maintain a functional extremity in the majority of these patients.

Selective factor Xa inhibition by recombinant antistasin prevents vascular graft thrombosis in baboons

A baboon model of high-shear, platelet-dependent vascular graft thrombosis was used to assess the antithrombotic effect of recombinant antistasin (rATS), a 119-amino acid protein with selective, subnanomolar inhibitory potency against coagulation factor Xa. In this model, a Dacron vascular graft segment of a femoral arteriovenous (AV) shunt provided the thrombogenic stimulus. Antithrombotic efficacy of rATS was assessed by continuous monitoring of 111In-labeled platelet and 125I-labeled fibrin(ogen) deposition onto the graft surface and blood flow through the vascular shunt. Systemic intravenous administration of rATS (2 or 4 micrograms/kg.min-1) dose dependently decreased both platelet and fibrin(ogen) deposition onto the graft. Vascular graft thrombus formation was completely inhibited at a systemic dose of rATS of 4 micrograms/kg.min-1. None of the AV shunts in animals receiving rATS at either dose occluded, and blood flow was maintained at 81 +/- 4% (2 micrograms/kg.min-1 rATS) or 96 +/- 3% (4 micrograms/kg.min-1 rATS) of basal flow. Systemic fibrinopeptide A elevations in response to exposure to the Dacron graft segment were completely suppressed by both doses of rATS. The ex vivo activated partial thromboplastin times were extended to greater than 150 seconds during infusion of both doses of rATS; however, even at fully antithrombotic doses, template bleeding times were not significantly increased. Thus, in this baboon model, rATS is a potent antithrombotic agent that inhibits both platelet and fibrin(ogen) deposition onto a Dacron vascular graft segment. Furthermore, these results demonstrate that selective inhibition of coagulation factor Xa by rATS can completely prevent vascular graft thrombus formation without significantly compromising primary hemostasis as measured by template bleeding time.

Immunocytochemical localization of platelets in baboon hepatic sinusoids using monoclonal mouse anti-human platelet glycoprotein IIIa following induction of thrombocytopenia

A commercially available mouse monoclonal antibody to human platelet glycoprotein IIIa was used to demonstrate sequestration of platelets in hepatic biopsies obtained from baboons following intravenous infusion of echistatin, a novel fibrinogen receptor antagonist derived from the venom of the snake Echis carinatus. Biopsies of liver and spleen were taken prior to administration of echistatin. The hepatic biopsies were either snap-frozen in Freon-22/liquid nitrogen or fixed in 10% neutral buffered formalin. Biopsies of spleen were snap-frozen. During infusion of echistatin (2.3 micrograms/kg/min), circulating platelet counts decreased from 331,000/mm3 to 167,000/mm3. Selective sequestration within the liver was confirmed using whole body gamma camera imaging to demonstrate 111Indium-oxine labeled platelet accumulation within the liver during the thrombocytopenic episode. Hepatic biopsies were again taken and either snap-frozen in Freon-22/liquid nitrogen or fixed in 10% neutral buffered formalin. Biopsies of spleen and inguinal lymph node were also snap-frozen. Platelet rich plasma smears, included as positive controls, dewaxed paraffin sections, and cryosections of liver, spleen, and lymph node were stained with monoclonal mouse anti-human platelet glycoprotein IIIa using an avidin biotinylated peroxidase complex (ABC) technique. Prior to infusion of echistatin, platelet staining within the liver was minimal. After echistatin infusion, hepatic cryosections showed prominent platelet staining within hepatic sinusoids. No localization was shown in lymph node, however, the spleen showed prominent platelet staining both before and after echistatin infusion. Platelet rich plasma smears were intensely positive. No prominent platelet staining was observed in formalin-fixed, paraffin-embedded material. Thus, this immunocytochemical technique may help localize platelets in cryosections of tissues from baboons and other primate species.

Antithrombotic efficacy of recombinant tick anticoagulant peptide. A potent inhibitor of coagulation factor Xa in a primate model of arterial thrombosis

BACKGROUND

Tick anticoagulant peptide is a specific, potent inhibitor of blood coagulation factor Xa. The effects of recombinant tick anticoagulant peptide (rTAP) and standard heparin (SH) were compared in an anesthetized baboon model of arterial thrombosis where platelet deposition onto a Dacron vascular graft segment of an arteriovenous (AV) shunt was studied.

