Biomedical subjects

A Adler

Publications and source records attributed to A Adler.

At least 55 records · Page 3Linked to original sources

PubMed1999

In vitro maturation of human preovulatory oocytes reconstructed by germinal vesicle transfer.

OBJECTIVE: To describe a micromanipulation-electrofusion procedure for transferring germinal vesicles (GVs) between immature human oocytes. DESIGN: Pilot study to assess oocyte maturation after an invasive micromanipulation procedure. SETTING: Research laboratory at a university medical center. PATIENT(S): Immature oocytes were discarded from intracytoplasmic sperm injection (ICSI)-IVF cycles of patients 23-48 years of age. INTERVENTION(S): Initially, GV removal and transfer were performed on the same oocyte; these "self-reconstructed" oocytes were then cultured in vitro for up to 50 hours and examined periodically for maturation as judged by the extrusion of the first polar body. In a second study, GVs from oocytes of "old" patients (>38 years old) were successfully transferred into enucleated immature oocytes of "young" patients (<31 years old). MAIN OUTCOME MEASURE(S): Extrusion of the first polar body was monitored in "reconstructed" and control oocytes; karyotypes also were analyzed at meiosis II. RESULT(S): From 48 oocytes from old patients, 12 GVs were successfully removed, transferred, and fused into previously enucleated oocytes from young patients. After in vitro culture, 7 of these "reconstructed" oocytes matured to meiosis II, a maturation rate not significantly different from that observed in nonmanipulated controls. A normal, second meiotic metaphase chromosome complement was observed in 4 of 5 reconstructed oocytes. CONCLUSION(S): Normal meiosis can occur after the transfer of a GV into an enucleated host oocyte. Germinal vesicle transfer may be a valuable research procedure that generates cell models to characterize the cytoplasmic-nuclear interplay for cell cycle regulation, maturation, and fertilization in the human oocyte; it also may be a potentially attractive alternative to oocyte donation.

Adult↗

PubMed1999

Electrical activation and in vitro development of human oocytes that fail to fertilize after intracytoplasmic sperm injection.

OBJECTIVE: To determine whether electrically stimulated Ca2+ influx can "rescue" fertilization and early embryogenesis in human oocytes that fail to fertilize after intracytoplasmic sperm injection (ICSI). DESIGN: Prospective, randomized trial of a laboratory procedure. SETTING: A research laboratory at a university medical center. PATIENT(S): Discarded oocytes from ICSI-IVF cycles. INTERVENTION(S): Oocytes (n = 104) that showed no evidence of fertilization 16-24 hours after ICSI were assigned to three treatment groups: group 1 (one direct current electrical pulse at 1.36-1.50 kV/cm for 40-60 micros), group 2 (three pulses every 15-20 minutes), or group 3 (treated the same as group 2 but with no electrical stimulation). MAIN OUTCOME MEASURE(S): After stimulation, the oocytes were cultured in vitro for 3-5 days. Oocytes that displayed two pronuclei and a second polar body within 16 hours were considered to have fertilized normally. Fertilization and embryo cleavage rates were compared between groups. RESULT(S): Fertilization occurred in 26 (70%) of 37 and 38 (78%) of 49 group 1 and 2 oocytes, respectively, but in only 5 (27%) of 18 group 3 oocytes. Within 3 days, group 2 embryos routinely developed beyond the two-cell to four-cell stage (61% versus 13% in group 1); 11% of these oocytes developed to the morula or early blastocyst stage. Sex chromosome analyses indicated 10 male and 8 female embryos. CONCLUSION(S): Oocytes that fail to fertilize by 24 hours after ICSI can resume apparently normal fertilization and early embryonic development in response to electrical stimulation. Moreover, the degree of cytoplasmic activation as determined by the number of pulses applied affects fertilization efficiency and early embryonic development.

Adult↗

PubMed1999

Gonadectomy in adult life increases tyrosine hydroxylase immunoreactivity in the prefrontal cortex and decreases open field activity in male rats.

