OUTBREAK OF SALMONELLA FOOD POISONING AT HIGH ALTITUDE

An outbreak of food poisoning occurred among soldiers of an army unit located at high altitude (3300m) in western Himalayas. A total of 78 of the 103 soldiers who had consumed the incriminated meal suffered from the illness. Sixteen of the 78 had symptoms severe enough to warrant admission to hospital. The symptoms consisted of diarrhoea, vomiting, fever, headache, vertigo and abdominal cramps of varying intensity. Salmonella enteritidis was isolated from 6 stool samples and in one blood sample. Epidemiologically, frozen fowl was traced as the probable incriminating food agent responsible for the outbreak. This is probably the first such outbreak being reported from high altitude. It is of significance for the Indian Armed Forces, as the cause of the food poisoning was traced to an inherent shortcoming in the supply of food items to the troops located in far flung and isolated regions and in the cooking practices being followed.

Assembled coronavirus from complementation of two defective interfering RNAs

In the presence of an RNA- temperature-sensitive (ts) mutant helper virus, two coronavirus mouse hepatitis virus (MHV) defective interfering (DI) RNAs complemented each other, resulting in the assembly of MHV particles; we used this ability to complement as a means to study coronavirus assembly. One of the two DI RNAs was DIssA, a naturally occurring self-replicating DI RNA encoding N protein and the gene 1 proteins that encode RNA polymerase function; DIssA supports the replication and transcription of other non-self-replicating DI RNAs. The other DI was a genetically engineered DI RNA that encoded sM and M proteins. Coinfection of these two DIs at the nonpermissive temperature for the ts helper virus resulted in replication and transcription of both DI RNAs but not in synthesis of the helper virus RNAs. MHV particles containing DI RNAs, N protein, and M protein, all of which were exclusively derived from the two DI RNAs, were released from the coinfected cells; the amount of sM protein was below the limits of detection. Analyses of DI RNAs with mutations in the two envelope protein genes demonstrated that M and sM proteins appeared to be required for assembly and release of MHV particles that contained DI RNAs and N protein, while S protein was not required for assembly and release of MHV particles.

Depth profiling of mammalian cells by photoacoustic spectroscopy: localization of ligands

Phase-resolved monitoring of photoacoustic signals can provide information about the depth profile of a sample. We describe an application of this principle to determine the depth profiles of ligands and antitumor agents in mammalian cells. Measurements of the in-phase and quadrature components of the photoacoustic spectra (which yield information from the surface and the interior, respectively) of a tumor cell line, AK-5, treated with the antitumor agent coralyne chloride have been made. They clearly show that the drug accumulates in the cell interior and is not seen on the cell surface, providing in situ evidence for the localization of this drug. Histochemical dyes which stain cells uniformly give identical in-phase and quadrature spectra; spectra of cells incubated with nuclear stains demonstrate a differential staining of the nucleus and the cytoplasm. These results demonstrate the usefulness of phase-resolved photoacoustic spectroscopy in monitoring differential interactions of drugs and other ligands with cells.

Aberrant external jugular vein phlebectasia with tongue pain

We have not encountered any other report of phlebectasia with tongue pain in the literature. The pain disappeared after the anomalous venous communication was excised.

Hyperbaric oxygen therapy and free radical production: an experimental study in doxorubicin (Adriamycin) extravasation injuries

