MicroStructured Omnifit acetabular components: concerns with locking system complications and excessive polyethylene wear

BACKGROUND

We began to use cementless MicroStructured Omnifit acetabular components in November 1988. Liner dislodging and excessive polyethylene wear later occurred in some of our patients. This finding prompted us to review our experience with the use of such modular acetabular components.

METHODS

A total of 887 hips in 672 patients, which had been fitted with cementless MicroStructured Omnifit acetabular components, were evaluated for locking system complications using radiographic examinations. Of the cases, 240 hips which had received a 26-mm femoral head (group 1) and 110 hips which had received a 32-mm femoral head (group 2) were compared using a digitiser to determine the influence of femoral head size on polyethylene wear.

RESULTS

There were two types of radiographic signs of locking system complications in 7 hips, at a mean time of 2.9 years after implantation. The incidence of liner locking system complications using this modular acetabular component was 0.8%. The mean liner wear rate per year was 0.15 mm in group 1 and 0.20 mm in group 2 (p <0.005). The initial polyethylene thickness ranged from 5.9 to 13.6 mm in group 1, compared with 3.9 to 10.6 mm in group 2 (p < 0.005).

CONCLUSION

A patient who has received a total hip arthroplasty that includes a MicroStructured Omnifit acetabular component should be monitored frequently for radiographic signs of locking system complications. In this study, the mean liner wear rate was significantly higher in group 2. Inadequate polyethylene thickness in this group was implicated as the major cause of excessive polyethylene wear.

Evaluation of linkage of markers on chromosome 6p with schizophrenia in Taiwanese families

Previous studies have indicated possible linkage of schizophrenia with chromosome 6p21-24. In an attempt to replicate these findings, we studied the linkage of schizophrenia with nine markers on chromosome 6p21-24 in 39 Taiwanese schizophrenic nuclear families with at least two affected siblings. Two diagnostic models (narrow: Diagnostic and Statistical Manual of Mental Disorders-IV schizophrenia only; and broad: including schizophrenia, schizoaffective, and other nonaffective psychotic disorders) were used to define the disease phenotypes. With the broad and narrow diagnostic models, the marker D6S296 produced maximum two-point lod scores of 1.46 (straight theta = 0.2) and 1.35 (straight theta = 0. 2), respectively, in the recessive inheritance model. Assuming locus heterogeneity, a multipoint lod score of 0.85 was obtained between markers D6S296 and D6S277 under the narrow/recessive model. Maximum nonparametric lod scores of 1.25 ( p= 0.09) and 1.36 (p = 0.08) were observed, but still not statistically significant, at D6S296 in the narrow and broad diagnostic models, respectively. Both two-point analysis of the dominant model (lod score 0.85) and nonparametric analysis (lod score 1.25) showed a mild peak lod score appeared at marker D6S 285 as well. The results add some support to the suggestive linkage of schizophrenia with markers in the regions of chromosome 6p22 and 6p24 in an ethnically distinct Taiwanese sample. Am. J. Med. Genet. (Neuropsychiatr. Genet.) 96:74-78, 2000.

Vascular ATP-dependent potassium channels, nitric oxide, and human forearm reactive hyperemia

Vascular ATP-dependent potassium (K+ATP) channels open and contribute to reactive hyperemia (RH) in animals. The contribution of K+ATP channels to ischemic vasolidation during RH and interactions with endothelium-derived nitric oxide have not been well characterized in human subjects. RH blood flow responses (mL/dL) following 5 minutes of cuff occlusion were measured using strain-gauge plethysmography in 22 normal human subjects age 42 +/- 2 years. Measurements were obtained at baseline and following intra-arterial administration of the K+ATP channel closer glibenclamide, the nitric oxide synthase inhibitor L-N-monomethyl arginine (L-NMMA), or both drugs simultaneously. Glibenclamide (100 micrograms/min) did not change basal flow (2.7 +/- 0.3 to 2.7 +/- 0.3 mL/min/dL), but L-NMMA (8 mumol/min) and combined glibenclamide and L-NMMA significantly (p < 0.05) decreased basal flow (3.0 +/- 0.5 to 2.0 +/- 0.2 and 3.3 +/- 0.5 to 2.5 +/- 0.3, respectively). Glibenclamide significantly (p < 0.01) decreased RH flow (18.2 +/- 1.3 to 14.8 +/- 1.3) and excess flow (5.3 +/- 1.2 to 1.3 +/- 1.3). L-NMMA significantly (p < 0.05) decreased RH flow (21.2 +/- 1.8 to 18.9 +/- 1.9) and tended to decrease excess flow (6.1 +/- 2.2 to 3.9 +/- 2.5). Combined drug infusion significantly (p < 0.1) decreased RH flow (21.6 +/- 2.2 to 18.0 +/- 2.4) and excess flow (6.3 +/- 1.6 to 1.6 +/- 1.6), with reductions in RH and excess flow similar to those following glibenclamide infusion alone. We conclude that forearm vascular K+ATP channels are closed at baseline. They open and contribute to RH vasodilation. The addition of nitric oxide inhibition to K+ATP channel blockade does not result in additive or synergistic inhibition of RH.