The prefrontal cortices in rats participate in a range of cognitive, emotional, and locomotor functions that are dependent on its rich catecholamine innervation. Sex differences identified in many of these functions suggest that the prefrontal cortex is also influenced by gonadal hormones. Previous studies have shown that prefrontal catecholamines can be modified by changes in the hormone environment in developing animals. The present analyses, carried out in male rats gonadectomized as adults, with and without supplementation with testosterone proprionate, and examined at intervals from two days to 10 weeks after surgery, revealed that both the anatomical organization of prefrontal catecholamine afferents, and a behavioral measure sensitive to their selective lesioning remain highly responsive to changes in testicular hormones in adulthood. Thus, gonadectomy in adult male rats rapidly led to a large but transient decrease in the density of tyrosine hydroxylase immunoreactivity in all layers of the dorsal anterior cingulate cortex. This was followed by a sustained period in which immunoreactivity in the supragranular layers returned to levels that were just below normal (between 72 and 79% of normal), and labeling in deep laminae stabilized at considerably elevated innervation densities (approximately 150% of normal). Neither the acute decrease nor the chronic over-innervation characteristic of gonadectomized animals was observed in rats that were gonadectomized and supplemented with testosterone proprionate. Open field activity assessed along a corresponding 10 week timeline showed that gonadectomized animals were significantly less active than hormonally intact controls, a behavioral pattern opposite to the hyperactivity which persists following prefrontal dopamine lesions. Gonadectomized animals supplemented with testosterone proprionate, on the other hand, had open field scores that were not significantly different from controls. Taken together, these findings indicate that the adult hormone environment provides a significant, and seemingly functionally significant influence over the catecholamine innervation of the rat prefrontal cortex. Such lifelong responsiveness of the prefrontal cortical catecholamines to circulating hormones suggests that gonadal steroids are an active component of the biology of normal adult cognition, and may also have relevance for cortical dysfunction in disorders such as schizophrenia which are not only strongly tied to the catecholamines, but exhibit considerable biases among men and women as well.

Age Factors↗

PubMed1999

The late, but not early, asthmatic response is dependent on IL-5 and correlates with eosinophil infiltration.

Early-phase reactions (EPRs) and late-phase reactions (LPRs) are characteristic features of bronchial asthma, although the pathogenetic mechanisms responsible for each of the responses are not fully defined. A murine model of EPRs and LPRs was developed to investigate the role of IL-5 and eosinophils in development of both responses. After initial intraperitoneal sensitization and airway challenge to ovalbumin (OVA), mice were provoked by additional exposure to OVA. An EPR, characterized by a transient increase in airway responsiveness, was observed 5-30 minutes after antigen provocation. This response was followed by an LPR that reached its maximum at 6 hours after challenge and was characterized by increased airway responsiveness and significant lung eosinophilia. The EPR was blocked by cromoglycate and albuterol, whereas the LPR was abolished by cromoglycate and hydrocortisone. Before provocation with allergen, administration of anti-IL-5 antibody prevented the influx of eosinophils into the lung tissue and abolished the LPR but not EPR. These results suggest that IL-5 and eosinophils are essential for development of the LPR, but not EPR, in this model.

Administration, Inhalation↗

PubMed1999

[Endoscopic therapy of ischemia-type biliary lesions in patients following orthotopic liver transplantation].

Ischemic-type biliary lesions (ITBL) mainly induce stenoses in liver transplants causing cholestasis thus endangering the allograft. ERC enables distinction of ITBL from other differential diagnosis. From 1988 to 1998, 1,026 liver transplantations had been carried out at our clinic. 2.4% (25 out of 1,026) of liver transplanted patients were afflicted from ITBL. 60% (15 out of 25) of patients were endoscopically treated by means of sphincterotomy and balloon dilation. Furthermore, some patients needed extraction of calculi (n = 3), bile duct sequester (n = 6) or stenting (n = 4), respectively. Three patients suffered from ITBL type 1 (= only extrahepatic lesions) and five other patients were afflicted from ITBL type 2 (= circumscript intrahepatic lesions). 90% of those patients revealed long-term benefit from endoscopic therapy (follow-up to seven years). Another 15 patients elicited ITBL type 3 (= multiple intra- and extrahepatic lesions). Therefrom, nine patients had to be retransplanted directly while eight others were assigned to endoscopic treatment. Follow-up investigations revealed that retransplantation could be avoided in 50% of ITBL patients by means of endoscopic therapy for at least three years. In contrast, only 27% of ITBL patients could survive for more than three years without endoscopic therapy. Endoscopic success depends on localization and severity of ITBL complications in the biliary tract of the liver allograft. Therefore, benefit of endoscopic therapy depends on proper diagnosis as early as possible guiding further therapeutic strategy. Conclusively, endoscopic success enables maintenance of liver function in ITBL afflicted liver grafts and avoids or at least, delays retransplantation.