The role of hyperbaric oxygen (HBO) therapy in free radical-mediated tissue injury is not clear. HBO has been shown to enhance the antioxidative defense mechanisms in some animal studies, but HBO has also been reported to increase the production of oxygen free radicals. To investigate this controversy, we studied the effect of HBO in a doxorubicin (Adriamycin) extravasation model, because the cytotoxic activity of doxorubicin is partly related to its quinone structure, which leads to the formation of cytotoxic oxygen intermediates. Fifty-four Sprague-Dawley rats underwent injection of 0.3 ml doxorubicin solution (2 mg per milliliter) intradermally on both flanks as described by Rudolph and colleagues. Group I (N = 28) received HBO treatment (2 hours at 2 ATA) for 3 days prior to injection and 7 days postinjection. Group II (N = 26) received no HBO treatment. At 2, 3, and 5 weeks, the size of the ulcers and the surrounding area of alopecia in group I (+HBO) were significantly larger than in group II (-HBO): 112.2 mm2 vs. 42.8 mm2 (p < 0.01) and 1,132.2 mm2 vs. 364.8 mm2 (p < 0.005). Biochemical analysis of the biopsied skin ulcers, to measure the parameters of oxygen free radical production, indicated (similar) low levels of xanthine oxidase for both groups. However, significantly elevated levels of malonyldialdehyde (MDA), indirect evidence of free radical production, was observed in group I (+HBO) in comparison with group II (-HBO): 36.58 vs. 5.84 ng per minute per milligram protein (p < 0.001), which might indicate free radical-induced cellular injury. It is concluded that in this animal study the cytotoxicity of doxorubicin is potentiated by HBO therapy. The elevated levels of MDA suggest a direct additive cytotoxic effect by increased membrane lipid peroxidation. HBO therapy, therefore, might be deleterious in the early (preulcer) stage of doxorubicin extravasation.

Murine coronavirus packaging signal confers packaging to nonviral RNA

Studies of defective interfering (DI) RNAs of the murine coronavirus mouse hepatitis virus (MHV) suggest that a 69-nucleotide-long packaging signal is necessary for MHV genomic RNA packaging into MHV particles. In this study we showed that when RNA transcripts that consisted of a non-MHV sequence and the packaging signal were expressed in MHV-infected cells, they were packaged into MHV particles. Those RNA transcripts that lacked the packaging signal or those containing a mutated packaging signal did not package efficiently. Thus, the presence of the packaging signal was sufficient for RNA packaging into MHV particles.

In vivo characteristics and localisation of carotenoid pigments in psychrotrophic and mesophilic Micrococcus roseus using photoacoustic spectroscopy

Photoacoustic spectra of cells of M. roseus were recorded to study the in vivo characteristics and localisation of the carotenoid pigments in these cells. The PA spectra indicated that both the psychrotrophic and mesophilic strains had similar chromophores. The cis carotenoids were prominent in the psychrotrophic M.roseus whereas shorter polyenes were more prominent in mesophilic M.roseus. Further, depth profiling photoacoustic studies revealed that in both the strains of M.roseus the bulk of the chromophore was associated with the cell membrane.

The use of cryopreserved microvenous allografts in the venous system without immunosuppression: an experimental study

Autogenous vein grafts are currently the number one choice in microsurgical practice for managing vessel length discrepancies. A significant percentage of these grafts is used in the venous system. Allografts may serve as a viable alternative source of vein grafts. Few studies in the past have described the use of cryopreserved vein grafts (1 mm in diameter) in the venous system. In the present study, we cryopreserved the femoral veins of rats and transplanted these across rat species (ACI to Lewis) as interpositional vein grafts into a defect in the femoral vein. Short-term patencies (21 days), expressions of systemic antigenicity, histology, and scanning electron microscopic studies were performed. We obtained 100% patencies with fresh control veins and cryopreserved veins at 21 days.

Comparative clinical study of the sure-closure device with conventional wound closure techniques

The Sure-Closure device, designed for wound closure, harnesses the viscoelastic properties of the skin. It has been used in clinical studies in the past. We have evaluated the role of this device in complex wound problems and compared it to closure achieved by conventional wound closure methods such as skin grafts and flaps. A total of 40 patients with multiple wound etiologies were examined. We used the device under local and general anesthesia. In addition, we performed cost analysis on the use of the device and compared this to traditional methods. We found a cost reduction trend associated with the Sure-Closure method (p < .05). All of the 24 patients in whom the device was used to close the wounds had complete primary closure. The device is also easy to use. When used for delayed stretching, as in some of our patients, the compliance rate was high.

