Intimate partner violence among HIV-positive women in Nairobi, Kenya

Purpose

This study was conducted to identify the prevalence and sociodemographic factors associated with four forms of intimate partner violence (IPV) among HIV-positive women attending the Comprehensive Care Centre at the Kenyatta National Hospital in Nairobi, Kenya.

Methods

A cross-sectional study was conducted among 600 sexually active HIV-positive women aged 18–69 years from May to August of 2012. A structured questionnaire including questions pertaining to sociodemographic characteristics, health care decisions, and forms of IPV (controlling behavior, emotional abuse, physical violence, and sexual violence) was administered to each woman.

Results

All women reported experiencing emotional abuse; 20%, 17%, and 15% experienced controlling behavior, physical violence, and sexual violence, respectively. Women who reported low/below average socioeconomic status (SES) had a greater likelihood of experiencing controlling behavior than women with high/average SES (adjusted odds ratio [aOR] =1.62, 95% CI 1.05–2.51). Women who were unemployed had greater odds of experiencing physical violence than those who were employed (aOR =2.35, 95% CI 1.31–4.23). Non-Christian women had higher odds of experiencing controlling behavior, physical violence, and sexual violence than Christian women (aOR =4.41, 95% CI 1.81–10.76 and aOR =3.33, 95% CI 1.43–7.80).

Conclusion

Based on the prevalence of IPV and the sociodemographic factors identified to be associated with IPV among women in this study it may be beneficial to include IPV screening as part of routine clinic visits for HIV-positive and other women. Furthermore, women who report emotional abuse or controlling behavior from spouse should not be overlooked, as these two forms of IPV may precede or accompany physical and sexual IPV. Women who report experiencing IPV during clinic visits may be referred to organizations and resources available to battered women in Kenya. Increased funding for anti-IPV programs and changes in policy may also contribute to a reduction in IPV among HIV-positive and other women in Kenya.

Al2O3 microring resonators for the detection of a cancer biomarker in undiluted urine

Concentrations down to 3 nM of the rhS100A4 protein, associated with human tumor development, have been detected in undiluted urine using an integrated sensor based on microring resonators in the emerging Al₂O₃ photonic platform. The fabricated microrings were designed for operation in the C-band (λ = 1565 nm) and exhibited a high-quality factor in air of 3.2 × 10⁵. The bulk refractive index sensitivity of the devices was ~100 nm/RIU (for TM polarization) with a limit of detection of ~10^-6 RIU. A surface functionalization protocol was developed to allow for the selective binding of the monoclonal antibodies designed to capture the target biomarker to the surface of the Al₂O₃ microrings. The detection of rhS100A4 proteins at clinically relevant concentrations in urine is a big milestone towards the use of biosensors for the screening and early diagnosis of different cancers. Biosensors based on this microring technology can lead to portable, multiplexed and easy-to-use point of care devices.

Boar semen proteomics and sperm preservation

Recently numerous proteomic approaches have been undertaken to identify sperm and seminal plasma (SP) proteins that can be used as potential biomarkers for sperm function, including fertilization ability. This review aims firstly to briefly introduce the proteomic technologies and workflows that can be successfully applied for sperm and SP proteomic analysis. Secondly, we summarize the current knowledge about boar SP and the sperm proteome, focusing mainly on its relevance to sperm preservation procedures (liquid storage or cryopreservation) and their outcomes in terms of sperm function and fertility.

