Muscle autografts in nerve gaps. Pattern of regeneration and myelination in various lengths of graft: an experimental study in guinea pigs

Denatured muscle autograft contains large inner basement membrane tubes, which are anatomically and chemically similar to peripheral nerve basement membrane tubes. These autografts can be used for bridging nerve gaps. In 30 Duncan-Hartley guinea pig sciatic nerves, experimentally induced gaps of 5 mm, 10 mm, and 15 mm were bridged with freeze-thawed gluteus maximus muscle autografts. The results were studied for up to 12 weeks. Functional and histological criteria, morphometry, and electron microscopy were used for the evaluation of regeneration and myelination. Functional recovery was seen by 12 weeks in 5-mm grafts. Morphometric study of 1-microm semithin sections was carried out, and the number of axons in each representative field was studied, as the percentage of myelinated and unmyelinated fibers; the thickness of myelin was also measured. The percentage of myelinated and unmyelinated fibers was estimated by transmission electron microscopy (TEM). Axonal repopulation in the distal segment was seen by the third week in the 5-mm graft, and myelination was more extensive in this group in comparison to the others. On morphometric analysis, the mean fiber diameter in the distal part of the graft was 3.81 microm in the 5-mm graft and 2.9 microm in the 15-mm graft at 12 weeks. The results of this experiment prove that the length of the graft is an important consideration for muscle autografts when they are used for mixed peripheral nerve repair.

The relation between nutrition indices and age in patients on continuous ambulatory peritoneal dialysis receiving similar small solute clearances

OBJECTIVE

To analyze the effect of age on nutrition indices in subjects on the same continuous ambulatory peritoneal dialysis (CAPD) schedule.

METHODS

We analyzed 613 sets of clearance values and nutrition indices in 302 CAPD patients. Small solute clearances included urea clearance (Kt/Vurea) and creatinine clearance (Ccr). Nutrition indices included body mass index (BMI), serum albumin, urea and creatinine, 24-h urea nitrogen and creatinine excretion in urine plus dialysate, protein nitrogen appearance (PNA), PNA normalized by standard weight (nPNA), lean body mass (LBM) computed by creatinine kinetics, and LBM/Weight. CAPD subjects were classified in 4 age quartiles (Q): Group Q1, age 33.7 +/- 7.6 years, N = 149; group Q2, age 49.5 +/- 3.8 years, N = 158; group Q3, age 61.5 +/- 2.6 years, N = 154; and group Q4, age 72.1 +/- 5.4 years, N = 152. Group comparison was done by one-way ANOVA or chi-square. Predictors of low nutritional parameters were identified by logistic regression. Selected variables were compared by linear regression.

RESULTS

Mean Kt/Vurea and Ccr were above the current adequacy standards and did not differ between the age quartiles. In contrast, older quartiles had, in general, lower nutrition indices than younger quartiles. However, the youngest quartile had the lowest BMI. By logistic regression, young age was a predictor of low BMI, while advanced age was a predictor of low creatinine and urea nitrogen excretion, low nPNA, and low LBM/Weight. The regressions of nPNA on Kt/Vurea differed between the age quartiles. By these regressions, the youngest quartile had higher nPNA values for the same Kt/Vurea than the oldest quartile in the clinically relevant range of Kt/Vurea and nPNA values.

CONCLUSIONS

Nutrition indices are worse in older than in younger CAPD patients with the same small solute clearances. Nutrition of CAPD patients is adversely affected by age and requires special attention in the older age group.

Familial presacral masses: Screening pitfalls

BACKGROUND/PURPOSE

Anterior sacral meningocele (ASM) and presacral teratoma (PT) are related malformations. Both can have familial occurrence. Surgical treatment of occult cases is essential. Hence, it is important to screen the asymptomatic relatives. Plain radiograph of the sacrum to look for any bony abnormalities is the usual accepted screening modality. The authors report ASM and PT in siblings (with positive family history) with no sacrococcygeal bony abnormality on imaging. Both the siblings had presacral mass on imaging.

METHODS

The medical records of 2 siblings with ASM and PT were reviewed for the clinical presentation, diagnostic workup, and family history.

RESULTS

One sibling was symptomatic, whereas the other was completely asymptomatic. A family history of sacral bony abnormalities and anterior meningoceles was present in father, 2 paternal cousins, paternal uncle, paternal aunt, paternal grandmother, and paternal grand uncle.