Residual silicone detection using MRI following previous breast implant removal: case reports

The current controversy surrounding the safety of silicone gel breast implants has resulted in an increasing number being removed. Although previous reports have suggested that remnants of the implant capsule are reabsorbed after explantation surgery, the persistence of the capsule in fact may be associated with implant fragments and silicone gel leakage. In this study we have used magnetic resonance imaging (MRI) to identify residual silicone gel and silicone granulomas following the removal of silicone gel breast implants. Four representative clinical case reports are presented. These patients, who had residual silicone present in their bodies, presented to us with breast pain, palpable masses, or abnormal calcific mass densities apparent on a mammogram. High-resolution MRI images were found to be helpful in identifying local and remote collections of silicone gel, silicone granulomas, and residual capsules that were incompletely removed from previous explantation surgery. MRI breast images demonstrated high resolution and provided the accurate anatomical locations of residual silicone gel and silicone granulomas in all the regions of breast parenchyma, chest wall muscles, and axillae. Patients with persistent local symptoms following explantation surgery may benefit from an evaluation of the breast using MRI.

Characterization of the effects of two new arginine/citrulline analogues on constitutive and inducible nitric oxide synthases in rat aorta

1. New potent inhibitors of nitric oxide synthase (NOS) may be useful in the treatment of septic shock, a disorder characterized by a vascular hyporeactivity to catecholamines caused by an overproduction of nitric oxide (NO-). We examined the effects of L-thiocitrulline (L-TC) and S-methyl-L-thiocitrulline (L-SMTC), novel NOS inhibitors, on the constitutive and inducible NOS in rat aorta and compared those effects with inhibition due to NG-methyl-L-arginine (L-NMA). 2. Phenylephrine evoked similar concentration-contraction curves in the control rings and in the rings treated with these different NOS inhibitors (10 microM), whereas 100 microM of L-NMA, L-TC or L-SMTC increased significantly, and to a similar extent, contractions evoked by phenylephrine in aortic rings with endothelium without significantly affecting the maximal responses. 3. Relaxations evoked by acetylcholine, adenosine triphosphate, or calcium ionophore were significantly inhibited in a dose-dependent manner by L-NMA, L-SMTC, or L-TC (10-100 microM). The potencies of these inhibitors in reducing the relaxations of these vasodilators were not significantly different. 4. In endotoxin-treated preparations with endothelium, the three L-arginine analogues (10 microM) significantly potentiated contractile responses to phenylephrine (pEC50: 6.73 +/- 0.12 and 7.3 +/- 0.12, 7.34 +/- 0.13, or 7.22 +/- 0.14; in the absence and the presence of L-NMA, L-TC, or L-SMTC respectively) and increased maximal contractions from 1.53 +/- 0.15 g to 1.95 +/- 0.13 g, 2.08 +/- 0.12 g, and 2.03 +/- 0.13 g with L-NMA, L-TC, and L-SMTC respectively. A higher concentration of these NOS inhibitors (100 microM)further increased contractions evoked by this alpha1-agonist without further enhancing the maximal contractions; however, contractions evoked by 10 nM phenylephrine were significantly greater in the presence of L-SMTC or L-TC than in the presence of L-NMA (100 microM) (L-NMA: 0.4 +/- 0.11 g; L-TC:0.78 +/- 0.14 g and L-SMTC: 0.82+/-0.17 g). The effects of these inhibitors on NO- synthesis induced by endotoxin were significantly reversed by addition of L-arginine (1 mM) but not by L-citrulline (1 mM). InLPS-treated rings with endothelium, all three NOS inhibitors (100 microM) shifted the concentration contraction curves evoked by phenylephrine significantly to the left (pEC5o: 7.19 +/- 0.03 and 7.79 +/- 0.08,8.01 +/- 0.07, or 8.02 +_ 0.07, in the absence and the presence of L-NMA, L-TC, or L-SMTC, respectively)and increased significantly maximal contractions from 2.05 +/- 0.05 g to 2.38 +/- 0.14 g, 2.5 +/- 0.12 g, and 2.4 +_ 0.21 g with L-NMA, L-TC, and L-SMTC, respectively. L-TC and L-SMTC were significantly more potent than L-NMA in potentiating contractions evoked by 10 nM and 30 nM phenylephrine.5. L-TC and L-SMTC produced dose-dependent increases in tone in LPS-treated aortic rings with and without endothelium. In LPS-treated rings with endothelium, L-NMA induced contractions but in preparations without endothelium low concentrations of L-NMA induced small contractions while high concentrations of this inhibitor evoked relaxations. In both preparations L-TC and L-SMTC were significantly more potent than L-NMA in increasing vascular tone.6. These results suggest that L-SMTC, L-TC and L-NMA were equipotent on basal and agonist stimulated NO- synthesis produced by the constitutive isoform of NOS, whereas the two new L-arginine analogues were more potent than L-NMA in inhibiting the production of NO- induced by endotoxin in rat aorta.