Bile Ducts↗

PubMed1998

Preimplantation genetic diagnosis of human embryos for Marfan's syndrome.

PURPOSE: Single-cell nested polymerase chain reaction (PCR) and Ddel endonuclease digestion were used to detect the presence of a Marfan's syndrome mutation in human preimplantation embryos derived from in vitro fertilization (IVF). These procedures were conducted to eliminate the possibility of transmission of the affected allele from the father to his offspring. The mutation on chromosome 15 is transmitted as an autosomal dominant trait, and the chance of having a child affected with the disease is 50%. METHODS: A couple presented to the Program for In Vitro Fertilization, Reproductive Surgery and Infertility for preimplantation genetic diagnosis. IVF was performed and embryo biopsy was done on day 3 embryos. Single blastomeres were removed from embryos and subjected to nested PCR analysis and endonuclease digestion to detect a Marfan's syndrome mutation located on chromosome 15 inherited from the father. RESULTS: Thirteen oocytes were injected with spermatozoa using intracytoplasmic sperm injection, and nine fertilized normally. Following embryo biopsy and polymerase chain reaction amplification-Ddel endonuclease digestion, five embryos were detected that were positive for the mutation. The four non-affected embryos were transferred to the uterus, resulting in a healthy and normal ongoing pregnancy.

Adult↗

PubMed1998

A sequential four-drug chemotherapy and biotherapy with interferon alpha and GM-CSF--an innovative protocol for the treatment of metastatic melanoma.

We present the results of our chemo-biotherapy protocol for patients with metastatic melanoma. The rationale for the design of the combined therapy was induction of systemic anti-tumor immunity by: (a) priming with IFN-alpha for enhancement of tumor and histocompatibility antigen expression, (b) therapy by the 4-drug regimen (BCNU, DTIC, cisplatin and tamoxifen) for maximal tumor destruction, followed by (c) an immunomodulatory, low dose of GM-CSF. Treatment was given in cycles of three weeks: first IFN-alpha (3 x 10(6) U/day on days 1, 3, and 5); then the 4-drug regimen given according to Del Prete et al., (4); followed by GM-CSF (20 micrograms/m2/day on days 15 to 21). All patients were previously untreated by chemotherapy, and had a performance status of ECOG 0-2. Treatment was discontinued upon severe toxicity or disease progression. In responding patients--once maximal response was achieved-IFN alpha treatment (3 x 10(6) U/day, three times weekly) was continued for a period of two years or until disease progression. All 40 patients (28 males and 12 females) who received the above program were evaluable for response and toxicity and received at least two cycles of therapy. At a median follow-up of one year, 50% had achieved an objective response, with 22.5% complete responses (CR), and 27.5% partial remissions (PR). Median duration of response is 11 months (12 for CR and 9 for PR patients). Median survival for all patients is 14 months (range, 7-21), increasing to 22 months (range, 15-29) in responding patients. Activation of patients' peripheral blood Macrophages and Dendritic Cells was observed following GM-CSF treatment. The chemo-biotherapy protocol presented above--while associated with acceptable toxicity--resulted in a relatively high response rate with an increase in the number of durable responses in patients with metastatic melanoma.

Adolescent↗

PubMed1998

Electrical impedance tomography can monitor dynamic hyperinflation in dogs.

We assessed in eight dogs the accuracy with which electrical impedance tomography (EIT) can monitor changes in lung volume by comparing the changes in mean lung conductivity obtained with EIT to changes in esophageal pressure (Pes) and to airway opening pressure (Pao) measured after airway occlusion. The average volume measurement errors were determined: 26 ml for EIT; 35 ml for Pao; and 54 ml for Pes. Subsequently, lung inflation due to applied positive end-expiratory pressure was measured by EIT (delta VEIT) and Pao (delta VPAO) under both inflation and deflation conditions. Whereas delta VPAO was equal under both conditions, delta VEIT was 28 ml greater during deflation than inflation, indicating that EIT is sensitive to lung volume history. The average inflation delta VEIT was 67.7 +/- 78 ml greater than delta VPAO, for an average volume increase of 418 ml. Lung inflation due to external expiratory resistance was measured during ventilation by EIT (delta VEIT,vent) and Pes (delta VPes,vent) and at occlusion by EIT (delta VEIT,occl), Pes, and Pao. The average differences between EIT estimates and delta VEIT,occl were 5.8 +/- 44 ml for delta VEIT,vent and 49.5 +/- 34 ml for delta VEIT,occl. The average volume increase for all dogs was 442.2 ml. These results show that EIT can provide usefully accurate estimates of changes in lung volume over an extended time period and that the technique has promise as a means of conveniently and noninvasively monitoring lung hyperinflation.