NG2 antigen is involved in leukemia invasiveness and central nervous system infiltration in MLL-rearranged infant B-ALL

Mixed-lineage leukemia (MLL)-rearranged (MLLr) infant B-cell acute lymphoblastic leukemia (iMLLr-B-ALL) has a dismal prognosis and is associated with a pro-B/mixed phenotype, therapy refractoriness and frequent central nervous system (CNS) disease/relapse. Neuron-glial antigen 2 (NG2) is specifically expressed in MLLr leukemias and is used in leukemia immunophenotyping because of its predictive value for MLLr acute leukemias. NG2 is involved in melanoma metastasis and brain development; however, its role in MLL-mediated leukemogenesis remains elusive. Here we evaluated whether NG2 distinguishes leukemia-initiating/propagating cells (L-ICs) and/or CNS-infiltrating cells (CNS-ICs) in iMLLr-B-ALL. Clinical data from the Interfant cohort of iMLLr-B-ALL demonstrated that high NG2 expression associates with lower event-free survival, higher number of circulating blasts and more frequent CNS disease/relapse. Serial xenotransplantation of primary MLL-AF4⁺ leukemias indicated that NG2 is a malleable marker that does not enrich for L-IC or CNS-IC in iMLLr-B-All. However, NG2 expression was highly upregulated in blasts infiltrating extramedullar hematopoietic sites and CNS, and specific blockage of NG2 resulted in almost complete loss of engraftment. Indeed, gene expression profiling of primary blasts and primografts revealed a migratory signature of NG2⁺ blasts. This study provides new insights on the biology of NG2 in iMLLr-B-ALL and suggests NG2 as a potential therapeutic target to reduce the risk of CNS disease/relapse and to provide safer CNS-directed therapies for iMLLr-B-ALL.

S100A7: from mechanism to cancer therapy

Within the tumor, malignant and stromal cells support each other by secreting a wide variety of growth factors and cytokines, allowing tumor growth and disease progression. The identification and regulation of those key factors in this crosstalk has opened the opportunity to develop new therapeutic strategies that not only act on the tumor cells but also on the stroma. Among these factors, S100A7 protein has gained interest in the last years. With key roles in cell motility its expression correlates with increased tumor growth, angiogenesis and metastatic potential. This work aims to deepen in the role played by extracellular S100A7 in the tumor microenvironment, offering a new integrative insight of its mechanism of action on each cellular compartment (tumor, endothelial, immune and fibroblast). As a result, we demonstrate its implication in cell migration and invasion, and its important contribution to the formation of a proinflammatory and proangiogenic environment that favors tumor progression and metastasis. Furthermore, we define its possible role in the pre-metastatic niche formation. Considering the relevance of S100A7 in cancer progression, we have developed neutralizing monoclonal antibodies, reporting for the first time the proof of principle of this promising therapeutic strategy for cancer treatment.

Histologic and Immunohistochemical Characterization of Pheochromocytomas in 20 Clouded Leopards ( Neofelis nebulosa)

Clouded leopards in North American zoological institutions have a high frequency of pheochromocytomas and were identified in 32 of 70 (45%) animals necropsied. Archival sections of adrenal gland from 20 adult clouded leopards with unilateral or bilateral pheochromocytomas collected between 1984 and 2011 were examined by light microscopy and immunohistochemistry, and case demographics were reviewed. Affected leopards were older than 10 years of age (mean, 16 years; range, 11-19 years), and males were overrepresented (12 males, 8 females). Pedigree analysis yielded no evidence for heritability. Five clouded leopards had bilateral neoplasms. Pheochromocytoma was the cause of death due to invasion of the caudal vena cava and fatal hemorrhage in 4 cases. Most pheochromocytomas were well-demarcated, nodular, and expansile masses composed of cords and packets of neoplastic polygonal cells. Five pheochromocytomas had vascular invasion, of which 4 resulted in hemorrhage that was the cause of death. One of the latter pheochromocytomas also had pulmonary metastasis. Ultrastructurally, neoplastic cells had cytoplasmic structures consistent with both norepinephrine- and epinephrine-containing granules. In all cases, neoplasms were immunohistochemically positive for chromogranin A, protein gene product 9.5, and synaptophysin. A subset of neoplasms evaluated by tissue microarray were positive for met-enkephalin and β-endorphin and negative for melan-A. Histologically, 7 of 20 (35%) clouded leopards with pheochromocytomas had retinal detachment, retinal degeneration, or intramyocardial muscular arteriosclerosis, suggestive of hypertension. Pheochromocytomas can cause mortality and may be a source of clinically significant hypertension in clouded leopards. These neoplasms share similar histologic, immunohistochemical, and ultrastructural characteristics with those of other species.