CONCLUSIONS

These case reports suggest that imaging for screening for ASM and PT should be directed at identifying the presacral mass rather than sacral bony defect. Hence, computed tomography or magnetic resonance imaging looking for presacral mass rather than plain radiograph should be the screening modality. J Pediatr Surg 36:1841-1844.

Painless destruction of the shoulder joint: a case report

A case of painless destruction of the shoulder joint is reported for its rarity and unusual presentation as a neuroarthropathic joint with no evidence of neurological disease. A differential diagntosis of Gorham-Stout syndrome and avascular necrosis was discussed.

Spectral karyotyping analysis of head and neck squamous cell carcinoma

OBJECTIVES/HYPOTHESIS

The genetic content of head and neck squamous cell carcinomas is ill defined. Spectral karyotyping (SKY) is a new technique that allows the simultaneous detection of all chromosomal translocations by labeling each individual chromosome with different fluorescent agents. In the current study we used SKY to analyze cell lines and a primary tumor derived from head and neck squamous cell carcinomas (HNSCC) to delineate recurrent translocations and breakpoints.

STUDY DESIGN

Spectral karyotyping analysis of head and neck cancer.

METHODS

Two cell lines (MDA886 and MSK922) and one primary tumor in short-term culture were subjected to metaphase growth arrest with colcemide in their exponential growth phase and fixed onto glass slides. Painting probes for each of the autosomes and the sex chromosomes were generated from flow-sorted human chromosomes using sequence-independent DNA amplification. The probes were labeled using a polymerase chain reaction-based reaction and hybridized to metaphase preparations for 2 days at 37 degrees C. Biotinylated probes were detected using avidin Cy5 and digoxigenin-labeled probes with an anti-mouse digoxigenin antibody followed by goat anti-mouse antibody conjugated to Cy5.5. Chromosomes were counterstained with 4,6-diamino-2-phenyliodole (DAPI), and a minimum of five metaphases were captured and analyzed for each case. Breakpoints on the SKY-painted chromosomes were determined by comparison of corresponding DAPI banding.

RESULTS

Spectral karyotyping analysis revealed a complex pattern of chromosomal abnormalities. A total of 66 translocations were identified in the three cases, with one new recurrent translocation at (der(4)t(4;20)(q35;?)). Nine complex translocations, involving three or more chromosomes, were identified in these cases. Overall, 96 breakpoints were assigned to metaphase chromosomes and another 74 breakpoints could not be assigned. Breakpoints most commonly involved chromosomes in genetic rearrangements were 1, 3, 5, 8, 13, 16, and 17.

CONCLUSIONS

Spectral karyotyping analysis reveals the true complexity of chromosomal aberrations in cell lines derived from head and neck squamous cell carcinomas. The use of SKY, in combination with other techniques, may allow for a more complete assessment of the genetic abnormalities of head and neck cancers and serve as a starting point for gene identification.

Fluorescent charge-neutral analogue of xanthosine: synthesis of a 2'-deoxyribonucleoside bearing a 5-aza-7-deazaxanthine base

A concise route is described to prepare the 5-aza-7-deazapurine 2'-deoxyriboside (4), which presents the puADA hydrogen-bonding pattern, analogous to the hydrogen-bonding pattern presented by 2'-deoxyxanthosine (2). The route begins with the commercially available 1-alpha-chloro-2-deoxy-3-5-bistoluoyloxyribofuranose (10), which proves to be a versatile point of entry to beta-2'-deoxyribofuranosides. In the first step, 2-nitroimidazole (8) is coupled with 10 to yield intermediate 11. Reduction of the nitro group to an amino group yields 12, which is treated with phenyl isocyanatoformate to complete the nucleobase to yield 13. Removal of the toluoyloxy protecting groups of 13 yields the target nucleoside 4 in 40% overall yield in four steps. In an alternative strategy, convergent coupling of 14 with 10 under basic conditions was attempted but found to yield the heterocycle glycosylated at the undesired position. Compound 13 displays potentially useful fluorescence properties. After excitation at 250 nm, a solution of 13 in MeCN shows a fluorescence emission with a maximum at 410 nm. Furthermore, 13 is neutral at physiological pH, a property that it shares with natural nucleobases but not xanthosine itself, which is an acid with a pK(a) of ca. 5.6. Furthermore, as part of the design, 4 is made capable of presenting an unshared pair of electrons to the DNA minor groove.