METHODS AND RESULTS

Animals were randomized to receive systemic administration of SH (10 or 100 U/kg i.v. bolus followed by 0.4 or 1.0 U/kg/min i.v. infusion, respectively) or rTAP (6.25, 12.5, or 25.0 micrograms/kg/min i.v. infusion). rTAP, but not SH, caused a significant (p less than 0.05), dose-dependent reduction of indium-111 labeled platelet and iodine-125 labeled fibrin (ogen) deposition onto the graft. Deposition was not significantly increased from baseline values during infusion of 12.5 or 25.0 micrograms/kg/min of rTAP. Blood flow was maintained at 64 +/- 9, 95 +/- 2, or 97 +/- 2% of baseline following infusion of 6.25, 12.5, or 25.0 micrograms/kg/min of rTAP, respectively. Both SH and rTAP significantly (p less than 0.05) decreased the systemic fibrinopeptide A (FPA) elevation during exposure to the Dacron graft. rTAP was fully antithrombotic at APTT values of 42.6 +/- 2.4 seconds (less than twofold basal value), while SH had no antithrombotic efficacy despite APTT values greater than 150 seconds (greater than fivefold basal value).

CONCLUSIONS

The demonstrated antithrombotic effect of rTAP in the absence of alterations in primary hemostasis suggests that controlling thrombin generation through inhibition of factor Xa may be a novel and effective pharmacological approach in the prevention of high-shear arterial thrombosis.

Vein patch angioplasty for brachial arterial occlusion after cardiac catheterization

Brachial artery thrombosis may be encountered after cardiac catheterization using the Sones technique. Differing opinions have been reported regarding the optimal management of this injury. During the past five years, 20 patients have had surgical repair of the brachial artery after trauma from cardiac catheterization. Satisfactory results have been obtained in the majority of cases with local arterial thrombectomy and debridement with vein patch angioplasty. Arterial resection or vein bypass was needed in unusual cases. This injury should be repaired acutely to avoid long-term functional disability in all patients who present with a pulseless upper extremity.

Peroneal arteriovenous fistula. A complication of Fogarty catheter thromboembolectomy

The Fogarty catheter is an important device used by vascular surgeons to simplify the surgical treatment of thromboembolic disorders. Complications from use of the catheter are rare. This case report is about a patient who developed a peroneal arteriovenous fistula following popliteal thromboembolectomy. The literature regarding this unusual injury is reviewed.

Unusual manifestations of brachiocephalic vascular disease

Vascular problems involving the brachiocephalic vessels may occur from atherosclerosis, trauma, vasculitis, infection, and procedures for congenital heart disease. A wide variety of symptoms and signs may result from such disorders. This study is a report of five unusual manifestations of brachiocephalic vascular diseases. Diagnosis, management, and previous surgical experience is discussed relating to each case illustrating the complexity and variability of brachiocephalic vascular pathology.

Extradural bupivacaine and methadone for extracorporeal shock-wave lithotripsy

Combined extradural bupivacaine and methadone analgesia was investigated in 144 patients who underwent extracorporeal shock wave lithotripsy (ESWL). Patients were assigned randomly to one of three groups: group I--extradural 0.5% bupivacaine hydrochloride 0.75 mg kg-1; group II--extradural 0.1% methadone hydrochloride 4 mg after the bupivacaine; group III--as group II, plus a continuous extradural infusion of methadone 0.3 mg h-1 after operation. In all patients, only partial motor deficit occurred. During ESWL, patients who received extradural bupivacaine and methadone had significantly less pain compared with those who had bupivacaine alone (P less than 0.025). Extradural anaesthesia and immersion in the warm water bath were accompanied by only mild fluctuations in arterial pressure. After ESWL, significantly more patients with continuous methadone infusion were pain free (P less than 0.05) and they required less systemic analgesics. The anaesthesia during and after the ESWL procedure may be carried out safely and effectively by the administration of small doses of bupivacaine combined with methadone followed by infusion of the opioid.

Open chest cardiac massage: a review

Open-chest cardiopulmonary resuscitation (CPR) is physiologically superior to all external CPR methods studied thus far (P. Safer, Ann. Emerg. Med., 13 (1984) 856). Open-chest CPR should again be taught to physicians, and used more often after prolonged cardiac arrest. An extensive review on open cardiac massage is presented herein.