S-alkyl-L-thiocitrullines. Potent stereoselective inhibitors of nitric oxide synthase with strong pressor activity in vivo

Nitric oxide synthase catalyzes the oxidation of a guanidino nitrogen of L-arginine to nitric oxide with concomitant formation of citrulline. Enzyme activity is inhibited by a variety of N omega-monosubstituted L-arginine analogs including N omega-alkyl-, N omega-amino-, and N omega-nitro-L-arginine derivatives. We report here that both constitutive and inducible isoforms of nitric oxide synthase are strongly inhibited by S-alkyl-L-thiocitrullines (N delta-(S-alkyl)isothioureido-L-ornithines) with n-alkyl groups of one to three carbons. These compounds represent a novel class of inhibitors and are the most potent nitric oxide synthase-inhibiting amino acids described to date. Inhibition is reversible, stereoselective, and competitive with L-arginine. Spectral studies show no direct interaction of inhibitor sulfur with heme iron, a result in contrast to that seen previously with the parent compound, L-thiocitrulline. The S-alkyl-L-thiocitrullines have strong pressor activity in normotensive control rats; S-methyl-L-thiocitrulline reverses hypotension in a rat model of septic peritonitis and in dogs administered endotoxin. These latter findings suggest that the inhibitors may have therapeutic utility in treating hypotension due to the overproduction of nitric oxide.

Evaluation of autogenous tissue breast reconstruction using MRI

Recent controversy encountered with silicone breast implants has increased the use of autogenous tissue for breast reconstruction following mastectomy. Surveillance of patients who have undergone autogenous tissue reconstruction is important in the evaluation of recurrent or new cancer. Magnetic resonance imaging (MRI) has proven to be a useful technique in the delineation of soft tissues and provides excellent resolution. Recently, MRI has been reported to be a valuable diagnostic imaging modality for the evaluation of augmented breast implant patients with regard to implant rupture detection, silicone granuloma identification, and silicone gel migration delineation. In this study, various autologous tissue donor sites currently available for breast reconstruction were imaged by MRI. The following donor flaps were included: fleur-de-lis, TRAM, gluteal, and tensor fasciae latae. A total of 10 clinical cases were investigated. The anatomic basis of each flap type is illustrated, and various tissue components of flap tissue (skin, fat, and muscle) are demonstrated on MRI scan. Anatomic knowledge of autogenous tissue types and MRI appearance of the flap-breast-chest-wall interface are critical in the surveillance and follow-up of breast cancer patients.