120 IMPACT OF SEASON ON SEMINAL CHARACTERISTICS AND SPERM CRYOPRESERVATION IN THE TUFTED DEER (ELAPHODUS CEPHALOPHUS)

The Tufted deer (Elaphodus cephalophus), a small deer species native to China, is listed as near threatened on the IUCN Red List and >70 animals are managed in North American zoos as a hedge against extinction. In this study, we 1) characterized the seminal traits, 2) assessed the impact of season on ejaculate traits and testosterone level, and 3) examined sperm sensitivity to cryopreservation. Semen (24 ejaculates) were obtained from five males (1–2 ejaculates/male per season) by electro-ejaculation and evaluated for volume, osmolality, pH as well as sperm concentration, motility (%M), forward progression (FP, scale = 0–5) and acrosomal integrity (%AI). Ejaculates were divided into two aliquots and cryopreserved (4% vol/vol glycerol final concentration; 50–200 × 106 sperm mL–1) over liquid nitrogen vapor using Beltsville extender (BF5F; Howard et al. 1986) or Triladyl® (TRIL; Minitüb GmbH, Germany) extender. Sperm motility and %AI were assessed immediately (subjective) upon thawing and following swim-up processing (SU; 30 min) using computer-assisted semen analysis after 1, 2, 3, and 4 h of incubation (37°C). Fecal samples were collected 3–5 times weekly for 2 years and analyzed for testosterone (T) metabolites using enzyme immunoassay as a function of season (autumn, September–November; winter, December–February; spring, March–May; and summer, June–August). Data were analyzed using Proc GLM or ANOVA with Tukey multiple mean comparison. Significance was set at P < 0.05. Male reproductive and semen traits peaked in autumn (volume, 2.0 mL; concentration, 207.6 × 106 mL–1; pH, 7.6; osmolality, 310.8 mOsm; %M, 76%; FP, 3.5; and %AI, 82.3). Mean testicular length and neck girth in autumn were 4.9 and 43.2 cm, respectively. Mean T concentration (~1.23 µg g–1 of dry feces) was higher (P < 0.05) in summer compared with winter (1.07 µg g–1 of dry feces) or spring (1.06 µg g–1 of dry feces). Sperm motility and %AI were lower (P < 0.05) immediately after thawing (BF5F, 34.6 and 34.7%, respectively; and TRIL, 23.1 and 29.1%, respectively) compared with fresh semen (76.9 and 74.6%, respectively). Motility characteristics immediately after SU (computer-assisted semen analysis) were higher (P < 0.05) in BF5F compared with TRIL: %M (56.4 v. 44.9%), progressive motility (42.5 v. 21.9%), %AI (41.2 v. 31.3%), straight-line velocity (68.0 v. 53.2 µm s–1), straightness (85.1 v. 75.1%), and linearity (54.3 v. 45.0%). At the end of 4 h of incubation, sperm %M and FP declined (P > 0.05) in both BF5F and TRIL (47 and 30%, respectively) but the %AI was higher (P < 0.05) in BF5F (32%) than TRIL (21%). Results indicate that tufted deer ejaculates exhibit seasonal variations in reproductive traits and cryopreservation in BF5F better preserves sperm motility and acrosomal membrane integrity compared with TRIL.

Anisotropic anomalous diffusion modulated by log-periodic oscillations

We introduce finite ramified self-affine substrates in two dimensions with a set of appropriate hopping rates between nearest-neighbor sites where the diffusion of a single random walk presents an anomalous anisotropic behavior modulated by log-periodic oscillations. The anisotropy is revealed by two different random-walk exponents ν(x) and ν(y) in the x and y directions, respectively. The values of these exponents as well as the periods of the oscillations are obtained analytically and confirmed by Monte Carlo simulations.

