Delayed enhancement of the bowel wall: a new CT sign of small bowel strangulation

PURPOSE

To report a new CT sign of small bowel strangulation.

MATERIALS AND METHODS

Two cases of small bowel obstruction evaluated by spiral CT with intravenous contrast injection.

RESULTS

In both cases we observed an absence of parietal enhancement of the diseased bowel loop, visible on early scans only. This feature was accompanied by signs of bowel obstruction. The two patients had a segment of necrotic ileum resected.

CONCLUSION

Delayed enhancement of a bowel loop in cases of small bowel obstruction should suggest the diagnosis of strangulation and lead to rapid surgical treatment.

Growth response of adult germ cells to rat androgen-binding protein and human sex hormone-binding globulin

Androgen-binding protein (ABP) is produced by Sertoli cells depending on the development and the stage of the spermatogenic cycle. Germ cell proliferation is at its peak when ABP is at its peak and secreted towards the testicular basal compartment containing spermatogonia and premeiotic spermatocytes. Rat isolated adult germ cell DNA synthesis was studied in vitro in the presence of ABP with and without steroids and in the presence of pure or recombinant sex steroid hormone-binding globulin (SHBG) using thymidine incorporation. Results are: SHBG is able to promote DNA synthesis in the absence of cofactors. Testosterone reacted negatively to the stimulatory effect of SHBG. We conclude that ABP, the physiological steroid-binding protein, should be considered as a paracrine regulator of spermatogenic DNA synthesis in the adult rat.

Hernia of the diaphragm: a clinical case and review of the literature

Diaphragmatic rupture occurs in 25% of the thoracic and abdominal blunt injuries. It may be discovered immediately or sometimes several months or even years after the trauma. The diagnosis can be made easily on the basis of a standard chest X-ray. Barium swallow examination, computerized tomography Scan and especially Magnetic resonance imaging can be helpful for differential diagnosis. Surgical treatment is always necessary.

Adenocarcinoma of the ileum. A case report, and review of the literature

A 47-year-old female presented with intestinal occlusion and a lower abdominal mass. On laparotomy, a 10 cm diameter mass was discovered involving the ileum, jejunum, vagina and the bladder. Pathological studies conclusion was a primary adenocarcinoma of the ileum involving the jejunum. Small bowel carcinoma is rare. It occurs between sixty- and seventy-year-old equally in male and female. It presents most frequently in the duodenum, sometimes in the jejunum, and occasionally in the ileum. The symptoms are not specific and do not point to the diagnosis which must be made radiologically and endoscopically. Currently, for a minority of patients, surgical resection remains the only hope of cure. Palliative resections and bypass procedures can prevent occlusion or subocclusion.

Evaluation of endoscopy in the treatment of rare meningoceles: preliminary results

BACKGROUND

Endoscopy is used on different occasions-for instance, to open the floor of the third ventricule in triventricular hydrocephalus, to open a cyst into the cerebrospinal fluid circulation, for biopsy or for partial resection of some tumors, or to insert a shunt in hydrocephalus or syringohydromyelia. However, the use of endoscopes for evaluating and treating meningoceles remains to be assessed.

METHODS

Five different kinds of rare meningoceles are presented. In each, neuroendoscopy was used as the main tool for exploration and treatment.

RESULTS

Two sacral meningoceles and one oral cephalocele were cured through a keyhole opening under endoscopic control. One posterior sacral meningocele was explored and no communication with normal subarachnoid spaces was observed, allowing a simple suture of the posterior to the anterior walls. And, last, a complex case with three intrasacral meningocles was explored and partially treated.

CONCLUSIONS

Meningocles with very small communication within the normal subarachnoid spaces appeared the most suitable to be cured by an endoscopic procedure. In case of a larger communication, the meningocele could be treated, or at least the morphology can be better understood, by using a keyhole procedure under endoscopic control. In all cases the surgery was of short duration (less than 1 hour) and very well tolerated.