Comparison of ELISA for antibody detection and biopsy urease test against H. pylori in cases of gastoduodenal disorders

Out of 156 cases of various gastro duodenal disorders studied H. pylori was diagnosed in 119 (76.28%) as indicated by Biopsy urease test and IgG ELISA. Biopsy urease test detected higher number of cases 119 when compared to IgG ELISA 107 cases. ELISA being a non invasive technique can be used successfully for the diagnosis of H. pylori infections.

The use of palivizumab monoclonal antibody to control an outbreak of respiratory syncytial virus infection in a special care baby unit

An outbreak of respiratory syncytial virus (RSV) infection affected seven premature infants in a special care baby unit during November and December 1999. Conventional infection control measures (cohorting infected babies, strict reinforcement of the use of gloves and aprons, emphasis on hand disinfection) failed to prevent spread. Palivizumab, a respiratory syncytial virus monoclonal antibody, was given to eight high-risk preterm infants. There were no further cases of RSV in the unit and none of the babies given palivizumab developed RSV. One baby who acquired RSV during the outbreak (and who was not given palivizumab) was subsequently admitted to hospital with another episode of RSV bronchiolitis. The role of palivizumab in the control of hospital outbreaks of RSV infection merits further investigation.

A measure for predicting audibility discrimination thresholds for spectral envelope distortions in vowel sounds

Both in speech synthesis and in sound coding it is often beneficial to have a measure that predicts whether, and to what extent, two sounds are different. This paper addresses the problem of estimating the perceptual effects of small modifications to the spectral envelope of a harmonic sound. A recently proposed auditory model is investigated that transforms the physical spectrum into a pattern of specific loudness as a function of critical band rate. A distance measure based on the concept of partial loudness is presented, which treats detectability in terms of a partial loudness threshold. This approach is adapted to the problem of estimating discrimination thresholds related to modifications of the spectral envelope of synthetic vowels. Data obtained from subjective listening tests using a representative set of stimuli in a 3IFC adaptive procedure show that the model makes reasonably good predictions of the discrimination threshold. Systematic deviations from the predicted thresholds may be related to individual differences in auditory filter selectivity. The partial loudness measure is compared with previously proposed distance measures such as the Euclidean distance between excitation patterns and between specific loudness applied to the same experimental data. An objective test measure shows that the partial loudness measure and the Euclidean distance of the excitation patterns are equally appropriate as distance measures for predicting audibility thresholds. The Euclidean distance between specific loudness is worse in performance compared with the other two.

Simian homologues of Epstein-Barr virus

Gamma-herpesviruses closely related to the Epstein-Barr virus (EBV) are known to naturally infect Old World non-human primates and are classified in the same lymphocryptovirus (LCV) genera. LCV infecting humans and Old World primates share similar biology, and recent studies have demonstrated that these viruses share a similar repertoire of viral genes. Surprisingly, the latent infection genes associated with cell growth transformation demonstrate the most striking sequence divergence, but the functional mechanisms for these genes are generally well conserved. The recent discovery of LCVs naturally infecting New World primates has rewritten the old paradigm of LCV host range restriction to humans and Old World non-human primates, so that these viruses are more widespread than previously believed. However, the New World LCV genome has significant and interesting differences from EBV and other Old World LCVs despite similar biological properties. Thus, the simian homologues of EBV can provide an important animal model for studying LCV pathogenesis, and the similarities and differences that have evolved among these related viruses can provide a unique perspective towards a better understanding of EBV.

The use of helical computed tomography in pregnancy for the diagnosis of acute appendicitis

OBJECTIVE

Accurate diagnosis of acute appendicitis in pregnancy by clinical evaluation is difficult. A safe, reliable test was sought to decrease a delay in diagnosis and to avoid unnecessary invasive procedures. A helical or spiral computed tomographic technique has proven to be a very accurate test in the nonobstetric population for the identification of acute appendicitis. We report its use in pregnant patients with suspected acute appendicitis.