Anomalous diffusion with log-periodic modulation in a selected time interval

On certain self-similar substrates the time behavior of a random walk is modulated by logarithmic-periodic oscillations on all time scales. We show that if disorder is introduced in a way that self-similarity holds only in average, the modulating oscillations are washed out but subdiffusion remains as in the perfect self-similar case. Also, if disorder distribution is appropriately chosen the oscillations are localized in a selected time interval. Both the overall random walk exponent and the period of the oscillations are analytically obtained and confirmed by Monte Carlo simulations.

Log-periodic oscillations for diffusion on self-similar finitely ramified structures

Under certain circumstances, the time behavior of a random walk is modulated by logarithmic-periodic oscillations. Using heuristic arguments, we give a simple explanation of the origin of this modulation for diffusion on a substrate with two properties: self-similarity and finite ramification order. On these media, the time dependence of the mean-square displacement shows log-periodic modulations around a leading power law, which can be understood on the basis of a hierarchical set of diffusion constants. Both the random walk exponent and the period of oscillations are analytically obtained for a pair of examples, one is fractal and the other is nonfractal, and confirmed by Monte Carlo simulations. The last example shows that the anomalous diffusion can arise from substrates without holes of all sizes.

Degradation of Chlorophenols by Alcaligenes eutrophus JMP134(pJP4) in Bleached Kraft Mill Effluent

The ability of Alcaligenes eutrophus JMP134(pJP4) to degrade 2,4-dichlorophenoxyacetic acid, 2,4,6-trichlorophenol, and other chlorophenols in a bleached kraft mill effluent was studied. The efficiency of degradation and the survival of strain JMP134 and indigenous microorganisms in short-term batch or long-term semicontinuous incubations performed in microcosms were assessed. After 6 days of incubation, 2,4-dichlorophenoxyacetate (400 ppm) or 2,4,6-trichlorophenol (40 to 100 ppm) were extensively degraded (70 to 100%). In short-term batch incubations, indigenous microorganisms were unable to degrade such of compounds. Degradation of 2,4,6-trichlorophenol by strain JMP134 was significantly lower at 200 to 400 ppm of compound. This strain was also able to degrade 2,4-dichlorophenoxyacetate, 2,4,6-trichlorophenol, 4-chlorophenol, and 2,4,5-trichlorophenol when bleached Kraft mill effluent was amended with mixtures of these compounds. On the other hand, the chlorophenol concentration and the indigenous microorganisms inhibited the growth and survival of the strain in short-term incubations. In long-term (>1-month) incubations, strain JMP134 was unable to maintain a large, stable population, although extensive 2,4,6-trichlorophenol degradation was still observed. The latter is probably due to acclimation of the indigenous microorganisms to degrade 2,4,6-trichlorophenol. Acclimation was observed only in long-term, semicontinuous microcosms.

The effect of vitamin C supplementation on plasma concentration and urinary excretion of vitamin C in cattle

We investigated the plasma concentration and urinary excretion of vitamin C in cows supplemented with vitamin C. Five cows (mean BW = 597 kg) were allocated to a 5 x 5 Latin square design and supplemented with a vitamin C preparation coated with hydrogenated soybean oil at 0, 10, 20, 40, or 60 mg of vitamin C per kg of BW per day for 9 d. Plasma and urine samples were collected for measuring vitamin C concentration. Urinary excretion of vitamin C was expressed as the ratio of vitamin C to creatinine. Plasma vitamin C concentration and urinary vitamin C excretion increased quadratically as dietary vitamin C increased (P < 0.001); that is, the lowest dose affected neither plasma vitamin C concentration nor urinary vitamin C excretion but the plasma vitamin C concentration and urinary vitamin C excretion increased (P < 0.05) with increasing supplementation of vitamin C at greater doses. This suggests that plasma vitamin C concentration affects urinary excretion of vitamin C in cattle and that plasma vitamin C concentration exceeded the renal threshold for vitamin C in the cows receiving vitamin C at 20 mg/kg of BW per day. Furthermore, increased urinary excretion of vitamin C appears to limit plasma vitamin C concentration in response to vitamin C intake. The daily excretion of vitamin C was estimated by the reported value of daily creatinine excretion, indicating that the daily amount of vitamin C excreted into urine was more than half of supplied vitamin C. Therefore, a large part of supplied vitamin C probably escapes ruminal degradation and is absorbed but excreted into urine.