Growth hormone directly affects the function of the different lobes of the rat prostate

In this study, we investigated the involvement of GH in rat prostate function. First, we demonstrated that specific transcripts corresponding to the GH receptor (4.5 kilobases) and to the GH-binding protein (1.2 kilobases) were expressed in the normal rat prostate, but also in all prostatic carcinoma cell lines tested (LNCaP, PC-3, MAT-Lu, MAT-LyLu, and Pif-1). Moreover, these transcripts were much more abundant in the human and rat carcinoma cells than in the normal tissue. One-year-old dwarf rats were supplemented for 7 days with saline (group DR1) or highly purified rat GH (group DR2). Northern blotting and quantitation of prostatic messenger RNAs (mRNAs) revealed that GH increases the steady state levels of transcripts coding for androgen receptor (2.4-fold), type I and II 5 alpha-reductases (2.6- and 2.2-fold), and several androgen-dependent proteins [prostatein C3 subunit (3.6-fold), probasin (11.0-fold), and R. W. B. (Royal Winnipeg Ballet) (12.5-fold)]. This suggests that GH might either potentiate the action of androgens on the prostate or act directly on this gland by a mechanism that does not depend on testicular androgens. To address this question, we supplemented hypophysectomized and castrated adult rats for 7 days with saline (group HC1), rat GH (group HC2), testosterone propionate (group HC3), or GH plus testosterone (group HC4), starting 3 days after castration. In this animal model, the abundance of C3 mRNA increased in all hormone-treated rats; the stimulation factors were 3.5 (group HC2), 25.5 (group HC3), and 9.5 (group HC4) compared to group HC1. Analysis of prostatein synthesis by Western blotting confirmed these results at the protein level. The same trend was observed for probasin and RWB mRNA levels. Probasin mRNA increased 4.5-fold in group HC2 and 12-fold in group HC3, but did not increase in group HC4 (both hormones combined); enhancement of RWB mRNA was, respectively, 5.0-, 28.0-, and 15.0-fold in groups HC2, HC3, and HC4. GH did not affect the abundance of androgen receptor mRNA. As described previously, the level of this mRNA dropped significantly in group HC3. GH alone did not significantly alter the level of either 5 alpha-reductase mRNA, whereas testosterone, alone or with GH, produced a 2-fold increase in type II 5 alpha-reductase mRNA (groups HC3 and HC4). Type I isoenzyme mRNA reached 1.6 times the control level (group HC1) in groups HC3 and HC4.(ABSTRACT TRUNCATED AT 400 WORDS)

Androgen-independent effects of prolactin on the different lobes of the immature rat prostate

In this study, we have examined the respective roles of androgens and prolactin (Prl) on rat prostate development and function. Hypophysectomized immature rats, castrated or not after hypophysectomy and treated or not with a 5 alpha-reductase inhibitor, were used to study the different aspects of Prl action on the rat prostate and its synergy with androgens in vivo. Using Northern blot analysis and quantitation of prostatic mRNAs, we have shown that Prl significantly increases the steady-state levels of transcripts coding for several lobe-specific proteins: the C3 subunit of prostatein, probasin, and RWB. We have confirmed these observations in vitro, on explants of immature rat prostate treated with either saline, Prl, or testosterone. In addition, we have demonstrated by a nuclear run-on assay that Prl significantly enhances the transcription rate of the C3 gene in the rat prostate. We conclude that the effects of Prl concern all lobes of the organ and are, at least in part, androgen-independent. Moreover, Prl is able, via an androgen-independent pathway, to increase the rate of transcription of the C3 gene, one of the major products of the rat prostate.

Expression and functionality of luteinizing hormone/chorionic gonadotropin receptor in the rat prostate

In addition to androgens that are essential for maintenance of prostate growth and function, nonandrogenic hormones must also be considered to explain some regulatory events occurring in the prostate. The detection of LH/CG receptor (LH/CG-R) gene expression in some nongonadal tissues, has led us to consider LH as a potential regulatory factor of prostatic development and function. In this study, we have demonstrated by RT-nested polymerase chain reaction and Northern blotting that the rat prostate contains the same LH/CG-R transcript as the gonads. Western immunoblotting, ligand blotting, and binding analysis have shown that rat prostate also contains a 93-kDa receptor protein that is able to bind [125I]hCG specifically and with a high affinity (6.0 x 10(9) M-1). Our results also indicated that the concentration of binding sites was lower in the prostate than in the gonads. LH/CG-R sites of expression have been localized in the prostate by immunohistochemistry: specific staining was observed in all the epithelial cells of the gland, but the ventral lobes are much more immunoreactive than the lateral and dorsal lobes. Finally, the ability of this prostatic LH/CG-R to induce a physiological response was evaluated in an explant culture system. A time course experiment was carried out, and we observed a significant dose-dependent stimulation of cAMP production after 3 h of treatment: 3.0 +/- 0.4, 4.2 +/- 0.4, and 5.0 +/- 0.5 pmol/ml of cAMP for 0, 100, and 500 ng/ml of LH, respectively. In conclusion, LH is able to act directly on the prostatic gland through specific receptors that are structurally and functionally very similar to those expressed in the gonads and are mainly localized in the ventral lobe of the organ. These data suggest that LH plays a significant physiological role in the prostate.

