Earliest gestational age for fetal sexing in cell-free maternal plasma.

OBJECTIVES: To evaluate at what gestational age fetal DNA can reliably be detected at the earliest in maternal plasma. METHODS: We performed consecutive blood sampling in the first trimester of pregnancy in 17 women who were pregnant after in vitro fertilization (IVF) or intrauterine insemination (IUI). DNA was isolated and the Y-chromosome specific SRY was amplified by real-time polymerase chain reaction (PCR). We likewise studied 31 women prior to invasive prenatal diagnosis procedures for test validation purposes. All test results were compared to cytogenetic sex or sex at birth. RESULTS: The earliest SRY detection was at a gestational age of 5 weeks and 2 days. In none of 4 pregnancies ending in a miscarriage was SRY detected. We detected SRY in maternal plasma in 1 of 2 patients (50%) carrying a male fetus at a gestational age of 5 weeks, in 4 of 5 (80%) at a gestational age of 7 weeks, in 4 of 4 (100%) at a gestational age of 9 weeks. In all 7 women pregnant with a male fetus, the correct fetal sex was detected by 10 weeks. In none of the 6 patients who delivered a girl was SRY detected. In the validation group, SRY was detected in 13 of the 13 male, and none of the 18 female fetuses. CONCLUSIONS: We conclude that real-time PCR of the SRY gene promises to be a reliable technique for early fetal sexing in maternal plasma.

Novel gene cassettes and integrons.

An increase in multiresistant Enterobacteriaceae was observed at one of the departments of the University Medical Center Utrecht. Nine different integrons and 17 gene cassettes were found, including the new gene cassette aadA8. This cassette was highly related to aadA3 and aadA2. In addition, an unknown promoter sequence was found for two integrons.

Control of nosocomial multiresistant Enterobacteriaceae using a temporary restrictive antibiotic agent policy.

An observational study on the epidemiology of multiresistant Enterobacteriaceae was conducted in the neurology and neurosurgery wards of a university hospital to determine the impact of hospital hygiene measures and an additional temporary restrictive antibiotic agent policy on the sudden rise in incidence of these bacteria. The incidence and prevalence of patients with multiresistant Enterobacteriaceae were assessed, and patient isolates were typed phenotypically and by random amplified polymorphic DNA analysis. All hospital hygiene measures implemented were recorded, and the influence of the restrictive policy on antibiotic use was analyzed. This policy consisted of a prior authorization requirement and the withdrawal of all antibiotics with a possible selective pressure on multiresistant strains (gentamicin, tobramycin, quinolones, cotrimoxazole, broad-spectrum penicillins, and cephalosporins). This ban left only carbapenems and amikacin for treatment. Typing showed that 17 of the 61 (28%) patients involved were infected or colonized with a single multiresistant strain of Klebsiella oxytoca, for which an environmental source was identified. The isolates recovered from the other patients comprised eight different species, and subsequent genotyping yielded a great variety of strains. The increased incidence could not be controlled with hospital hygiene measures alone. Only after implementation of the restrictive antibiotic policy did the epidemic strain vanish and the endemic incidence of multiresistant Enterobacteriaceae decrease to <50% of the level before intervention. In the years since, the incidence has remained at this low level, and the antibiotic costs have decreased to a level lower than before intervention.

The use of fibrin sealant in the prevention of seromas.

Seroma formation is a difficult problem to treat and prevent. Its sequelae include wound infection, dehiscence, and skin-flap necrosis. The purpose of this study was to determine the effects of fibrin sealant on seroma formation and wound healing. Seromas were created in a rat model by harvesting the latissimus dorsi muscle. In group I (n = 20), only the latissimus dorsi muscle was harvested. In group II (n = 20), the latissimus dorsi muscle was harvested and fibrin sealant applied. Seromas were routinely aspirated. In group III (n = 20), the latissimus dorsi muscle was harvested, and once a seroma was evident clinically, it was aspirated and injected with fibrin sealant. Fibrin sealant was created by combining virally deactivated fibrinogen and thrombin (American Red Cross, Rockville, Md.). In group I, 90 percent of the animals formed seromas compared with only 20 percent in group II. The average total fluid aspirated in group I was 21 cc versus 6 cc in group II. Sixty percent of the animals in group I and 5 percent in group II required serial drainage for chronic seromas. Skin-flap necrosis occurred in 80 percent of the animals in group I, in 10 percent of group II, and in 40 percent of group III. Histologic evaluation confirmed that group II underwent better wound healing. At necropsy, group I animals with seromas had gross capsular formation; this was not readily apparent in the fibrin sealant groups. We conclude that (1) the harvesting of the rat latissimus dorsi muscle is a reliable model for creating seromas, (2) fibrin sealant effectively prevents seroma formation when applied intraoperatively, (3) wound healing in the seroma rat model is improved with intraoperative fibrin sealant application, (4) closed injection of fibrin sealant for existing seromas cannot be recommended at this time, (5) virally deactivated fibrin sealant retains its hemostatic and adhesive properties, and (6) current clinical trials of virally deactivated fibrin sealant may facilitate its use in the United States.