Complications of liner locking system in Micro-structured Omnifit acetabular components: a radiographic evaluation of 887 hips followed for 5-10 years

We evaluated 887 hips in 672 patients with uncemented MicroStructured Omnifit acetabular components for liner locking complications. We found 2 types of radiographic signs of liner locking system complications in 7 hips, developing between 2 and 4 years postoperatively. The incidence of liner locking system complications was 0.8% using this modular acetabular component. We recommend that a patient who has received a total hip arthroplasty including a MicroStructured Omnifit acetabular component should be monitored frequently for radiographic signs of liner locking system complications, especially with a polyethylene thickness of less than 8 mm.

Adult monteggia fracture with ipsilateral distal radius fracture: case report

Although the adult Monteggia fracture is a well-known injury, the combination of a Monteggia fracture and an ipsilateral distal radius fracture is extremely rare. It is important for the treating physician to recognize that this injury involves not only the bone elements but also their articulations. The distortion of the integrity of both the elbow and the wrist results in the potential for functional compromise, if inadequately treated. The case report presented here describes a 21-year-old woman with this complex injury resulting from a fall. The injury included a Monteggia type II fracture and an ipsilateral distal radius intra-articular fracture in the left forearm. An excellent result was obtained by surgical intervention in both the radial and ulnar bones. The factors we believe contributed to the excellent result were early diagnosis, anatomic reduction, stable fixation, and early physical exercise. The mechanism of injury giving rise to this rare combination of fractures is discussed, as well as a review of the literature.

A fast encoding algorithm for fractal image compression using the DCT inner product

In this paper, a fast encoding algorithm is developed for fractal image compression. At each search entry in the domain pool, the mean square error (MSE) calculations of the given range block and the eight dihedral symmetries of the domain block are obtained simultaneously in the frequency domain, in which the redundant computations are all eliminated in the new encoding algorithm. It is shown in software simulation that the encoding time is about six times faster than that of the baseline method with almost the same PSNR for the retrieved image. The fast algorithm is performed to deal with the eight dihedral symmetries at each search entry. Therefore, it can be applied to various enhanced algorithms which are equipped with quadtree, classification, and other mechanisms.

Early polyethylene wear and osteolysis in cementless total hip arthroplasty: the influence of femoral head size and polyethylene thickness

We examined initial polyethylene thickness, early polyethylene liner wear, and osteolysis in 350 primary, cementless total hip arthroplasties (THAs). All of the prostheses were of identical design and used Omnifit components. In the 32-mm head group, the mean liner wear correlated significantly with polyethylene thickness (P<.001) and increased rapidly with initial thinner polyethylene following a logarithmic model, although this increase was not statistically significant (r = -.633). Inadequate polyethylene thickness in the 32-mm head group was implicated as the major cause of higher liner wear. A minimal polyethylene thickness of 7 mm is recommended in cementless metal-backed THAs. The use of a large head combined with poor prosthetic design appeared to be responsible for the unacceptably high incidence of femoral osteolysis.

Role of inducible nitric oxide synthase in transplant arteriosclerosis

1. Transplant arteriosclerosis is a major obstacle to long-term allograft survival. Nitric oxide (NO) has been implicated as a mediator in the development of this disease. 2. We and others have shown that inducible nitric oxide synthase (iNOS) is up-regulated in allografts with transplant arteriosclerosis. Despite the acute cytotoxic effects produced by high levels of NO, a chronic increase in NO availability is protective against neointimal hyperplasia, mainly by suppressing the inflammatory cell recruitment and neointimal smooth muscle cell accumulation. 3. Currently, we have the technology to directly transfer the iNOS gene to allografts. We have demonstrated that this exciting strategy is feasible and therapeutic and may improve the long-term survival and function of allografts. Future challenges include optimizing the methods and the vectors of gene delivery.