STUDY DESIGN

All pregnant patients who were undergoing helical computed tomography at our institution from April 1997 to February 1998 for the suspected clinical diagnosis of acute appendicitis were retrospectively reviewed. Helical computed tomography was performed by standard departmental protocol. A positive study was reported if an enlarged appendix, which did not fill with contrast material, was present with periappendiceal inflammatory changes. Outcomes were determined by the results of surgery and pathologic examination or clinical follow-up.

RESULTS

Seven patients were identified in the study period. Two patients had positive findings on helical computed tomography, and acute appendicitis was confirmed at laparotomy and by pathologic inspection. There were no further prenatal complications and both patients delivered at term. Five patients had a normal-appearing appendix on helical computed tomography, and all of these patients had resolution of their pain and symptoms.

CONCLUSION

Helical computed tomography appears to be a useful, noninvasive test to accurately diagnose acute appendicitis in pregnancy.

Inhibitors of p38 MAP kinase increase the survival of transplanted dopamine neurons

Fetal cell transplantation therapies are being developed for the treatment of a number of neurodegenerative disorders including Parkinson's disease [10-12,21,22,24,36,43]. Massive apoptotic cell death is a major limiting factor for the success of neurotransplantation. We have explored a novel protein kinase pathway for its role in apoptosis of dopamine neurons. We have discovered that inhibitors of p38 MAP kinase (the pyridinyl imidazole compounds: PD169316, SB203580, and SB202190) improve survival of rat dopamine neurons in vitro and after transplantation into hemiparkinsonian rats. In embryonic rat ventral mesencephalic cultures, serum withdrawal led to 80% loss of dopamine neurons due to increased apoptosis. Incubation of the cultures with p38 MAP kinase inhibitors at the time of serum withdrawal prevented dopaminergic cell death by inhibiting apoptosis. In the hemiparkinsonian rat, preincubation of ventral mesencephalic tissue with PD169316 prior to transplantation accelerated behavioral recovery and doubled the survival of transplanted dopamine neurons. We conclude that inhibitors of stress-activated protein kinases improve the outcome of cell transplantation by preventing apoptosis of neurons after grafting.

Correlation of marrow dose estimates based on serial pretreatment radiopharmaceutical imaging and blood data with actual marrow toxicity in anti-CD20 yttrium-90 monoclonal antibody radioimmunotherapy of non-Hodgkin's B-cell lymphoma

The purpose of this study was to investigate whether marrow radiation absorbed dose estimates predict haematotoxicity following radioimmunotherapy with an yttrium-90 labelled anti-CD20 monoclonal antibody in non-Hodgkin's B-cell lymphoma (NHL). Radiopharmaceutical data from 12 NHL radioimmunotherapy patients were analysed retrospectively using three methods of marrow radiation absorbed dose estimation based on serial pretreatment indium-111 labelled anti-CD20 monoclonal antibody activity versus time data (0-144 h): (i) lumbar spine (LS) image counts; (ii) blood clearance (BL); and (iii) whole body (WB) activity. Linear regressions were performed between the methods, and between each method and the 0-6 month post-treatment platelet and white blood cell count nadir and absolute drop in count (ADC). For the range of yttrium-90 activities (740-1547 MBq), absorbed dose estimates (mean +/- sigma) were: LS, 142+/-50 cGy (range 62-233 cGy); BL, 89+/-21 cGy (range 63-140 cGy); and WB, 54+/-10 cGy (range 36-63 cGy). The LS and BL marrow estimates differed significantly (P <0.003), with a correlation coefficient r of 0.36 (P = NS), while WB correlated significantly with both LS (r = 0.50, P < 0.05) and BL (r = 0.58, P < 0.05). The range of r with platelet nadir and ADC was -0.20 < or = r < or = 0.01, except for WB with ADC (r = 0.38) (all P = NS). Values of r for white blood cell nadir were unexpectedly positive, being 0.13 for BL and 0.29 for LS (P = NS), and 0.60 for WB (P < 0.025). Values of r for white blood cell ADC were 0.36 for BL and -0.26 for LS (P = NS), and 0.50 for WB (P < 0.05). These results indicate that different commonly employed methods of estimating marrow radiation absorbed dose may yield significantly differing results, which may not correlate with actual radiation toxicity. Therefore, caution must be exercised in relying on these results to predict haematotoxicity.