Starling resistor vs. distensible vessel models for embolic pulmonary hypertension

We investigated whether the Starling resistor model (Mitzner et al. J. Appl. Physiol. 51: 1065-1071, 1981) or a distensible vessel model (Haworth et al. J. Appl. Physiol. 70: 15-26, 1991) best describes pulmonary vascular pressure-flow (Q) relationships in embolic pulmonary hypertension. Mean pulmonary arterial pressure (Ppa)-Q plots at constant left atrial pressure (Pla) and Ppa-Pla plots at constant Q were investigated in seven dogs before and after 500-micron glass bead pulmonary embolism. Embolization to a mean angiographic obstruction of 78% increased the slope and extrapolated pressure intercept (P(i)) of Ppa-Q plots and increased the inflection point of Ppa-Pla plots, above which an increase in Pla is transmitted to Ppa in a ratio of approximately 1:1. The Starling resistor and the distensible vessel model provided a reasonably good fit to the Ppa-Q and Ppa-Pla coordinates before and after embolism. However, contrary to the prediction of the Starling resistor model, no correlation was found between the inflection point of Ppa-Pla plots and P(i). We therefore conclude that an increased closing pressure is unlikely to contribute to embolic pulmonary hypertension.

The definitive stoma: complications and treatment in 50 patients

Intestinal stomas remain required in many operations for inflammatory bowel disease, for colorectal tumours, trauma and diverticulitis. During one year, 50 patients (20 ileostomies and 30 colostomies) underwent an intestinal stoma and were followed by an enterostomal therapist. The morbidity, the local complications and the treatment are analyzed. An appropriate skin protection is mandatory in the early post-operative period after performing ileostomy or right colostomy. The mucocutaneous dehiscence can be treated by local protection. The quality of life of patients with a stoma is improved by information and careful medical attention given by the surgeon and the enterostomal therapist.

Duodenal diverticula--diagnosis and management of complicated forms: report of two clinical cases and review of the literature

Duodenal diverticula are frequent, they are present in 22% of the cases at autopsy. However, radiological assessment demonstrates duodenal diverticula in 1 to 5% of the patients only. Perforation, the main complication, is very rare. Preoperative diagnosis is exceptional. In a 69-year patient admitted for diffuse abdominal pain, a computerized abdominal tomography, completed by opacification of the gastroduodenal transit allowed diagnosis. In the second case, diagnosis was made peroperatively. Based on these two observations, the authors review the elements of diagnosis and management in complicated duodenal diverticula.

Development of digoxigenin-labeled peptide: application to chemiluminoenzyme immunoassay of bradykinin in inflamed tissues

A new ultrasensitive chemiluminoenzyme immunoassay (CLEIA) using digoxigenin-labeled bradykinin (BK) as a tracer is proposed to quantify kinins in tissue samples. Rabbit polyclonal IgGs anti-BK directed against the C-terminal end were used for the immunoconcentration step along with dioxetane derivative for the revelation step. The sensitivity of the assay for BK was 0.1 fmol/ml with ED50 of 0.78 pmol/ml. This method was applied on extracts of normal and carrageenan-inflamed tissues. The edema produced by the injection of carrageenan in rat hindpaws was associated with a sevenfold increase of immunoreactive kinins in the inflamed paw extract (from 0.021 +/- 0.007 to 0.141 +/- 0.021 pmol/g tissue; p < 0.01), the immunoreactivity corresponded to BK, kallidin, and T-kinin after HPLC separation. When a mixture of inhibitors of kininase I (mergepta) and kininase II (captopril) was coinjected with carrageenan, the carrageenan-induced edema was unaffected but the kinin tissue content was significantly enhanced (0.207 +/- 0.003 pmol/g tissue; p < 0.01). However, the kinin tissue content and the edema response were unaltered by inhibitors given separately. Hence, this highly sensitive assay provides a biochemical evidence that kinins may act as proinflammatory mediators, and highlights a compensatory increase of kininase I and II activities in inflamed tissues.