Management of splenic artery aneurysms: the significance of portal and essential hypertension

BACKGROUND

Splenic artery aneurysm(s) (SAA) are rare. But the incidence and significance of SAA among patients with portal hypertension (PHTN), especially among those who undergo orthotopic liver transplantation (OLT), have not been clearly delineated.

STUDY DESIGN

An 11-year (February 1987 to June 1998) retrospective review of our experience with treated SAA was performed. Patient characteristics, risk factors, clinical presentation, surgical management, aneurysm characteristics, and patient outcomes were assessed. Patients were separated according to a history of PHTN for analysis. Patients were also subdivided into ruptured versus elective presentations.

RESULTS

Thirty-four patients (22 in the PHTN group) were treated for SAA during the study period. Sixty-two percent (21 of 34) were women; the average age was 50.6 years. In patients without a history of PHTN (n = 12), essential hypertension was a significant risk factor (p < 0.001) for development of SAA. All patients underwent surgical treatment for SAA: resection with splenectomy (n = 23), ligation with splenectomy (n = 5), ligation of SAA only (n = 4), and vascular reconstruction (n = 2). The average size of all treated SAA was 4.8 +/- 2.6 cm, ranging from 1.5 to 12cm. Operative mortality after SAA rupture (n = 15) was 40%, compared with zero mortality for elective SAA repair (n = 19, p < 0.005). Rupture of SAA was associated with a higher mortality in patients with PHTN compared with patients without such history (56% versus 17%, respectively). After a mean followup period of 46 months, survival after rupture was 60% in contrast to 84% after elective repair. The majority of our patients with a history of PHTN (20 of 22) has undergone OLT, representing 0.46% of all OLT recipients (n = 4,374) during the study period. In four patients, SAA were repaired concurrently during transplantation. Of the 7 patients presented with rupture of SAA after OLT, 6 patients presented within 3 to 16 days postoperatively, with a median of 6 days and an overall mortality of 57%.

CONCLUSIONS

Essential hypertension and PHTN appear to be significant risk factors for development of SAA. Rupture of SAA is associated with a significant mortality, highest among patients with PHTN. Elective repair remains a safe and effective method of treatment. The significance of SAA is recognized among patients undergoing liver transplantation. A decision should be made to screen and electively treat SAA found in liver transplant patients, especially if the aneurysm is larger than 1.5 cm. Awareness of the increased rupture risk is crucial in management during the immediate posttransplant period.

Percutaneous transluminal coronary angioplasty for renovascular hypertension in a child: a case report

Since its introduction, percutaneous transluminal coronary angioplasty has become an alternative therapeutic modality to surgical and medical treatment for renovascular hypertension. We report the case of a nine-year-old boy who had hypertension caused by renal arterial stenosis. The patient's high blood pressure was 164/100 mmHg, which was discovered incidentally during a physical check-up. A selective renal angiography showed a severe short-segment stenosis with post-stenotic dilatation of the left renal artery. A 4-mm balloon catheter was advanced through the stenotic area and was inflated five times to dilate the stenosis. After the procedure, the selective renal angiography showed a significant increase in the diameter of the left renal artery. Blood pressure decreased to normal immediately after the procedure. During the one-year follow-up period, the patient remained normotensive without the use of antihypertensive drugs.

Impaired wound healing and angiogenesis in eNOS-deficient mice

A role for nitric oxide (NO) in wound healing has been proposed; however, the absolute requirement of NO for wound healing in vivo and the contribution of endothelial NO synthase (eNOS) have not been determined. Experiments were carried out using eNOS gene knockout (KO) mice to determine the requirement for eNOS on wound closure and wound strength. Excisional wound closure was significantly delayed in the eNOS KO mice (29.4 +/- 2.2 days) compared with wild-type (WT) controls (20.2 +/- 0.4 days). At 10 days, incisional wound tensile strength demonstrated a 38% reduction in the eNOS KO mice. Because effective wound repair requires growth factor-stimulated angiogenesis, in vitro and in vivo angiogenesis assays were performed in the mice to assess the effects of eNOS deficiency on angiogenesis. Endothelial cell sprouting assays confirmed in vitro that eNOS is required for proper endothelial cell migration, proliferation, and differentiation. Aortic segments harvested from eNOS KO mice cultured with Matrigel demonstrated a significant reduction in endothelial cell sprouting and [(3)H]thymidine incorporation compared with WT mice at 5 days. Capillary ingrowth into subcutaneously implanted Matrigel plugs was significantly reduced in eNOS KO mice (2.67 +/- 0.33 vessels/plug) compared with WT mice (10.17 +/- 0.79 vessels/plug). These results clearly show that eNOS plays a significant role in facilitating wound repair and growth factor-stimulated angiogenesis.