Degradation of 2,4,6-trichlorophenol via chlorohydroxyquinol in Ralstonia eutropha JMP134 and JMP222

The aim of this work was to study the catabolic pathway of the pollutant 2,4,6-trichlorophenol in Ralstonia eutropha JMP134. 2,6-dichlorohydroquinone was detected as transient intermediate. Enzymatic transformations of 6-chlorohydroxyquinol to 2-chloromaleylacetate, and of this compound to maleylacetate were detected in crude extracts. Therefore, the degradation of 2,4,6-trichlorophenol proceeded through an hydroxyquinol pathway, different from the other chloroaromatic pathways reported in this strain. The same results were observed in two other 2,4,6-trichlorophenol degrading strains: R. eutropha JMP222, a derivative of strain JMP134 lacking the chlorocatechol catabolism-encoding pJP4 plasmid, and a river isolate, Ralstonia sp. PZK.

[Chordoma of the ethmoidal sinus. A case report]

Chordomas are dysembryogenic tumors originating from the notochordal process. The case of a 9-month-old male infant with involvement of the ethmoidal sinus and anterior fossa is reported. These tumors are rare in ENT practice and in children arise in the clivus. The diagnosis was made by biopsy, CT and MRI. Surgery is the only effective treatment, with chemotherapy and radiotherapy having little value. The complication and relapse rates are high.

Regulation of peptide YY homeostasis by gastric acid and gastrin

Peptide YY (PYY) is a gut hormone localized primarily in the distal bowel. Because circulating PYY inhibits gastric acid secretion, we investigated the effects of gastric acid secretion and gastrin on gene expression and secretion of PYY. In conscious dogs, PYY release in response to oral food was inhibited (P < 0.05) by pharmacologic inhibition of gastric acid secretion (omeprazole, famotidine). In rats, omeprazole treatment resulted in a significant elevation in serum gastrin concentrations and a simultaneous decrease in PYY messenger RNA (mRNA) and peptide levels in the colon; administration of a gastrin receptor antagonist (L365, 260) prevented the inhibitory actions of omeprazole on colonic PYY mRNA levels. In athymic-nude mice, implantation of a human gastrinoma resulted in an elevation of serum gastrin concentrations and a concomitant depression of colonic PYY mRNA levels. We conclude that endogenous gastric acid secretion up-regulates PYY release and PYY mRNA expression. Circulating gastrin acts to down-regulate PYY release and PYY mRNA expression. This study provides evidence that foregut functions (i.e., gastric acid secretion and gastrin release) exert control over an antiacid signal (e.g. PYY release) emanating from the hindgut.

Urinary 3 alpha,17 beta-androstanediol glucuronide is a measure of androgenic status in Eld's deer stags (Cervus eldi thamin)

To determine the primary excretory by-products of testosterone (T), 85 microCi [3H]T was administered i.v. to two adult Eld's deer stags. Blood (10 ml) was collected by jugular venipuncture at 0, 5, 10, 15, 30, 45, 60, 90, 120, 150, 180, 240, and 480 min after isotope infusion, and all urine and feces were collected for 96 h after injection. Seventy percent of labeled circulating steroid was conjugated by 30 min postinfusion. The majority (80.4 +/- 3.2%) of T metabolites were excreted into urine, and 95.0 +/- 0.9% of these were conjugated, 95.8 +/- 0.2% being hydrolyzable with glucuronidase. Seven urinary androgen metabolites, including androstanediol (5 alpha-androstan-3 alpha-17 beta-diol and 5 beta-androstan-3 alpha-17 beta-diol), were identified in glucoronidase-hydrolyzed, ether-extracted Eld's deer urine pools after gas chromatography/mass spectrometry. A double-antibody 125I RIA for 5 alpha-androstanediol-3 alpha, 17 beta-diol,17-glucuronide (3 alpha-diol-G) was validated for unprocessed urine. Longitudinal assessments of urine samples collected from 13 stages for 3 yr revealed biological concordance between fluctuations in urinary 3 alpha-diol-G and serum T, as well as seasonal changes in secondary sexual characteristics. Overall correlation between "same-day" matched serum T and urinary 3 alpha-diol-G was 0.58, (n = 6; p < 0.001). Thus, monitoring urinary 3 alpha-diol-G provides a noninvasive, alternative method for characterizing male endocrine interrelationships in an endangered ungulate species.