Airway Resistance↗

PubMed1998

Airway-parenchymal interdependence after airway contraction in rat lung explants.

The constriction of pulmonary airways is limited by the tethering effect exerted by parenchymal attachments. To characterize this tethering effect at the scale of intraparenchymal airways, we studied the pattern of parenchymal distortion due to bronchoconstriction in a rat lung explant system. First, we measured the elastic modulus under tension for 2% (wt/vol) agarose alone (37.6 +/- 1.5 kPa) and for agarose-filled lung (5.7 +/- 1.3 kPa). The latter is similar to the elastic modulus of air-filled lung at total lung capacity (4.5-6 kPa) (S. J. Lai-Fook, T. A. Wilson, R. E. Hyatt, and J. R. Rodarte. J. Appl. Physiol. 40: 508-513, 1976), suggesting that explants can be used as a model of lung tissue distortion. Subsequently, confocal microscopic images of fluorescently labeled 0.5-mm-thick explants prepared from agarose-filled rat lungs inflated to total lung capacity (48 ml/kg) were acquired. Images were taken before and after airway constriction was induced by direct application of 10 mM methacholine, and the pattern of parenchymal distortion was measured from the displacement of tissue landmarks identified in each image for 14 explants. The magnitude of the radial component of tissue displacement was calculated as a function of distance from the airway wall and characterized by a parameter, b, describing the rate at which tissue movement decreased with radial distance. The parameter b was 0.994 +/- 0.19 (SE), which is close to the prediction of b = 1 of micromechanical modeling (T. A. Wilson. J. Appl. Physiol. 33: 472-478, 1972). There was significant variability in b, however, which was correlated with the fractional reduction in airway diameter (r = 0.496). Additionally, parenchymal distortion showed significant torsion with respect to the radial direction. This torsion was similar in concentric zones around the airway, suggesting that it originates from inhomogeneity in the parenchyma rather than inhomogeneous airway constriction. Our results demonstrate the significance of the nonlinear mechanical properties of alveolar walls and the anisotropy of the parenchyma in determining the nature of airway-parenchymal interdependence.

Animals↗

PubMed1997

Intestinal disease in acquired immunodeficiency: evaluation by CT.

Intestinal symptoms affect most AIDS patients at some point in their disease. The purpose of this study was to evaluate the use of CT in this setting. A total of 339 abdominal CT exams were reviewed for signs of intestinal disease. Abdominal CT scans of 45 patients with intestinal symptoms were compared with colonoscopy and histologic data. The CT results were correlated with CD4( +) T-lymphocyte counts and patient survival. More than 14 % of all abdominal CT exams displayed signs of enteric disease. Of the 45 patients studied with both CT and colonoscopy, 35 (78 %) had signs of intestinal disease by CT. Of these 35 patients, colonoscopic signs of an intestinal lesion were found in 29 and histologic proof of disease was established in 30 cases. Colonoscopy and histology detected 8 lesions missed by CT. There were 14 cases of unspecific colitis, 15 cases of cytomegalovirus (CMV) colitis, and 4 cases of enteric tuberculosis as per biopsy. Five patients presented with Kaposi's sarcoma and 1 with a non-Hodgkin's lymphoma. Neither colonoscopic nor CT signs of intestinal disease did reliably distinguish between histologic subgroups. Specifically, CMV colitis could not be distinguished from unspecific colitis. CD4( +) T-lymphocyte counts for histologic subgroups were not significantly different, either. No colonoscopic or histologic feature predicted survival, whereas low CD4 counts and ascites on CT indicated a poor prognosis. Whereas CT detects signs of intestinal disease in most AIDS patients, these signs remain largely unspecific. Colonoscopy and biopsies provide no consistently valid standard with which to compare CT because of controversial sensitivity and specificity of these methods. The CT technique detects small bowel as well as extraintestinal disease. Therefore, CT is an important diagnostic modality in abdominal disease of immunocompromised patients.