Diarrhea-associated over-anticoagulation in a patient taking warfarin: therapeutic role of cholestyramine

We present a case of significant over-anticoagulation temporally associated with a bout of protracted diarrhea in a patient on warfarin therapy. Cholestyramine was utilized to interrupt the enterohepatic recycling of warfarin and for its antidiarrheal effects to prevent gastrointestinal vitamin K wasting. Cholestyramine enabled the use of very low doses of sc vitamin K1 (2 mg total) with subsequent attainment of a therapeutic International Normalized Ratio in 39 h.

Chemoprophylaxis against leprosy: expectations and methodology of a trial

Because of the great efficacy of multidrug therapy (MDT), it had been hoped that the widespread use of MDT would bring about a rapid decrease of the incidence of leprosy. To the present, a decrease of incidence has not been observed, possibly because of the long incubation period of the disease, and because general implementation of MDT is still recent. Other reasons, such as environmental sources of infection or the role of healthy carriers in transmitting Mycobacterium leprae, cannot be excluded. Therefore, one must seek alternative or supplementary strategies, such as chemoprophylaxis. Household contacts of leprosy patients are at greater risk of developing leprosy than is the general population. Therefore, a randomized, controlled trial of chemoprophylaxis, using a single 10 mg/kg dose of rifampicin, or a placebo, is planned in nine projects in India, among the household contacts of newly detected leprosy patients. Based upon assumptions of a protective efficacy of the chemoprophylaxis of 50%, an annual incidence of 2 per 1000 contacts, a desired power of the study of 90%, and a level of significance of 95%, 15,000 household contacts will be allocated randomly by household to each arm of the study, and followed for 5 years. Considered as household contacts will be all persons living in the same household as an index case and sharing the same kitchen. Pregnant women and infants will be excluded. To be certain that transmission of the organisms from the index case cannot occur once the prophylaxis is administered, rifampicin will be administered 2 months after diagnosis of the index case. Diagnosis of leprosy will be clinical, and confirmed independently. Although household contacts usually constitute only a small proportion of the new patients detected in a control programme, their high-risk status makes them particularly appropriate for a study of the potential effect of chemoprophylaxis. Following the trial, one could evaluate the usefulness and feasibility of using the same strategy in other population-groups, based on the number of persons necessary to treat to prevent one case.

Cloning of the rhesus lymphocryptovirus viral capsid antigen and Epstein-Barr virus-encoded small RNA homologues and use in diagnosis of acute and persistent infections

Epstein-Barr virus (EBV) is the most common cause of infectious mononucleosis and is associated with the development of several human malignancies. A closely related herpesvirus in the same lymphocryptovirus (LCV) genera as EBV naturally infects rhesus monkeys and provides an important animal model for studying EBV pathogenesis. We cloned the small viral capsid antigen (sVCA) homologue from the rhesus LCV and developed a peptide enzyme-linked immunosorbent assay (ELISA) to determine whether epitopes in the rhesus LCV sVCA are a reliable indicator of rhesus LCV infection. In order to define a "gold standard" for rhesus LCV infection, we also cloned the EBV-encoded small RNA 1 (EBER1) and EBER2 homologues from rhesus LCV and developed a reverse transcription (RT)-PCR assay to detect persistent LCV infection in rhesus monkey peripheral blood lymphocytes. Animals from a conventional and a hand-reared colony were studied to compare the prevalence of rhesus LCV infection in the two groups. There was a 100% correlation between the peptide ELISA and EBER RT-PCR results for rhesus LCV infection. In addition, specificity for LCV infection and exclusion of potential cross-reactivity to the rhesus rhadinovirus sVCA homologue could be demonstrated using sera from experimentally infected animals. These studies establish two novel assays for reliable diagnosis of acute and persistent rhesus LCV infections. The rhesus LCV sVCA peptide ELISA provides a sensitive and reliable assay for routine screening, and these studies of the hand-reared colony confirm the feasibility of raising rhesus LCV-naive animals.