[Outpatient surgery in pediatric ENT]

Adenotonsillectomy is a common surgical procedure. For many patients, outpatient adenotonsillectomy is safe and cost-effective. During the 1993-1994 school year, 365 patients were operated. Complications (1.2%) were minimal and similar to those occurring in inpatients (2%) in the same 1992-1993 period. We believe that surgery of the tonsils, adenoids and myringotomy can be performed safely as an outpatient procedure if the candidates for ambulatory surgery are carefully selected by the surgeon.

Reversal of doxorubicin resistance and catalytic neutralization of lysosomes by a lipophilic imidazole

A number of lipophilic nitrogenous bases, designed to act as membrane-active, catalytic proton transfer agents, were tested for their ability to neutralize the acidity of lysosomes, a model for other acidic intracellular vesicles involved in drug sorting. The most successful of these, an imidazole 1, caused a 1.7 unit rise in lysosomal pH of RAW cells at 100 microM, compared to a 0.2 and 1.4 unit rise for ammonium chloride at 100 microM and 10 mM, respectively. Compound 1 also exhibited potent reversal of doxorubicin (DOX) resistance in the HCT116-VM46 cell line by a factor of 14 over the sensitive strain, and superior to that of widely used verapamil (VRP) by a factor of 1.75 at 20 microM. It also has antiviral properties, and potential applications in other lysosome-related areas such as immunotoxin potentiation and the control of bacterial toxins, immune response, prion replication, malaria and intralysosomal microorganisms.

[Laparoscopic cholecystectomy in pediatrics. A report of the first case in the Mexican literature]

The authors present the case of a 9.8-year-old girl with 5 a month history of epigastric pain which was due to gallstones as demonstrated by ultrasound. After an extensive work-up failed to reveal associated hematologic problems, she was successfully treated by laparoscopic cholecystectomy, resulting in complete recovery, hospitalization of 22 hours and return to school three days after major surgery. We could not find references of laparoscopic cholecystectomy in the pediatric age group in the Mexican literature and only 3 in English language publications. In cases of cholelithiasis without associated diseases in children, the operation of choice should be laparoscopic cholecystectomy.

Exclusive asymptomatic neonatal infections by human rotavirus strains having subgroup I specificity and "long" RNA electropherotype

A large number of stool specimens, of healthy newborn infants, collected from various hospitals and clinics in Bangalore City, India, have been examined for the presence of asymptomatic rotaviral excretion. Out of 370 samples analysed during a three year period from 1988 to 1991, 133 specimens (36%) were positive for rotavirus RNA. All these asymptomatic neonatal strains, without exception, showed "long" RNA pattern, but subgroup I specificity. Serotype analysis by ELISA or by hybridization with serotype-specific probes indicated that these strains probably represent a new serotype in newborn children. We find an exclusive association of human rotaviruses having "long" RNA pattern and subgroup I specificity with asymptomatic neonatal infections in contrast to the earlier observations of association of such unusual strains with acute gastroenteritis in young children.