Prolonged bradycardia and hypotension after neostigmine administration in a patient receiving atenolol

A 78-year-old woman admitted for an elective hip operation was maintained on atenolol for control of her hypertension. She received neostigmine and atropine for reversal of muscle relaxation at the end of general anaesthesia. She then developed prolonged bradycardia and hypotension which necessitated the use of adrenaline and isoprenaline. Such an adverse reaction with atenolol has not been described previously.

Shock-wave treatment for stones in the kidney and ureter. The Jerusalem experience

We report on our first 6 months' experience with the extracorporeal shock-wave lithotripter (ESWL). During this period, 410 treatments were given to 350 kidneys and ureters. Our series was characterized by a particularly high proportion (40%) of multiple and large calculi and included 25 complete staghorns. The latter required multiple treatments (up to five), but no adjunct percutaneous nephrolithotomies were used in this series. A percutaneous nephrostomy was inserted in 20 cases. Thirty-six ureteric calculi above the pelvic level were treated in situ, with 95% success. The presence of a ureteric catheter is useful in these cases. Posttreatment pain was graded, and 61% of the patients did not require any analgesia. High-frequency jet ventilation was used in 91% of the 172 patients receiving general anesthesia and was of great value in minimizing respiratory-stone movement. The principal complication encountered was ureteric obstruction due to impacted particles. Temperature greater than 38 C occurred in 8.5% of the cases. It is suggested that the availability of the ESWL should encourage the early treatment of both renal and ureteric calculi, as well as enable the treatment of certain patients rejected for conventional surgery.

Early recognition and successful management of pelvic cellulitis following hemorrhoidal banding

Reports have focused attention on a rare but potentially serious complication following rubber band ligation of internal hemorrhoids: pelvic cellulitis with progression to shock and death. This report documents the successful treatment of pelvic cellulitis. The timely use of broad-spectrum antibiotics at an early stage is critical. Emphasis is placed on early recognition and treatment of this potentially fatal complication.

Ruptured aneurysm of the internal iliac artery

Our case and others reported in the literature illustrate that isolated aneurysms of the internal iliac artery are uncommon lesions with a highly lethal potential. The classic signs of ruptured abdominal aneurysm--pain, palpable mass, and shock--are usually altered with rupture of these aneurysms because of their deep location in the pelvis. Rectal examination will aid diagnosis. Surgical management of IIA aneurysms 4 cm or larger is indicated at the time of diagnosis, since rupture is usually fatal.

Unsuccessful control of abdominal aortic aneurysm by bypass and ligation

Two patients developed abdominal aortic aneurysm rupture following bilateral iliac artery ligation and axillobifemoral bypass. The first patient developed his rupture several weeks after outflow ligation and apparent thrombosis of the aneurysm. At autopsy, the aneurysmal rupture occurred in the left posterior junction between the thrombosed aneurysm and the normal aorta. In the second case, the aneurysm was not completely thrombosed and plans were in progress for thrombosis of the aneurysm when the patient developed frank rupture, necessitating operative intervention. The authors await the published experience of others with bilateral common iliac artery ligation and extra-anatomic bypass for abdominal aortic aneurysm, but these authors do not currently recommend this management plan.

An investigation of the role of lactic acid production in the causation of metabolic acidosis resulting from raised intracranial pressure in rabbits

Intracranial pressure (ICP) was acutely raised in anaesthetized rabbits by the injection of saline into the cisterna magna. The raised ICP was maintained at 200 mm Hg for 3 min after which it was allowed to return to baseline values. The profound metabolic acidosis produced (mean base deficit reaching 17.99 +/- SD 4.06 mmol/1 30 min after raised ICP) was found to be in part related to an increase in arterial blood lactate (from mean 7.04 +/- SD 3.26 mmol/l before raised ICP to mean 13.57 +/- SD 5.28 mmol/l 30 min after raised ICP). It would appear that systemic sympathetic nervous system discharge consequent upon raising ICP results in intense vasoconstriction and thus an increase in anaerobic metabolism and inorganic acid production.

[Initial studies on the intraoperative use of spinally administered somatostatin]

7 cases are reported demonstrating that intrathecal or epidural administration of somatostatin intraoperatively reduced the requirement for other anaesthetics. Somatostatin acts as a potent analgesic, which does not impair circulatory parameters and which possesses no centrally depressing effect. Spinal administration of somatostatin could therefore gain importance in high-risk category patients with normal metabolism.