Early results and long-term follow-up after corrective surgery for total anomalous pulmonary venous return

OBJECTIVE

An ever increasing number of patients with an operated congenital cardiac anomaly is reaching adulthood. Insight in the long-term characteristics of these patients is steadily growing for the more common anomalies, but is still scarce for the less frequent entities. In this regard we report our results and long-term follow-up of surgically treated total anomalous pulmonary venous return (TAPVR).

METHODS

Since 1973 44 patients with TAPVR were treated with surgery. There were 23 girls and 21 boys. Hospital mortality concerned six patients and additionally one patient died 2.5 months after surgery. Follow-up data could be collected from all the surviving patients at last outpatient visit or by phone contact. The mean duration of the follow-up was 12 years (range 1 month to 24 years).

RESULTS

The Kaplan-Meier estimate of survival at 15 years was 84% (95% CI 73-95%). Reoperations were performed for five patients at 7 days to 4.5 years after surgery. In one patient this involved obstruction of pulmonary venous return, in four complications of the primary repair. The reoperation-free survival at 15 years was 74% (95% CI 61-87%). At the end of follow-up all survivors were in NYHA functional class I and, at appropriate age, normally attended school or were employed. None of the patients was using cardiac medication.

CONCLUSIONS

We conclude that, despite a possible hectic initial postoperative course of surgery for TAPVR, only a limited number of reoperations is necessary relatively short after initial surgery. The long-term perspective for those surviving surgical treatment is good.

Evaluation of cytokeratin 19 fragment (CYFRA 21-1) as a tumor marker in malignant pleural effusion

BACKGROUND

The aim was to investigate the diagnostic utility of CYFRA 21-1 (cytokeratin 19 fragment) as a tumor marker in pleural effusion and evaluate the value of combining CYFRA 21-1 and carcinoembryonic antigen (CEA) assays as a diagnostic aid in the malignant pleural effusion.

METHODS

One hundred and twenty-six patients (72 malignant and 54 benign pleural effusion) were included in this retrospective study. The effusion levels of CYFRA 21-1 and CEA were measured using radioimmunometric assay.

RESULTS

The median values of CYFRA 21-1 in benign and malignant pleural effusion are 15 and 70 ng/ml, respectively. Using a cut-off value of 50 ng/ml, defined at 94% specificity, the diagnostic sensitivity of CYFRA 21-1 for non-small cell lung carcinoma (n = 61), squamous cell carcinoma (n = 21), adenocarcinoma (n = 40) and small cell lung cancer (n = 11) was 64, 71, 60 and 18%, respectively. Regardless of cell types, the diagnostic sensitivity of CYFRA 21-1 and CEA in malignant pleural effusion (n = 72) was 57 and 60%, respectively (cut-off value of 10 ng/ml in CEA assay). Combining CEA with CYFRA 21-1, the diagnostic sensitivity may increase up to 72%, which was defined at 89% specificity.

CONCLUSION

CYFRA 21-1 assay may be a useful tumor marker for discriminating benign from malignant pleural effusion, especially in those of non-small cell lung cancer. The combined use of CEA and CYFRA 21-1 assay in the malignant effusion may increase the diagnostic yield compared with CEA or CYFRA 21-1 alone.

Treatment of pulmonary atresia with intact ventricular septum in early infancy

BACKGROUND

Early treatment for the neonate with pulmonary atresia and intact ventricular septum (PA-IVS) is important if a high mortality rate is to be avoided. The treatment includes prostaglandin administration, balloon atrial septostomy, pulmonary valvotomy, a shunting procedure and patch repair for the right ventricular outflow tract (RVOT). This study discusses the early treatment and risk factors of this disease that are essential for assessing the risk of surgery and predicting outcome.

METHODS

The medical records, echocardiograms, catheterization data and cineangiograms of 29 patients with PA-IVS diagnosed at our institution from 1987 to 1997 were reviewed retrospectively. Clinical manifestations including age, body weight, sex ratio, type of surgery and outcome were analyzed.