Pregnancy-associated aplastic anemia--report of 3 cases

3 patients with pregnancy-associated aplastic anemia are reported. Management throughout most of the pregnancy consisted of supportive care. In 2 patients an improvement in blood counts occurred after delivery and, in 1 of these, the pancytopenia recurred during a subsequent pregnancy. In 1 case no improvement occurred after delivery and the patient ultimately required an allogeneic bone marrow transplantation. The outcome of these 3 cases demonstrates that pregnancy-associated aplastic anemia can be managed successfully. The improvement that often occurs after delivery suggests a pathogenetic role for pregnancy in the development of this disease.

Effect of progesterone on norepinephrine release from mouse adrenergic terminals in vitro

1. The in vitro effect of progesterone on norepinephrine (NE) release and contractile activity was analyzed in uterine horns from estrogen-primed and progesterone-primed mice. 2. Progesterone (6-10 nmol/ml) evoked the release of [3H]NE above basal levels from uterine horns in both experimental conditions, the effect of progesterone on estrogen-primed being more important than on progesterone-primed mice uterus. 3. Progesterone also increased electrically evoked [3H]NE release in estrogen-primed uterine tissue, nevertheless no effect was observed in progesterone-primed ones. 4. Progesterone (0.6-10 nmol/ml) inhibited uterine horn isometric contractions only in estradiol-primed mice. This effect was partially blocked in uterine horns from reserpine-treated mice and when propanolol (1 microM) was added to the preparation of estradiol-primed mice uterus.

Polytetrafluoroethylene microprosthesis in the arterial system of the rat

The experimental behavior of a 1-mm internal diameter (i.d.) polytetrafluoroethylene (PTFE) microprosthesis, as a substitute for an abdominal aortic segment in the rat, was reviewed. Fifty Wistar rats were divided into four groups: Group I--12 rats with autotransplant of an abdominal aortic segment (AAS); Group II--12 rats with allotransplant of an AAS obtained from Long-Evans rats; Group III--12 rats with xenotransplant of an AAS taken from rabbit femoral arteries; and Group IV--14 rats with substitution of an AAS by a 1-mm i.d. PTFE microprosthesis. The rats were sacrificed at different time intervals ranging from five to 360 days, with previous aortography. In Group I, there was a 100 percent patency at a mean of 152.41 days; in Group II, a 91.6 percent patency at a mean of 100.08 days; in Group III, an 83.3 percent patency with a 75 percent aneurysmal dilation at a mean of 107.58 days; in Group IV, a 71.42 percent patency with two anastomotic aneurysms at a mean of 105 days (P less than 0.05, chi square) between Groups I and IV, autotransplant vs. PTFE). The 1-mm PTFE microprosthesis placed in the arterial system of the rat proved to be a reliable alternative for microvascular substitution.

Polytetrafluoroethylene microprosthesis in the venous system of the rat

In this study, a 2 mm internal diameter (i.d.) polytetrafluoroethylene (PTFE) microprosthesis was used in the venous system of the rat, to determine whether or not it could serve as an acceptable microvenous substitute. Forty Long-Evans rats were divided into four groups: Group 1-10 rats with autotransplant of an inferior vena cava segment; Group 2-10 rats with a segment substitution of the inferior vena cava by a 2 mm i.d. PFTE microprosthesis; Group 3-10 rats with a laterolateral portacaval shunt; and Group 4-10 rats with a portacaval shunt and interposition of a 2 mm i.d. PTFE microprosthesis (new model). The rats were sacrificed at different time intervals up to 100 days, with cavography (femoral access) in Groups 1 and 2 and spleenoportography (direct puncture of the spleen) in Groups 3 and 4, before sacrifice. In Group 1, a 100 percent patency was observed at a mean of 49 days; in Group 2, a 70 percent patency with a 30 percent stenosis at a mean of 39.4 days (p less than 0.05); in Group 3, a 100 percent patency at a mean of 42.5 days; and in Group 4, a 30 percent patency at a mean of 38.4 days (p less than 0.01). Results showed that the 2 mm i.d. PTFE microprosthesis placed in the venous system of the rat is not an efficacious procedure, and that the search for better microvenous substitutes should focus on those of biologic origin.