Hypobaric spinal anesthesia in the operative management of orthopedic emergencies in geriatric patients

Hypobaric spinal anesthesia was administered to 40 patients undergoing lower limb surgery. Twenty-nine of the patients were debilitated geriatric patients who presented with orthopedic emergencies, in most cases a fractured hip. Hypobaric spinal anesthesia was found to be a simple and safe procedure that provided adequate analgesia. Due to its inherent nature, hypobaric spinal anesthesia does not necessitate positioning of the patient on the injured, painful side (unlike hyperbaric spinal or epidural anesthesia) and, therefore, facilitates a smooth and painless transfer of the patient to the operating table. Complications encountered were similar to those following hyperbaric anesthesia.

Physostigmine antagonizes morphine-induced respiratory depression in human subjects

The effect of physostigmine on the respiratory depression induced by morphine was studied in human subjects who received morphine as part of their preanesthetic medication. After pretreatment with droperidol (2.5-5 mg, iv) to prevent nausea, the change in minute ventilation was measured in 16 patients in response to increasing concentrations of inspired CO2 (CO2-response curve) by the rebreathing method. This was repeated 30 min after morphine (0.166 mg/kg, iv) in nine subjects and in seven controls who did not receive morphine and again 5-10 min after physostigmine (13-33 micrograms/kg, iv) in all subjects. All subjects were given N-butylhyoscine hydrobromide (5 mg, iv) to antagonize any peripheral cholinergic effects of physostigmine. Morphine decreased the mean slope of the CO2-response curve from 1.78 +/- 0.18 to 1.12 +/- 0.14 1 X min-1 X mmHg-1 (P less than 0.01) and increased the alveolar PCO2 for a fixed minute ventilation (position of curve) from 45.0 +/- 1.3 to 51.9 +/- 1.5 mmHg (P less than 0.001). Physostigmine restored the mean slope after morphine to control value, i.e., 1.79 +/- 0.231 X min-1 X mmHg-1, and position to 46.2 +/- 1.2 mmHg (P less than 0.001). Physostigmine did not increase the slope or alter the position of the CO2-response curves of subjects given droperidol alone. The authors conclude that physostigmine can reverse the respiratory depressant effect of morphine and restore the sensitivity of the respiratory center of CO2, presumably by raising acetylcholine levels in the brain after these have been reduced by morphine.

Vaginal delivery following previous cesarean birth

Because of the rising cesarean birth rate in the United States, renewed interest in vaginal delivery after prior abdominal operation has been evident. In a prospective collaborative study 789 patients were evaluated for inclusion into this investigation. Of the 717 subjects who entered the study 162 chose to attempt vaginal birth and 101 were successful. Desire for tubal sterilization and the lack of prior vaginal delivery were significant correlates of the group selecting repeat abdominal birth and of those who were unsuccessful when vaginal delivery was attempted. There were eight dehiscences and three uterine ruptures among the 717 patients and none was related to catastrophic outcome for the mother or neonate. Perinatal losses (12) were not related to uterine rupture or method of delivery. There were no significant differences in uterine disruption between patients selecting either route of delivery. Likewise ancillary factors such as a prior febrile puerperium (endometritis), number of prior cesarean births, low-vertical uterine incisions, recurrent operative indications, the use of epidural anesthesia, or oxytocin administration were not discriminating factors in whether women chose to attempt or were successful in completing vaginal delivery after prior abdominal birth. From our data vaginal birth after cesarean section appears to be safe if conducted in a carefully selected population that is closely monitored in a prospective manner.

Crohn's disease of the esophagus

In 1932 Crohn, Ginzburg, and Oppenheimer described a distinct pathologic and clinical entity characterized by a chronic inflammatory process of unknown etiology involving the terminal ileum. Since then, Crohn's disease has been recognized in all portions of the alimentary canal from mouth to anus. Crohn's disease of the esophagus is a rare process. Such a patient is reported with a review of the literature. A review of the English literature reveals reports of 20 patients with Crohn's disease of the esophagus. One-third of these patients had regional enteritis requiring resection. Esophageal stricture, stenosis, or fistula were frequent complications requiring resection. Regional esophagitis is difficult to distinguish from carcinoma, frequently leads to esophagitis, and is associated with a higher mortality rate than Crohn's disease in other portions of the alimentary tract.