Benign prostatic hyperplasia and normal prostate aging: differences in types I and II 5 alpha-reductase and steroid hormone receptor messenger ribonucleic acid (mRNA) levels, but not in insulin-like growth factor mRNA levels

Benign prostatic hyperplasia (BPH) is so common in elderly men that the development of adenomatous nodules in this organ can be seen as a normal age-dependent process. In this work, we used Northern blotting to compare the levels of androgen, estrogen, and insulin-like growth factor-I (IGF-I) receptor in young (age range, 23-33; n = 3), old normal (age range, 52-80; n = 3), and BPH-affected subjects (age range, 66-87; n = 15). We have also investigated in these groups the expression of genes coding for the two 5 alpha-reductases (types I and II), aromatase, IGF-I, and IGF-II. Our results show significantly increased levels of IGF mRNA in old healthy and BPH-affected subjects; the respective rises for IGF-I, IGF-II, and IGF-I receptor mRNAs were 3.0-, 2.9-, and 1.5-fold (BPH) and 2.7-, 2.4-, and 1.8-fold (old normal controls). For estrogen receptor, androgen receptor, and type I and II 5 alpha-reductase mRNAs, a marked but opposite effect was observed in adenomatous tissues only; the respective levels were 2.2-, 1.8-, 3.9-, and 1.7-fold lower than those in young adult subjects, whereas no significant differences were recorded between the two normal groups. Morphometric analysis of each tissue specimen confirmed the significantly lower epithelium/stroma ratio in adenomas compared to young or old healthy tissues. Together, these observations suggest that prostatic adenomas may result from at least two conjugate processes: one characterized by a drop in the mRNA levels of steroid hormone receptors, which might be associated with a lower epithelium/stroma ratio, and another characterized by normal aging phenomena, of which the increased production of IGFs and IGF-I receptor transcripts could be biochemical markers.

Does esophagectomy cure a resectable esophageal cancer?

During the years 1978-1990, 401 patients with esophageal cancer were evaluated for curative resection. A retrospective study was undertaken to estimate the efficacy of surgery and select criteria for long-term survival. After investigation, 187 patients (47%) underwent surgery. To evaluate the long-term results, 101 curative esophageal resections classified into stage I (11 patients), II (24 patients), and III, pathological TNM (66 patients), with at least 2 years' follow-up, were considered. Esophagogastrectomy was performed in 91% of the cases and gastric transposition was achieved in 96% of the patients. The anastomoses were intrathoracic (98%) and at the apex of the right thorax for tumors of the middle third of the esophagus. Staplers were used in 76% of sutures. Postoperative hospital mortality was 5.9%. Specific morbidity included strictures 11%, esophagitis 12%, and anastomotic leak 2%. Actuarial 5-year survival was 90.9% in stage I, 52.3% in stage II, and 17.7% in stage III. The overall 5-year survival rate was 34.2%, 64.8% for the N0 patients, and decreased to 17.7% when node involvement was observed. Five- to 8-year survival is also considered. It is concluded from this study that esophagectomy is actually the appropriate treatment in patients with nonmetastatic resectable carcinoma with an overall 34.2% 5-year survival. The operation can be performed with a low morbidity and mortality rate if done in experienced centers.

Results of surgical resection for hepatocellular carcinoma

During the past 13-years, 35 patients with hepatocellular carcinoma (HCC) were treated by hepatic resection. There were 11 females and 24 males, the age ranged from 17 to 82 years with a mean of 59 years. HCC was associated with liver cirrhosis in 17 patients (48%). Fifteen patients underwent a major hepatectomy, 18 patients a partial hepatectomy (single or bisegmentectomy) and 2 patients had a wedge resection. One patient presenting with a spontaneous tumor rupture died immediately after surgery. Out of the 34 others, 3 died in the postoperative period (8.8%). Early complications occurred in 57% of the patients. The actuarial 5-years survival rate is 30%. The only prognostic factor is tumor extension to a single or both lobes. A significant difference in the survival rate has been observed between patients with or without underlying cirrhosis. Our experience suggest that long-term survival can be expected after surgical resection for HCC.