RESULTS

Three of four patients with a right ventricular volume of less than 1 ml died, and all patients with a right ventricular volume of greater than 2 ml survived. Four of six patients with a tricuspid valvular area of between 0.25 and 0.5 cm2 died, but patients with an area of greater than 0.5 cm2 survived. One case with a monopartite right ventricle died. Patients with a bipartite or tripartite right ventricle had higher survival rates than those with a monopartite right ventricle. Patients with a the right ventricle dependent coronary sinusoid had a higher risk for mortality, even after surgery, than those with normal coronary circulation.

CONCLUSIONS

A small right ventricular volume, the presence of a coronary sinusoid involving the right ventricle, a short linear length of the tricuspid valve and a small area of the tricuspid valve were the risk factors associated with a negative outcome in neonates with PA-IVS.

Testicular abnormalities in male rats after lactational exposure to nonylphenols

Lactational exposure of male rat pups to nonylphenols (NPs) decreased the size of their testes and male accessory glands. At 31 d of age, NP-treatment of male rats resulted in less cellular differentiation of the seminiferous tubules (STs) and increased intertubular space compared to controls. At maturity, NP-treated males showed varying degrees of abnormalities in the affected testes. In the moderately affected ones, about 20-30% of their STs had poorly differentiated germinal elements. Cell lineage was less organized. In extreme cases, all STs of the affected testis failed to differentiate into germinal elements. These abnormalities in germinal element differentiation might be the primary cause for a number of the NP-treated males having a lower epididymal sperm count and a lower percentage of motile sperm compared to age-matched control males. Zymogram analysis of testis homogenates by sodium dodecyl sulfate gelatin gels revealed two major forms (64-66 kDa and 50-52 kDa) of gelatinases. Only the 50-52-kDa form was greatly reduced or absent in the affected testis. Lactational exposure of male pups to NPs thus leads to various testicular abnormalities including lack of differentiation of STs, lowering of sperm count, and reduction in the percentage of motile sperm and modulation of a specific form of testicular proteinases.

The risk factors for gallstone disease among senior citizens: an Oriental study

BACKGROUND/AIMS

Few Occidental studies have addressed the risk factors for gallstone disease (GSD), among aged people. It is unknown whether these factors also present in the Orientals. Therefore, we studied the prevalence and risk factors for GSD among aged people in Taiwan.

METHODOLOGY

1441 aged subjects (> or = 60 years) who received a paid physical checkup at this hospital were investigated. Their demographic characteristics and biochemical parameters were recorded and compared. Ultrasonographic diagnosis revealed a normal gallbladder in 1092 subjects, gallbladder stones in 171, cholecystectomy for gallstones in 65, gallbladder polyps in 83, mixed gallbladder stones/polyps in 10, and miscellaneous results in 20. We enrolled 236 subjects showing either gallbladder stones or cholecystectomy for gallstones as the GSD group.

RESULTS

Excluding those subjects with mixed gallbladder stones/polyps, the overall prevalence of GSD in our series was 16.6%. Using multivariate analysis, the encountered factors manifesting risk for the development of GSD were old age (p<0.001), lower serum high-density lipoprotein level (p<0.01), diabetes mellitus (adjusted odds ratio: 2.127; p<0.001) and glucose intolerance (adjusted odds ratio: 1.954; p<0.001), whereas past history of alcohol consumption (adjusted odds ratio: 0.335; p<0.01) exhibited a protective effect against the development of GSD. Other demographic characteristics and biochemical parameters, such as body mass index, ABO blood type, cigarette smoking, blood pressure, serum cholesterol level, hepatitis B virus carrier, liver function, and parity, did not have any correlation to GSD.

CONCLUSIONS

Among the aged senior citizens in Taiwan, individuals with old age, lower serum high-density lipoprotein level, diabetes and glucose intolerance are at high risk for developing GSD.