AIDS-Related Opportunistic Infections↗

PubMed1997

Endoscopic access to the papilla of Vater for endoscopic retrograde cholangiopancreatography in patients with billroth II or Roux-en-Y gastrojejunostomy.

BACKGROUND AND STUDY AIMS: Endoscopic retrograde cholangiopancreatography (ERCP) is an established modality for the diagnosis and treatment of pancreaticobiliary disorders. In contrast to ERCP in patients who have not undergone gastrectomy, ERCP in patients with a Billroth II gastrojejunostomy or a Roux-en-Y anastomosis is considerably more difficult. It was nevertheless considered that ERCP might be possible in most patients with gastrectomies, and this hypothesis was tested. PATIENTS AND METHODS: A total of 2256 patients were admitted to our hospital for ERCP from 1990 to 1994. Of these, 65 (3%) had gastrojejunostomies, either with Billroth II reconstructions or with the Roux-en-Y procedure. ERCP was always performed with a conventional side-viewing endoscope. RESULTS: We examined the 65 patients with gastrojejunostomies. Of these, 91% had Billroth II anastomoses and 9% had received Roux-en-Y reconstructions. We successfully reached the papilla of Vater with the endoscope in 92% of the patients with Billroth II gastrojejunostomies (54 of 59), but in only 33% of the patients with Roux-en-Y reconstructions (two of six). In 8% of the cases of Billroth II anastomosis, it was not possible to advance the endoscope into the duodenal stump, due to intestinal stenoses (5%) or excessive intestinal length (3%). Failure in case of regular Billroth II anatomy occurred only in patients who had not received Braun enteroenterostomies. Failure also occurred in 67% of the Roux-en-Y gastrojejunostomy cases due to excessive intestinal length. CONCLUSIONS: Most patients with Billroth II gastrojejunostomy (92% of those in the present study) and some patients with Roux-en-Y anastomosis (33% of those in the present study) can be investigated by ERCP and endoscopically treated in cases of pancreaticobiliary disorder. Braun enteroenterostomy has no negative impact on the endoscopic access to the papilla of Vater in patients with Billroth II gastrojejunostomy. Surgical reconstruction of the gastrointestinal tract to perform gastrojejunostomy should also take endoscopic requirements into account. In view of both the potential postoperative complications and endoscopic requirements, the jejunojejunostomy should be placed nearer to the gastrojejunostomy than 60 cm, and the afferent loop should be as short as possible.

Adult↗

PubMed1997

Endoscopic sphincterotomy using an S-shaped sphincterotome in patients with a Billroth II or Roux-en-Y gastrojejunostomy.

BACKGROUND AND STUDY AIMS: Some patients admitted for endoscopy present a gastrojejunostomy with a Billroth II anastomosis or Roux-en-Y reconstruction. The gastrointestinal reconstruction hampers endoscopic diagnosis and treatment of the biliary and pancreatic tract. The present paper describes a new procedure facilitating endoscopic retrograde cholangiopancreatography (ERCP) in patients who have undergone gastrojejunostomy. PATIENTS AND METHODS: ERCP was attempted in 65 patients with gastrojejunostomy. A conventional side-viewing endoscope was advanced into the duodenal stump, and a modified catheter was pushed through the endoscope. The cutting wire of the modified catheter winds round the catheter at a pivotal point between the catheter's proximal and distal holes. This allows the catheter tip to be forced into an S-shape when the wire is pulled. Since the cutting wire can easily be adjusted to the papillary roof, safe and successful endoscopic sphincterotomy can be carried out. RESULTS: We were able to advance the conventional side-viewing endoscope into the duodenal stump in 92% of the patients (n = 59) with Billroth II gastrojejunostomies, and in 33% of the patients (n = 6) with Roux-en-Y anastomoses. Whenever it was possible to reach the duodenal stump, cannulation and sphincterotomy of the papilla of Vater was successful. Ninety-six percent of the patients who underwent sphincterotomy (n = 54) immediately benefited from biliary decompression. One major complication occurred, with a patient suffering a retroperitoneal perforation during endoscopic sphincterotomy; the patient later died, despite three subsequent surgical operations. CONCLUSIONS: In spite of previous gastrojejunostomy, most patients with Billroth II anastomoses (92%) and many patients with Roux-en-Y reconstructions (33%) can be treated endoscopically for biliary diseases. The use of a conventional side-viewing endoscope in conjunction with an S-shaped sphincterotome can be recommended. This allows safe and successful endoscopic treatment of all patients in whom endoscopic access to the papilla of Vater is possible.