Growth hormone and prolactin stimulate androgen receptor, insulin-like growth factor-I (IGF-I) and IGF-I receptor levels in the prostate of immature rats

In this study we investigated the involvement of several different pituitary hormones on rat prostate development. 22-day-old Wistar rats, hypophysectomized (hypox) at 19 days of age were supplemented with highly purified human prolactin (hPRL), human luteinizing hormone (hLH), porcine follicle-stimulating hormone (pFSH), and bovine growth hormone (bGH) or with saline. Quantitative analysis of RNAs shows that treatment with either PRL or GH increases significantly steady-state mRNAs levels of the following genes in the prostate: androgen receptor (AR) (respectively 3.5- and 4.8-fold above hypox controls), IGF-I (5- and 2.7-fold), and IGF-I receptor (2.9- and 2.3-fold). LH and FSH, by contrast, have negative effects on these parameters. To test whether the enhancing effect of PRL and GH on AR-mRNA abundance was followed by increased content in the protein itself, binding assays were performed with the androgen agonist [3H]R1881 (131 and 153 fmol/mg protein while hypox controls contained 110 fmol/mg protein). In addition to the well-documented presence of prolactin receptors in prostatic tissues, we have further demonstrated, by means of nuclease S1 protection assays plus dot- and Northern-blot analyses, that a GH receptor mRNA is produced in the immature rat prostate. Moreover, we observed not only strong lactogenic but also purely somatogenic binding to be occurring in the immature prostates. Finally, we have studied IGF-I mRNA content in separated epithelial/stromal cell fractions and have concluded that IGF-I expression is principally located in the prostatic stroma. Taken together, these results suggest that PRL and GH are involved in regulating AR synthesis, at least partially by direct action on the organ. In this context IGF-I appears as a paracrine factor playing a role in epithelium/stroma interactions during prostatic development.

Cellular localization of IGF-I and IGF-II mRNAs in immature hypophysectomized rat testis and epididymis after in vivo hormonal treatment

IGF-I and II genes expression has been localized by in situ hybridization in testis and epididymis of immature hypophysectomized rats treated in vivo with either pFSH, hLH, bGH, hPRL or with saline. IGF-I mRNA expression was found in both Sertoli and Leydig cells after treatment with either FSH or LH. IGF-I mRNA was highly expressed in germ cells after FSH stimulation and to a lesser extent after GH or LH treatments. However, its expression was very low in hypophysectomized control or PRL treated rats. IGF-I mRNA was also expressed in stromal cells of epididymis after LH treatment and to a lesser extent after GH stimulation. In contrast, IGF-II mRNA expression was detected in all testicular cell types whatever the hormonal treatment (FSH, LH, GH, PRL). For each hormonal treatment testicular sections were examined after immunohistochemical staining with specific antisera against IGF-I and IGF-II. Both in situ hybridization and immunohistochemical data were examined in order to determine the testicular sites of synthesis of IGF-I and IGF-II.

Dose-dependent effects of human prolactin on the immature hypophysectomized rat testis

We have studied dose-dependent effects of highly purified human PRL (39 IU/mg) on the testis of immature (22-day-old) hypophysectomized rats daily supplemented for 7 days with 2, 10, or 30 micrograms hormone. Dose-dependent stimulation was observed for all parameters: testis weight (1.6- and 2-fold above control for 10 and 30 micrograms PRL), basal and hCG-stimulated testosterone (14- and 21-fold), intratesticular testosterone (7- and 21-fold) and estradiol (1.2- and 1.5-fold), LH receptor concentration (1.8- and 2.5-fold), in vitro pregnenolone production by cholesterol side-chain cleavage enzyme (3-, 5- and 7-fold), and aromatase activity (2.1- and 2.4-fold). The number of Leydig cells exhibiting immunoreactivity toward anti-P450scc, anti-P450(17 alpha), and anti-3 beta-hydroxysteroid dehydrogenase antibodies also underwent a dose-dependent increase (under conditions revealing many immunopositive cells in hypox control animals). The respective increases were 8- to 14-fold for anti-P450scc and P450(17 alpha) and 1.5- to 2-fold for anti-3 beta-hydroxysteroid dehydrogenase. The number of germ cells and the percentage of tubular sections containing late pachytene spermatocytes as most advanced stages of spermatogenesis were subject to similar dose-dependent effects. These results suggest that during puberty PRL stimulates testicular function by promoting multiplication and differentiation of Leydig cells (acting at various steps of steroidogenesis and on tissue responsiveness to LH) and germ cells.