Genetic analysis of the APAF1 gene in male germ cell tumors

Cytogenetic and molecular analyses have shown that the chromosome band 12q22 is recurrently deleted in male germ cell tumors (GCTs), indicating the presence of a candidate tumor suppressor gene (TSG) in this region. To identify the TSG, we mapped the APAF1 gene, a proapoptotic mammalian homologue of ced-4, to chromosomal band 12q22, that suggested that this might be the candidate deleted gene in GCTs. We further localized the gene between the polymorphic markers D12S1671 and D12S1082 at 12q22 to determine the role of APAF1 in the pathogenesis of GCT, and we characterized its normal genomic structure and analyzed its alterations in GCTs. The APAF1 gene comprises 27 exons, with the coding region spanning 26. The region containing APAF1 was found to be deleted in GCT by fluorescence in situ hybridization analysis, but without evidence of coding sequence alterations. RT-PCR and Western blot analysis showed APAF1 gene expression at detectable levels in all GCT cell lines analyzed. An aberrant-sized APAF1 protein was seen in one cell line. This and 2 other cell lines carrying APAF1 deletions also exhibited defects in dATP-mediated caspase-3 activation. Caspase-3 activity was effectively restored by addition of recombinant caspase-9 and APAF1 proteins, and to a lesser extent by caspase-9 alone, but not by APAF1 alone. These data do not support a TSG role for APAF1, but defects in other components of the apoptotic pathway that may be related to 12q22 deletion cannot be ruled out. Genes Chromosomes Cancer 28:258-268, 2000.

An assay for angiotensin-converting enzyme using capillary zone electrophoresis

A sensitive and rapid method was developed for angiotensin-converting enzyme (ACE) activity determination by capillary zone electrophoresis. Hippuryl-l-histidyl-l-leucine, a synthetic tripeptide, was used as the ACE-specific substrate. Capillary zone electrophoresis was employed to separate the products of the enzymatic reaction and the ACE activity was determined by quantification of hippuric acid, a result of the enzymatic reaction on the tripeptide. The capillary electrophoresis was performed in a 27 cm x 75 micrometer i.d. fused-silica capillary using 200 mM boric acid-borate buffer (pH 9.0) as a run buffer with an applied voltage of 8.1 kV at a capillary temperature of 23 degrees C. The electrophoresis was monitored at 228 nm. Each electrophoretic run requires only a nanoliter of the enzymatic reactant solution, at only 6 min, rendering a powerful tool for the ACE assay.

Small-solute clearances in diabetic subjects on continuous ambulatory peritoneal dialysis: comparison to nondiabetic subjects

Normalized clearances for urea and creatinine were compared between 121 diabetic subjects (256 clearances) and 181 nondiabetic subjects (357 clearances) on continuous ambulatory peritoneal dialysis (CAPD) with four 2-L exchanges daily. Urea clearance was normalized by VWatson (Kt/Vur), while creatinine clearance was normalized by both VWatson (Kt/Vcr) and body surface area (Ccr). Height, weight, body water (V), and body surface area did not differ between the diabetic and the nondiabetic groups. Also, renal Kt/Vur, renal Kt/Vcr, renal Ccr, and peritoneal Kt/Vur did not differ between the groups. Weekly peritoneal Kt/Vcr (diabetic group 1.36 +/- 0.38, nondiabetic group 1.31 +/- 0.31, p = 0.048) and weekly peritoneal Ccr (diabetic group 47.6 +/- 11.0 L/1.73 m2, nondiabetic group 45.4 +/- 9.2 L/1.73 m2, p = 0.012) were both higher in diabetic subjects. The percentage of high/high-average transporters was higher in the diabetic group (64.9% vs 48.6% in nondiabetic group, p = 0.006). The following total (peritoneal + renal) weekly clearances were obtained: Kt/Vur, diabetic group 2.07 +/- 0.63, nondiabetic group 2.02 +/- 0.56, NS; Kt/Vcr, diabetic group 2.06 +/- 0.78, nondiabetic group 1.92 +/- 0.74, p = 0.026; Ccr, diabetic group 72.7 +/- 28.5 L/1.73 m2, nondiabetic group 67.2 +/- 26.4 L/1.73 m2, p = 0.013. Normalized total creatinine clearances are higher in diabetic subjects than nondiabetic subjects on the same CAPD schedule and with the same renal clearances of urea and creatinine and the same total Kt/Vur, because peritoneal creatinine clearances are higher in the diabetic subjects. This finding is caused by higher peritoneal transport in the diabetic subjects and is not an artifact caused by the normalization process.