Ampulla of Vater↗

PubMed1997

Clinical significance of magnetic resonance cholangiopancreatography (MRCP) compared to endoscopic retrograde cholangiopancreatography (ERCP).

BACKGROUND AND STUDY AIMS: The clinical importance of magnetic resonance cholangiopancreatography (MRCP) as a noninvasive diagnostic modality for investigation of the biliary tree and pancreatic duct system is under debate. Using endoscopic retrograde cholangiopancreatography (ERCP) as the gold standard, this study determined in a prospective, blinded fashion the sensitivity and further statistic values of MRCP findings for evaluation of the biliary and pancreatic tract. PATIENTS AND METHODS: Seventy-eight patients referred for ERCP were studied prospectively with MRCP and ERCP during a 12-month period. All images were interpreted on a blinded basis by two radiologists. Any dilations, strictures, and intraductal abnormalities were recorded and correlated with the clinical diagnoses. RESULTS: MRCP images of diagnostic quality were obtained in 76 of the 78 patients (97%). Magnetic resonance cholangiography (MRC) showed sensitivities (and positive predictive values) of 71% (62%) for recognition of normal bile ducts, 83% (91%) for recognition of dilation, 85% (100%) for recognition of strictures, 77% (91%) for correct stricture location, and 80% (100%) for diagnosing bile duct calculi. In addition, the sensitivity of MRC in classifying benign and malignant strictures was 50% and 80%, respectively. The statistical values (sensitivity and positive predictive value) for magnetic resonance pancreatography findings were determined for the recognition of normal pancreatic ducts (33% and 50%), recognition of dilation (62% and 100%), recognition of strictures (76% and 87%) and correct location (66% and 100%), diagnosis of benign strictures (87% and 87%) and malignant strictures (60% and 75%), and for diagnosing pancreatic duct stones (60% and 100%). CONCLUSIONS: MRCP is capable of providing diagnostic information equivalent to ERCP in many patients, and should be applied whenever established techniques provide no results, or inadequate results.

Adolescent↗

PubMed1997

Management of traction wire fracture complicating mechanical basket lithotripsy.

BACKGROUND AND STUDY AIMS: The application of basket catheters has become the main method of removing calculi from the biliary and pancreatic duct. However, larger or impacted stones have to be crushed and fragmented by mechanical lithotriptors before removal is possible. Sometimes, fracture of the traction wire occurs as a severe and fraught complication. We describe a precautionary measure which helps to manage this complication. PATIENTS AND METHODS: In a series of 569 consecutive patients suffering from bile or pancreatic duct stones we found 60 (10.5%) who required mechanical lithotripsy for oversized or impacted calculi. Mechanical lithotripsy was always performed initially with a long metal sheath (80 cm) in combination with a standard traction wire. If the traction wire fractured we replaced the long metal sheath stepwise by shorter ones (70cm, 60cm and 50 cm, respectively), allowing immediate continuation of the lithotriptic procedure using the same traction wire. RESULTS: During the lithotriptic procedure three of our patients (5%) were afflicted by traction wire fracture. Two patients could be relieved directly by changing the initial metal sheath to shorter ones. Because of the exceptional hardness of a pancreatic duct stone the third patient needed stone fragmentation by extracorporeal shock wave lithrotripsy (ESWL) before complete mechanical clearance of the duct could be accomplished. CONCLUSION: We advocate the initial use of a long metal sheath (80cm) to perform mechanical lithotripsy. In case of traction wire fracture the use of a shorter metal sheath allows immediate successful continuation of the procedure, thereby frequently avoiding procedures such as ESWL or surgery.

Bile Duct Diseases↗

PubMed1997

A simple and objective approach to identifying human round spermatids.