Purification and characterization of a bovine pregnancy-associated glycoprotein

A 67000 Mr bovine pregnancy-associated glycoprotein (bPAG) has been isolated from fetal cotyledons and purified to homogeneity by HPLC. The purification was monitored by a double immunodiffusion test and by RIA in conjunction with an antiserum raised against a crude fraction of placenta-specific antigens. The molecular weight of bPAG was estimated to be 67000 by SDS-PAGE. The isoelectric points (pI) of the four isoforms, determined by high-resolution analytical electrofocusing in polyacrylamide gel, were 4.4, 4.6, 5.2, and 5.4. The carbohydrate content of the bPAG consisted of approximately 10.02 +/- 1.09% neutral sugar and variant amounts of sialic acid (from 0.29 +/- 0.06% in the most basic isoform to 2.1 +/- 0.31% in the most acidic isoform). A specific antiserum was raised against the purified bPAG. A specific RIA showed that the bPAG was antigenically unrelated to BSA, alphafetoprotein (AFP), and human schwangerschafts-spezifischen (pregnancy-specific) beta 1 glycoprotein (SP1). According to some characteristics (e.g. the molecular weight), the purified bPAG may correspond to a form of the pregnancy-specific protein B previously described by Sasser and colleagues (Biol Reprod 1986; 35:936-942).

Effects of bovine, human and rat growth hormones on immature hypophysectomized rat testis

In this study we have compared the effects of the homologous rat growth hormone with its human and bovine counterparts on the testicular development of immature hypophysectomized rats, after 7 days of treatment. Each hormone increased (12- to 13-fold) the body weight gain and IGF-I blood level (12- to 16-fold). Human GH increased testis weight (1.3-fold) the pregnenolone production (4-fold), the LH dependent steroidogenesis (7-fold), the aromatase activity (5-fold), the concentration of LH receptors (1.6-fold) and spermatogenesis. Bovine and rat growth hormones had marked effects only on pregnenolone production (2- to 3-fold). Incorporation of 5-bromodeoxyuridine in testicular cells after hGH treatment was positive (0.47 per 100 cells), an effect which was 2-fold higher than those produced by bovine and rat GHs (0.25 per 100 cells). These results have led us to conclude that the in vivo action of rat growth hormone on rat testis is comparable to bovine GH and thus might be considered as purely somatogenic. In addition to the known effects on growth promotion, rat GH affected the rate limiting step of steroidogenesis and the Leydig cell multiplication.

Effects of PEEP on pulmonary hemodynamics in intact dogs with oleic acid pulmonary edema

The effects of positive end-expiratory pressure (PEEP) on the pulmonary circulation were studied in 14 intact anesthetized dogs with oleic acid (OA) lung injury. Transmural (tm) mean pulmonary arterial pressure (Ppa)/cardiac index (Q) plots with transmural left atrial pressure (Pla) kept constant were constructed in seven dogs, and Ppa(tm)/PEEP plots with Q and Pla(tm) kept constant were constructed in seven other dogs. Q was manipulated by using a femoral arteriovenous bypass and a balloon catheter inserted in the inferior vena cava. Pla was manipulated using a balloon catheter placed by thoracotomy in the left atrium. Ppa(tm)/Q plots were essentially linear. Before OA, the linearly extrapolated pressure intercept of the Ppa(tm)/Q relationship approximated Pla(tm). OA (0.09 ml/kg into the right atrium) produced a parallel shift of the Ppa(tm)/Q relationship to higher pressures; i.e., the extrapolated pressure intercept increased while the slope was not modified. After OA, 4 Torr PEEP (5.4 cmH2O) had no effect on the Ppa(tm)/Q relationship and 10 Torr PEEP (13.6 cmH2O) produced a slight, not significant, upward shift of this relationship. Changing PEEP from 0 to 12 Torr (16.3 cmH2O) at constant Q before OA led to an almost linear increase of Ppa(tm) from 14 +/- 1 to 19 +/- 1 mmHg. After OA, Ppa(tm) increased at 0 Torr PEEP but changing PEEP from 0 to 12 Torr did not significantly affect Ppa(tm), which increased from 19 +/- 1 to 20 +/- 1 mmHg. These data suggest that moderate levels of PEEP minimally aggravate the pulmonary hypertension secondary to OA lung injury.