Metabolism of nonylphenol by rat and human microsomes

The in vitro metabolism of [14C]-nonylphenols (NPs) by rat hepatic microsomes in vitro was examined. Product formation was NADPH dependent and inhibited by the cytochrome P450 inhibitors, piperonyl butoxide and SKF525. Hepatic microsomes isolated from various inducer-treated rats (including beta naphthoflavone, phenobarbital, ethanol, dexamethasone, and clofibrate which selectively induce CYP1A, 2B, 2E, 3A and 4A, respectively) all metabolized NPs. Only microsomes from phenobarbital-treated rats exhibited a significantly higher activity towards NPs and showed a different profile of NP metabolites compared to control, untreated rats. Microsomes from human CYP2B6 transfected cells with endogenous NADPH-P450 reductase activity but not microsomes from the non-transfected parent cells metabolized NPs. The metabolism of NPs using microsomes from phenobarbital-treated rats was inhibited by 4-amino-2, 6-dinitro-1-t-butylxylene, a specific CYP2B enzyme inhibitor. Addition of a general anti-CYP2B sera to the reaction mixture attenuated the enzyme activity of microsomes from phenobarbital-treated rats to metabolize NPs. This metabolic reaction was, however, insensitive to a specific anti-CYP2B1 sera that had been shown to inhibit enzyme activities attributed only to CYP2BI suggesting that the CYP2B2 pathway is predominant in NP metabolism. The results indicate that hepatic cytochrome P450 enzyme(s) can metabolize NPs and that CYP2B isozymes are probably involved.

Early weaning induces jejunal ornithine decarboxylase and cell proliferation in neonatal rats

Increased ornithine decarboxylase (ODC) activity is associated with rapid cell proliferation in many cell types. The cellular effects of early weaning on intestinal development are not well established. To investigate whether ODC is involved in intestinal growth after early weaning, we precociously weaned suckling rats on postnatal d 15 and followed through d 21 (6 d after early weaning). Age-matched suckling pups served as controls. Rat pups were killed 1, 2, 3 and 6 d after early weaning and jejunal mucosa was assayed for ODC and sucrase activities, and protein and DNA contents. Jejunal cell proliferation was monitored by bromodeoxyuridine immunohistochemistry. Elevated jejunal ODC activity 1 d after early weaning was the earliest cellular event that was detected in the current study. ODC activity peaked at d 3 (about 15-fold greater than age-matched unweaned suckling controls). Sucrase activity was elevated at d 2 after weaning and peaked at d 3 (about 10-fold greater than controls). Greater bromodeoxyuridine immunostaining in early weaned rats occurred on d 3. Protein and DNA contents were greater in jejunal mucosa of early weaned rats at d 6. Serum corticosterone levels were elevated on d 1 and d 2 after early weaning compared to controls. To explore whether the intake of nonpurified diet played a role, we also compared the induction of jejunal ODC activity in early weaned pups and pups that were food-deprived for 1 d. ODC activity was not greater in the food-deprived group compared to suckling controls while the early weaned group had 6-fold greater activity 1 d after early weaning. Early weaning stimulates jejunal cell proliferation and differentiation. The temporal sequence of increased ODC activity followed by increases in other growth variables suggests that the induction of ODC activity may act as an early marker of intestinal growth during early weaning.

Dopamine D4 receptor gene polymorphisms and neuroleptic response in schizophrenia

BACKGROUND

Dopamine D4 receptor (DRD4) gene polymorphisms are associated with various pharmacologic activities. This study investigated whether polymorphisms of 48-bp tandem repeats in the exon 3 of the DRD4 gene are related to neuroleptic response.

METHODS

The neuroleptic response at the acute stage of schizophrenia was assessed in 80 (48 men, 32 women) schizophrenic patients. The negative symptoms at remission were also rated. DRD4 genotype was established using the polymerase chain reaction. Patients with genotypes containing an allele with only two repeats (2-2, 2-3, 2-4, 2-6) were assigned to group I (n = 38). Those homozygous for four 48-bp repeats were assigned to group II (n = 42).

RESULTS

Thirteen (34.2%) of the 38 group I subjects and 26 (61.9%) of the 42 group II subjects had good neuroleptic response during acute stage treatment (chi 2 6.12, df = 1, p < .02). In remission, the rates of negative symptoms of blunt affect, avolition, and global negative rating were higher in group I than in group II. This was more prominent in men than in women.

CONCLUSIONS

The presence of homozygous four 48-bp repeats in both alleles in exon 3 of the DRD4 gene is associated with good neuroleptic response during acute treatment, and with a lower prevalence of negative symptoms at remission, especially in male schizophrenic patients.