Although round spermatids have been studied extensively using staining techniques and electron microscopy, little information is available about their appearance in living conditions. We describe a method of collecting and identifying round spermatids from ejaculates and testicular biopsies. The validity of the selection procedure was confirmed by fluorescence in-situ hybridization. Based on cell size, morphological characteristics of nucleus and cytoplasm, and on the nucleus/cytoplasm ratio, we harvested a population of cells that was 84% haploid. This procedure can be applied to select spermatids for clinical or research purposes.

Biopsy↗

PubMed1997

Treatment-related chromosome abnormalities in human embryos.

Mosaicism was studied in good quality embryos from four different centres in order to assess the effects of follicular induction and exposure to laboratory conditions on chromosomal status. The donated embryos were fully biopsied and analysed by fluorescence in-situ hybridization using probes for chromosomes X, Y, 13, 18 and 21, simultaneously. The number of abnormal cells present indicated the division at which mosaicism first occurred (4/4 cells at first division, 2/4 cells at second, 2/8 at third). The rate of mosaicism in embryos from different centres varied greatly (P < 0.001). Most of the mosaic embryos were obtained before 1991. In one clinic increased mosaicism was found in embryos obtained before 1991 when compared to embryos obtained thereafter. The results suggest that certain culture conditions and/or hormonal stimulation protocols may induce chromosomal abnormalities and partly explain differences in pregnancy rates between in-vitro fertilization centres.

Biopsy↗

PubMed1997

Monitoring changes in lung air and liquid volumes with electrical impedance tomography.

Electrical impedance tomography (EIT) uses electrical measurements at electrodes placed around the thorax to image changes in the conductivity distribution within the thorax. This technique is well suited to studying pulmonary function because the movement of air, blood, and extravascular fluid induces significant conductivity changes within the thorax. We conducted three experimental protocols in a total of 19 dogs to assess the accuracy with which EIT can quantify changes in the volumes of both gas and fluid in the lungs. In the first protocol, lung volume increments from 50 to 1,000 ml were applied with a large syringe. EIT measured these volume changes with an average error of 27 +/- 6 ml. In the second protocol, EIT measurements were made at end expiration and end inspiration during regular ventilation with tidal volume ranging from 100 to 1,000 ml. The average error in the EIT estimates of tidal volume was 90 +/- 43 ml. In the third protocol, lung liquid volume was measured by instilling 5% albumin solution into a lung lobe in increments ranging from 10 to 100 ml. EIT measured these volume changes with an average error of 10 +/- 10 ml and was also able to detect into which lobe the fluid had been instilled. These results indicate that EIT can noninvasively measure changes in the volumes of both gas and fluid in the lungs with clinically useful accuracy.

Anesthesia↗

PubMed1997

Accuracy of staging rectal tumors with contrast-enhanced transrectal MR imaging.

OBJECTIVE: Our objective was to evaluate the accuracy of contrast-enhanced transrectal MR imaging in staging rectal adenoma and carcinoma by correlating with histopathologic findings. SUBJECTS AND METHODS: Thirty-five patients underwent transrectal MR imaging on a 1.5-T superconducting unit using unenhanced T1-weighted and T2-weighted spin-echo and turbo spin-echo sequences, a dynamic gadopentetate dimeglumine-enhanced turbo fast low-angle shot sequence, and enhanced T1-weighted spin-echo sequences. For all patients, histopathologic correlation was available from biopsy (n = 15) or surgical resection (n = 20). Two radiologists unaware of each other's interpretations of the scans interpreted each case from which we evaluated qualitative and quantitative data. RESULTS: Rectal adenomas (n = 15) were identified when imaging revealed an intact muscularis mucosae, a homogeneous internal structure, and high contrast enhancement of the lesion. Carcinomas staged as T1 by TNM criteria (n = 6) were best revealed by dynamic turbo fast low-angle shot sequences, in which an intact muscularis propria could be seen. Visualization of enhancing tumor tissue in the muscularis propria indicated T2 carcinoma (n = 5). All T3 (n = 5) and T4 (n = 4) carcinomas were correctly staged with dynamic and static MR imaging. The stage revealed by MR imaging correlated well with histologic staging results in 89% (observer 1) and 86% (observer 2) of interpretations. However, when interpreting MR imaging, observers tended to overstage and never understaged. CONCLUSION: Transrectal surface-coil MR imaging provided reliable information in staging patients before surgery and in evaluating rectal adenoma and carcinoma.

Adenoma, Villous↗