Successful treatment of fungal prosthetic valve endocarditis: case report and review.

We report a case of Candida albicans prosthetic valve endocarditis in a patient who was still alive 1 year following a homograft aortic root and valve replacement and antifungal therapy. Only 33 other cases of successfully treated fungal prosthetic valve endocarditis have been reported. We review these 33 cases and six cases of late recurrence following treatment, as well as the clinical features, diagnosis, and options for treatment of fungal prosthetic valve endocarditis.

Harvesting of the latissimus dorsi muscle: a small animal model for seroma formation.

A common complication of soft tissue dissection and muscle harvesting is seroma formation. In order to manage and understand the formation of seromas, we developed a small animal model for seromas in the Sprague Dawley rat. Skin flaps and subcutaneous tissue were elevated and the latissimus dorsi muscle was harvested in 20 animals. Eighteen of the 20 rats (90%) formed clinically significant seromas. Sixteen animals had associated skin flap necrosis and 12 required serial drainage for recurrent seromas. At necropsy, gross capsular formation occurred in all animals who developed seromas. Microscopically, a fibrous capsule enveloping the seroma was seen associated with a local chronic inflammatory cell infiltrate. We conclude: (1) Elevation of the latissimus dorsi muscle in the rat is a reliable and practical animal model for seroma formation; (2) Sequelae of clinically significant seromas are often as severe as skin flap necrosis; (3) An inflammatory reaction may be associated with seromas.

In vivo exposure to the currently available peritoneal dialysis fluids decreases the function of peritoneal macrophages in CAPD.

Previous in vitro studies have revealed that the currently available peritoneal dialysis fluids (PDF) inhibit several functions of phagocytic cells. To investigate the clinical relevance of those in vitro findings, we compared the in vivo effect of PDF pH on peritoneal macrophage (PMO) function in chronic peritoneal dialysis patients. In a randomized crossover setting, each of eight patients used exclusively PDF at pH five (D5) or pH seven (D7) on day one. The next day the patients who used D5 were switched to D7 and vice versa. Likewise the effect of glucose-mediated hypertonicity was studied in eight other patients, using PDF with 1.36% glucose (D136) or 3.86% glucose (D386). PMO were isolated from the effluents and studied for their phagocytic and killing capacity, and their ability to mount a respiratory burst (chemiluminescence response). PMO obtained after the intraperitoneal instillation of D7 were significantly better able to phagocytize both S. epidermidis (65 +/- 9 vs 37 +/- 8% uptake, p < 0.005) and E. coli (43 +/- 8 vs 25 +/- 4% uptake, p < 0.005). In addition, PMO harvested from D7 effluents revealed a significantly higher killing capacity than PMO derived from D5 effluents for S. epidermidis (60 +/- 5 vs 38 +/- 6%, p < 0.005) as well as for E. coli (51 +/- 10 vs 25 +/- 9%, p < 0.025). Moreover, PMO derived from D7 effluents mounted a significantly higher respiratory burst as compared to PMO in vivo exposed to D5 for the same time.(ABSTRACT TRUNCATED AT 250 WORDS)

Peritoneal defense in continuous ambulatory versus continuous cyclic peritoneal dialysis.

Several centers have reported a lower rate of peritonitis among adult patients on continuous cyclic peritoneal dialysis (CCPD) as compared to those undergoing continuous ambulatory peritoneal dialysis (CAPD). Preliminary results of our ongoing prospective randomized study comparing CAPD-Y with CCPD also suggest a lower peritonitis incidence among CCPD-treated patients. To investigate whether the two dialysis regimens could result in differences in local host defense, we studied peritoneal macrophage (PMO) function and effluent opsonic activity in eight patients established on CAPD-Y matched with eight chronic CCPD patients. Since short and long dwell times are inherent to both dialysis modalities, and we previously found that dwell time has an impact on PMO function and effluent opsonic activity, patients were studied after both a short (4 hr) and a long (15 hr) dwell time. In both groups PMO phagocytic capacity increased significantly with dwell time (39 +/- 3.3% at 4 hr vs. 58 +/- 4.2% at 15 hr in CAPD patients, and 40 +/- 3.9 vs. 72 +/- 3.3% in CCPD patients; P less than 0.01), as did PMO peak chemiluminescence response (31 +/- 4.9 vs. 77 +/- 7.2 counts.min-1/10(4) cells in CAPD, and 22 +/- 3.9 vs. 109 +/- 21.2 counts.min-1/10(4) cells in CCPD; P less than 0.01) and effluent opsonic activity (41 +/- 7.6 vs. 73 +/- 5.8% in CAPD and 39 +/- 6.2 vs. 70 +/- 5.9% in CCPD; P less than 0.01). However, no significant difference was found in either variable between CAPD and CCPD patients when dwell times were equal.(ABSTRACT TRUNCATED AT 250 WORDS)

Another reason to restrict the use of a hypertonic, glucose-based peritoneal dialysis fluid: its impact on peritoneal macrophage function in vivo.