Bronchiolar morphology after systemic arterial interruption

To assess ischemic lesions as a factor in obliterative bronchiolitis after lung transplantation, the authors severed the left bronchial arteries of 15 dogs, together with the left stem bronchus, the latter being immediately reanostomosed. They examined the bronchioles at weekly interfals up to three and a half months. On the week chosen each dog was anesthetized, totally heparinized, and exsanguino-perfused with saline. Just after heart arrest, the thoracic aorta was injected with a barium solution until this white medium appeared in the bronchial arteries. The heart-lung blocs were excised en bloc, submitted to soft-tissue x ray, fixed, and then sliced to 1 cm. Corresponding right and left 5-mm-thick samples of these slices were prepared for contact microradiography followed by histologic 5-to-20-micron-thick, stained, correlated specimens. For two weeks the left bronchial arteries remained empty, but there was no necrosis or edema. Between two and four weeks barium solution appeared in the bronchial arteries, and the bronchiolar epithelium had become multistratified. Later the left bronchiangiogram became similar to the right, but there were more folds of the mucosa and a little submucosal fibrosis. These studies provide proof that no significant ischemic lesions occurred during repermeation of the bronchiolar vascular bed. Ischemia, if existent, is not a significant factor in obliterative bronchiolitis.

Nature of pulmonary hypertension in canine oleic acid pulmonary edema

It has recently been suggested that pulmonary hypertension secondary to oleic acid lung injury mainly results from an increase in the critical closing pressure of the pulmonary vessels [Boiteau et al., Am. J. Physiol. 251 (Heart Circ. Physiol. 20): H1163-H1170, 1986]. To further test this hypothesis, we studied 1) the pulmonary arterial pressure- (Ppa) flow (Q) relationship with left atrial pressure (Pla) kept constant (n = 7) and 2) the Ppa-Pla relationship with Q kept constant (n = 9) in intact anesthetized and ventilated dogs before and after lung injury induced by oleic acid (0.09 ml/kg iv). Q was manipulated by use of a femoral arteriovenous bypass and a balloon catheter inserted in the inferior vena cava. Pla was manipulated with a balloon catheter placed by thoracotomy in the left atrium. Ppa-Q plots were rectilinear before as well as after oleic acid. Before oleic acid, the extrapolated pressure intercept of the Ppa-Q plots approximated Pla. Oleic acid administration resulted in a parallel shift of the Ppa-Q plots to higher pressure; i.e., the pressure intercept increased, whereas the slope was not modified. Increasing Pla at constant Q before oleic acid led to a proportional augmentation of Ppa. After oleic acid, however, changes in Pla over the same range affected Ppa only at the highest levels of Pla. These results suggest that oleic acid lung injury increases the critical closing pressure that exceeds Pla, becomes the effective outflow pressure of the pulmonary circulation, and is responsible for the pulmonary hypertension.

Sinoaortic deafferentation reduces intrapulmonary shunt in dogs with oleic acid lung injury

Hypoxic stimulation of the peripheral chemoreceptors has been reported to inhibit hypoxic pulmonary vasoconstriction. To evaluate the pathophysiological importance of this observation, we investigated the effects of surgical peripheral chemoreceptor denervation on pulmonary vascular tone and gas exchange in 17 pentobarbital-anesthetized dogs with oleic acid pulmonary edema. Pulmonary arterial pressure-cardiac index (Ppa/Q) plots, blood gases, and intrapulmonary shunt measured by the SF6 method were obtained at base line, after peripheral chemodenervation (n = 9) or after sham operation (n = 8), and again after 0.09 ml.kg-1 intravenous oleic acid. Over the range of Q studied (2-5 l.min-1.m-2), Ppa/Q plots were best fitted as first-order polynomials in most dogs in all experimental conditions. Chemoreceptor denervation increased Ppa at the lowest Q, while sham operation did not affect the Ppa/Q plots. Oleic acid increased Ppa over the entire range of Q and increased intrapulmonary shunt. This latter was measured at identical Q during the construction of the Ppa/Q plots. Chemoreceptor-denervated dogs, compared with sham-operated dogs, had the same pulmonary hypertension but lower intrapulmonary shunt (36 +/- 4 vs. 48 +/- 5%, means +/- SE, P less than 0.04) and venous admixture (43 +/- 4 vs. 54 +/- 3%, P less than 0.02). We conclude that in intact dogs chemoreceptor denervation attenuates the rise in intrapulmonary shunt after oleic acid lung injury. Whether this improvement in gas exchange is related to an enhanced hypoxic pulmonary vasoconstriction is uncertain.