Disruption of male reproductive tract development by administration of the xenoestrogen, nonylphenol, to male newborn rats

Nonylphenol (NP) treatment of neonatal male rat pups decreased the size of their testes, epididymis, seminal vesicle, and ventral prostate, and increased the frequency of cryptorchidism (60.7%, n = 56 vs 0% in vehicle-treated control, n = 58) when examined at 31 d of age. NP effects are dose-dependent. These effects were only seen when NP was given at > or =20.8 mg/kg daily for 15 d. There is a critical period of vulnerability to NP during male reproductive development in the neonatal stage. Changes were found when NPs were given to male pups before 13 d of age, but not when given at > or =13 d of age. NP acts on the male reproductive tissues through the estrogen receptor (ER), since concomitant treatment with ICI 182,780, a specific ER antagonist, blocked NP's effects on the testis and male accessory organs. NP-treated males in the neonatal period had greatly reduced their subsequent capacity to impregnate young fertile females. Our results suggest that exposure of neonatal male rats to NP is potentially deleterious to their reproductive development and affects their reproductive performance.

Technique charts for Kodak's new film-screen systems for portal localization

In July 1996, Kodak released new film-screen systems with enhanced contrast (EC) for portal localization with megavoltage therapeutic beams. This study presents the generation of general-purpose technique charts for Kodak's new film-screen combinations: the Enhanced-Contrast localization (EC-L) film in EC-L cassette and the EC-L film in fast ECL (fECL) cassette for use with cobalt-60, 6 MV, 10 MV, and 18 MV beams. These technique charts were based on the assumption that a film with an optical density (OD) of 1.8 provides the best viewing density. The doses to produce such as OD, Dexp, were obtained from the H & D curves and were 1.5, 1.6, 1.7, and 1.8 cGy for cobalt-60, 6 MV, 10 MV, and 18 MV beams, respectively, with the EC-L-film + EC-L-cassette combination. The corresponding values were 1.3, 1.3, 1.3, and 1.4 cGy, respectively, for the above four beams with the EC-L-film + fEC-L-cassette combination. The dose to the film is assumed to be proportional to the calibrated dose rate (D0), field size factor (FSF), inverse square factor relative to 100.0 cm (INV), and the transmission factor through the patient, which is equal to e-uT, where u is the broad beam attenuation coefficient and T is the patient thickness. With the above assumptions, the exposure time or monitor unit, t, is then calculated from the following equation: t = Dexp/(D0*FSF*INV*e-uT). For an average port size of 15 x 15 cm, the attenuation coefficients were obtained from the fitting of TAR (cobalt-60) or TMR (6 MV, 10 MV, and 18 MV) as a function of depth from 10 to 30 cm and were 0.0564 cm-1, 0.03714 cm-1, and 0.02271 cm-1 for cobalt-60, 6 MV, 10 MV, and 18 MV beams, respectively. The FSF were explicitly obtained from the clinical physics data books and were 1.028, 1.032, 1.036, and 1.053 for cobalt-60, 6 MV, 10 MV, and 18 MV, respectively. For cobalt-60 beam, the D0 was assumed to be 100.0 cGy/min. For the 6 MV, 10 MV, and 18 MV beams, the D0 in cGy per monitor unit is 1.030, 1.051, and 1.061, respectively. Technique charts were then generated as a function of patient thickness from 10 to 45 cm for filming distance from 110 to 140 cm for all four beams. These technique charts can be easily customized to portal localization practices in a radiation therapy department.

Effect of the replication mode of a plasmid on the stability of multimeric endoxylanase genes in Bacillus subtilis

Effect of the replication mode of a plasmid on the stability of tandemly multimerized endoxylanase genes and a gene dose-dependent expression of the endoxylanase were studied in Bacillus subtilis. The structural genes encoding an endoxylanase, carrying its original promoter and ribosomal binding sequence, were tandemly multimerized and cloned into the Escherichia coli-B. subtilis shuttle plasmid, pJH27 delta 88 or pMTL500e, which has a rolling circle-replicon or a theta (theta)-replicon in B. subtilis, respectively. The cloned dimers in pJH27 delta 88, which has a rolling circle-replicon, spontaneously rearranged to monomers in B. subtilis DB104, whereas those in pMTL500e, having a theta (theta)-replicon, were stably maintained. Expression level of the endoxylanase was proportional to the gene dosage in multimers. The endoxylanase activity in the supernatant increased from 80 U ml-1 with pMTL-1x containing a monomer of the gene to 165 U ml-1 with pMTL-4x containing a tetramer. These results indicate that high level expression of the endoxylanase gene can be obtained by tandemly multimerizing the genes in a plasmid with a theta (theta)-replicon.