Previous in vitro studies have revealed that the currently used peritoneal dialysis fluids (PDFs) inhibit several functions of phagocytic cells. Glucose-mediated hypertonicity was demonstrated to be one of the major detrimental factors. To investigate the clinical relevance of these in vitro findings, we compared the in vivo effect of a PDF with 3.86% glucose (D386) and a PDF containing 1.36% of glucose (D136) on peritoneal macrophage (PMO) function in eight CCPD patients. In a randomized cross-over setting, each patient used exclusively D136 or D386 on day one. The next day the patients who used D136 were switched to D386 and vice versa. PMO were isolated from the effluents and studied for their phagocytic capacity and chemiluminescence response. PMOs obtained from D386 effluents were significantly less phagocytic as compared to PMOs obtained after the in vivo use of D136 (38 +/- 7.1 vs 63 +/- 8.3%, p less than 0.02). In addition PMOs exposed to D386 were less able to mount a respiratory burst (peak response 4 +/- 1.0 vs 15 +/- 1.4% of control cells, p less than 0.05). Thus, the in vivo use of D386 was accompanied by significantly decreased PMO functions. These findings further stress the need to search for alternative solutions that do not rely on glucose-mediated hypertonicity for ultrafiltration.

The effect of glycerol-containing peritoneal dialysis fluid on peritoneal macrophage function in vivo.

Though glucose is universally applied as osmotic agent in CAPD, there is great interest in the use of alternative osmotic agents. Glycerol-containing peritoneal dialysis fluids (G-PDF) have been used in an attempt to minimize the metabolic effects of long-term exposure to glucose, especially in patients with diabetes. Since data were lacking, we studied the effect of G-PDF on peritoneal macrophage (PMO) function. In a randomized cross-over setting eight stable diabetic CAPD patients performed the third and fourth exchange of the day with either G-PDF or with glucose-containing PDF (D-PDF) of comparable osmolality. The next day the patients who had used G-PDF were switched to D-PDF and vice versa. PMO were isolated from the effluents and tested for their phagocytic capacity and chemiluminescence response. No differences were encountered in total and differential white cell counts between G-PDF and D-PDF effluents. PMO phagocytic capacity for both S. epidermidis (SE) and E. coli (EC) was significantly depressed after the instillation of G-PDF as compared to D-PDF (SE: 52 +/- 2.7 vs 69 +/- 5.0%, p less than 0.02, and EC: 44 +/- 5.7 vs 63 +/- 6.7%, p less than 0.02). The same held true for peak chemiluminescence response (5.3 +/- 1.36 vs 7.2 +/- 1.43% of control cells, p less than 0.005). Thus, G-PDF may compromise PMO function in vivo more than D-PDF despite its more favourable metabolic profile as compared to D-PDF for diabetic patients.

Cell surface antigens associated with murine leukemia virus: definition of the GL and GT antigenic systems.

Two new serological specificities were identified on the surface of murine leukemia virus (MuLV)-infected cells by direct and absorption immunofluorescence tests. Both antigens were detected with antisera prepared in rats that were growing transplants of syngenic MuLV-induced leukemias. Antigen G(L) was defined with the AKR leukemia K36 as the test cell; antigen G(T) was defined with the W/Fu leukemia C58(NT)D as the test cell. G(L) and G(T) antigens were serologically and genetically independent of the MuLV-induced Gross and G(IX) cell-surface antigens. G(L) and G(T) antigens were found in normal lymphoid cells of mice from high-leukemic strains, but not in lymphoid tissues of mice from most low-leukemic strains. Tumors and leukemias of mice of low-leukemic strains often were G(L) and G(T) positive. Similarly, infection of normal cells with MuLV resulted in expression of G(L) and G(T). With ferritin-labeled antibody the G(L) and G(T) antigens were observed on virus-free segments of the cell surface. Genetically, G(L) and G(T) antigens were each controlled by two dominant unlinked genes in AKR mice; these same antigens were each controlled by three or more dominant unlinked genes in C58 mice. Penetrance of G(L) and G(T) regulatory genes was dependent upon the Fv-1 genotype of the host. Expression of G(L) antigen was closely associated with virus production, whereas expression of G(T) antigen was less closely associated.