L-thiocitrulline. A stereospecific, heme-binding inhibitor of nitric-oxide synthases

Nitric-oxide synthase (NOS) catalyzes the oxidation of L-arginine to citrulline and nitric oxide (NO). The enzyme is inhibited by a variety of N omega-monosubstituted L-arginine analogs, and some of these compounds are useful in reversing pathologies associated with the overproduction of NO (e.g. the hypotension of septic shock). We report here that L-thiocitrulline (gamma-thioureido-L-norvaline) is a potent, stereospecific inhibitor of the constitutive brain and endothelial isoforms of NOS as well as the isoform induced in vascular smooth muscle cells by lipopolysaccharide and interferon-gamma. Steady state kinetic studies show L-thiocitrulline inhibition is competitive with L-arginine (Ki approximately 4-20% of KArgm), indicating that initial binding is as a substrate/product analog. In contrast to L-arginine and N omega-methyl-L-arginine, the prototypic NOS inhibitor, L-thiocitrulline binding elicits a "Type II" difference spectrum, indicating a high spin to low spin transition of the iron in the heme cofactor. This finding suggests that L-thiocitrulline is contributing the sixth ligand to heme iron, probably through the thioureido sulfur. Such interaction with heme iron neither stimulates nor inhibits the direct flavin-mediated cytochrome c reduction activity of the enzyme, but it does inhibit heme-dependent superoxide formation. In vivo, L-thiocitrulline is a potent pressor agent in both normal and endotoxemic rats, the latter finding suggesting utility in treating the hypotension of septic shock.

Closure of large postradiation vesicovaginal fistula with rectus abdominis myofascial flap

We report the case of a patient who developed a large radiation-induced vesicovaginal fistula. She also had a paucity of the omentum due to previous laparotomy and adhesions. We were able to treat this patient successfully with a pedicled myofascial rectus abdominis flap.

In vivo anatomic study of cutaneous perforators in free flaps using magnetic resonance imaging

Adequate knowledge of perforator location preoperatively will enable the surgeon to achieve optimal flap design and flap survival. Most previous attempts have relied on the use of Doppler ultrasound and earlier anatomic knowledge. With ultrasound, there may at times be signals from overlapping blood vessels. Magnetic resonance imaging (MRI) is sensitive to flowing blood and, on an MRI scan, dark-flow void characterization is used to identify perforators. This study was undertaken to evaluate the anatomic location and the number of perforators in the flap zone, based on inherent blood flow, and to determine information about the dominant perforators for free-flap design, using MRI. The CSMEMP technique allowed the characterization of flow void signals, which appeared in the image as dark spots. This technique also enabled differentiation of the surrounding tissue, with a high degree of accuracy. The relationship of the perforators aided in an "ideal" flap design. No necrosis was noted in any of these cases. It appears from this study that MRI can be a useful imaging modality, to assess the location and number of perforators in musculocutaneous flaps.

Synthesis of L-thiocitrulline, L-homothiocitrulline, and S-methyl-L-thiocitrulline: a new class of potent nitric oxide synthase inhibitors

Nitric oxide synthase catalyzes the NADPH- and O2-dependent conversion of L-arginine to L-citrulline and nitric oxide. L-Thiocitrulline, L-homothiocitrulline, and S-methyl-L-thiocitrulline, novel citrulline analogs, have been synthesized and are shown to be potent inhibitors of both the constitutive brain and the inducible smooth muscle isoforms of nitric oxide synthase. Although many N omega-monosubstituted arginine derivatives inhibit nitric oxide synthase, inhibitory citrulline derivatives have not previously been reported. S-Methyl-L-thiocitrulline is significantly more potent than N omega-methyl-L-arginine, the prototypic nitric oxide synthase inhibitor.

Cryopreserved microvascular conduits: current applications and future prospects

Modern cryopreservation techniques have resulted in the clinical use of cryopreserved allograft heart valves and large diameter veins. In addition to these large vascular tissues, there is a need for small-diameter vascular allografts. We review our studies of cryopreserved rat microvenous allografts (1 mm diameter) in both the arterial and venous systems. The clinical utilization of cryopreserved allografts in reconstructive microsurgery and the potential problems associated with the use of allogeneic tissues will be addressed. Further applications for vascular cryopreservation in reconstructive surgery include small-diameter arteries, vascularized tissue flaps, and limbs.